CHAPTER I INTRODUCTION Research-based

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CHAPTER I INTRODUCTION Research-based reforms in science education have emphasized the importance of employing learning progressions as a means for mapping curricular materials in a coherent way that promotes better understanding and retention of learned scientific concepts. Learning progressions are defined as “descriptions of the successively more sophisticated ways of thinking about a topic that can follow one another as children learn about and investigate a topic over a broad span of time” (Duschl, Schweingruber & Shouse, 2007; National Research Council [NRC], 2007). Using learning progressions is considered by many researchers as an effective pedagogical approach that provides a cognitive model for deepening students’ understanding of “big ideas” over broad time spans and describes the learning performances students are expected to achieve at different levels along the progression. Two important features of learning progressions are scope and grain size. The scope could range from a relatively single topic to an interrelated set of topics within a subject discipline. Grain size refers to the level of achievement showing descriptive details of what students are expected to accomplish at each stage. These learning progressions are anchored on the lower end by the ideas that students bring to school and on the upper end by scientific knowledge and practices (NRC, 2007). Intermediate levels of achievements describe patterns of qualitative differences in student performances from the lower to the upper anchor. Advocates of learning progressions claim that such extensive details of levels of achievement can better guide teachers in planning their instruction and assessing student learning. Learning progressions also accord with a constructivist view of knowledge whereby students’ understanding builds incrementally (Philips, 1995). More importantly, the development of learning progression is guided by theory and research findings on how students

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learn a topic/concept with a great consideration of the misunderstandings/ misconceptions students might have with that particular concept/topic rather than by conventional wisdom or consensus processes as in the case of scope and sequence curriculum framework (Duncan & Hmelo-silver, 2009). These qualifications of learning progressions make them effective pedagogical tools - as claimed by learning progressions advocates - that would lead to a better coherence of currently fragmented and unconnected science curriculum, assessments and classroom instruction (Duncan & Hmelo-Silver, 2009; NRC, 2007). This would also help in designing appropriate instructional activities and assessment tasks that provide better quantifiable measures of students’ understanding (Alonzo & Steedle, 2009; Furtak, Roberts, Morrison, Henseon & Malone; 2010). Many researchers have argued for the need of a new tool that would improve existing standards and curricula. For instance, the NRC (2007) report criticized the existing USA national standards for lacking operational definitions of learning outcomes which makes it difficult to ascertain how learning should be assessed. In addition, research has shown that curricular materials based on national, state, or local science education standards tend to support shallow coverage of a broad range of concepts instead of promoting the development of an integrated understanding of a few key ideas (Schmidt, Wang& McKnight, 2005). This can result in students acquiring fragmented elements of knowledge and being unable to explore the coherence within and between science disciplines and as a result fail to apply their knowledge to explain new phenomena and solve new problems (Johnson, &Tymms, 2011;Sirhan, 2007). Researchers claim that many of the above problems in the national and local standards and curricula in the USA could be avoided by using learning progressions as the basis for these standards and curricula; and prompt curricula developers in other countries to consider using the

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learning progression approach when thinking about improving their curricula or standards (NRC, 2007; Smith, Wiser, Anderson, & Krajcik, 2006).Nowadays, learning progressions are considered a key component in the design of the Next Generation Science Standards (Board on Science Education [BOSE], 2012; NRC, 2011), a reform in standards that stresses coherence in the conceptual growth of scientific knowledge and reasoning across grades. Recently, several researchers called for designing not only learning progression for core disciplinary ideas but also for the science practices associated with learning those ideas. In that sense, several attempts were done to design and evaluate assessment tasks focusing on science knowledge that is a fusion of core disciplinary ideas and science practices (e.g., Gotwals & Songer, 2013). However, many studies are still needed in this area and in all subject areas. Summary and Research Problem In Lebanon, as in other countries, science teachers claim that students’ acquisition of knowledge is impaired by weak curricular units that lack the proper organization and sequencing which is needed to favor deep and thorough understanding of the learned concepts. Several meetings which involve teachers, coordinators and curriculum writers were held by the ministry of Education and Higher Education to evaluate the present Lebanese curriculum in all subjects’ areas. These meetings revealed a total agreement among science teachers that students have many science misconceptions and face difficulties in learning many major scientific concepts. They claimed that the existing science curriculum includes irrelevant themes and concepts and unnecessary concepts which impair student learning. They attributed this problem to the fact that selection of themes and core concepts is solely dependent on the judgment of people who are involved in writing curricula, which most often does not take into consideration the cognitive level of students of different age groups and the complexity of the concepts. Moreover, these

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teachers argued that a new and more valid approach in revising, refining and even implementing science curricula must be considered by curriculum designers in any future attempt for improving and enhancing curricular units. Currently, the Lebanese curriculum is under revision and almost, all Lebanese teachers, at this time, are calling for the need to start thinking about sequencing the content of the different subject areas in this curriculum in a developmentally appropriate manner. However, there has been no research on learning progressions to determine the adequacy of teaching and learning of any topic at each grade level and to identify the misconceptions and difficulties encountered by students in any subject area. Apparently, there is a need for learning progressions in all subject areas. The focus in this study, however, is on genetics, an important and difficult topic in the Lebanese curriculum. One big challenge for educators and researchers in developing a genetics curriculum would be the identification of the appropriate genetics concepts to be taught in and across grade levels which is based on evidence stemming from cognitive research studies, theories of science teaching and learning and research on the topic. Effective dialogues between teachers, curricular developers and designers would be an essential initial step in constructing the genetic learning progression. Questions such as: Do we need to teach polygenic inheritance to high school students? Would the idea of Eugenics favor students’ deep understanding and appreciation of genetics in improving human life? Is it preferable to include genetic variations in a population under the themes of evolution or ecology or genetics…and at what grade level? And still many other similar questions could be important issues for these discussions. However, these dialogues must be based on scientific argumentations anchored in results of research drawn from studies done in that field rather than solely on personal judgment and expertise.

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Moreover, curriculum developers are challenged to design a biology curriculum that would prepare genetically-literate citizens who are able to comprehend information about genetic phenomena and related technology and make appropriate decisions about recent techniques in genetics such as genetic screening, stem cell research, genetically manipulated food, DNA fingerprinting, personalized medicine etc. Along with the work on the learning progression, there is a need to evaluate the Lebanese national biology textbooks and determine whether a logical and developmentally appropriate sequence of genetics ideas occurs from primary grades through high school, and to determine the extent to which the existing genetics curriculum prepare genetically literate citizens. It is necessary to determine whether the sequencing of core ideas is driven by evidence grounded in theories of learning and cognitive science or based on the judgment of experienced curricular designers and the logic and structure of the discipline. Additionally, in 2001, the Lebanese Ministry of Education and Higher Education had omitted several chapters from the biology curriculum to reduce the content and align it with the time allocated for biology in each grade level. Many biology teachers criticized this resulting truncated biology curriculum because of their perception that it would hinder student learning. Therefore, to get a comprehensive idea about these biology textbooks the omitted chapters need to be examined to understand their relevance to student learning of genetics. Rationale of the Study Research findings suggest that student learning increases when content matter is organized in such a way to match their developmental levels and assert the need to study core topics at varying levels of difficulty and abstractness. Moreover, this research points out to the scarcity of studies at the upper elementary and middle school on this topic. In light of these

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findings, it is crucial to conduct studies in Lebanon that address problems encountered by curriculum designers and others when designing or reviewing the curriculum. Such studies would be helpful for curriculum designers, assessment specialist in the public or private sectors and policy makers. However, this will be of most benefit to curriculum and assessment materials developers because they will be able to design more valid and reliable coherent genetics curricular sequences and learning progression-guided assessments which would improve students’ understanding of genetics. More importantly, the implementation of learning progression-driven genetics unit with real students in the course of instruction with real teachers would allow us to identify educational practices that need to be considered thoughtfully in any attempt for a learning progression-based curriculum reform and to ensure a better design and implementation of learning progressions for enhancing student learning. Purpose of the Study and Research Questions The purpose of the study was to investigate, using a mixed methods (quantitative and qualitative) design-based research approach, the coherence and sequencing of the core ideas in genetics as presented in the Lebanese national biology curriculum and textbooks for grades 7-12 and to design and validate an organized and integrated knowledge structure, that is learning progressions, to help students consolidate their understanding of key ideas in genetics and develop conceptual understanding of genetic content. Moreover, this study aimed at developing a learning progression-driven genetics curricular unit, evaluating its impact on student learning in a classroom setting and identifying variables that impact the design and implementation of any newly designed learning progression- based curriculum. In addition, the study sought to discover students’ and teachers’ opinion and perception of the existing genetics curriculum and examine ways for improvement. Furthermore, the study

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aimed to determine how Lebanese students themselves perceive genetics instruction and identify patterns in students thinking and cognitive abilities that might give insight that would produce better designs of instructional units. Finally, the study aimed to begin the initial steps of sequencing the content of the genetics curriculum across all levels in a developmentally appropriate manner. Specifically, this study aimed to: 1- Determine Lebanese teachers’ perception of the coherence and organizational levels of the genetic curriculum across grade levels. 2- Determine Lebanese teachers’ perception of the role of the genetics curriculum in fostering genetic literacy among students. 3- Identify the major misconceptions and difficulties encountered by Lebanese students, from both public and private sectors, during genetics instruction. 4- Investigate any variation in the nature of the misconceptions and difficulties encountered by public and private school Lebanese students during genetics instruction. 5- Examine ways of improving the genetics curriculum, from teachers’ and students’ perspectives, to achieve improved student understanding in genetics. 6- Develop a valid and reliable learning progression based on data collected from research questions 1-4 and a literature review in the same field that would improve students’ understanding of genetic concepts. 7- Investigate the level of the content coherence of the existing genetics curriculum and the learning progression-driven genetics unit and the extent to which this content presentation enhances student understanding of genetics 8- Determine the extent to which the existing genetics curriculum and the learning

progression-driven genetics unit promote the development of genetically literacy citizens.

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Furthermore, we have extended our study to develop a genetics unit for grade 9 based on students’ and teachers’ suggestions and the proposed learning progression and to evaluate its effectiveness on student learning. In designing our learning progression-driven genetics unit, we aimed to answer the following questions: 9- Does instruction based on the learning progression as compared to a biology textbook based approach result in higher achievement in genetics? 10- What are the major educational practices that might support the proper design and implementation of learning progression-driven curricular unit? This study has the potential to contribute to the process of improving the national curriculum and help educators design science lessons that are developmentally and academically appropriate; lessons that are grounded both in data and research-based understanding of student learning and development.

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CHAPTER II LITERATURE REVIEW

Despite all efforts to develop effective science curricula, a review of the literature revealed that many students still face difficulties in understanding many physical and earth science concepts (e.g., Lee & Liu, 2009) and continue to have reasoning problems when explaining genetics phenomena, change over time in communities, and Lamarckian evolutionary change (Lewis & Kattman, 2004; Lewis & Wood-Robinson, 2000). The continuous expansion of scientific knowledge makes it difficult to teach all science ideas in exhaustive details during the K-12 years. Furthermore, the breadth of coverage of the science curricula and lack of student motivation to study science set the stage for considering new orientations in developing science curricula. Such curricula should focus on fewer topics related to the interest and life experiences of students and connected to societal and personal concerns that require scientific knowledge and skills. Identifying and focusing on meaningful topics and core ideas would allow more time for teachers and students to engage in scientific inquiry and argumentation to achieve in-depth understanding of the science content. Consequently, this might motivate and encourage students to continue their development as science learners, a situation that might affect their educational and career choices. For many researchers, the selection of the core science ideas to include in the curriculum must be based on cognitive development theories and research and not only on the nature of the discipline and personal judgment of experts (Wiser & Smith, 2009), which provides a strong argument for using learning progressions. Furthermore, the exponential increase of technological and scientific information over the last decades has challenged researchers and educators to design curricula that prepare students to become scientifically literate and help them acquire scientific practices essential for responsible

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citizenship; a preparation that permits students to use their knowledge to explain and predict outcomes of their actions. These challenges are particularly noticeable in modern genetics and nano-scale science and engineering (NSE) that have extensive societal implications on health care, agriculture, food, water and environment (PCAST, 2005), to name only a few. Moreover, developing curricula should emphasize the teaching of technology and engineering along with science to highlight the interconnections between these areas and give students the opportunity to apply their scientific knowledge in engineering design problems related to their lives. Based on the above, the role of science educators would be to equip students with essential core knowledge and to help them develop skills and practices that foster the use of this scientific knowledge in their daily life. This would help students make appropriate decisions related to the application of learned scientific concepts and skills and be producers rather than consumers of knowledge (NRC, 2010). Another major role of curricular designers, besides selecting the appropriate science topics and concepts for each grade level, is rearranging and re-sequencing of these core concepts within and between the scientific themes across the grade levels. Research indicates that one of the best ways for students to learn the core ideas in science is to learn successively more sophisticated ways of thinking about them over multiple years. The same ideas regarding sequencing of subject matter are emphasized in a study conducted by Lehrer and Schauble (2009) who claimed that students can achieve better learning when given the opportunity to revisit the same ideas and apply them in a coordinated way across several grade levels. Likewise, Arzi (1988) found that students who studied related science topics with increasing complexity across grade levels performed significantly better and had a higher retention level for the learned concepts than students who did not learn and use the same concepts across years. This researcher

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attributed the long term retention of science concepts to the continuous and coordinated learning experiences that the students underwent. Moreover, Margel, Eylon, and Scherz (2008) proposed a spiral approach in teaching the structure of matter where the basic ideas are presented, repeated, extended and refined. They argued that a spiral curriculum provides learning opportunities which promote knowledge integration and retention. This can profoundly deepen student understanding of the learned concepts and maximize their performance. Other researchers made use of data collected from international tests such as TIMSS (Trends in International Mathematics and Science Study) to explain variations in students’ performance on achievement tests. TIMSS researchers attributed the high achievement of students in Singapore to the Singapore curriculum which has fewer topics, less repetition of the same ideas, more careful articulation of topics across the grades, and more connections among topics. They argued that such a curriculum would allow students to build more sophisticated understandings of scientific concepts and consequently provide students with a better opportunity to score higher on these tests compared to peers at the same grade levels in other countries. Drawing on all the above, curriculum designers are faced with the challenge to explore new and valid tools that can lead to better curriculum coherence and consequently, better student achievement; all based on research and experiences drawn from case studies on student learning. Learning progressions are one of these tools. Students’ Difficulties with Genetics and Related Areas Previous studies have shown that students encounter difficulties when studying modern genetics in areas such as differences between genes and traits, gene expression, the meiotic model, genetic technology, patterns of inheritance, genetic bases of diseases (Banet & Ayuso,

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1995; Duncan & Resier, 2007; Haambokoma, 2007; Henderson & Maguire, 2000; Kindfield, 1992; Lewis & Kattmann, 2004, Leach & Wood- Robinson, 2000; Marbach-Ad & Stavy, 2000; Shaw, Horne, Zhang & Boughman, 2008; Stewart & Van Kirk, 1990; Tsui & Treagust, 2003; Venville & Treagust, 1998) and the meaning of probability in relation to genotypic and phenotypic frequencies in offspring (Browning & Lehman, 1988; Cho, Kahle & Nordland, 1985). Major causes attributed to these difficulties are:(a) the interdisciplinary nature of genetics which requires understandings of chemical and physical interactions at the molecular level (b) the high level of reasoning needed to interpret and explain genetics information, (c) the inability of demonstrating genetic information in lab settings and (d) the current methods of teaching genetics. In the same sense, Chattopadhyay (2005) reported that the majority of Indian secondary students showed a weak understanding of cells and transmission of genetic information during reproduction. He attributed this low level of genetic comprehension to the fact that major genetics concepts are taught without providing any conceptual framework and to the low-quality content which encourages rote learning, without giving much importance to “higher order thinking” through problem solving. The author strongly argued that teaching classical and molecular genetics which are often taught at different levels with no coherent connection remains an obstacle to the development of a holistic concept of genetics which is essential to foster student understanding of genetics. Consequently, he recommended that the teaching of genetics be reviewed and strengthened considerably. Additionally, the results of the study conducted by Haambokoma (2007) which surveyed high school students and biology teachers about the nature and causes of learning difficulties students encounter in genetics in Zambia revealed that inadequate explanation of lessons by teachers is the most important factor that impeded student understanding of genetics (29%).

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Other factors were: scheduling teaching of genetics topic near examination time (16%), unfriendly teachers (6%), speed of lesson presentation (20%), negative attitude towards a topic (12%), in addition to students’ poor mathematical knowledge, lack of practical activities, unfamiliarity of the topic, and extensive genetics terminology. Moreover, the results of this study showed, as with other studies, that students in Zambia find Mendelian crosses the most difficult genetic theme (41%),followed by mitosis, meiosis and mutation (27%), sex determination (25%), knowledge of genetic terms (22%), calculations in solving genetics problems (10%), codominance (10%) and genetics variations (8%). Furthermore, several researchers posited that the difficulty encountered by students in learning genetics, particularly human genetics, is largely due to the intrinsic complexity of this domain whereby adequate understanding of major genetics processes and mechanisms requires “to and fro” thinking among molecular, cellular, organism, and population levels (Knipples, 2002) and necessitates a deep understanding of the interaction between genetics identities, such as DNA, RNA, and proteins, with one another and with the environment (Morange, 2005b). Additionally, Clement in 2004 suggested that this complexity arises from the fact that the acquisition and comprehension of the newly learned genetics ideas and processes rely on the interaction between these ideas and student ideology and values. Lewis and Wood-Robinson (2000) reported that students have difficulties understanding the relationships between DNA, nucleotides, genes and chromosomes. Their study results are similar to those of other researchers who claimed that students tend to conceive genes as passive particles and objects attached to chromosomes rather than as information carrying entities for making biological molecules which in turn determine the macro-level features and behaviors that

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are commonly called traits (Falk, 2012; Gericke, Hagberg, dos Santos, Joaquim& El- Hani, 2012; Lewis & Kattmann, 2004; Meyer et al., 2011). Duncan (2007) pointed out that students’ ability to explain the link between genes and traits relies on understanding the role of biological molecules such as, proteins in determining an organism’s traits which is poorly illustrated in many biology textbooks. Moreover, findings from a study conducted by Wood Robinson et al. (1997) revealed that students had very poor understanding of the purposes, processes, and products of cell division and are confused between mitosis and meiosis. Also, Stewart and Dale (1989) reported that students of grades 9 and 10 are unable to relate the mechanism of meiosis to patterns of inheritance and cannot think genetically despite their ability to algorithmically solve genetics problems. These researchers recommended delaying teaching Mendel and inheritance of traits to a higher level after students demonstrate comprehensive understanding of meiosis and gametes formation. Shaw, Horne, Zhang and Boughman (2008) analyzed 500 essays submitted by high school students in response to a genetics contest organized by the National Assessment of Educational Progress (NAEP) in the USA. Results of the analysis revealed that students’ most common misconceptions in genetics fall into the categories of genetic technology and patterns of inheritance. This study revealed that students did not demonstrate a deep understanding of the complexity of genetic engineering techniques, failed to explain how multiple genetic and epigenetic factors interfere in regulating gene expression, and always viewed single mutation as being the origin of one disease. Also, students seemed unable to manipulate genetic materials in laboratory settings. A number of studies revealed that the genetics curriculum seldom considers the interaction of genetic and environmental factors in determining human traits (Abou-Tayeh, 2003; Abrougui & Clément, 2005; Carlson, 2004; Sarkar, 1999; Schwartz, 2000) and this can

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lead to many misconceptions in genetics. They claimed that a reform in teaching gene-trait relation is highly needed where content should address explicitly the interaction between genetics, epigenetics, and environmental influences for the interpretation of the phenotype. These researchers argued that such illustrations represent an important step in response to the challenges of fostering genetically-literate citizenship at the school level. More importantly, several researchers also posited that the existing genetics curricula do not promote the development of genetically literate citizens who can apply their knowledge of genetics to daily life (Eklund et al., 2007; Lewis & Kattmann, 2004) and that teaching genetics do not prepare students for future reasoning in socio- scientific issues, e.g. DNA fingerprinting, gene therapy and others (Lewis & Leach, 2006).As a result, many students would fail to understand trends in genetics research and the application of genetic technologies with regard to the social, legal, and ethical issues involved. In the same sense, Clément’s study (2007) showed a highly reduced coverage of ethical and ideological dimensions from the biology school textbook designed for 14-15 age groups in France and its total absence in Tunisia. He argued that students’ conceptions of genetics are influenced by their scientific knowledge and their value system which includes their opinions, faiths, ideologies, philosophical and moral positions. Consequently, any lack of this essential component in teaching genetics would lead to segmented body of knowledge and failure of students to understand properly the relatedness of the learned genetics concepts in classrooms to daily life experiences, a learning outcome which should be central in the teaching of genetics. In addition to the above, several researchers attributed students’ inability to understand genetics phenomena to the low quality of biology textbooks which lack coherence across concepts and include inaccurate vocabulary, inaccurate and unclear representations and images,

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and unnecessary concepts and details that do not favor deep understanding (American Association for the Advancement of Science [AAAS], 2006; Castéra et al., 2008; Clément, 2007; Deadman& Kelly, 1978; Duncan, 2007; Kedisou & Roseman, 2002; Kurth &Roseman, 2001; Longden, 1982; Lucas, 1987; Marbach-Ad, 2001; Roseman et al., 2006). Many researchers claimed that the terminology used in textbooks is a major issue that might hinder student learning of many essential genetics concepts and processes (e.g. Cho et al., 1985; Lewis et al., 2000). Lewis et al. (2000) found that many students are confused by the words used to describe the processes of cell division, e.g.: duplication, copying, splitting, multiplication, which could appear contradictory. These researchers argued that in the absence of a coherent conceptual framework for cell division and the role of chromosomes and cells, students’ confusion and little understanding of these terms lead to their inability to understand complex mechanisms underlying these notions and consequently to their inability to understand the continuity of genetic information within or between organisms. In the same direction, several studies done by Clément and his colleagues (2007) revealed that the type of terminology and expression used in the student textbooks could carry implicit values and be a major source of misconceptions that hinder student learning of many genetics concepts and processes. Clément (2008) in analyzing the content of student biology textbooks published in France by Nathan, Hatier and Vandeg found that different expressions with the same implicit value are used inconsistently in different grade levels. Results also showed that even with the same publisher, e.g. Hatier, the notions of “genetic information ““genetic program are used synonymously across different grade levels with no reasonable justification. Furthermore, a comparative study of school biology textbooks in sixteen different countries done under Biohead- Citizen European research Project revealed the absence of the notion “genetic program” from Germany and Cyprus

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biology textbooks (Castera et. al, 2008). These authors ascribed this absence to a desire to avoid using the metaphor of a computer program and a realization of the importance of environmental factors as well. These researchers pointed out that terms like “hereditary patrimony” and “genetic patrimony” can be used whereby these expressions are more neutral than “genetic program”. Moreover, content analysis revealed that student biology textbooks frequently use the expression “the DNA molecule forms a code, which instructs the cell…”.Clément et al. (2007) argued that the expression “Programmed by genes” has implicit value and should be replaced by “genetic instructions”. They claimed that such an expression might convey the message that the cells could simply follow these instructions to produce the phenotype, just like a computer program and in his opinion, the textbook emphasizes the notion of “hereditarianism” with the notion of a “genetic program”, and this again might lead to difficulty in understanding major genetics concepts and mechanisms. Furthermore, these authors stressed the fact that expressions, such as hereditary project, hereditary instruction, and genetic project suggest that cell structure and function is dictated by its DNA, neglecting that cellular differentiation is also the result of the interaction between cells in an organism and environment, would lead to further student misconceptions. Additionally, Clement and his colleagues (2007) found that the visual representation of twins in the biology textbooks of 14 countries demonstrated nearly the same pattern where monozygotic twins are dressed identically and have the same hairstyle and body posture. These authors argued that such a representation could convey the message that these latter features are genetically determined and thus give evidence of a strong obstinacy of a determinist reductionist ideology that would influence student learning.

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Similarly, other recent research showed that the way genetics concepts are addressed and presented in school biology textbooks is a major source of difficulties in students’ understanding of genetics (Gericke & Hagberg, 2007; Pitombo et al., 2008; Xavier et al., 2006). Over the last twenty years, there were serious debates among educators about what a gene is and the way this concept should be presented in textbooks and taught in classrooms. Several researchers claimed that the gene concept is currently in crisis (Falk, 2000; Meyer et al., 2013). Consequently, they proposed revising the way this concept is illustrated in student biology textbooks in order to enhance its understanding and accommodate the increasingly known complexity of genomic architecture and dynamics. Interestingly, some researchers considered the gene as a useless word that must be eliminated from the biological discourse because it is confusing and might lead to student misconceptions (Gelbart, 1998; Keller, 2000; Portin, 1993). These researchers argued that the problems with the gene concept are mostly related to its interpretation as a stretch of DNA that encodes a functional product, a single polypeptide chain or RNA molecule. They believe that such a classical molecular gene concept which treats the gene as an interrupted unit in the genome must be reconsidered in light of recent findings obtained from research in genetics and molecular biology. This modernization of the gene concept would lead to a new understanding of genes among educators and teachers and consequently to a different mode of teaching about the nature of genes and their role in living systems. Furthermore, these researchers argued that such a change in the understanding and teaching of genes would influence both teachers’ practices and student learning of genetics. These findings are consistent with the study conducted by Santos, Joaquim and El- Hani (2012) who analyzed 18 biology textbooks used in Brazil and found out that these books convey hybrid views about the gene

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concept and favor genetic deterministic discourse that may lead to serious student misunderstanding of genes. Furthermore, several researchers (e.g., Clément, Forissier & Carvalho, 2003; Leite 2006, 2007) highlighted the influence of the “simplifications “of some genetics concepts, which might occur either in the textbook or most of the time unintentionally during instruction, on student learning. They pointed out that any attempt for initial simplification is dangerous, because the first concepts taught are those mostly remembered by students, are resistant to change, and cannot be easily replaced by more accurate scientific concepts. These researchers concluded that some students fail to explain correctly major genetics concepts due to prior misconceptions acquired in early school years and which hinder the acquisition of new accurate scientific explanations to the same genetics concepts. Also of important value are teachers’ spoken language and the expressions used during instruction which can lead to student misconceptions and later to errors and difficulties in explaining complex genetics concepts and processes. When teachers for example speak about the genes as being white, this could create a mental picture of the gene which is difficult to adjust to a more developed model of the gene and its function. This expression communicates that the gene is white, regardless of what the teachers actually meant. Lemke (1990) argued that if words are used wrongly or simply left out, teachers can still make sense of what is said; however, students cannot judge whether what the teacher says is just a way of speaking or sort ideas to be understood when new content is presented. At this point, it is noteworthy to highlight that for many researchers (e.g. Clement, 2006), teacher’ practices and expressions used during instruction are largely shaped by the interaction among three parameters: scientific knowledge to be taught (K), teachers’ values and beliefs

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regarding this knowledge (V) and social practices (P). Extensive research on teachers’ conceptions has been done under the European research project Biohead-Citizen, to assess teachers’ conceptions of six topics including human genetics (e.g. Castera et al. 2007) and human brain and cerebral epigenesis (e.g. Clement et al., 2008) in 19 European and nonEuropean countries, including Lebanon. This work had lately been extended to include 5 other countries: Denmark (Europe), Burkina Faso and Cameroon (Africa), Brazil and Australia to enlarge the sample in order to produce a more valid transnational comparative study (Castera & Clement, 2012). In one of these Biohead studies, a total of 6379 pre-service and in-service teachers of primary school and secondary school (biology and language arts teachers) filled out a questionnaire including 31 questions related to the genetic determinism of human performances. Results showed a small significant difference between teachers regarding their scientific knowledge related to human genetics and cerebral epigenesis. On the other hand, the study revealed significant differences related to teachers’ conception of the genetic determinism of human features, behaviors and performances between countries. These differences were most prominent in teachers’ answers to questions dealing with genetic factors of parents that predispose their children to be good at school (B10), very good violinist (B20), aggressive (B14), homosexual (B11) or even alcoholic (B8). This study also showed that innatism is stronger for in service- teachers than for pre-service teachers. Additionally, the study done by Castera and Clement in 2012 revealed that teachers in Africa and Lebanon have a more innatist conception of human behavior or performance than teachers in European countries. Researchers attributed the difference in teachers’ conceptions of innatism to the way genetics is presented in biology textbooks, the way students are taught by the oldest teachers (Castera & Clement, 2009) and to other parameters such as religion, degree of religious practices, level of training and level of

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knowledge of biology (Castera & Clement, 2012; Clement & Carvalho, 2007). For instance, these authors argued that teachers who are fatalists, thinking that everything has already been “written” in advance, would tend to agree easily with genetic determinism. Despite its importance, analyzing teachers’ conceptions of genetics is beyond the scope of this study which focuses primarily on teachers’ perceptions regarding the nature of problems encountered by students in learning about genetics and curriculum features that might enhance or impair student learning and understanding of genetics. We strongly believe that teachers’ conceptions is a key step in the didactic transposition of genetics concepts and processes and which is directly related to student learning ; however, this dimension can be the subject for future research. Sequencing Genetics Concepts Even though there was research on difficulties that students encounter when studying genetics, limited research has been done to identify what genetics concepts are appropriate to be taught at different grade levels and how these concepts should be sequenced to enhance understanding. Russ, Scherr, Hammer and Mikeska (2008) reported that students at the lower elementary level can provide mechanistic explanations of natural phenomena, and Engel- Clough and Wood- Robinson (1985) suggested that the idea of environmental influence on traits can be introduced in very simple forms at the elementary level. Likewise, the recent NRC report (NRC, 2007) provides evidence that children can learn and reason about abstract concepts such as the concepts of genes and chromosomes, when given the proper instruction. Conversely, a study conducted by Stewart and Dale (1989) reported that students of grades 9 and 10 are unable to relate the mechanism of meiosis to patterns of inheritance and cannot think genetically despite their ability to algorithmically solve genetics problems. Based on this study, Duncan, Rogat and

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Yarden (2009) recommended postponing teaching the DNA structure to secondary grades and proposed teaching the details of the meiotic process and the interaction of genes and environment on shaping features and behaviors to the middle and high school grades. Also, Duncan (2007) suggested focusing on the relation between the structure and function of proteins rather than discussing the molecular structure of proteins in the middle school. Upon analyzing biology textbooks, Kurthand &Roseman(2001) revealed that Mendelian inheritance is presented before DNA and that DNA is presented in a way that does not clearly show its relation to the actions of proteins, which might lead to misconceptions and the inability to understand genetic phenomena. In this respect and in response to problems identified in science textbooks, Duncan (2007), Deadman and Kelly (1978), Lewis (2000), Longden (1982), Lucas (1987), Marbach-Ad (2001) and Roseman et al. (2006) recommended teaching the concept of proteins before the concept of DNA and introducing DNA before genes and chromosomes. They argued that the molecular model must be introduced before the genetic model because it is more logical and developmentally appropriate to introduce concrete physical entities such as proteins and DNA before discussing the abstract notions of genes and alleles.Other researchers suggested that understanding the genetic, meiotic, and molecular models is essential to explain any genetic phenomena and is a challenging task for learners (Kindfield, 1994; Lewis & Robinson, 2000; Stewart & Dale, 1989; Stewart & Van Kirk, 1990). Based on the above, it seems that mapping the important genetics concepts and analyzing the scope and sequence of the ideas related to each concept, driven by research findings, would be an essential step towards developing curricula and teaching materials that will help deepen students’ understandings in genetics. While necessary, this step is not sufficient. There is a need for organizing and sequencing the concepts of a scientific topic - genetics in our case - in a

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developmentally appropriate matter advocated in the studies above, an organization and sequencing conceptualized in the idea of learning progressions. Well-grounded learning progressions are visualized as strategic sequencing of a set of ideas instead of isolated strands of knowledge and which can uncover the ways in which students develop understanding of the important concepts and show the connections among related concepts both within and across domains (Steven, Shin, Delgado & Krajcik, 2007). There are different ways of sequencing a subject depending on experts’ judgment on which ideas are privileged. Whether one way is more appropriate than another with regard to students’ learning is an empirical question. There must be a theoretical framework and learning progressions are among these valuable tools and frameworks. Teaching Genetics Meaningfully Several studies have shown that genetics is an area in which many high school students harbor multiple misconceptions and significant misinformation and that current methods of teaching genetics do not help learners develop full understanding of the models of inheritance and the genetic basis of diseases (Henderson & Maguire, 2000) or to apply their knowledge to daily life (Lewis & Kattmann, 2004). On the other hand, some other researchers (e.g., Banet & Auso, 1995; Pashley, 1994) claimed that traditional teaching strategies have little effect on students’ acquisition of meaningful understanding of inheritance and suggested that significant changes in both curriculum planning and sequencing of learned concepts are highly important features that would enhance student understanding of genetics at the secondary school level. Yet, despite these different perspectives regarding the weight of the proper sequencing of concepts versus the impact of teaching methodology used during genetics instruction on student level of understanding, many researchers argued that the implementation of adequate

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instructional methods and techniques can still help students make connections among essential genetics ideas and apply their knowledge to a range of new situations (Ausubel, 1968; Lee & Liu, 2009; Linn et al., 2004; Taber, 2001). Also, a number of researchers claimed that the principles of genetics cannot be easily learned only from lectures, even with excellent descriptive textbooks (e.g. Pukkila, 2004; Stewart et al. 1992;Sved, 2010) and that genetics computer simulation programs can be valuable supplements for direct lecturing and problem solving used in teaching genetics, in particular, Mendelian genetics. However, Sved (2010) argued that the impact of instructional software for genetics on learning still needs to be investigated. Several researchers have designed interventions for high school students and have showed that animation–based activities, interactive computerized learning environments, and inquiry–based learning in genetics are successful in promoting conceptual understanding of many aspects of the genetic, meiotic and molecular models of genetics (Buckley et al., 2004; Cartier & Stewart, 2000; Gelbart & Yarden, 2006; Rotbain et al., 2006) and others. However, a review of literature showed that interventions in teaching genetics designed for upper elementary and middle school are very few with only one successful intervention conducted by Venville and Donavan (2007) who designed an activity that illustrates the organizational structure of genes on a chromosome and the relationship between the chromosomal make up of parents and offspring by a concrete analogical model using different colored wool segments. A Need for Learning Progressions Based on the above, it is clear that there is a need to develop learning progressions for a variety of science topics because of the potential that these progressions provide for students to develop in-depth understandings of scientific topics. Furthermore, and as importantly, there is a need for evaluating the effectiveness of these progressions in improving student learning.

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Finally, there is a need for developing instructional materials aligned with the developed learning progression (Furtak, Roberts, Morrison, Hensen & Malone, 2010) that scaffold both student and teacher learning along that progression. Learning Progressions: Promises As stated previously, learning progressions can be used as conceptual frameworks that guide the design of instructional materials and improve curricula. It is important at this point to describe other conceptual frameworks designed by several researchers to improve curricula and to highlight major differences between these tools which are also known as “Learned Knowledge” and learning progressions. The idea of using conceptual frameworks in science education is not new. The first conceptual frames were constructed in 1983 and aimed at designing resource materials that clarify the scientific knowledge to be taught at a given grade level and guide teachers in their instruction and preparing their lessons and curricula planners in writing a coherent curriculum. These conceptual frameworks are primarily focused on analyzing the subject taught (Giordin, 1987) by describing the interrelatedness between the major scientific concepts (also referred to as internal relationships) that should be taught at a certain grade level and related concepts surrounding these constituent concepts ( external relationships). Thus, these frameworks were considered as graphical models to visualize the connectedness of concepts and their hierarchy within an educational progression, and in most of the cases, they were developed to meet the problems posed by teachers in teaching science. A review of the literature revealed the work of some researchers who developed conceptual frames for teaching about digestion ( Sauvageot,1994) ; ecosystem and energy (Aster , 1986) and nervous communication and reflexes (Canguilhem, 1955).

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Sauvageot in 1994 developed a vertical relative conceptual framework to teach about digestion for grades CM2, 6e, 3e, and 1reS. She specified the concepts to be taught at these different grade levels and proposed a path, which she considered a logical sequence from her perspective that links the concepts within and across grade levels. In the study, the researcher identified the foundation of her conceptual framework, the mechanics of designing it and the challenges that educators might face in designing similar conceptual frameworks. The researcher pointed out that the selection of concepts of digestion are usually derived from an obstacle faced by teachers in delivering classroom instruction or a discrepancy in teaching these concepts by a group of teachers. Moreover, she emphasized that the design of the conceptual framework is rooted in publications related to the didactic and transposition of teaching about nutrition, views of high school biology teachers and college teachers and textual information on digestion as presented in biology textbooks and popular articles. Sauvageot (1994) identified several challenges in designing the conceptual framework on digestion. First, selection of the concepts to be taught, defining each concept and specifying the location of each concept within the progression were a big challenge. Second, building the conceptual framework usually reflects discrepancies among researchers in prioritizing the concepts to be taught, relating and connecting them in a hierarchical format and locating spatially the concepts along the progression. This might results in designing several pathways for teaching the same concepts in case disagreement prevailed and where each group of researchers adopts its own strategy thus, ending up with various textbooks which present the same concepts for a given topic in a different manner. Importantly, the researcher declared that in case a confrontation between colleagues exists, the design process would include the use of trial and error in re-adjustments of the sequenced concepts in an attempt to develop a logical construction. The researcher argued that these

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designed conceptual frameworks, which stem mainly from teachers’ insight and opinion gained from experience and teaching practices, need further validation and experimentation in classrooms. Consequently, these conceptual frameworks, which have important educational value, differ from our proposed learning progressions in several dimensions: First, the construction of such conceptual frameworks is driven by the need to analyze deeply the teaching materials and to help teachers in their transposition of the teaching material and is not centered on student learning. Second, they are purely teacher- oriented and refined by judgments of experts in the field rather than on research about student learning, students’ misconceptions and difficulties encountered by students during learning. Third, although concepts to be learned across years are sequenced in increasing level of complexity in both types of progressions; yet in the latter this sequencing is centered on well-defined big ideas and sub ideas which is not the case for conceptual frameworks constructed by Sauvageot. Fourth, and more importantly, the design of learning progressions is associated with the developing of performance tasks that specify the level of student understanding along the progression, a unique practice which guides teachers to provide each student with the adequate teaching support to ensure the proper acquisition of the desired concepts and skills. Drawing on all the above, many researchers view learning progressions as a promising tool that helps improve standards, curricula and teaching. Currently, many researchers are criticizing the existing USA science standards which are framed in terms of what students are expected to learn (desired outcomes) without considering the wide range of students who might exhibit different levels of understandings and thinking about a particular topic taught at a given grade level. In practice, this means that during

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instruction a teacher might find some students who think about the taught topic in sophisticated ways, while others think about the same topic in a way characteristic of “earlier” consolidations of the related content. Learning progression-based standards, in contrast to traditional scope and sequence standards, provide useful direction to teachers that would help them respond constructively to all their students’ needs; in particular, identifying students who are “behind” the desired target and focusing on practices that enable these students to show progress in the context of that particular topic. Researchers claimed that the scope and sequence approach focuses on the products of students’ thinking rather on the ways that thinking develops over time, reveals shallow specification about how instruction mediates between the presentation of content and student outcomes, and provides little guidance for what teachers should do to ensure that their students meet or exceed the standards (Dougherty et al., 2011; Gross et al., 2005; Hoffman & Barstow, 2007).They argued that standards and learning goals should be considered not merely as a collection of ideas organized under various topic heading, but rather as a progression of understanding that includes what leads up to each specific goal and where it then leads and call for a comprehensive evaluation of the content of these standards and their quality. Furthermore, findings revealed that the major concern of the proponents of learning progressions, besides maintaining good standards, is primarily focused on teaching, learning, and exploring procedures that would guide teachers to determine the level of achievement of each student along the progression. They argued that the developmental characteristic of a learning progression has a significant impact on student learning. First, it helps teachers identify precursor ideas that may be missing from their students’ background knowledge before beginning instruction on a new topic, and consequently stimulate them to explore supporting ideas that would enhance students’ learning rather than simply repeating the original instruction. Second,

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learning progressions can provide more information about the range of students’ abilities, or levels of sophistication and can track their developmental progress over time (Corcoran, Mosher & Rogat, 2009;Gotwals, Songer & Bullard, 2012;Songer, Kelcey & Gotwals, 2009) and this can help in designing appropriate instructional activities and assessment tasks that provide better quantifiable measures of students’ understanding at each level (Alonzo & Steedle, 2009; Furtak, Roberts, Morrison, Henseon & Malone; 2010). It is worth noting that providing learning performance indicators that exemplify how students are likely to think and what they are likely to know, understand, and be able to do at particular points along the progression is a crucial component in the process of developing a learning progression. This requirement to discriminate reliably and validly between levels of performance rather than to discriminate among students represents a subtle, but quite fundamental, shift in the purpose of assessment. However, Anderson, Alonzo, Smith and Wilson (2007) claimed that, in practice, designing assessment items that provide evidence of student understanding at multiple points along a learning progression is a highly challenging task. Another key characteristic that differentiates learning progressions from traditional content-centered scope and sequence standards documents is that their development is guided by theory and research findings on how students learn a topic/concept with a consideration of the misunderstandings/ misconceptions students might have with that particular concept/topic rather than by conventional wisdom or consensus processes as in the case of scope and sequence curriculum frameworks (Briggs, Alonzo, Schwab& Wilson, 2005; Duncan & Hmelo-silver, 2009). Thus, tested and validated learning progressions would provide more realistic pictures of the kinds of progress or growth students are likely to demonstrate within a given time, and more

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accurate descriptions of students’ progress that specify the particular instructional approaches, or the range of approaches, that were associated with the described progress. In summary, learning progressions can provide curriculum developers with a deep understanding of the instructional objective appropriate at each level, the pre- requisite ideas that contribute to it, types of activities and lessons that address each objective and the conceptual connections that should be highlighted within lessons, from lesson to lesson, from unit to unit and from year to year. Johnson and Tymms (2011) argued that a learning progression serves as a guide and reference for connecting topics in logical and useful ways without duplicating topics and skills and without leaving gaps in the progression of ideas within units and from unit to unit. With such coherence in the curriculum the concepts and processes that students learn can become more complex as they construct new ideas and develop new skills based on previous knowledge. Research has demonstrated that what students already know about a topic is one of the most significant factors in determining their success in learning new, related content. This result is aligned with the constructivist theory of learning which recognizes that learners interpret new ideas and knowledge in terms of prior experiences and understandings of the world phenomena which have developed from an early age. In learning progressions, students’ ideas are an essential component of this conceptual framework which guides instruction and assessment. In such an approach, teachers become aware and sensitive to the knowledge and ideas, whether accurate or not, that students bring to the classroom and which might interfere with the acquisition of newly learned concepts. Moreover, teachers would frame their learning questions and assessment items based on students’ prior knowledge and thus evoke rather than convey

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meaning (Wheatly, 1991). Consequently, this shift in paradigm would shape the type of instruction and assessment in classrooms. Recently, many researchers went beyond considering learning progressions as maps which only include the grain size and levels of understanding with their upper and lower anchors. Furtak et al. (2010) urged that learning progression move from being simply a research construct to also become a tool useful to teachers that would influence classroom instruction. Furtak and his colleagues (2010) developed the concept of an educative learning progression that scaffolds both student and teacher learning. This approach is receiving much attention and support from many educators who claim that learning progressions should also provide how students’ level of understanding may be assessed and the kind of instruction which would take place at each level to foster a more sophisticated level of understanding (Krajcik et al., 2012; Neumann, Viering, Boone& Fischer, 2013). These researchers argued that such a complete conceptual model and approach which includes instructional components associated with the learning progression would guide curriculum and material development, ensure proper implementation of newly designed teaching units and consequently can lead to a better student learning of scientific knowledge and development of skills and practices. Shavelson (2009) identified two types of learning progressions, the “curriculum and instruction” type that represents progressions of students’ understandings of a certain topic as guides for curriculum development, and the “cognition and instruction” type that traces the development of student ideas from naïve to scientifically accepted as supports for assessment design. Furtak (2012) and Corcoran et al. (2009) argued that both types of learning progressions are potentially useful in supporting instruction. These researchers viewed learning progressions as “curriculum frameworks” for determining what, and

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in what order and level of complexity, specific content and skills should be taught, and provide as well a basis for designing “ instructional regimes” that would specify ways of responding pedagogically to individual student’ stage of progress and learning problem. Currently, there is a growing body of research to assess students’ understanding of core genetics ideas, and also the ways in which students use these ideas to interpret and explain genetically related concepts and phenomena. However, both types of learning progressions: Core disciplinary ideas progression and progressions for explanations have limited research support and little is known about the influence of either type of learning progression on instruction (e.g., Corcoran et al., 2009; NRC,2007). Despite this shortage in research, several attempts have been made to develop learning progressions for both core ideas and practices associated with the scientific understanding of these core ideas. Furtak (2012) investigated how the core ideas in learning progression on natural selection can support teachers’ ability to make inferences about student thinking during formative assessment conversations. Results showed that the majority of teachers seemed to use the learning progression simply as a catalog which identifies common student misconceptions and misunderstanding of a learned topic or concept. These results also showed that using this learning progression failed to help teachers respond to student ideas and adapt their instruction. Similarly, Gotwals and Songer (2013) assessed the extent to which assessment tasks are able to provide evidence about students’ knowledge and scientific practice (evidence-based explanation) of core disciplinary ideas illustrated in learning progression for ecology. This study revealed that assessment tasks helped to distinguish between different ability-level students, but not in locating students at a given level on the constructed progression. These authors claimed that much research is still needed for the design of core disciplinary ideas progressions and process

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progressions for evidence-based explanations, together with the design of assessment tasks that help in collecting empirical data on student understanding of knowledge and practices in core disciplinary ideas. They added that although, assessments play a critical role in informing the development, validation, and use of individual learning progressions, designing and evaluating assessments which focus on science knowledge that is a fusion of core disciplinary ideas and science practices is a serious challenge for educators. Likewise, several researchers (Corocan et al., 2009; Furtak, 2012; Neumann et al., 2013) claimed that designing assessment items that allow students to demonstrate their integrated knowledge at multiple levels, and teachers to develop the ability to draw inferences from students’ responses with respect to the learning progressions are two essential steps that are needed to make progress in research on the strength of learning progressions and their impact on student learning. Additionally, valid data collecting tools and valid interpretation should provide insights on students’ successes and difficulties in generating integrated core ideas and practices so as to learn more about the intricacies and complexities of the ways in which students develop complex reasoning in science (e.g., Pellegrino, 2012). Furthermore, currently, there is an increasing interest in developing learning progressions that consider the trio of concepts, practices, and epistemology which are essential for deep understanding of science and that should be integrated throughout instruction across all grades (Duncan & Rivet, 2013). Yet, the framework for Science Education Standards (NRC, 2011) stressed that research on learning progressions is still at an early stage and many aspects encompassing the development, implementation and validation of learning progressions are still unexplored territory. They added that educators need to be mindful of the promises and pitfalls that accompany the design and implementation of learning progressions; a situation which can

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guide them to make well- informed conjectures regarding the best practices to ensure the best alignment of standards, curriculum and assessment in an attempt to enhance student learning. Research on Learning Progressions In recent years, learning progressions have been developed for multiple purposes, as guides for curriculum design, frameworks for assessment development, and scaffolds for teaching practices. These progressions span a wide range of topics and concepts such as energy (Neumann et al., 2013), water in socio-ecological systems (Gunckel, Covitt, Salinas & Anderson, 2012),celestial motion (Plummer & Krajcik, 2010), molecular nature of matter (Smith, Wiser, Anderson, & Krajcik, 2006; Stevens, Delgado, & Krajcik, 2009), structure of matter (Margel, Eylon, & Scherz, 2007), evolution (Cately, Lehrer, & Reiser, 2005; Furtak, 2012), biodiversity(Songer, Kelcey & Gotwals, 2009; Zesaguli et al., 2009), carbon cycle (Gunckel, Mohan, Covitt & Anderson, 2012; Mohan, Chen & Anderson, 2009), and force and motion (Alonzo & Steedle, 2009). In addition, there are a number of studies that focused on genetics and they are presented below. Duncan, Rogat, and Yarden (2009) designed a progression which provides details about the expectations of what genetics concepts can be learned with proper instruction at the grade bands: 5-6 (level 1), 7-8 (level 2), and 9-10 (level 3). They organized the concepts in the form of questions around two fundamental genetics ideas: (a) how do genes influence how humans and other organisms look and function? And (b) why do humans and other organisms vary in how they look and function? To illustrate a logical explanation of these two major questions, the researchers adopted three conceptual models: (1) the genetics model which deals with patterns of inheritance observed during sexual reproduction; (2) the meiotic model which explains the mechanisms of gene recombination during cell divisions and the process of fertilizations and (3)

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the molecular model which explains the relatedness of genes to their biological outcomes i.e. an organism’s trait and features. The researchers described eight essential big ideas needed to answer these questions and analyzed each idea in light of research findings about students’ misconceptions. They broke these ideas further into components relying on the three models and provided argumentation for the sequencing of these components based on research findings. Additionally, the authors argued that genetics literacy is about connecting the molecular, meiotic, and genetics models and introducing them at an early stage to be continually revisited and elaborated in subsequent years. The researchers determined the proficiency level of students in genetics by their ability to explain physical traits based on principles of molecular and cellular biology at the three grade-band levels and also provided an illustrative example of how learning acquired in the genetics progressions can be described and assessed in terms of learning performances. The researchers found that most students fail to develop deep understandings of fundamental ideas in modern genetics by the end of high school, and consequently called for planning instruction in genetics according to learning progressions which require building a coherent set of genetics ideas across the elementary, middle, and high school grades. They pointed out that instruction and assessment must focus on a few core ideas that need to be revisited in greater depth from late elementary to high school to build increasingly more sophisticated understandings of the key genetics concepts. However, they suggested that the progression model is conjectural and needs to be validated empirically. Project 2061 (AAAS) proposed a learning progression for a coherent understanding of the molecular basis of heredity and emphasized teaching DNA before genes and chromosomes but teaching proteins before DNA. Project 2061 built this progression based on studies which reported learning difficulties students have with Mendelian inheritance (Banet & Ayuso, 2000;

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Moll & Allen, 1987; Smith, 1988; Stewart, 1982, 1983). The learning progression of project 2061 proposed a logical and developmentally appropriate sequencing of the two major roles of DNA: (a) determining the characteristics of an organism and (b) passing information through generations from the primary grades through high school. In their study, Roseman, Caldwell, Gogos and Kurth (2006) unpacked the learning goals stated in benchmarks for science literacy of the heredity section (AAAS, 1993; NRC, 1996). They clarified the main ideas in each benchmark and described the boundaries of each idea in terms of what specific knowledge students are or are not expected to know. Because of lack of research on the topic, several rounds of interviews were conducted with students to identify the most common students’ ideas and misconceptions. Then, the research group developed a learning progression which identified the aligned phenomena or instances with examples that help students understand these ideas. This was accompanied by constructing assessment items that monitor students’ progress in learning the specified ideas. Both the learning activities and test items were drawn from students’ misconceptions and from research studies. The researchers found that many students were not able to give examples on how proteins can do different work in cells and carry out many essential functions needed to sustain life and to give examples on these functions. Also, the study showed that many students were not able to explain logically the relation between DNA, shape of proteins and their functions. However, it is worth to note that the progression developed by Roseman et al. (2006) was not tested empirically. Based on the above, developing learning progressions in science and gathering evidence to support their validity is still at an early stage, and there is much to be learned about their value as guides to development of curricula, assessments, and instructional support tools, as well as about the consequences of their use for improving students’ learning. In Lebanon, we are in the

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process of curriculum reform, and it would be useful to adopt learning progressions as effective pedagogical tools that will enhance the design of our curricula in more meaningful way that promote better student learning. In this study, we intended to determine the scope and sequence of the core genetics concepts by using a new educational vision which considers the developmental approach to learning. We seek to determine whether this scope helps student develop more sophisticated ways of understanding and reasoning as they move across grade levels. Our assumption is that students who receive instruction based on the progression are more likely to master the target concepts than students who receive conventional instruction using the existing genetics curriculum. We also, intended to validate the learning progression-driven genetics unit by implementing it with real students in the course of instruction. This would allow us to gather evidence regarding the difficulties encountered in teaching and learning genetics and the characteristics of classroom artifacts that impact student learning. Moreover, we hope that this validation of the learning progressions, even at a small scale, will provide evidence about students’ progress in acquiring the concepts embedded in the learning progression and then, using this information to iteratively align curriculum, instruction and assessment to foster students’ mastery of genetics in the best possible way. Specifically, this study aims to: 1- Determine Lebanese teachers’ perception of the coherence and organizational levels of the genetic curriculum across grade levels. 2- Determine Lebanese teachers’ perception of the role of the genetics curriculum in fostering genetic literacy among students.

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3- Identify the major misconceptions and difficulties encountered by Lebanese students, from both public and private sectors, during genetics instruction. 4- Investigate any variation in the nature of the misconceptions and difficulties encountered by public and private school Lebanese students during genetics instruction. 5- Examine ways of improving the genetics curriculum, from both teachers’ and students’ perspectives, to achieve better students’ understanding in genetics. 6- Develop a valid and reliable learning progression based on data collected from research questions 1-4 and a literature review in the same field that would improve students’ understanding of genetic concepts. 7- Investigate the level of the content coherence of the existing genetics curriculum and the learning progression-driven genetics unit and the extent to which this content presentation enhances students understanding of genetics. 8- Determine the extent to which the existing genetics curriculum and the learning

progression-driven genetics unit promote the development of genetically literacy citizens. Furthermore, we have extended our study to develop a genetics unit for grade 9 based on students’ and teachers’ suggestions and the proposed learning progression and to evaluate its effectiveness on student learning. In designing our learning progression-driven genetics unit, we aimed to answer the following questions: 9- Does instruction based on the learning progression as compared to a biology textbook based approach result in higher achievement in genetics? 10- What are the major educational practices that might support the proper design and

implementation of learning progression-driven curricular unit?

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CHAPTER III METHODOLOGY This chapter presents a detailed description of the methodology used in this study including participants, data collection tools, procedures and data analysis procedures. The present study consisted of two major parts and therefore, this chapter describes the methodology used for each part in turn. Research Design The design of this study consisted of two main phases: a descriptive phase and a quasiexperimental phase. In addition, this study adopted a mixed-methods approach in which quantitative and qualitative data collection methods were used in both phases of the study. A mixed-methods approach was used in order to obtain an in-depth understanding of teachers’ and students’ perceptions and evaluate the quality of a research based newly designed genetics unit. During the first phase of the study, questionnaires and interviews were used with students and teachers of grades 7 to 12. The descriptive approach was chosen in order to describe the participants’ perspectives and experiences pertaining to the understanding of genetics concepts by intermediate and secondary school students. Moreover, this phase involved the analysis of the content of the genetics curriculum for middle and secondary school. The information collected during phase one was used to design a learning progression and a new unit in the area of genetics. The second phase of the study involved a quasi-experimental design which aimed at measuring the effectiveness of the developed learning progression and the newly designed genetics unit based on this progression on students’ understanding of genetics concepts. During this part of the study we also employed a design-based research (DBR) approach in an attempt to

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identify artifacts and practices that may potentially have a positive effect on learning within naturalistic settings (Barab & Squire, 2004; Cobb, diSessa, Lahrer & Schauble, 2003). This study reports the findings of one iteration of the design based cycle. Phase I: Descriptive Design Participants Schools. Three private and three public schools participated in the first part of the study. These schools are located in three different geographic areas of Lebanon: Beirut, suburbs of Beirut and south Lebanon (Saida). Each of the six selected schools had at least two sections for each grade level, from grade 7 to grade 12, with a minimum of 20 students per section. This helped in obtaining a large enough sample for the study and ensured the possibility of having an experimental group and a control group for implementing the second phase of the study. Moreover, these schools use the same national biology textbook which limited the interference of any extraneous variables that might have threatened the internal validity of the present study. Official permission from the director general of the Ministry of Education and Higher Education was acquired before conducting the study, particularly in the public schools. Afterwards, an official letter was sent to the school principals of the participating schools in order to inform them about the purpose of the study. The researcher first met with the participating school principals and then with the biology coordinators and teachers of all the cooperating schools. Students. Seven hundred and twenty nine students from grades 7 to 12 participated in the study by filling a questionnaire prepared for the purposes of the study. These students provided a wide range of educational levels, socio-economic levels, academic abilities and gender. Therefore, such a large sample of students promotes the generalizability of the results of the study. Of those students, 393 (53.9%) were from public schools and 336 (46.1%) were from private schools. It should be noted that only the sciences section was chosen for grade 11 and

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only the Life Science section was chosen for grade 12. Among the students who filled the questionnaire, 52.7% were female and 46.4% were male and 0.9% did not specify their gender. In addition, the students were almost evenly distributed among the different grade levels: 18.4% in grade 7, 20.9% in grade 8, 15.6% in grade 9, 18.8% in grade 10 and 18.4% in grade 11. Only 8% of the students were from grade 12 and this may be explained by the fact that many 12th graders were out school preparing for the official examinations when the study was conducted and some students did not volunteer to fill out the questionnaire. Two weeks following the completion of the questionnaire, a total of 62 out of the 729 students (8.5%) were randomly selected and interviewed. The interviews aimed to uncover the way students viewed genetics and to identify misconceptions commonly held by students. Within each of the six participating schools, one classroom section was randomly selected from each grade level (i.e. six sections in each school). After collecting all the questionnaires, a number was assigned for each student questionnaire. For the purpose of the interviews, two numbers were randomly selected from each grade level in each participating school. The researcher provided the biology teachers with the names of the randomly selected students, who in turn provided a time table for visiting the school and interviewing the students. In cases where students were absent or unavailable on the assigned interview day and time, either another student was selected in his/her place or no interview was done. Table 1 presents the distribution of the interviewed students by grade level and by school. Each student interview lasted for 20-30 minutes and was done at the schools separately either during recess time or free time, according to each students’ time availability.

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Table 1 Number of Students Selected for Interviews by Grade Level and by School (N=62)

Grade 7 8 9 10 11 12 Total

1 2 2 2 2 2 1 11

2 2 2 3 2 2 2 13

3 0 1 1 0 2 1 5

School 4 2 2 0 2 2 3 11

5 2 2 2 2 2 2 12

6 2 2 2 2 2 0 10

Total 10 11 10 10 12 9 62

Teachers. A total of 20 biology teachers also participated in the first phase of the study. Out of these 20 teachers, 17 were biology teachers from the six cooperating schools: 10 public school teachers and 7 private school teachers. Additionally, 3 biology teachers who also work as inspectors and trainers at the Lebanese Center for Educational Research and Development (CERD) and Department of Guidance and Counseling (DOPS) volunteered to participate in this study. Among these 20 teachers, 17 were female and 3 were male, 45% had more than 20 years teaching experience and 55% had a BA/BS. Sixty percent of these biology teachers teach at both the intermediate and secondary levels. The majority of these participants (55%) were coordinators as well as teachers and 50% of them (especially teachers in the public sector) had received in-service training in genetics over the last 5 years. All the participating teachers completed a questionnaire that targeted their perceptions of the intermediate and secondary genetics curriculum and the main difficulties encountered by Lebanese students when learning genetics. Following completion of the questionnaire, eight teachers out of the 20 were randomly selected and interviewed. The purpose of the interviews was to gain more insight about the

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problems encountered by intermediate and secondary students when studying genetics and about teachers’ opinions regarding the genetics content of the existing biology curriculum and their suggestions for improvement. Data Collection Tools and Procedures Data collection tools used for the first phase of the study included: a) student questionnaires and interviews, b) teacher questionnaires and interviews, and c) curriculum document which includes the learning objectives specified in the Lebanese National genetics curriculum and the genetics units presented in student biology textbooks assigned for grades 7 to 12. Student questionnaire. The student questionnaire was designed by the researcher and aimed to determine students’ understanding level of the core ideas in genetics and identify the misconceptions and difficulties encountered by students during genetics instruction. Figure one below illustrates the method followed in designing the questionnaire. The first step in designing the student questionnaire consisted of reviewing previous research on the major misconceptions and difficulties encountered by students in studying genetics and on the teaching and learning of genetics. Many of the questionnaire items were drawn from assessment programs, tests piloted by other researchers and findings of studies done in the same domain. Once constructed, content validity of the questionnaire was determined by four qualified Lebanese biology teachers and a science educator. A draft of the paper and pencil questionnaire was then piloted with a sample of 100 students from grades 7 to 12 from four schools (two public and two private) different from those that participated in the study. The students’ responses were examined and the biology teachers who administered the questionnaire were interviewed in order to collect further data on the content validity, applicability of the

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questionnaire, and the major difficulties encountered by the students while answering the questionnaire. Further modifications were done and the final version of the questionnaire (Appendix I) was then administered to the whole sample of participants (729 students). The final questionnaire consisted of the following:1) 12 items which assessed student’s opinions about the existing genetics curriculum and addressed misconceptions held by some students. These items used 5 points Likert-type scale; 2) 11 ordered-multiple choice (OMC) items - a special type of multiple choice (MC) question in which students’ response to each item corresponds to students’ level of conceptual understanding. These items identified students’ level of conceptual understanding in certain genetics concepts; and 3) 6 open-ended items which addressed students’ level of genetics literacy and understanding of some major genetics concepts.

Comprehensive review of literature Construction of a paper-and-pencil student questionnaire Revision by biology teachers and a science educator

Administering the questionnaire to the whole sample ( 729 students)

Modification of the questionnaire Piloting on a sample of 100 students in 4 schools

Checking students answers Interviewing teachers for feedback Final modification of student questionnaire

Figure 1. Method followed in designing the student questionnaire.

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It is worth noting that the same questionnaire was purposefully used for students of all grade levels in order to measure students’ understanding at different grade levels and to identify whether or not students’ level of understanding of major genetics concepts was progressing across increasing grade levels. Moreover, although 7thand 8th graders do not study genetics, they were given the questionnaire in order to uncover any prior knowledge they may have about basic genetics concepts from media, family, and other sources. This approach was used because it served the purpose of designing a genetics unit that takes into account students’ prior ideas that, if erroneous, could interfere with the acquisition of scientifically acceptable knowledge about genetics. The questionnaire was administered to all 729 participating students in their regular biology period during the first week of May,2011when they had already finished learning the genetics unit. Student interviews. Semi-structured interviews, each lasting for about 20-30 minutes, were conducted with 62 students in grades 7 to 12. The interview consisted of 11 open-ended questions which required students to verbalize their understanding of real-world genetics phenomena and speak aloud about specific genetic content and about the way they apply what has been learned in genetics (Appendix II).All interviews were tape- recorded, transcribed, coded, and categorized. The analysis of the interviews was done by the researcher herself, an expert biology teacher and an assistant researcher who separately analyzed students’ answers, categorized them into groups and then discussed them. These researchers met twice and each time attained more than 85% inter-rater agreements when comparing the categories and all disagreements were then adjudicated. Then, the frequencies and percentages of each category for each question were determined.

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The data from both the questionnaire and interviews were used to explore any existing similar pattern of answers within a particular age level as well as patterns between different age levels and provided insights into how students develop understanding of important genetics concepts over time. The data also helped in determining the number of transition or intermediate levels of achievement needed for the proposed learning progression and incorporated only the necessary concepts that help students explain phenomena appropriate to each level. Moreover, data drawn from students’ interviews helped uncover the potential power of students in connecting several ideas when explaining and predicting genetics phenomena and concepts. Teacher questionnaire. In designing the teachers’ questionnaire the same procedure followed for constructing the student questionnaire was used. The items of this questionnaire were grounded in evidence collected from research on students’ and teachers’ misconceptions in genetics, difficulties students encounter in learning genetics and Lebanese biology teachers’ critique of the current scope and sequence of the core concepts of genetics presented in the Lebanese curriculum. It is important to note that this questionnaire did not aim to measure the knowledge level of teachers but rather to determine their perceptions regarding the coherence of genetics concepts as presented in the Lebanese national biology textbooks for grades 7-12, identify students’ common difficulties in learning genetics and shed light on teachers’ suggestions for improving content curriculum. This questionnaire was reviewed by four biology teachers and a science educator and piloted with four teachers who were not part of the study sample. Based on their suggestions and feedback a final version of the questionnaire was developed and administered to the study sample of 20 teachers. The final questionnaire consisted of 46 items: 9 items (items 1-9) which described the profile of teacher; 3 items (items 10-12) in which teachers evaluated their genetics knowledge and pedagogy; 15 items (items 13-27) which

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identified teachers’ perceptions of the existing genetics curriculum; 16 items (items 28-43) which determined teachers’ perceptions of students’ conceptual understanding of genetics; and 3 items (items 44-46) which addressed teachers’ suggestions for improving the genetics curriculum. The questionnaire is shown in Appendix III. Teacher interviews. The teacher questionnaire was followed by semi-structured interviews that were conducted with 8 teachers who were randomly selected from the 20 participating teachers. The purpose of the interviews was to gain more insight about the problems encountered by intermediate and secondary students when studying genetics and about teachers’ opinions regarding the content of the existing genetics curriculum and their suggestions for improvement. Participants were asked 26 open-ended questions which were grouped under three main sections: 1)10 questions which aimed at uncovering students’ thinking processes and problems encountered by them when studying genetics; 2) 13questions which aimed at determining teachers’ opinions on various issues related to the teaching of genetics and genetic literacy; and 3) 3 questions which aimed at identifying teachers’ opinions regarding aspects of the genetics content that could be hindering students’ learning of genetics (Appendix IV). The interviews lasted for about 50 minutes each and were conducted with teachers according to each teacher’s schedule. All interviews were tape- recorded, transcribed, coded, and categorized. The analysis of the interviews was done by the researcher herself, an experienced biology teacher and an assistant researcher who separately analyzed teachers’ answers, categorized them into groups and then discussed them. These raters showed more than 80% inter coder agreement in coding of teachers’ responses.

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Content Analysis of the Lebanese National Genetics Curriculum A systematic analysis of the genetics curriculum was performed to identify the learning objectives and key and sub-key ideas that middle and secondary school students are expected to learn as proposed by Lebanese curriculum which was approved by in Decree No: 10227 issued on May, 8, 1997.The analysis involved the following: a) identifying the learning objectives of the genetics curriculum designed for intermediate and secondary school students; b) determining the sequence of genetics concepts across grade levels; c) exploring the alignment of the sequencing of the genetics concepts as presented in student biology books with the content of the genetics curriculum document; d) determining the developmental progression of these learning objectives ; and e) determining the extent to which the Lebanese curriculum prepares genetically literate students who are capable of making well-informed decisions related to societal and controversial genetic issues. Analysis was based on the premise that such content evaluation may shed light on possible gaps in the organization and coherence of the core concepts in the existing genetics curriculum which could be major factors that influence students’ understanding of genetics. For the purpose of determining whether the statements which describe the learning objectives for genetics show any level of developmental progression across years, we listed the learning objectives associated with the teaching of genetics for grades 9-12 and mapped the increasing level of complexity of the genetics themes and concepts across years. Moreover, the theoretical framework “Genetics Literacy Assessment Items” (GLAI) (Bowling et al., 2008) was used to assess the level of genetics literacy in the existing genetics curriculum. Bowling et al. identified 17 sub-concepts that are considered essential for teaching genetic literary. These concepts are presented in Table 2. For reliability purposes, the analysis of the Lebanese genetics

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curriculum document and genetics units presented in school biology textbooks using GLAI was done by the researcher and four other biology teachers. First, the raters met and applied GLAI to categorize a section of the genetics curriculum of grade 9 to insure that they had a common understanding of the GLAI. Then, raters categorized separately the content of another section of the genetics curriculum of grade 11. In this round, raters showed approximately 75% inter coder agreement and any disagreement in the differences in the rating were discussed until consensus was reached. These raters then coded the rest of the genetics curriculum for grades 9-12 separately and showed approximately 95% inter coder agreement. Table 2 Concepts and Sub-Concepts of Genetic literacy Concept I.

Nature of the genetic material

a. b. c.

d.

II.

III.

Sub- Concepts DNA is the genetic material of virtually all different types of organisms. Occasional errors in DNA structure and replication result in genetic variation. DNA is organized into cellular structures called chromosomes. Genes are segments of DNA within chromosomes. Virtually all cells within an individual contain the same genetic constitution. Different cells and tissues are produced through differential gene activity.

Transmission

a. Chromosome number is reduced by half during meiosis, which results in the formation of genetically different gametes. b. Understanding Mendelian patterns of inheritance, and their biological basis, allows probability statements about the occurrence of traits in offspring.

Gene Expression

a. Many genes code for proteins, which in turn produce individual traits. b. The functions of a gene and its protein product can be affected by the environment at one or many steps involved in producing a given trait. c. Most human traits, including diseases, result from the products of multiple genes interacting with environmental variables, e.g. include height, heart disease and cancer

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V.

VI.

Gene Regulation

a. Some genetic variation results in disease in virtually every environment, for example, the mutations associated with Huntington disease, Tay-Sachs disease, and cystic fibrosis. b. There are other genetic variations that results in disease less consistently, for example, the BRCAI mutation associated with breast cancer. c. Much of gene regulation involves turning genes on and off at the right time.

Evolution

a. Genetic variation is the rule rather than the exception in the living world and is the basis for evolution by natural selection; without genetic variation there can be no differential selection, and no survival of any species. b. Genetic variation is much greater within traditional human ethnic groups than among them. Superficial phenotypic differences do not reflect the high degree of genetic relatedness among traditional ethnic groups.

Genetics & Society

a. The current and future application of genetics and genetics technology to such areas as health care, forensic analysis, genetically modified organisms, etc. holds great potential for improving life. b. Like all technologies, genetic technologies are fallible and have unintended consequences, some of which can be harmful to individuals, families, or groups. c. Science often can tell us we can or cannot do, but it does not always indicate clearly what we should do. Those decisions arise from the intersection of science with ethics, the law, and public policy.

Data Analysis Procedures In order to analyze the data collected from the student questionnaires, descriptive statistics were used. More specifically, means, standard deviations, frequencies and percentages of the students’ responses on questionnaire items were computed. The percentages of responses were compared across the different grade levels. Also, for each item a chi-square test was done to determine whether or not there were statistically significant differences in students’ responses across the grade levels. In cases of a significant chi-square, adjusted residuals were used to determine which responses were contributing to the significance. This analysis was done at the

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level of the whole sample and by type of school (public and private). Moreover, in order to determine whether or not there were significant differences in the responses of students in public and private schools, independent-samples t-tests were done. In addition, a one-way ANOVA was done to determine whether students’ level of misconceptions differed across the different grade levels where grade level was taken as the independent variable and students’ misconceptions were taken as the dependent variable. In order to analyze the open-ended items of the student questionnaire (items 22 and 3438), the common responses for each item were determined and placed into categories. To increase validity and reliability of item analysis, we used as guidelines the same categories of misconceptions and sub ideas identified by Shaw and Horne (2007) for categorizing students’ responses to items 22 and 34-38. These categories are: Nature of genetic information; deterministic nature of genetics; genetic basis of disease; patterns of inheritance; genetic technology; reproductive technology; and evolution and natural selection. For further reliability, two researchers categorized and compared students’ responses based on this framework. Any discrepancies in the categories were discussed until a consensus was reached. Reliability of the student questionnaire was also determined using Chronbach’s alpha which showed that the reliability of items 10-15; 16-21 and 23-33 was.26,.34 and.7 respectively. With regard to the teacher questionnaires, descriptive statistics were also computed in which the frequencies and percentages of each of the items was determined. The reliability of the teacher questionnaire as measured by Cronbach’s alpha was .73 for the whole questionnaire. As for each part of the questionnaire, the reliabilities were as follows: .54 for items 10-12, .68 for items 13-26 and .88 for items 29-53.

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Regarding the analysis of the interviews, the audio-tapes were transcribed and then coded. The coded responses were closely examined and categorized under genetics themes and concepts in order to determine similarities or differences in students’ conceptual understanding of some real-life genetics problems, their awareness level for the societal issues encompassing the genetics concepts taught and their views of the existing genetics curriculum. Moreover, this interpretational analysis technique was used to compare teachers’ views regarding the teaching and learning of genetics at schools. Examples and excerpts from both students and teachers’ responses were used for further illustration of the data analysis. The analysis of the interviews was done by the researcher herself, an experienced biology teacher and an assistant researcher who separately analyzed teachers’ and students’ answers, and categorized them into groups. First, the three raters arrived at a shared agreement about how to categorize the answers, followed by identifying the categories themselves. Any disagreements on the categories were discussed among the three raters until consensus was reached. Also, inter-rater agreement was calculated and was found to be 90%. Phase II: Quasi-Experimental Design During the second phase of the study, a learning progression was constructed and used as a guide for designing a newly sequenced genetics unit for grade 9 students which was tested at one school for an initial empirical validation. The purpose of this part of the study was to investigate the effectiveness of the learning progression and the learning progression-driven genetics unit in promoting students’ understanding of genetics. The following sections provide a description of the methodology used in three different stages of this phase of the study: 1) before implementation of the genetics unit intervention which involved designing a learning progression for grades 7-12 and a new genetics curriculum for grade 9,2) during the implementation phase

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which is characterized by administering a pre-test to experimental and control groups, empirical testing of the learning progression- driven genetics unit and carrying out field observations in the experimental group, and 3) after implementation of the new genetics unit which involved a posttest administered to the same groups of students, students focus group interviews and a teacher questionnaire to evaluate the quality of both the existing genetics unit and newly designed unit for grade 9. Developing the Learning Progression A preliminary learning progression for the learning of genetics was constructed based on the analysis of all the data collected from the first phase of this study (student and teacher questionnaires and interviews and content analysis of genetics curriculum). Moreover, the development of this learning progression was based on recent learning progression studies (Duncan, Rogat & Yarden, 2009; Roseman et al., 2006) and the strands maps for genetics presented in project 2061, Atlas of Science Literacy. The scope and sequence of the genetics curriculum in the “Science de la vie et de la Terre”(SVT) French baccalaureate program and the researcher’s experience were also taken into account. The purpose of the proposed learning progression was to design a more coherent genetics unit in which concepts were logically sequenced across the grade levels. A learning goals-driven design process (Krajcik, McNeill &Reiser, 2008) and ConstructCentered Design (CCD) approach (Gagné, Wager, Golas& Keller, 2005;Krajcik, McNeill &Reiser, 2008) were used for developing instructional materials and assessment. In this process, major constructs

Figure 2.Staggered Learning Progression

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or “big ideas” that students were expected to learn were identified (for example, nature of genetic information, inheritance and variation of traits, evolution….). Then, sub-key ideas that would favor a deep understanding of these constructs across grades 7-12 were determined. To sequence the ideas, a staggered form, illustrated in figure 2,(Wilson, 2009) was used in which big ideas were first identified and then more complicated concepts of the big idea were added in progression as the grade levels increased from lower to higher ones. This method ensures a depth of students’ understanding of each big idea across the years. In organizing the learning progression, the same theoretical framework used by Duncan, Rogat and Yarden (2009) for the teaching of modern genetics was used. Their learning progression that spans grades 5-10 is centered on two major themes or constructs (also called “big ideas”) which are essential for students’ understanding of genetics: (1) nature of the genetic information and the biological mechanisms that link genes to their traits and (2) inheritance of traits and variation of the genetic information within a species and among different populations. Within these two constructs, Duncan and his colleagues identified eight sub ideas which help students explain genetically related phenomena by integrating their knowledge of three conceptual models: the genetic model, the molecular model and the meiotic model. These models are illustrated in increasing levels of complexity along the learning progression to ensure their proper alignment with the cognitive level of students at different grade levels. For the purpose of this study, one more subidea was added under the construct “Inheritance and Variation of traits” which addresses the mechanisms by which humans can control and manipulate genetic information through genetic technologies in order to improve different aspects of people’s lives. This sub-idea was added based on the recommendations of the participating students and teachers to include modern genetics and issues related to genetic engineering. Table 3 below presents the big ideas which are

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essential for genetics understanding and the corresponding sub-ideas that lead to a better understanding of these two central ideas. Table 3 Big Ideas and Sub-ideas of the Proposed Learning Progression Theme

Genetic Information and Traits

Inheritance & Variations of traits How are the characteristics of one generation of organisms related to the next generation? Why do we, and other organism, vary in how we look and function?

Question

How do genes influence how, we, and other organisms, look and function?

Big Idea

All organisms have genetic information that is universal and specifies the molecules (mainly proteins) that carry out the function of life. While all cells have the same information, cells can regulate which information is expressed.

There are patterns of gene transfer across generations. Cellular and molecular mechanisms drive these patterns and result in genetic variation. The environment interacts with our genetic makeup leading to variations. Man can control and manipulate the genetic information which has impact on our life. Technological tools help in analyzing the human genome and detecting many genetic disorders.

Sub-Ideas

A. All organisms have genetic information that is hierarchically organized. B. The genetic information contains universal instructions that specify protein structure. C. Proteins have a central role in the functioning of all organisms and are the mechanism that connects genes and traits. D. All cells have the same genetic information but different cells use (express) different genes.

E. Organisms reproduce by transferring their genetic information to the next generation. F. There are patterns of correlation between genes and traits and there are certain probabilities with which these patterns occur. G. Changes to the genetic information can cause changes in how we look and function (Phenotype), and such variation in the DNA

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can serve as a way to identify individuals and species. H. Environmental factors can interact with our genetic information and alter phenotypes. I. Humans can control and manipulate the genetic information to serve different purposes that affect our lives, and this role is enhanced by advanced development of genetic technologies.

We have also expanded the proposed learning progression to include elementary grades as well, because data from students’ questionnaire and interviews revealed that a large number of grade7students showed familiarity with the notion of genes and traits, held many genetics misconceptions and were interested in knowing more about new innovations in genetic engineering. Additionally, it is well known that genetics instruction constitutes an integral component of non-national biology curricula adopted by several Lebanese private schools at the elementary level. For these reasons, different levels of progressions than those utilized by Duncan et al. (2009) were used. This subtle change was done to reach better alignment of the proposed genetics content and sequence with the cognitive levels of students in the four cycles of schooling as mandated by the Lebanese Educational system and to ensure its inclusion within school genetics curriculum. Drawing on the above facts, our designed learning progression embraces five levels which target students at different grade levels who have different knowledge and experiences that influence their learning: 1) level 1: KG-3; 2) Level 2: 4-6; 3) level 3: 7-8; 4) Level 4: 9-10; and 5) Level 5: 11-12 (Appendix V).It is important to note that the genetics concepts to be taught for students who are at levels 1, 2, and 3 in Duncan’s (2009) learning progression coincided with levels 3, 4, and 5 respectively of this study’s learning

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progression. These modified levels of the proposed learning progression were defined in terms of the concepts and knowledge that students should demonstrate at different grade levels, i.e. instructional objectives and analysis of domain (upper anchor). The lower anchor of the learning progression is described based upon research on students’ understanding defined for a preceding stage of schooling (e.g., middle school learning objectives may be used to define the lower anchor for a secondary school). The intermediate steps are identified in terms of difficulties encountered by Lebanese students in studying genetics as revealed by data collected from students’ and teachers’ questionnaires and interviews, and previous research on common students’ misconceptions in genetics as reported by researchers in this domain. This systematic organization of the core and sub-core ideas for each level along the learning progression helped in the development of evidence-based scope and sequence of the genetics concepts for the new genetics curriculum. Therefore, the next step in designing the learning progression was the development of a detailed description and sequencing of the core and sub-core ideas across the five grade levels. In writing the new sequence, we have also considered the mapping proposed by the National Research Council on reforming K-12 science education (2010) and the AAAS Atlas of scientific literacy in the same domain. For each level, we posed a specific question which can help curricular developers view the link of core idea and its sub-core ideas to a certain biological phenomena of the world. For example, Table 4 shows questions that were addressed in activities that dealt with the origin and inheritance of traits. Refer to Appendix V for the whole sequence of the learning progression.

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Table 4 Questions Addressed in Each Grade Level for the “Origin and Inheritance of Traits” Grade Levels Level 1: KG.-3

Questions How are parents and offspring alike?

Level 2: Grades 4-6

Do parents and offspring have similar cells that carry similar functions? Why do offspring resemble their parents?

Level 3: Grades 7-8

How are the inherited characteristics distributed to offspring?

Level 4: Grades 9-10

How are the inherited characteristics stored inside the nucleus and distributed to offspring?

Level 5: Grades 11-12

How does the genetic information which is stored within the chromosomes of a cell determines our traits?

Furthermore, our proposed learning progression suggested several sub-core ideas that would help 12th graders exhibit a better understanding of the relationship between two highly interrelated major biological themes: Natural Selection and Variation of Traits. These recommended sub-core ideas, which are presented below, are in fact related to the notion of evolution which has been deleted from the 12th graders biology curriculum. 

Some DNA sequences can vary between species while others do not; therefore, we share some genes with other species.



Changes in environmental conditions can affect the survival of individual organisms and entire species.



Natural selection leads to organisms well suited for survival in particular environments. (related to variation and advantage)



Spontaneous mutations provoke genetic variations in the population of bacteria. Some of these newly formed bacteria develop resistance to antibiotics. The application of

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antibiotics to these resistant forms of bacteria permits their development. Thus, treatment with antibiotics would increase the frequency of these resistant forms by natural selection. (related to natural selection and evolution) 

Offspring of advantaged individuals, in turn, are more likely than others to survive and reproduce in that environment. The proportion of individuals who have advantageous characteristics will increase, thus, natural selection alters allele frequency.(related to gene population)



The continuing operation of natural selection on new characteristics and in changing environment, over and over again for millions of years, has produced a succession of diverse new species. (related to evolution)



Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow its survival. (related to evolution)

Designing a New Genetics Curriculum based on the Learning Progression Following the development of the learning progression, a highly descriptive learning progression - driven genetics curriculum document was designed for the intermediate and secondary levels. Much effort was exerted to translate the key and sub-key ideas in the learning progression into a content-based curriculum. The proposed genetics curriculum document included a set of chapters and activities, accompanied by their corresponding learning objectives for each grade level (Appendix VI). Evaluating the developed learning progression. In order to assess the quality, feasibility and reliability of the designed learning progression, a questionnaire was administered to four experienced biology teachers who have over 20 years of teaching experience (Appendix VII). The first five items of the questionnaire dealt with background information about the

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teachers. Items 6-16 addressed teachers’ perceptions of the degree of alignment between the content of the learning progressions and students’ cognitive level, the logical sequencing and coherence of the content and the extent to which the content enhanced students’ genetics understanding and dealt with updated genetics issues. For each of these items, teachers responded with “agree” or “disagree”. The inter-rater reliability of these items was measured by Cronbach’s alpha and a value of .73 was obtained. In item 17, teachers were asked to propose a sequence of genetics topics that should be provided for each grade level. These teachers were also asked to independently evaluate the proposed new sequencing of the genetics content, and to suggest changes, additions, or deletions of any instructional objectives or genetics concepts, whenever they found it appropriate. Based on the feedback received, two concepts that were considered difficult to teach to grade 7 students were eliminated. Additional modifications were made on the concepts that targeted grade 8 students (13-14 years) to make the content more aligned with the level of students’ understanding at this age group. The designed learning progression was revised and the finalized version is presented in Appendix VIII. Designing a learning progression-driven genetics unit. For the purpose of this study, only a detailed genetics unit was designed and implemented for grade 9 students. Although the data collected from students’ and teachers’ questionnaires and interviews revealed a need for improving the genetics curricula for all grade levels, the grade 9 textbook particularly needed significant improvement. Before designing the actual teaching unit, possible genetics misconceptions associated with each big idea were identified in order to insure the development of a unit that would took into account students’ misconception. For this purpose, an extensive literature review of studies addressing students’ genetics misconceptions was conducted (Kindfield, 1994; Lewis et al, 2000; Marbach-Ad, 2001; Marbach-Ad & Stavy, 2000; Stewart et

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al., 1990; Venville & Treagust, 1998; Wood- Robinson, 2000). The obtained list of misconceptions (Appendix IX) can be considered a guide to help teachers in planning their instruction and constructing assessment items. The newly designed teaching unit reflects a non-traditional scope and sequence of content which is driven by results of the first phase of this study, findings from current research on teaching and learning genetics and students’ common misconceptions in the field. It also includes several features to promote deeper understanding of genetics such as: 1) contextualizing the content whenever possible; 2) including a research and technology section at the end of each chapter; 3) providing descriptive statements of learning objectives for each activity; and 4) using multiple external representations that clarify abstract genetics concepts and processes. In writing the teaching unit, we have adopted the same organizational structure presented in the French Baccalaureate biology student textbooks which show a great resemblance to the organization of the Lebanese National student biology textbook. The designed teaching unit was reviewed by three experienced biology teachers and a research assistant. Based on the feedback received, several modifications were done. The final version of the genetics teaching unit and material for grade 9 is illustrated in Appendix X. Content organization of the learning progression - driven genetics unit. The newly designed genetics unit consists of 4 chapters: 1) Human traits and nature of genetic information, 2) Chromosomes, genetic information and traits, 3) Transmission of genetic information, and 4) Variation of traits. Chapter 1 has three activities/lessons which provide examples of observable and non-observable human traits, identify the nature of genetic information and its localization in a cell, and clarify the relation between chromosomes and DNA. We have started chapter 1 by providing concrete examples of traits at the macroscopic level to help students understand the

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concept of traits before dealing phenotypes at the molecular and cell level which are considered unfamiliar to many students. In this chapter also, students are expected to perform lab experiments for observing chromosomes and their constituents, DNA. Chapter 2 consists of four activities which guide students through direct analysis of human karyotypes abnormalities to infer that chromosomes are themselves the carriers of genetic information and illustrate the organization of genetic information in chromosomes by providing familiar personal examples such as blood groups and skin color. Furthermore, this chapter clarifies the connections between genes, proteins, and traits with specific examples of common genetic diseases such a cystic fibrosis and sickle cell anemia. The molecular basis of a certain disease such as sickle cell anemia is explained in terms of the hemoglobin gene and the hemoglobin protein product which leads to the deformation of red blood cell (microscopic phenotype or trait). Ultimately, this approach will allow students to view the gene-protein-trait link in a more coherent way rather than seeing genes, proteins and traits as distinct entities studied in entirely separate activities as presented in many traditional biology text books. We also attempted to identify phenomenological examples in a biological context which are personally meaningful and relatively easy for students to understand. For example, cystic fibrosis was presented within an informational text on Cystic Fibrosis Association of Lebanon (CFLB) to contextualize the concept and motivate students. Additionally, this chapter addresses three essential genetics notions which are absent from the existing 9th graders genetics curriculum, despite their importance in favoring deep understanding of some major genetics phenomena. These notions are: polygenic inheritance, gene expression and gene regulation. Two techniques: genetic fingerprints and amniocentesis were also presented in the research and technology section to increase students’ awareness of some genetics - related innovations that help identify

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chromosomal abnormalities and detect relatedness among individuals. Also, in this chapter we introduced a genetic computer program “Biologica” which is considered by many researchers a very useful and interesting educational tool that enhances and deepens students’ understanding of genetics. Under the same section, we provided examples on careers in genetics that might help students think of future careers in this discipline. Chapter three includes two activities which describe the behavior of chromosomes during cell division and the main events of mitosis. We highlighted the importance of mitosis for our body and revealed how uncontrolled cell division might lead to cancer. In this same activity on mitosis, we included an informational text about the Lebanese National campaign for breast cancer in an attempt to motivate students and present the content in a more personal meaningful way to students. Furthermore, to increase students awareness of some ethical and moral issues associated with mitosis, we included under the section of research and technology readings about uterine cancer, cloning and some carcinogenic substances and encouraged students to provide their point of view regarding these issues. The fourth chapter, variation of traits includes 4 activities which describe the mechanisms behind genetic variations among species in a given population. Activity 1 addresses variations in terms of alleles; where we provided examples of traits in increasing levels of complexity beginning with two alleles trait (hair aspect: curly and smooth), to 3 alleles trait (blood type) and ending up with more variations (3 and more alleles) of a given trait in a population. In Illustrating the ABO blood group system, we focused on the relation between alleles, proteins and blood group traits to reinforce the understanding of the genotype-phenotype relation covered in chapter 1. We also described the pattern of inheritance of ABO traits which is influenced by the specific relationship between the alleles (dominant, recessive, co-dominant).

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The third activity of this chapter illustrates the need for a reduction division, meiosis, for the formation of gametes and continuity of the species and explains how errors during meiosis lead to new traits, in this case leads to abnormalities, and consequently to more variations (Down syndrome, Klinefelter syndrome, Turner syndrome…). It is worth noting that students are not expected to study in excessive details the steps of meiosis, rather; the focus is centered on understanding that meiosis in sexual reproduction is another cause for human diversity. To simplify this notion, we provided as an example the inheritance of blood group and Rhesus factor from parents to offspring. Then, we showed students the localizations of the two genes associated with these traits on chromosomes of gametes and how the different recombination brings offspring with similar or new phenotypes than those found in parents. The last and fourth activity deals with the interaction between environmental factors and genes as another cause for the variation of traits observed among us and elaborated the idea that not all genetic diseases are hereditary ones. We found it very useful to clarify these genetic notions in which many students hold misconceptions either due to the absence of these notions from the existing genetic curriculum or due to inaccurate information and facts revealed by the surrounding media or family discussions. Again, these concepts and notions are explained using familiar phenomena relevant to students’ lives such as obesity and the increased number of RBCs among the soldiers of Lebanese army who have missions at places with high altitudes. Descriptive features of the designed learning progression- genetics unit. This 8- week teaching unit (3 periods/ week) included many features designed to 1) provide a better sequencing and organization of concepts which favors a better student understanding of genetics,

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2) motivate and increase student interest in genetics and 3) help teachers provide high quality instruction. Below is a description of these major features. Instructional objectives. Several learning objectives that are aligned with the identified core and sub-core ideas are presented at the beginning of each activity. These objectives can be useful means that guide instruction and student learning. Moreover, the specified learning objectives help organize the developmental progression of activities associated with the concepts covered in each activity and design appropriate assessment questions that measure the level of students’ understanding of that content. Driving questions. Each chapter starts with an introductory paragraph which poses a meaningful and relevant question that directs students thinking to the concept to be learned and favor engagement in classroom discussion. Examples of these questions are: How would you explain the similarities and differences which exist among human beings? How do chromosomes determine the inherited characteristics of individuals? What mechanisms cause genetic variability? Also, central to this work was the introduction of questions that precede the introduction of any new genetic concept or notion within each activity. Examples of these questions are: Can the normal gene be modified? Do all organisms have the same number of chromosomes? How do you explain that cells with same genetic information exhibit different structures and functions? The purpose of the integration of meaningful driving questions was to raise students’ interest and stimulate their thinking regarding the investigated biological genetic phenomena and to avoid revealing the content as a mere collection of facts as presented in many traditional biology text books. Examples/phenomena. A challenging task in designing the curricular unit was to incorporate meaningful and interesting examples or genetics phenomena that support students

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learning of most abstract genetics concepts. A further challenge was the sequencing of all activities with their associated phenomena in a way which manifests coherence among concepts that would foster more sophisticated way of student thinking about the content. Biological phenomena were presented in a simple form that matches students’ cognitive level at this age and provide traits so familiar to the students such as eye color, sickle cell anemia, and skin color. External representations. Data collected from students’ and teachers’ responses on questionnaire and interviews showed the need to incorporate good quality representations that help students get a better understanding of the learned concepts. Indeed, the teaching unit was enriched with clear and illustrative figures, drawings, and pictures that would provide students with a better opportunity to make sense of the abstract genetics concepts. Enrichment activities. The newly designed unit includes a list of useful resources (handouts activities, simulations, virtual labs, web sites…) under the section entitled “Research and technology” of each chapter to enable students extend their knowledge and deepen their understanding of the learned concepts. Assessment items .In addition to the probing questions presented at the end of each activity, a set of exercises that help students evaluate their understanding of the learned concepts for each chapter was developed. These diagnostic and summative assessments items were organized in increasing complexity from simple multiple choice questions which measure understanding (low thinking skills) to analysis and reasoning (high thinking skills) where students make predictions, analyze data and provide justifications for observable traits. It is worth noting, that many of these questions were adopted and adapted from assessment items used in several SVT French Baccalaureate student biology textbooks.

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Summing up. A review section that summarizes the main genetic notions and processes learned in each activity for a given chapter was included. This summing up would help students re-visit the main genetic notions and review for exams. Learning progression- driven genetics unit versus existing genetics unit. A comparison between the existing grade 9 genetics curriculum and the learning progressiondriven genetics unit was done in terms of: learning objectives, content, number of chapters and activities, and the sequence of lessons and genetic concepts within and between activities (Appendix XI). This appendix also reveals the content alignment of the designed genetics unit with the key and sub-key ideas of the proposed learning progression. Figures 3 and 4(a and b) summarize the sequencing of genetics concepts as presented in the genetics unit developed by CERD and the LP-driven genetics unit respectively. In developing the learning progression–driven genetics unit, we have used as a reference point the key and sub-key concepts identified previously in the proposed learning progression. As stated previously, the selection and sequencing of the genetics concepts were based primarily on findings derived from phase I of this study and other research studies done in the same field. For example, Mendel’s work which is the first teaching activity in the existing genetics curriculum for 9th graders is not tackled in the new genetics unit. We agreed with other researchers on delaying the teaching of Mendel’s laws until students show deep understanding of gametes and segregation of chromosomes during meiosis. Rather, we started the genetics unit by illustrating examples on traits observed at the level of the organism and then, investigating the cause of parents resemblance to their offspring. This was followed by a thorough explanation of the relation between gene, DNA and chromosomes which is usually considered a difficult relation by most students. Furthermore, in the new unit mitotic phases are introduced after

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Fig. 4a. Sequence of concepts within and between chapters of the LP- driven genetics Unit for the key idea: Nature of Genetic Information and Traits

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Fig. 4b. Sequence of concepts within and between chapters of the LP- driven genetics Unit for the key idea: Inheritance and Variation of traits

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explaining the idea of duplication and condensation of chromatin material needed to conserve the number of species; this sequence is reversed in the existing genetics unit. More importantly, the new unit includes additional concepts (shown in italics and bolded) related to gene regulation, role of proteins as intermediary products between genes and traits, and interaction between genes and environment that are all absent from the existing genetics unit, and which are considered by many researchers essential to strengthen student understanding of major genetics phenomena. Implementing the Learning Progression-Driven Genetics Unit Participants. An essential step in the work on the learning progression was the empirical validation of the learning progression-developed teaching unit. For this purpose, the researcher contacted the same six cooperating schools which were involved in the first phase of the study before the beginning of academic year 2012-2013. The researcher explained the intervention phase of the study and asked if they were willing to participate in the study. Of these six cooperating schools, only two schools accepted to participate in the intervention. There were two main reasons behind the principals’ unwillingness to participate: the grade level in which the study was to be conducted and the time of intervention. These school principals were against involving grade 9 students in any new learning experience that could hinder the completion of their teaching programs on time and distract the biology teacher from the thorough preparation of students for the official exams. Additionally, three of the participating schools teach the genetics unit at the end of the academic year (April-May) and thus refused to re-schedule its teaching at the beginning of the academic year which was the proposed time for conducting the study. Moreover, of the two schools that accepted to implement the teaching unit, one (a public school) claimed that no additional time could be given in case the intervention required more teaching

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hours since the biology teacher needed to finish the biology program early before taking her maternity leave during May. The discrepancy between the time allotted for teaching biology between public (2 periods/week) and private (3 periods/week) schools was also a major factor for not being able to conduct the study in the public schools. However, the principal of the private school located in Saida, who is also a biology teacher, accepted to cooperate and implement the intervention. In order to select which two classroom sections (out of the three that existed in the school) would be involved in the intervention the following was done: the letters A, B and C were randomly assigned to the three grade nine sections in this participating school; then, a control group (section A) and an experimental group (section B) was selected. These two groups were taught by the same biology teacher who is the only teacher for this grade level at this school. A total of 20 students were in the control group and 19 students were in the experimental group. Data collection tools and procedures. The implementation and collection of data for the intervention can be divided into three separate chronological stages: the pre-intervention stage, the intervention stage and the post-interventions stage. A summary of these stages is presented in Table 5 and a detailed description of each stage is provided in the following sections. Pre-intervention stage. During the pre-intervention stage, the researcher held two meetings with the biology coordinator and the grade 9 teacher to discuss the features of the learning progression-driven genetic unit and some effective ways for the enactment of the unit concepts. A rationale for the new sequence of the chapters and activities was provided. In addition, common student misconceptions in genetics and issues related to instructional strategies and instructional time were addressed. A constructivist teaching approach was advocated whereby students actively engage in classroom discussion, discourse and practices of

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scientific inquiry to construct and build their own knowledge. Moreover, the teacher was stimulated to create a positive and safe classroom environment that would encourage students to ask questions, make predictions, analyze data, construct explanations and conduct experiments. The biology coordinator and the teacher implementing the study were given two weeks to review the unit in case additional clarification and support were needed. The proposed teaching time (24 teaching periods) was discussed and the biology teacher claimed that a few additional teaching periods might be needed in order to complete the unit at the same time as the control group. There was consistent contact (weekly meetings, e-mails, phone calls…) with both the biology coordinator and the teacher to reflect continuously on the impact of the new teaching materials and practices on student learning. Students in both the control and experimental groups were informed about the purpose of this study together with their parents. Section B students (experimental group) were taught using the newly designed genetics unit, while section A students (control group) were taught using the existing genetic unit presented in the national biology textbook. After explaining the purpose of the study to the students, students in both sections were administered a pre-test that assessed their content knowledge and genetic literacy of a range of key ideas specified by the learning progression. The pre-test consisted of a total of 10 questions which included both multiple choice and open-ended items. These items were drawn from the AAAS project 2061 assessment items and from test items written and piloted by Lewis et al. (2000a, 2000b, 2000c) and Sadler and Zeidler (2005). All question items were aligned with the designed learning progression covering the two key ideas and their corresponding sub-key ideas (see Table 6). This helped in determining the achievement level of students along the proposed

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learning progression and in exploring ways to help students progress towards achieving the targeted learning objectives. The pre-test is presented in Appendix XII. Table 5

Post- intervention Stage

Intervention Stage

Pre- intervention Stage

Summary of the Stages of Implementation of the Teaching Unit Intervention

 Discussion of content with the biology teacher  Informing students about the aim of the study

 Analysis of students’ responses on quizzes and tests  Weekly meeting for reflection

 Administering post-test to experimental and control groups

 Administering Pre- test for the two sections  Data collection and scoring of students results  Analysis of students answers and comparing results

 Classroom observations: videotaping, if possible, to analyze teachers practices and pedagogy and assess the level of students interest and class

 Focus groups Interviews to determine students’ perception of the genetic unit  Teacher interview to determine her perception of the new unit and

suggestions

 Teachers’ questionnaire to compare the effectiveness and quality of the designed LP-driven genetic unit with the existing genetic unit

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Table 6 Key Ideas Measured by the Questions in the Pre-test Question

Key idea(s)

I

- All organisms are made up of cells and contain chromosomes and genetic information

II

- The genetic information is hierarchically organized. - Relation between chromosome, gene, DNA and allele

III

- Genes determine same traits have the same locus on homologous chromosome. - Relation between gene, allele, chromosomes, chromatid, and homologous chromosomes

IV

-

V

- All body cells of an individual have the same genetic information (same DNA) but different cells use (express) different genes

VI

-Proteins have a central role in the functioning of all cells in living organisms and they are the connection between genotype and traits - Both an organism's physical characteristics and the function of the organism's cells could be influenced by the actions of protein molecules in an organism's cells

VII

- Chromosomes X and Y vary in boys versus girls - Changes to the genetic information can cause changes in traits - A somatic cell is a diploid cell with two identical sets of chromosomes, except for X and Y chromosomes, any deviation in the number of its chromosomes can be detected by karyotype - Errors in the separation of chromosomes might occur during meiosis and lead to new phenotypes which could be harmful

VIII

- There are patterns of correlation between genes and traits and there are certain probabilities with which these patterns occur

IX PART 1

PART 2

X

All somatic cells contain the same genetic information The same genetic information is found in similar types of cells of different organisms Sex chromosomes are found in all body cells and sex cells Each sperm contains a unique combination of genetic information.

- In mitosis, the dividing cell and the two daughter cells derived from it contain the same genetic information - Mitosis ensures the proper growth of an organism ( whether animal or plant) and the renewal of dead and injured cells - Each chromosomes is one DNA molecule -Genetic information in the form of DNA is transferred from parents to offspring during sexual reproduction - Meiosis leads to the formation of haploid sex cells or gametes - A sex cell of an organism contains half as many DNA molecules as a fertilized egg cell of that organism - In sexually reproducing organisms, such as humans, half of the chromosomes contain genetic information from one parent and half from the other parent. - Some traits are complex traits determined by several genes and environment - Environmental factors can interact with our genetic information and alter phenotype

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Intervention stage. The biology teacher began her teaching with both the control and experimental group on September 15, 2012, for three 50-minute sessions per week. The control group completed the program in mid-December while the experimental group reached the end of December with an additional six periods left to complete the program. The whole study, which was expected to finish by the end of November extended due to several uncontrolled factors (underprepared experimental group; teacher strikes and holidays during the intervention period). During the intervention, the researcher held weekly meetings with the biology teacher and coordinator. The purpose of these meetings was to evaluate the new teaching unit, discuss student’s progress and difficulties that they may have encountered. These meetings were considered one aspect of on-site teacher training that enabled the researcher to discuss effective strategies (inquiry-based learning, problem solving, jigsaw, wait-time I and II questioning techniques…) that would ensure proper teaching of the genetics unit and identify possible solutions to major problems encountered in its implementation. Moreover, the researcher attended several class sessions (10 periods) in the experimental section during the enactment of the designed genetic unit to collect data that would help analyze the type of teacher-student discussion, level of student engagement; assess teacher use of the new teaching material and describe teaching practices that had supported or inhibited student learning. It is worth noting that classroom observation was done as an alternative approach to classroom video-taping since the later was not feasible to do during the study. Since a design-based approach was adopted in this study, data collected during the implementation of the study were deemed useful for future improvements on the learningprogression based unit. According to Wang and Hannafin (2005), design-based research is “a systematic but flexible methodology aimed to improve educational practices through iterative

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analysis, design, development, and implementation, based on collaboration among researchers and practitioners in real-world settings, and leading to contextually-sensitive design principles and theories (page 6). Thus the researcher’s involvement in the implementation of the intervention was an integral component on this design based-approach. However, time constraints allowed only for one iteration to be implemented. Post-intervention stage. Three sources of data were used to help assess the quality and effectiveness of the implemented genetics unit: a post-test, student focus groups and teacher questionnaire. This data triangulation was used to help provide a more comprehensive evaluation of the implementation of learning progression-based unit from different perspectives. Post-test. One week following the completion of the intervention, the researcher administered a post-test which was identical to the pre-test administered at the beginning of intervention for both the experimental and control groups. The researcher was interested in determining whether or not the genetics instruction based on the learning progression-based unit yielded higher achievement for most students and to ultimately assess the validity of the proposed learning progression-based unit in describing a path that most students progress through when learning genetics. Student focus groups. Another source of data used for evaluating the new genetics unit was conducting a focus group with students. First, the researcher secured the school principal’s permission to conduct focus groups with students. Then, one week following the administering of the post-test, two separate focus group interviews were conducted with 10 students from each of the control and experimental groups. Students were selected through stratified random sampling whereby they were first grouped according to their academic performance (as measured by their biology grades) as: very good, good, average, below average and weak. Then,

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the biology teacher randomly selected two students from each category to ensure that the sample was representative of the full range of abilities in the class. The aim of forming these focus groups was to explore students’ opinions and attitudes regarding the genetics unit. The focus group also aimed to identify the strengths and weaknesses of the newly designed genetics unit so that further improvements may be made in future implementations of the unit. Each focus group interview lasted for 50 minutes and took place during students’ physical education period and recess time. Students were highly motivated and cooperative in answering the six open-ended questions (Appendix XIII) which were read out loud to the group in the same order that they were written by the researcher. The researcher herself read each question and allowed time for each student in the focus group to state his/her opinion. In some cases, students were asked to clarify and provide evidence to support their answers. Both focus groups were audio-taped for later coding and analysis. Teacher questionnaire. Four biology teachers (teachers E, F, G and H) were given a questionnaire that aimed at evaluating the genetics unit presented in the national biology student textbook (CERD series) and the newly designed genetics unit in terms of seven main areas: 1) content alignment with instructional objectives, 2) content coherence: connection among key ideas, 3) content coherence: connection to pre-requisite and related ideas, 4) developing and using scientific ideas, 5) genetic literacy, 6) problem solving and reasoning and 7) assessing progress (Appendix XIV). It should be noted that two of these four teachers, one of whom was the teacher who implemented the unit (Teacher E), were involved in the validation and evaluation of the designed learning progression. The questionnaire included a checklist which consisted of 26 items whereby teachers responded with “Agree” or “Disagree”, and 3 openended questions. The development of the checklist was based on methods used by other

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researchers in analyzing biology curricula such as Project-2061 (AAAS, 2005), Roseman, Stern and Koppal (2010), and Bowling et al. (2008). Before evaluating the unit the researcher explained the definition of each component of the checklist and used one lesson from grade 9 as a sample to illustrate the use of the checklist. Afterwards, each teacher was given one week to apply the same process in evaluating the quality of the two curricula using the same checklist. Data Analysis Procedures Pre/post-test. In order to analyze the pre- and post-tests, students’ responses on each item were first marked as either correct or incorrect. The correct responses for each question are presented in an answer key in Appendix XV. The frequencies of correct and incorrect responses for both the pre- and post-tests were calculated for each question. Then, the percentage of correct responses was determined for each question for the pre and post-tests. It should be noted that the percentages were calculated based on the total number of students that answered rather than the total number of students that completed the pre/post-test. In other words, blank responses were not considered as valid answers. This was done for the following reason: since the researcher was not present when the students were filling out the pre/post-test, it was not possible to determine whether or not students’ blank responses were due to a lack of understanding or merely due to time constraints. For each question, two levels of comparisons between the experimental and control groups were done:1) performance on the post-test as represented by the percentage of correct responses on the post-test and 2) the extent of knowledge gained in each group as determined by the difference in the percentages of the pre-test and post-test further analysis of data collected from the pre-post-test was done. The total number of correct responses for each student was computed. Then, an average score was determined by dividing the number of correct responses

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by the total number of questions answered. This was done for the pre and post-test in both the experimental and control groups. The difference between the pre and post-test mean scores was then calculated and represented by a % gain. The significance of the % gained was determined using a paired samples t-test between the pre and post-test. This method of data analysis was used rather than a statistical test because we were interested in detailed comparisons between the experimental and control groups. It is worth noting that the large number of items which measured a wide range of genetics concepts on the pre-test and post-test did not allow for the use of a t-test to compare the experimental and control groups due to the risk of accumulating errors. In addition, since a large portion of the test items were left blank, the validity of the t-tests would also have been affected. Student focus groups. In order to analyze the focus groups, the audio-tapes were transcribed and then coded. The coded responses were closely examined and categorized under themes and concepts in order to determine similarities or differences in students’ views from both focus groups of the newly designed genetics curriculum and gauge ideas for improvement. The analysis was completed by the researcher herself, an experienced biology teacher and an assistant researcher who separately analyzed teachers’ answers, categorized them into groups. Any disagreements on the categories were discussed until consensus was reached. Teacher evaluation questionnaire. Frequencies of each questionnaire item were used to describe the responses of the four biology teachers who evaluated the new genetics unit and the existing genetics curriculum. In addition, the average rating given by the four teachers in the seven main areas of the questionnaire was computed. The reliability of the questionnaire items as measured by Cronbach’s alpha was .80 for the CERD genetics unit and .52 for the newly designed genetics unit.

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As a summary, Table 7 below presents an overall description of the methodology used in the present study.

Table 7 Summary of the Methodology used in the Present Study Stage

Sample Phase One: Descriptive Design

Tools

Purpose

Data Analysis

Lebanese genetics curriculum for grades7-12

National Biology Textbook (NCERD) GLAI

Content analysis &GLAI(Genetic s Literacy Assessment Items)

729 students (grades 7-12) from 6 schools

Questionnaire

62 students (grades 7-12)

Interview

20 biology teachers and experts

Questionnaire

8 biology teachers

Interviews

Assess and evaluate the objectives and content of the Lebanese genetics curriculum for grades 7 -12 Assess students’ understanding of essential genetics concepts and the progression of this understanding across grade levels Uncover the way students view genetics and gain a more in-depth understanding of the difficulties encountered during genetics instruction Determine teachers’ perceptions of the existing genetics curriculum and the main difficulties encountered by students when learning genetics Gain more insight about the problems encountered by students when studying genetics and view their opinions regarding the existing genetics and suggestions for improvement

Descriptive statistics, independentsamples t-test, ANOVA

Analytical approach

Descriptive statistics

Analytical approach

82 Phase Two: Quasi-Experimental Design 4 experienced teachers, previous research

Stage 1 Preintervention

39 grade 9 students (19 experimental, 20 control)

Pre-test

Stage 2: During Intervention

Experimental group (19 grade 9 students)

Classroom observations

39 grade 9 students (19 experimental, 20 control)

Post-test

Assess the knowledge Descriptive gained by students statistics, gain after the intervention scores by comparing to pretest scores

20 grade 9 students (10 experimental, 10 control)

Focus group

4 biology teachers

Questionnaire

Obtain feedback from students on the new genetics unit and the already existing curriculum Evaluate the existing genetics curriculum and the new genetics unit

Implementation Phase

PreImplementation phase

Designed learning progression

Stage 3: Postintervention

On-site teacher training

Develop and evaluate a learning progression in genetics for grades 712 to guide the design of a new and coherent genetics unit for grade 9 Assess students’ understanding of key genetics concept prior to implementation of the new genetics unit Evaluate the quality of the designed genetics unit and reflect on the difficulties encountered by students/teachers during implementation

Descriptive statistics

Descriptive statistics, gain scores

Analytical approach

Analytical approach

Descriptive statistics

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CHAPTER IV RESULTS This chapter presents the results of this study in two main sections. The first section provides the results of the analysis of the data collected before designing and implementing the new genetics unit. This section consists of the results of the following: student questionnaires, student interviews, teacher questionnaires, teacher interviews, and content analysis of the national genetics curriculum for middle and secondary schools. The second part of this chapter deals with the analysis of the data collected after designing and implementing the new genetics unit. This section includes the analysis of: student focus groups, teachers’ evaluation of the newly designed genetics unit and pre and post-tests. Results of Data before Implementation of the Newly Designed Genetics Unit Student Questionnaire The student questionnaire aimed to address aims 3 and 4 of this study (as presented in the introduction): #3 Identify the major misconceptions and difficulties encountered by Lebanese students during genetics instruction and #4 Compare the misconceptions and difficulties encountered by public and private school Lebanese students during genetics instruction. For the purpose of analysis of the student questionnaire, the following questionnaire items were grouped and presented together: student’s opinions (items 10-15), students’ misconceptions (items 1621), students’ level of conceptual understanding (23-33) and open-ended items (items 22 and 3438). In the following sections, the results of each group of items will be presented individually. Students’ opinions. Items 10 to 15 of the questionnaire investigated students’ opinions of genetics using a 5-point Likert type scale (1 = totally disagree and 5 = totally agree). Means and standard deviations for each item were determined at the level of the whole sample, by type

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of school (public and private) and by grade level (Appendix XVI). Results show that on average students partially agree that genetics concepts are interesting and meaningful (M = 3.94, SD = 1.16) and that genetic technology can improve the quality of life (M = 3.67, SD = 1.14). In addition, they agree that they rely on memorization to learn genetics (M = 2.64, SD = 1.28) and prefer avoiding cloning even if the intention targets curing human diseases (M = 2.93, SD = 1.50). Finally, students partially disagree that genetics concepts are difficult (M = 2.38, SD = 1.24). A comparison of the opinions of students in public schools and private schools reveals overall similarities. Some differences are found in the difficulty of understanding genetics concepts where students in private schools reported less difficulty (M = 2.04, SD = 1.05) than those in public schools (M = 2.66, SD = 1.31). In addition, students in private schools (M = 3.10, SD = 1.38) seem to be less favorable than public school students toward performing experiments on animals in order to treat human genetic diseases (M = 2.80, SD = 1.58). In order to determine the majority of students’ opinions by grade level, the frequencies and percentages for each item by grade level were determined. The frequencies are presented in Appendix XVII and the percentages are shown in Tables 8, 9, 10, 11, 12 and 13. Table 8 shows that most students in grades 7 (53.8%), 9 (63.7%), 10 (69.8%), 11 (70.1%) and 12 (88%) disagree that genetics concepts are difficult to comprehend. In contrast, 60.6% of the students in grade 8 agree that genetics concepts are difficult to comprehend. As for relying on memorization to study genetics, no grade level differences are evident where Table 9 shows that most of the students in grades 7 (53.4%), 11 (52.2%) and 12 (66.1%) disagree while most of the students in grades 9 (51.3%) and 10 (60.2%) agree. In addition, the percentages of students who disagree and agree are equal in grade 8 (50%). Students of all grade levels agreed that genetics is

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interesting and applicable to daily life whereby the percentages ranged from 85.4% in grade 8 to 94.8% in grade 12 (Table 10). Similarly, at all grade levels, most of the students agreed that applying genetic engineering principles and techniques would improve the quality of life with grade 12 having the highest percentage (94.7%) (Table 11).Table 12 further shows that a majority of the students in all grade levels agree that genetic technologies may have harmful effects (ranging from 67.9% in grade 7 to 81.1% in grade 9). Finally, Table 13 shows that most of the students in grades 7 (65.2%), 8 (54.5%), 10 (63.2%), 11 (56.5%) and 12 (66.6%) agree that animal cloning is unethical even for the purpose of treating human diseases. On the other hand, most of the grade 9 students (54.2) disagreed with this statement. A chi-square test was conducted to examine the relationship between grade level and students’ responses on each of the opinion items at the p < .05 level. In items where the chisquare value was significant, adjusted residuals were used in order to determine which cells were contributing to the significance (indicated by asterisks on the tables). The chi-square tests indicate a significant relationship between grade level and students’ responses on the following items: difficulty in understanding genetics concepts (2 (20, N= 715) = 103.5, p = .000), reliance on memorization when studying for genetic exams (2 (20, N= 706) = 32.412, p= .039), opinions on the use of genetic technology for improving the quality of life (2 (20, N= 697) = 41.776, p = .003) and opinions on the ethics of using animal clones as models for human diseases (2 (20, N= 683) = 59.673, p = .000). With regard to the remaining items the chi-square values were insignificant in which the chi-square values for each item were the following: find genetics content interesting and applicable to life (2 (20, N= 713) = 25.093, p = .198) and genetic technologies might have harmful effects (2 (20, N= 701) = 24.98, p = .202).

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Table 8 Percentages of Item 10 “Have Difficulty Understanding Most Genetics Concepts” by Grade Level Totally Partially Grade Disagree (%) Disagree (%) 7 27.3 26.5 8 14.1* 25.4* 9 27.4 36.3 10 36.0* 33.8 11 26.1 44.0* 12 62.1* 25.9 * Adjusted residual is significant

Agree (%) 28.0* 25.4* 14.2 14.0 10.4* 3.4*

Partially Agree (%) 12.1 23.2* 11.5 7.4* 17.2 8.6

Totally Agree (%) 6.1 12.0* 10.6 8.8 2.2* 0.0

Table 9 Percentages of Item 11 “Rely Merely on Memorization to Study Genetics for a Test” by Grade Level Totally Partially Disagree Disagree Grade (%) (%) 7 29.0* 24.4 8 19.1 30.9 9 24.8 23.9 10 15.4* 24.3 11 20.9 31.3 12 30.4 35.7 * Adjusted residual is significant

Agree (%) 22.1 25.0 28.3 25.7 22.4 14.3

Partially Agree (%) 9.2* 11.8 15.9 21.3* 17.9 14.3

Totally Agree (%) 15.3 13.2 7.1 13.2 7.5 5.4

Table 10 Percentages of Item 12 “Find Genetics Content Interesting and Applicable to Life” by Grade Level

Grade 7 8 9 10 11 12

Totally Disagree (%) 4.6 7.6 2.7 2.2 4.5 0.0

Partially Disagree (%) 6.1 6.9 8.0 3.7 8.2 5.3

Agree (%) 28.2 22.2 23.9 28.4 30.6 28.1

Partially Agree (%) 13.0 13.9 16.8 14.9 22.4 22.8

Totally Agree (%) 48.1 49.3 48.7 50.7 34.3 43.9

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Table 11 Percentages of Item 13 “Application of Genetic Technology to Different Areas Would Definitely Improve Quality of Life: by Grade Level Totally Partially Disagree Disagree Grade (%) (%) 7 2.3 3.8* 8 8.0* 11.7 9 1.8 9.9 10 6.0 12.0 11 1.6 11.8 12 3.5 1.8 * Adjusted residual is significant

Agree (%) 44.7* 22.6* 36.0 32.3 38.6 36.8

Partially Agree (%) 14.4 19.7 23.4 23.3 18.1 15.8

Totally Agree (%) 34.8 38.0 28.8 26.3 29.9 42.1

Table 12 Percentages of Item 14 “Genetic Technologies Have Harmful Effects” by Grade Level

Grade

7 8 9 10 11 12

Totally Disagree (%) 16.8 7.4 4.5 10.6 9.0 10.3

Partially Disagree (%) 15.3 19.9 14.4 11.4 18.8 20.7

Agree (%) 29.8 28.7 37.8 35.6 36.1 36.2

Partially Agree (%) 22.1 24.3 18.0 18.2 16.5 15.5

Totally Agree (%) 16.0 19.9 25.2 24.2 19.5 17.2

Table 13 Percentage of Item 15 “It is Unethical to Create Cloned Animals to Serve as Models for Human Diseases” by Grade Level Totally Partially Disagree Disagree Grade (%) (%) 7 24.2 10.6* 8 32.1 13.4 9 28.0 26.2* 10 20.0 16.8 11 27.5 16.0 12 16.7 16.7 * Adjusted residual is significant

Agree (%) 22.0 18.7 26.2 16.8 14.5 35.2

Partially Agree (%) 9.1 10.4 8.4 21.6* 22.9* 11.1*

Totally Agree (%) 34.1* 25.4 11.2* 24.8 19.1 20.4

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Students’ misconceptions. In the questionnaire, items 16 to 21 measured students’ misconceptions about specific genetics concepts on a 5-point Likert type scale (1 = totally disagree and 5 = totally agree). The reliability of these items as measured by Cronbach’s alpha was 0.34. This low value is due to the fact that each of these items measures a different genetics concept. For the purpose of determining students’ misconceptions, students’ responses were identified as correct or incorrect for each item. Items were considered correct if students answered “totally disagree” for all items except item 19 which was considered correct if students answered “totally agree”. The frequencies and percentages of correct and incorrect responses for each of these items by grade level were determined (Appendix XVIII). Bar graphs were then constructed to show the percentage of students in each grade level who gave a correct or incorrect answer for each of the items 16-21. These graphs were used to compare performance across grade level in order to identify any differences in students’ understanding of some fundamental genetics concepts. The bar graph for each item is presented below in Figure 5. The graphs generally show that students of all grade levels have high levels of misconceptions in certain genetics concepts as indicated by the high percentage of incorrect responses as compared to the percentage of correct responses especially in items 16, 18, 20 and 21. What is also evident in the latter items was that the percentage of correct responses tends to increase by grade level. More specifically, in item 16 which stated “change in DNA is always expressed and leads to harmful consequences on an individual” less than 10% answered correctly in grade levels 7 to 10. This percentage increases to reach 29.1 % for students in grade level 11 and drops back to 22.8% in grade 12. Most students did not answer item 18 correctly which stated “information in the DNA of a human does not affect the behaviors of the human”; however, there seems to be an overall increase in the percentage of correct responses by grade

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level where the peak occurred at grade 10 (49.2%). As for item 20 “each cell contains only the specific genetic information required for its function” and item 21 “all diseases which have genetic origin are hereditary diseases” the percentage of correct answers was very low ranging. In item 20, the percentage of correct responses increased from 16.5% in grade 8 to reach 38.9% in grade 12. Similarly, there was a general increase in the percentage of correct responses for item 21 where it increased from 6.2% in grade 7 to 19.3% in grade 12. In contrast to the previously mentioned items, in item 17 which stated “different cell types found in an individual’s body contain different DNA” the percentage of correct and incorrect responses was more or less equal. The graph shows that there was an increase in the percentage of correct responses from grades 9 (37.8%) to 12 (59.6%). Surprisingly, a high percentage of students in grades 7 and 8 responded correctly. Finally, the only item which had a higher percentage of correct responses than incorrect ones was item 19 “like humans, plant cells and fungi have genes that determine their traits” indicating a low level of misconceptions. Moreover, comparison by grade level did not reveal any clear pattern. In order to determine students’ level of misconceptions, the total number of correct items (out of the 6 total items) was determined. Then students were categorized as having low (five or more correct responses), average (four correct responses) or high (three or less correct responses) levels of misconceptions. Tables 14 and 15 show the frequencies and percentages of the misconception levels of students of the whole sample and by type of school, respectively. Table 14 shows that most of the students in all grade levels had a high level of misconceptions; however, this level decreased across grade levels from 94% in grade 7 to 79.3% in grade 12. The percentages in Table 15 further reveals that most students in all grade levels in both public and

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private schools have high levels of misconceptions and that this percentage decreases with an increase in grade level.

Item 16: Change in DNA is always expressed and leads to harmful consequences on an individual.

Item 17: Different cell types found in an individual’s body contain different DNA.

Item 18: Information in the DNA of a human does not affect the behaviors of the human.

Item 19: Like humans, plant cells and fungi have genes that determine their traits.

Item 20: Each cell contains only the specific genetic information required for its function.

Item 21: All diseases which have genetic origin are hereditary diseases.

Figure 5.Percentages of correct and incorrect responses of items 16 to 21.

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Table 14 Frequencies and Percentages of the Misconception Level by Grade Level for the Whole Sample High Grade 7 8 9 10 11 12

N 126 146 100 111 102 46

Average % 94.0 96.1 87.7 81.0 76.1 79.3

N 7 6 14 23 22 3

Low

% 5.2 3.9 12.3 16.8 5.2 5.2

N 1 0 0 3 10 9

% 0.7 0.0 0.0 2.2 7.5 15.5

Table 15 Frequencies and Percentages of the Misconception Level by Grade Level and Type of School

Grade 7 8 9 10 11 12

High N % 77 75 54 62 54 21

93.9 93.8 88.5 80.5 83.1 75.0

Public Average N % 4 5 7 13 8 2

4.9 6.2 11.5 16.9 12.3 7.1

Low N

%

1 0 0 2 3 5

1.2 0.0 0.0 2.6 4.6 17.9

High N %

Private Average N %

N

%

49 71 46 49 48 25

3 1 7 10 14 1

0 0 0 1 7 4

0.0 0.0 0.0 1.7 10.1 13.3

94.2 98.6 86.8 81.7 69.6 83.3

5.8 1.4 13.2 16.7 20.3 3.3

Low

Two further analyses were done with regard to students’ misconceptions. In order to determine if there was a statistically significant difference in students’ misconceptions between public and private schools, independent samples t-tests were conducted. In addition, for the purpose of determining if there was a statistically significant difference in students’ misconceptions across grade level, one-way ANOVA analyses were carried out. For these analyses, the total number of correct responses for items 16-21 was used (described previously). An independent-samples t-test was conducted to compare the mean number of correct answers for items 16-21 between public and private schools. Results showed that there was a significant difference at the .05 level in the mean number of correct items between public (M = 1.94, SD = 1.35) and private (M = 1.71, SD=1.43) schools with t (694.618) = 2.302, p = .022.

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This indicates that the level of misconceptions of genetics concepts varies significantly between public and private schools. Individual independent-samples t-tests were then conducted at each grade level to compare the mean number of correct answers for items 16-21 between public and private schools. The results revealed that there was a significant difference between public and private schools for grades 7 and 8 but not for grades 9, 10, 11 and 12 (details found in Appendix XIX). A one-way between subjects ANOVA was conducted to compare the effect of grade level on the mean number of correct responses for items 16-21 for the whole sample. The results indicated that there was a statistically significant difference in the mean scores of the six different grade levels at the p