Download Heredity Biology IE

Biology and Heredity
Why do the same parents have different looking children?
Instructional Episode 1 (Compare Mitosis and Meiosis)
Students will model Mitosis and Meiosis in various methods. Teachers will start off by giving
each card 2 similar numbered and colored playing cards and walk them through the stages of
Mitosis/Meiosis. Students then will be given maps of each stage and compare and contrast the
differences. Students will then be given independent pictures of multiple stages and have to deduct
which stage is being illustrated. Teacher led discussion about the role of mitosis and meiosis in asexual
and sexual reproduction.
Lists:
Explain the significance of meiosis and fertilization in genetic variation.
Using models to discover patterns
Relating cause of meiosis to effect of allele distribution
Identifying patterns of meiosis and mitosis and relating to function.
Assessment:
Students should be able to identify different stages of mitosis and meiosis. This could be done
as a quiz, teacher assessing group ability, or a writing activity where students address three
major differences between the two in a letter to a peer.
Instructional Episode 2 (When is Sexual and Asexual Reproduction favored?)
Teacher will explain the basic difference between sexual and asexual reproduction. Students
will then in groups brainstorm benefits and limitations of each type in a competition where the group
with the most correct answers wins. Teacher allows but controls the dialog as ideas are presented with
opposing groups that can rebuff ideas.
Lists:
Compare sexual and asexual reproduction
Relate benefits in terms of scale, proportion, and quantity of each type of reproduction
Identify patterns between similar and different types of organisms and the reproduction they
undergo
Assessment:
Students can be assigned differing conditions of an organism, its environment, and its fitness.
Based upon those conditions, students should write an argumentative paper which explains
which type of reproduction would be most beneficial under the given conditions.
Instructional Episode 3 (How do we predict what traits one will get)
Teacher will explain Mendel’s law of segregation and independent assortment and relate it back
to meiosis (instructional episode 1). Teacher, without explaining, will give out new terms such
as heterozygous, homozygous, dominance, recessive, and alleles. Student will formulate into
groups and define the words from a text and then, as a group, reword each into their own words
after reaching a consensus. Teacher then illustrates how recombination of differing parents
allows for new genetic combination in the offspring with illustrating how to use a punnett
square.
Lists:
Students should be able to relate cause and effect of parental genotypes to offspring
recombinations
Students should be able to model results of genetic crosses utilizing mathematical models
and/or punnett square
Predict and interpret patterns of inheritance in sexually reproducing organisms
Demonstrate possible results of recombination in sexually reproducing organisms relating to
dominance and recessive
Relate modern day plant/animal breeding to mendelian principles
Assessment:
Students analyze and interpret data to perform simple monohybrid crosses and calculate the
probability of differing traits, this could be done as a simple worksheet or summative quiz/test.
Students should be able to relate the principles of Mendelian genetics to modern breeding in a
argumentative paragraph.
Instructional Episode 4 (Why does Mendelian genetics fail?)
Teacher will broadcast or give out pictures of traits that are not explain by mendelian genetics.
Incomplete dominance, codominance, polygenic and sex-linked trait conditions can all be show
and illustrated. With each, have students formulate hypotheses of mechanisms that are
responsible for each observed phenomenon. As you move from each category, lead the class in
discussion until each condition is explained. Illustrate nomenclature used and have students
relate why such nomenclature is important.
Lists:
Demonstrate possible results of recombination in and compare and contrast with the following
type crosses: dominance/recessive, incomplete dominance, codominance, polygenic
inheritance, and sex linked traits.
Relate differing types of inheritance utilizing models and patterns
Assessment:
Give picture or descriptions of varying types of inheritance. Have students work in groups to
match up correctly each condition with its unique type of inheritance. Have them use argument
to back up their conclusion and present to the teacher.
Culmination Experience: Making babies
Students will be “married” in class and have to analyze their independent genotypes (as well as possible)
from looking at their own traits and the traits of their parents. Students will then “sexually reproduce”
by exchanging their genetics with their “spouses” and performing a punnett square for the possible
recombinations. Students will then randomly (using dice/number generator/etc) select each trait that
their “offspring” will have. Traits can be mendelian, codomiance, incomplete dominant, and polygenic
depending upon depth and breadth of class understanding. Student then can present their child in class
and trace certain traits back to certain parents.