Download Unit Design Title: Why do I look like this?

Unit Design
Capstone 2007- Joy Paul
Title: Why do I look like this?
Introduction/Description:
In this unit, students will investigate the connections between some of their
physical traits; how they look, and the source of those traits, their genes. By observing,
discussing, reading, role-playing and using technology, they will uncover some of the
laws and processes that govern inheritance. Students will understand that each cell in
their body contains the exact same genetic information passed down from parent cell to
daughter cell through the process of mitosis. Students will gain an understanding of
gamete formation via meiosis and how to predict genotypes and phenotypes. Students
will design and conduct an online experiment using virtual fruit flies to investigate the
concepts of inheritance, genotypes and phenotypes. A role playing activity will be used to
demonstrate the processes of transcription and translation. Students will be able to
determine how a change in a single base pair within their DNA can have phenotypic
effects at the whole organism level. Finally, students will discuss genetic testing and
therapy as they relate to ethics and Jewish law.
This unit will be taught to the 8th grade students of Saligman Middle School, a
Conservative Jewish Day School in the Philadelphia region. All students are of the
Conservative, Reformed or Reconstructionist Jewish faith. Jewish laws and values are a
mainstay within the school culture. Since all students study Jewish laws and values as
part of their daily classes, using the genetic defect which causes Tay-Sachs disease, a
disease primarily affecting Ashkenazi Jews, as part of this unit will help to increase the
level of relevancy for these students.
Unit Enduring Understandings:
To be able to answer the title question, “Why do I look like this?” students must
be able to understand the following:
1. Physical traits are the result of gene expression. These genes are found on the
chromosomes within every cell of an organism.
2. Genes are passed from one generation to the next using gametes. Punnett squares
can predict the outcome of gamete fertilization and the resulting traits.
3. Changing one gene on a chromosome may produce large changes at the organism
level.
4. There is an ethical component to genetic testing and therapy.
Each of these enduring understandings is tied very closely to Project 2061’s Benchmarks
for Science Literacy (American Association for the Advancement of Science, 1993)
found under the National Standards section below. While having an enduring
understanding about genetic testing and therapy may, at some schools, present cultural
issues, this EU will be explored within the classroom as it pertains to Jewish law.
Unit Essential Questions:
Certain questions will guide the students’ explorations within this unit. The
structure of these questions is further discussed in the body of this paper.
•
Why do humans have two basic types of cells, somatic and reproductive?
•
How do cells reproduce?
•
How do I inherit traits?
•
What do genes have to do with how I look?
•
How does a disease like Tay-Sachs happen?
•
How do I feel about genetic testing and therapy?
Skill Sets:
Other than the enduring understandings listed above, there are certain skills and
knowledge students will gain throughout this unit on genetics and inheritance. They are:
•
Students will be able to use a model to replicate the stages of a cell undergoing
the process of mitosis.
•
Students will describe meiosis, identify the stages, and understand the role chance
plays in gamete formation and fertilization. They will be able to use Punnett
squares to predict genotypic and phenotypic outcomes
•
Students will be able to model the processes of transcription and translation.
•
Using virtual fruit flies, students will be able to conduct an experiment on
inherited traits, predicting and explaining genotypic and phenotypic outcomes in a
correctly formatted lab report.
National Standards:
Genetics and heredity are key concepts that should be taught within the middle
school science curriculum. Specific content standards for genetics and heredity are stated
within Project 2061’s Benchmarks. The Benchmarks state that “Now (Grades 6-8) is the
time to begin the study of genetic traits-what offspring get from parents (AAAS, 1993).
Specific standards that will be addressed in this unit are:
1. In sexual reproduction, a single specialized cell from a female merges with a
specialized cell from a male. As the fertilized egg, carrying genetic information
from each parent, multiplies to form the complete organism with about a trillion
cells, the same genetic information is copied in each cell (Chapter 5 Heredity
section, Grades 6-8).
2. In some kinds of organisms, all the genes come from a single parent, whereas in
organisms that have sexes, typically half of the genes come from each parent
(Chapter 5 Heredity section, Grades 6-8).
3. Genes are segments of DNA molecules. Inserting, deleting, or substituting DNA
segments can alter genes. An altered gene may be passed on to every cell that
develops from it. The resulting features may help, harm, or have little or no effect
on the offspring's success in its environment (Chapter 5 Heredity section, Grades
9-12).
4. The genetic information encoded in DNA molecules provides instructions for
assembling protein molecules. Before a cell divides, the instructions are
duplicated so that each of the two new cells gets all the necessary information for
carrying on (Chapter 5 Heredity section, Grades 9-12).
5. In research involving human subjects, the ethics of science require that potential
subjects be fully informed about the risks and benefits associated with the
research and of their right to refuse to participate. Science ethics also demand that
scientists must not knowingly subject coworkers, students, the neighborhood, or
the community to health or property risks without their prior knowledge and
consent (Chapter 1, Scientific Enterprise section, Grades 6-8).
While two of the Benchmarks listed above are for grades 9-12, I have had previous
success within my 7th and 8th grade classrooms teaching this material in a somewhat
simplified version. The activities described within the unit plan below lend further
explanation.
Common Misconceptions:
The difficulties in teaching and learning genetics are well documented. Knippels,
Waarlo and Boersma (2005), report that genetics is one of the most difficult topics for
both students and their teachers. While students are expected to have the basic
understandings of inheritance as listed in the standards above, these concepts can be very
difficult to teach (Finnerty, 2006). Teacher knowledge of commonly held student
misconceptions is crucial to aide in choosing effective teaching methods to try to change
the preconceived notions of students. Student preconceptions most likely originate from
general experiences, such as noticing inherited traits in themselves, television programs,
books and/or magazines (Clough & Wood-Robinson, 1985). The “inheritance” of family
heirlooms or gifts may also contribute to student misconceptions toward the inheritance
of traits (Lewis & Kattman, 2004). Some relevant, specific student misconceptions are
described below.
In studies reported by Clough and Wood-Robinson (1985), almost 50% of
students interviewed do not even mention some sort of genetic component as a necessity
for an inherited trait. Only 7% have some understanding of the function of a gene. Lewis,
Leach and Wood-Robinson (2000) reported similar findings. A substantial portion of
their student sample had no understanding of the relationship between the genes and cells
within one individual. Student responses to a study conducted by Lewis and Kattman
(2004) suggest that traits and genes are more or less the same thing. Most students do not
recognize that a gene has a specific location on a chromosome (Lewis, et al., 2000).
Overall, students believe that the inheritance of traits can be explained by the transfer of
unchanged features or particles from one generation to the next (Lewis & Kattman, 2004).
Several misconceptions surround mitosis. The study conducted by Lewis, et al.
(2000) describes a basic premise held by 59% of the studied students that all cells contain
different chromosomes and each type of cell only contains the chromosomes it needs to
function. The authors of the study call for the necessity of students to recognize that
chromosomes are the organizers of genetic information, and that replication of
chromosomes during cell division is also a replication of genetic information that
determines traits. Each new cell must contain the same information as the parent cell.
Studying mitosis also helps students understand the concept that all cells of an organism
have the same chromosomes and genetic information based on the continuing process of
mitosis from the zygote (Knippels, Waarlo & Boersma, 2005).
Meiosis is also a topic that many students have difficulty understanding. Many
believe that reproductive cells carry the same amount of information as somatic cells
(Lewis, et al., 2000). There is often a lack of understanding as to the equality of parental
gene contribution (Clough & Wood-Robinson, 1985).
Using a role playing model within the unit to simulate transcription and
translation will help students move away from the common belief that developmental
defects, not gene mutation, are the primary source of intra-specific variation (Clough &
Wood-Robinson, 1985). Few students understand the difference between a gene and the
information within that gene. For example, many do not understand that there is a gene
for eye color, and that the gene may be for either brown eyes or blue (Lewis, et al., 2000).
In a study reported by Lewis and Kattmann (2004), 73% of the sample students
understood that genes were responsible for traits, but did not know the mechanism of
how that occurred.
To begin addressing these and other important student held beliefs, it is critical
that the study of genetics and inheritance be sequenced properly. Often meiosis is
separated from the study of inheritance and genetics. Little distinction is made between
the cellular processes of mitosis and meiosis. Students often have very little
understanding of how these processes relate to each other or inheritance (Knippels, et al.,
2005).
Unit Design:
Background:
To address these learning difficulties, a learning/teaching strategy described as the
“yo-yo” method was researched and developed by Marie-Christine Knippels (2002). In
the yo-yo strategy, students are led backward and forward between the levels of
biological organization and explore genetic concepts amongst these different levels.
Much like a yo-yo, the students go up and down the levels of biological organization,
always returning to the “hand” or main concept of the individual organism, themselves.
The unit study should begin at the organism level having students examine some of their
own and their families’ traits. This will help motivate students’ interest and help them
form meaningful questions (Knippels, et al., 2005). The yo-yo learning and teaching
design also has a problem posing component. By using class discussions to help elicit
meaningful questions from the students, a learning sequence is developed. The problem
posing structure helps to form the content structure. Problems are asked, explored and
answered in a systematic way that encourages further exploration. Students’ prior
knowledge is activated and discussed (Knippels, 2002). This problem posing approach is
a type of constructivist learning strategy described by Lijnse and Klaasen (2004).1 The
format of having students reflect on their answers and use them to develop new questions
allows the students themselves to examine their own conceptions and reflect on how they
fit into the scientific explanations being taught. This is an important step in enhancing
student learning of genetics (Lewis & Kattmann, 2004).
1
A schematic of the general design of formulating questions, designing activities and discussions, and
reflection of concepts learned for the yo-yo strategy is seen in Appendix A (Knippels, 2002, p. 147).
Introduction:
Standard addressed:
•
In some kinds of organisms, all the genes come from a single parent, whereas in
organisms that have sexes, typically half of the genes come from each parent.
(The concept of genes is not addressed here, but single parent vs. 2 parent
reproduction is.)
To begin the unit, students would be introduced to the unit question “Why do I
look like this?” This question forms the overarching theme of the unit, to help students
learn how inheritance patterns and their genes determine their traits. Although genes are
certainly not the only factor in determining one’s appearance, the unit focus will be on
genetics. Class discussion of environmental factors may occur after the completion of the
unit if there is time. An introductory questionnaire begins the unit.2
After filling out the questionnaire, a teacher led discussion would lead students to
realizing and verbalizing that although they may look similar to family members, they are
not identical. Students would be reminded of organisms studied earlier in the year that
did look exactly like their parents (for example, California Blackworm or paramecium).
In groups, students would reflect on these previous organisms studied in class, how these
organisms appeared as parental duplicates and how they, the students are not duplicates
of their parents. Each group would be required to come up with a question about the
differences between themselves and these organisms, such as: “What is the difference in
how those offspring were created versus the way I was created?” This is an example of a
“partial question” referred to in the yo-yo learning/teaching strategy (Knippels, 2002).
Each group would be given a large piece of chart paper to write and display the unit
question and their group’s partial question. All succeeding partial questions and answers
will be placed on this chart and displayed throughout the unit. This is an excellent way
for students to monitor their own learning progress, as well as giving the teacher an
opportunity to do so. The addition of answers to partial questions also provides students
with visual feedback and reminders as the class works toward answering the unit question.
2
An example of student questionnaire to begin the unit is seen in Appendix B.
Recall of asexual and sexual reproduction terminology would occur from the
previous units on different organisms. Discussions similar in format to the previous one
would lead to the formation of the next partial question: “What are the differences
between sexual and asexual reproduction?” This question leads students to the idea of
one parent versus two for the different types of reproduction. Asexual reproduction
would also be defined as mitosis. These questions and discussions guide students down to
the cellular view of genetics. This would conclude the introductory unit (1-2 days).
Cell processes-mitosis
EU addressed:
• Physical traits are the result of gene expression. These genes are found on the
chromosomes within every cell of an organism.
Standards addressed:
• In sexual reproduction, a single specialized cell from a female merges with a
specialized cell from a male. As the fertilized egg, carrying genetic information
from each parent, multiplies to form the complete organism with about a trillion
cells, the same genetic information is copied in each cell
• In some kinds of organisms, all the genes come from a single parent, whereas in
organisms that have sexes, typically half of the genes come from each parent.
• The genetic information encoded in DNA molecules provides instructions for
assembling protein molecules. Before a cell divides, the instructions are
duplicated so that each of the two new cells gets all the necessary information for
carrying on
This portion of the unit would begin by providing students with the partial
question: “What is the purpose of mitosis?” as they enter the room. Students would
engage in group discussions to write down some of their answers. “Í don’t know” is, in
this teaching method, an acceptable answer to a partial question before activities and
reflections occur. Using string and other supplies, students would begin modeling the
stages of mitosis.3 The National Science Education Standards (National Resource
Council, 1995) states that models are objects that correspond to real events, have
explanatory power and help scientists understand how things work. Students would work
in groups to use the materials to copy textbook diagrams of the stages of the cell cycle.
The diagrams would contain terminology used in mitosis to familiarize students with the
3
See Appendix C for a list of provided materials. Stickers with letters would be added to represent genes
on the chromosome strings. Reproduced from Clark & Mathis, 2000
terms. Onion root tip cells and whitefish blastula cells undergoing mitosis would be
available for viewing. Students would need to be told by the teacher that these slides
represent areas where these organisms are growing. Students would compare these slides
to the textbook diagrams. Student viewing of the following mitosis animation provides
another opportunity for students to view mitosis:
http://www.csuchico.edu/~jbell/Biol207/animations/mitosis.html. Using the different
methodologies described above and throughout the rest of the unit provides students with
many alternate routes to learning the stages of the cell cycle. Collaborative, hands-on
instruction between the students facilitates student learning of middle school science
content (Mastropieri, et al., 2006).
After having examined the slides and working with the models, students would
re-group to reflect and discuss the partial question. The teacher would circulate amongst
the groups to guide the discussions. Answers would be posted and would serve as a
formative assessment to see if students connect the process of mitosis with organism
growth and with the production of daughter cells containing the exact same number of
chromosomes as the parent cell. These collaborative discussions and activities lead the
students to these connections rather than being told by the teacher. Continued reflection
and partial answers to the unit question “Why do I look like this?” also provides
continued formative assessment as the students gain understanding about how genetics
and inheritance determine what they look like.
As a summative assessment on the stages of mitosis, student groups would use
the string and stickers materials from earlier in the class to demonstrate the stages of
mitosis. As the teacher called out stages and circulated throughout the classroom, the
students would work together to use the materials to demonstrate their ability to correctly
design their models in regard to number and placement of chromosomes throughout the
cell cycle. Each group would be able to reconfigure their materials until they were told by
the teacher that they were correct. This would conclude the mitosis unit (1-2 days).
Cell processes-meiosis
EU addressed:
•
Genes are passed from one generation to the next using gametes. Punnett squares
can predict the outcome of gamete fertilization and the resulting traits.
Standards addressed:
• In sexual reproduction, a single specialized cell from a female merges with a
specialized cell from a male. As the fertilized egg, carrying genetic information
from each parent, multiplies to form the complete organism with about a trillion
cells, the same genetic information is copied in each cell
• In some kinds of organisms, all the genes come from a single parent, whereas in
organisms that have sexes, typically half of the genes come from each parent.
Before continuing with meiosis, students would reflect on the process of mitosis
and its purposes by reviewing their posted charts from the previous days. Students would
be called to write on the board organisms they know that use mitosis to asexually
reproduce, guiding them to the realization that humans are not on that list. The next
partial question would form: “How do we reproduce?” To answer this partial question,
students would use the same materials as the mitosis activities to explore the steps of
meiosis. Appropriate terminology would be introduced via the textbook diagrams that
students use to create their string models. Computer animation of meiosis would also be
available to offer another alternative for students to learn the steps of meiosis.
Assessments of student knowledge about the process of meiosis would be the
same as for the mitosis activity described above. As another summative assessment,
students would be required to demonstrate their knowledge about the differences between
mitosis and meiosis be creating a chart or graphic organizer. The teacher would look for
the chart to include the number of steps, the number of daughter cells created, the number
of chromosomes in each, and the purpose of each process. The chart would be collected
and graded. This would conclude the meiosis unit (2-3 days).
Gamete fertilization and return to the organism level
EU addressed:
•
Genes are passed from one generation to the next using gametes. Punnett squares
can predict the outcome of gamete fertilization and the resulting traits.
Standard addressed:
•
In sexual reproduction, a single specialized cell from a female merges with a
specialized cell from a male. As the fertilized egg, carrying genetic information
from each parent, multiplies to form the complete organism with about a trillion
cells, the same genetic information is copied in each cell
As students enter the class, string and sticker materials are given to each group to
review meiosis. Class discussion about the purposes of meiosis would ensue. As
students reflected about the formation of haploid gametes, class discussion would
lead to the next partial question: “What happens to these reproductive cells that form
in meiosis?” Investigating this question would begin to lead the student back up to the
organism level. Different combinations of gametes would be explored as the process
of meiosis was repeated by the students using the string materials. All possible
gamete combinations would be listed by the students as they repeatedly model
meiosis. The teacher would circulate throughout the classroom, monitoring student
activity, asking students to think about how chance is playing a role in gamete
formation. The teacher would also check the student list of gamete combinations to
ensure that students are correctly separating the chromosomes during meiosis and
variation of gametes is occurring. Appropriate feedback to the student groups would
be provided as necessary.
String gametes from different groups would “fertilize” each other, helping
students see that the original number of chromosomes and genes were restored. The
fertilized cells that are created could again go through the process of mitosis, showing
the students how mitosis of the zygote then creates an equal number of chromosomes
in all body cells throughout the organism. Non-kinesthetic learners could draw
gametes from chromosome diagrams and use Punnett square diagrams to demonstrate
their understanding of gamete formation and fertilization. Having learned meiosis as a
predecessor to the formation and union of gametes, the Punnett square becomes a
learning tool rather than a meaningless mathematical exercise by showing students
where the gametes listed on the sides of the square came from. Students see that
filling in the Punnett boxes is the fertilizing of gametes and restoration of the diploid
number of chromosomes, not just multiplying terms as they may do in algebra class
(Knippels, et al., 2005).
As a summative assessment on gamete formation, students would be given several
lists of genotypes and asked to write down all possible gametes that could form. This
could be a written exercise, or re-use of string models to accommodate kinesthetic
learners. Continuing with using the answers to partial questions as a formative
assessment tool, students would reflect on the partial question, “What happens to
these cells that form in meiosis?” and be asked to write down and share new
questions that have formed. The teacher would look for student understanding that
these gametes fertilize each other to restore the full number of chromosomes and
genes in an organism. This fertilized cell then reproduces using mitosis.
Students would use their answers to all preceding partial questions to again
approach answering the unit question “Why do I look like this?” The teacher will
check student responses to see if they have included understanding of the following
concepts: that they look like they do because the have come from the meeting of an
egg and sperm, each with the same number of chromosomes which is half the original
number. Once fertilization occurred, the cell divided over and over using mitosis to
create all of the cells in their body. Teacher review of student reflections on the unit
question are a constant source of assessment in this model of learning. This would
conclude the fertilization unit (1 day).
Genes determine traits
EU addressed:
• Physical traits are the result of gene expression. These genes are found on the
chromosomes within every cell of an organism.
The yo-yo learning/teaching design would descend away from the organism level
down to the molecular level as transcription and translation are explored. Return to the
organism level would occur as the processes relate to phenotypic expression.
Class sharing of previous reflections and the ensuing discussion would lead to
the formation of the next partial question, “How do the chromosomes determine the
different traits in an organism?” It is here that students would refer back to their string
model or Punnett squares and be introduced to the idea of the stickers representing genes,
and whether the genes are dominant and recessive. The standard use of capital and lower
case letters to designate dominant and recessive genes would be shared with students.
Terms such as homozygous, heterozygous, dominant, recessive, genotype and phenotype
would be delivered in a standard lecture format. A brief written matching type quiz
would be used as a summative assessment to determine student learning of these
definitions.
To demonstrate their understanding of how the letters or genes on their models
are determining traits, students would form gametes, “fertilize” them with different
groups, and draw the traits of the organism that results based upon a gene/trait key
designed by the class. They would be assessed on whether the genotype of the fertilized
egg matched the drawn phenotypic traits. Used as a formative assessment, students would
practice drawing the physical traits created until the teacher told them they were doing it
correctly. The activity “Learning genetics with paper pets” (Finnerty, 2006)4 would be
an extremely fun, useful tool to aid and assess student learning. This activity would be
conducted through the creation of the F-2 generation. No mutations would be used at this
time. This activity would serve a summative assessment to determine student
understanding of how genotype determines phenotype. Reflection and posted, written
answers to the partial question would conclude the genes to traits unit (2-4 days).
Transcription and translation
EU’s addressed:
•
•
Physical traits are the result of gene expression. These genes are found on the
chromosomes within every cell of an organism.
Changing one gene on a chromosome may produce large changes at the organism
level.
Standards addressed:
• The genetic information encoded in DNA molecules provides instructions for
assembling protein molecules. Before a cell divides, the instructions are
duplicated so that each of the two new cells gets all the necessary information for
carrying on
• Genes are segments of DNA molecules. Inserting, deleting, or substituting DNA
segments can alter genes. An altered gene may be passed on to every cell that
4
See Appendix D for a photocopy of this activity
develops from it. The resulting features may help, harm, or have little or no effect
on the offspring's success in its environment
Students would be invited to display and describe their paper pets from the
previous activity. Class discussion would center on the connection between the letters
used to determine the phenotypes and how that process actually works. The next partial
question would form: “How do genes work?” To aid students in exploring their own
concepts on genes, Learning Experience 1 from the text Traits and Fates (1998) would be
used5. Students would also be given current newspaper or magazine articles on recent
gene findings. They would read and summarize their article, sharing with the class. This
exercise helps students see that science influences society, influencing them in the way
they think about themselves (NRC, 1995).
For students to begin to answer this partial question, they would first be
introduced to the structure of DNA, using models, diagrams, worksheets and web sites,
providing varied learning modalities. Appropriate terminology would be used and
assessed with a brief matching quiz. The procedure “The DNA Shuffle” from Traits and
Fates (1998)6 would be used as a classroom activity to teach the processes of
transcription and translation. The teacher would guide the students through the role
playing activity. The formation of a protein chain at the end of this activity follows the
yo-yo format by again returning to the organism level. This role playing activity would
be repeated with different students playing different parts until all had participated in the
different stages of transcription and translation.
Changing of the original DNA coding strand would emphasize the idea of genetic
mutations within the DNA as a source of both genotypic and phenotypic variations within
a population, but also as the source of certain diseases. One of the changes to the DNA
template would involve the insertion of an additional 4 base pairs responsible for TaySachs disease. This would bring further relevance to this group of students who are
primarily Conservative Jews. Returning to the paper pets described in Appendix D,
5
6
See Appendix E for photocopy of this activity
See Appendix F for photocopy of this activity.
students would again investigate the effects of changes in an organism’s DNA by
completing the activities on mutations7.
Reflecting, discussing and writing the answers to the partial question “How do
genes work?” would continue as a formative assessment. Teacher monitoring of the
discussions and answers, along with guidance as needed, would continue until all
students are able to determine that transcription and translation are the mechanism by
which genes are expressed. As a summative assessment, students would repeat the role
playing activity without teacher guidance. They would be assessed on whether or not they
performed the processes properly, forming the correct protein at the end. Immediate
feedback would be given as the students check with the teacher to see if they were correct
in forming their protein. This would end the unit (2-4 days).
Meta-Reflection
The meta-reflection phase of the yo-yo teaching/learning strategy would follow
the protein synthesis activity. Students would first reflect and share their answers to all
partial questions within the unit. A final summative written assessment would be based
upon student answers to the unit question, “Why do I look like this?” The format can be
their choice; a diary entry, a newspaper article, a scientific journal article, or even a
PowerPoint or videotape presentation. Their answers should include the following points:
•
I look similar to my parents but not identical
•
I look different because of sexual reproduction
•
Meiosis creates gametes, each with half of the original number of
chromosomes seen in a somatic cell
•
The chromosomes that are in each gamete, and which sperm fertilizes the
egg are based on chance. Each possible combination produces a possible
different combination of genes
7
No sex-linked or multigenic traits would be used for this activity. These concepts are too advanced for
middle school students.
•
Genes are what determine traits, and genes are found on the chromosomes
that are passed down from parent to offspring
•
Genes are made of DNA, and through the processes of transcription and
translation, different proteins, and thus different traits, are made
•
A change in the DNA may cause a change in a trait of an organism
Performance Assessment
As a final summative assessment tool, students will use virtual fruit flies to
conduct genetic experiments. They will play the role of early genetic scientists, trying to
unlock the secrets of heredity. They must use fruit flies to see if they can determine
certain hereditary patterns. The virtual fruit fly experiment can be found at the following
web address: http://www.sciencecourseware.org/vcise/. 8Groups of 2-4 students will
conduct genetic crosses on these fruit flies. Students will read background information on
the fruit flies and follow the directions for a mating. The first cross will be teacher
directed, mating wild type males and vestigial winged females. Students collect their data,
analyze it and create a hypothesis of the resulting offspring ratios for an F2 generation.
The F1 generation is crossed to create the F2. Again, data is collected after the mating.
Students can then analyze their findings and determine whether their hypothesis was
correct. This program uses chi-square tests. This is too advanced for middle school
students, so they would judge if their results were “close” to their hypotheses. Students
would then complete another cross, using traits of their choice to create an F1 and F2
generation. They would compose a report of their results using this feature of the
program. Reports would be presented to the class as a science symposium. Students
would be assessed using the rubric provided within the virtual fruit fly program. Some
requirements would be deleted due to their inappropriate level for middle school. These
items have been crossed out on the printed rubric.
Ethic discussion
EU addressed:
8
Desharnais, B. et al., (2005). See Appendix G for activity contents. Visit web site for more information
•
There is an ethical component to genetic testing and therapy
Standard addressed:
•
In research involving human subjects, the ethics of science require that
potential subjects be fully informed about the risks and benefits associated
with the research and of their right to refuse to participate. Science ethics also
demand that scientists must not knowingly subject coworkers, students, the
neighborhood, or the community to health or property risks without their prior
knowledge and consent
The purpose of this unit is not to use any assessments, but rather to introduce
students to the relationship between medicine, ethics and their religious beliefs. School
rabbis will be invited to participate in this unit by attending class discussions and reading
student essays described below.
Students will be given an article to read that pertains to the ethics of genetic
screening and therapies as they relate to Jewish law9. The class will be divided into small
groups of 3-4 students each. Each group will read a portion of the article (depending on
the number of groups in the class), and complete an oral report 5-10 minutes in length on
their reading. The report should include:
•
Summarize your reading in 5-8 sentences.
•
Were any specific diseases mentioned in your portion? Briefly describe the
disease.
•
Were any portions of Jewish law referenced in your reading? Briefly explain
the references and what they mean
After groups present their oral reports, class discussion will ensue. As a final activity for
this part of the unit, students will write a reflective essay about their thoughts on this
issue. Their essay should address the following:
•
What are your thoughts about genetic testing and screening? Why do you feel this
way?
9
See Appendix H for photocopy of article Judaism, Genetic Screening and Genetic Therapy (Rosner, 1998).
•
What does Jewish law say about genetic testing and screening? Do you agree with
this? Why or why not?
•
Site at least two other Jewish laws not mentioned in the article to back up your
statements.
Students may share their essays with the class if they wish. The sharing would end this
activity (2-3 days).
The ethics exploration and discussion ends the unit on genetics and inheritance.
References:
American Association for the Advancement of Science. (1993). In Benchmarks for
Science Literacy. Retrieved July 29, 2007 from
http://www.project2061.org/publications/bsl/online/bolintro.htm.
Clark, D. C., & Mathis, P. M. (2000). Modeling mitosis and meiosis A problem solving
activity. The American Biology Teacher, 62(3), 204-206.
Clough, E. E., & Wood-Robinson, C. (1985). Children's understanding of inheritance
[electronic version]. Journal of Biological Education, 19(4), 304-310.
Desharnais, B. et al., (2005). Virtual courseware for inquiry based science education.
Retrieved 07/30, 2007, from http://www.sciencecourseware.org/vcise/
Finnerty, V. (2006). Learning genetics with paper pets [electronic version]. Science
Scope, March, 18-23.
Knippels, M., Waarlo, A., & Boersma, K. (2005). Design criteria for learning and
teaching genetics [electronic version]. Journal of Biological Education, 39(3), 108112.
Knippels, M. (2002). Coping with the abstract and complex nature of genetics in biology
education : The yo-yo learning and teaching strategy [electronic version]. CDb series
on research in science education,
Lewis, J., & Kattman, U. (2004).
Traits, genes, particles and information: Re-visiting students’ understandings of
genetics [electronic version]. International Journal of Science Education, 26(2),
195-206.
Lewis, J., Leach, J., & Wood-Robinson, C. (2000). What's in a cell-young people's
understanding of the genetic relationship between cells, within an individual
[electronic version]. Journal of Biological Education, 34(3), 129-132.
Lijnse, P., & Klaassen, K. (2004).
Dactical structures as an outcome of research on teaching–learning sequences?
[electronic version]. International Journal of Science Education, 26(5), 537-554.
Mastropieri, M., Scruggs, T., Norland, J., Berkeley, S., McDuffie, K., Tornquist, E., et al.
(2006).
Differentiated curriculum enhancement in inclusive middle school science: effects on
classroom and high-stakes tests [electronic version]. The Journal of Special
Education, 40(3), 130-137.
Miller, J., S., Sandler, J., O., & Pallant, A., R. et al., (Eds.). (1998). Traits and fates
insights in biology. United States: Education Development Center, Incorporated.
National Resource Council. (1995). In National Science Education Standards. Retrieved
July 29, 2007 from http://www.nap.edu/readingroom/books/nses/.
Rosner, F. (1998). Judaism, genetic screening and genetic therapy [electronic version].
Mount Sinai Journal of Medicine, 65(5-6), 406-413.
Appendix A
Appendix B
Name ____________________________
Inheritance Questionnaire
1. List three traits you share with your parents or a related family
member. Describe the trait and list the family member you share it
with.
2. Write at least three sentences explaining how you inherited this trait.
3. If you have children, would you expect to see this trait in your child?
Why or why not?
4. Could you see these inherited traits when you were born? Why or why
not? If not, where were they?
5. Write at least two questions you have about inheriting traits. You will
have the opportunity to share these questions with the class if you
choose.
Appendix C
Appendix D
Appendix G
Appendix H
Copy of Default Rubric
•
Introduction
1. The objective and rationale of the activity is clearly understood.
2. The background information provides an introduction to the experiment.
Hypothesis
•
3. The hypothesis is well formulated, clearly stated, and testable.
Experimental Design
•
4. The design of the experiment accurately tests the hypothesis.
Materials and Methods
•
5. The written procedure can be followed so that the experiment can be
easily replicated.
Results and Discussion
•
6. Collection of data is appropriate.
7. The figures and tables are adequately labeled.
8. The data are described accurately.
9. The results are interpreted correctly.
Knowledge Demonstrated
•
10. Student understands the genetic principles of segregation and independent
assortment
11. Student understands the mating of dominant and recessive traits
12. Student understands the chromosomal basis of sex-determination –not
included
13. Student understands genetic linkage and recombination –not included
14. Student understands the process of scientific inquiry
Conclusion
•
15. Offers a convincing argument for confirming or rejecting the hypothesis.
16. Reaches a conclusion that is supported by the data.
17. Interprets the results consistent with the principles of genetic inheritance.
Summary
•
18. The main points have been concisely summarized.
19. The significance of the experiments was clearly stated.
•
General
20. Grammar
21. Clarity of expression
22. Spelling
23. Punctuation