zang te860 unitplan by M6Fyt1u


									TE 860: Unit Plan Guide

Name: Richard Schneeberger and Ian Zang

Part I: Information about the Lesson or Unit
Topic: Genetics
Type of Class
      ●        Grade level(s): 10/11/12 High school elective/high track
      ●        Type of school: Urban
      ●        Tracking level: College bound

With a series of prerequisites already in place, students in this class will have a fundamental understanding of DNA and other
biological properties. Our lesson relies heavily on previous understanding of basic biological terminology and concepts. A
relative understanding of sexual reproduction will be required to demonstrate the allocation and crossing of alleles on genes during
meiosis. Students ought to be knowledgeable of mitosis and meiosis. Also, introduction of Mendel’s Laws will be discussed.

Examples of new terms introduced are alleles, genes, Punnett Squares, sex-linked, dominant, codominant, and polygenic traits,
genetic recombination, sister chromatid, independent assortment, segregation, and monohybrid and dihybrid crosses. Major
examples to students will include the new terms: ie, Huntingtons’s Disease (sex-linked traits), human blood types (codominance),
hemophilia (sex-linked), etc. New ideas to discuss are how the Punnett Squares can predict the probability of certain genotypes and
phenotypes to be present, what impact does genetic recombination have on alleles, and how does a dihybrid cross compare to a
monohybrid cross (for multiple generations)?
                                          Part II: Clarifying Your Goals

Big Ideas
Genetics and heredity require quite a lot of knowledge dealing with cellular function and processes. Understanding genetics
requires a background with an emphasis on cellular replication. Mitosis, meiosis, sexual reproduction, and encoding of genetic
information are of utmost importance coming into this subject.
Heredity is an observable aspect of genetics that can be used as a springboard to dive into the microscopic levels of the science.
Gregor Mendel’s groundbreaking work on his pea plants shows how alleles work in pairs, and can be represented visually as a
punnett square. This tool allows us to see the probabilities of inheritance based on the genotypes of the parents. Expanding on this,
we can then examine why this pattern occurs. This will lead to the fact that chromosomes have two matching spots that each have
one aspect of the allele. During meiosis, these two spots will split, one of which will go to the haploid cell.
Chromosomes contain genetic information that encode for the entirety of the cell. Deformations or mutations of the chromosomes
can cause significant changes in cell physiology. Within a chromosome, there are many individual genes, each with different
alleles, that encode information for specific components and functions within a cell; these encompass proteins, organelles, and
cellular processes and functions. It gives us a very good picture of why cells work the way they do.
The way we organize these genes in a conceptual manner is through allele organization. For each trait, there are typically two
alleles to express it, dominant and recessive. Alleles are traits that can be passed from parent to offspring, and can be homozygous
or heterozygous. When an allele has two dominant traits or two recessive traits we call it homozygous. When there is one
dominant allele and one recessive allele, we call this heterozygous. When mixed, the dominant trait will typically mask over that of
the recessive. Demonstrating this in a Punnett Square and showing the mathematical probabilities of different crosses helps to
predict future generation genotypes and phenotypes.
When dividing, it is important for the cell to distribute its genetic information equally. When a cell splits, the two new cells are
called daughter cells. If the process of division does not occur properly, mutations can occur, oftentimes to the detriment of the
organism. Rarely, however, the mutation allows the organism to express a beneficial trait, increasing the chances of survival.
(Adapted from the Michigan HSCE’s)
Observations, Patterns, and Models

    Observations or experiences (examples,          Patterns (laws, generalizations, graphs,                   Models
              phenomena, data)                                 tables, categories)                     (explanations, theories)
                   WHAT                                              HOW                                       WHY

Fruit fly eye color following a cross                Punnett Square probabilities for           Heredity in the form of how traits are
Presence/size of wings of F1 and F2 generations monohybrid and dyhibrid crosses                 passed down through alleles
Presence of the dominant/recessive alleles in future
generations of fruit flies                           Variation from expected probabilities in   Genetic recombination - the basis for
Differences in body size of offspring in fruit flies class Punnett Squares due to random        genetic variability
Unexpected results in eye color and body size        chance
obtained from crossbreeding fruit flys
Results of one monohybrid cross in a                 Patterns developing from the results of    Reproduction - The actual molecular
Punnett Square                                       Punnett Squares versus the expected        process of how specific alleles (points
                                                     results                                    on DNA) are passed to offspring
Results of a dihybrid cross in a
Punnett Square
                                                     Trends across species in regards to        Concept of Random Chance in nature
                                                     dominant and recessive genes
Pea pod size
Pea pod color
                                                     Dominant vs Recessive traits
Pea pod number of seeds
                                                     Codominance shows different color than
Rose offspring color                                 either parent

Blood type coagulation lab                          Genotype vs. Phenotype patterns
Rh value for newborn children (via internet)

Family tree for Huntington’s Disease to see who is Unexpected variations in species
a carrier and who is affected
                                                    phenotype due to recessive gene
Family tree for hemophilia (royal lineage) to see   expression (when not evident in the
who is a carrier and who is affected                parental generation)
                                                                                              Sex-linked traits effect males more
What traits can a male pass on to subsequent        Sex-linked traits are passed on via the X than females
generations? Females?                               chromosome

Students’ Prior Knowledge

A. Examining the results of meiosis and comparing it to those of mitosis, students will understand where each
“half chromosome”, or sister chromatid, comes from. Building on this understanding, we can use real-world
examples to demonstrate dominant vs recessive alleles. Students also ought to be familiar with using tables for
scientific inquiry. This dichotomy of previous knowledge creates a scaffold to introduce Punnett Squares, which
will help demonstrate patterns. Additionally, meiosis will be examined from a hereditary standpoint, comparing
daughter cells from meiosis to those of mitosis. Following meiosis, only half of each chromosome exists by
itself, lending the organism to genetic variation through sexual reproduction.

B. Discussion of common misconceptions in genetics will help students understand why one trait may or may
not be dominant over another (ie, a smaller, shorter prey animal will be better able to hide from predators;
peppered moths will hide better from predators under normal conditions, but dark colored moths will hide better
before/after the Industrial Revolution, etc).
Just because a parent has a trait, does not necessarily mean that parents’ offspring will also show that trait, as
shown via genetic recombination. Why men are more susceptible to some diseases, and women are more
susceptible to others is not very well explained by most high schoolers.
Passing on of genetic diseases is not well understood in high school. Examining different diseases, as well as
other genetic traits, most notably those on the X and Y chromosomes, will yield a better concept of why males go
bald, why men can’t get Huntington's but are more likely to become colorblind, and why the Royal Family has
higher incidents of hemophilia.
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Objectives for Student Learning

                                                 Michigan Objectives                                                                           Type
1. B4.1A: Draw and label a homologous chromosome pair with heterozygous alleles highlighting a particular gene                     Content - Constructing
2. B4.1B: Explain that the information passed from parents to offspring is transmitted by means of genes that are coded in         Content - Using
DNA molecules. These genes contain the information for the production of proteins.
3. B4.1C: Differentiate between dominant, recessive, codominant, polygenic, and sex-linked traits.                               Content - Using
4. B4.1D: Explain the genetic basis for Mendel’s laws of segregation and independent assortment.                                 Content - Using
5. B4.1E: Determine the genotype and phenotype of monohybrid crosses using a Punnett Square.                                     Content - Using
6. B1.1D: Identify patterns in data and relate them to theoretical models.                                                       Inquiry - Reflecting
7. B1.1H: Design and conduct a systematic scientific investigation that tests a hypothesis. Draw conclusions from data           Inquiry - Constructing
presented in charts or tables.
                                            Synthesized Unit Objectives
1. Students will be able to perform and follow (on a basic statistical level) a homozygous cross for at least two generations.
2. Students will be able to identify how alleles combine to express dominant or recessive traits
3. Students will be able to draw and label chromosomes and how cell division occurs. In addition, they should understand
the makeup of a chromosome on the level of DNA.
4. Students will be able to identify different forms of dominance and predict how crosses will occur.
Part III: Assessment and Activities
Students will perform a fruit fly lab throughout the unit to exemplify the results of genetic recombination, crossing over of alleles on
a gene, and the outcome of a cross between a male and a female. The students will show that the traits of the offspring can be
predicted based on the known heredity of the parents. They will be given a theoretical homozygous parental cross, and be asked to
perform a Chi squared analysis to determine the ideal proportions of offspring in the next two generations. They will be given flies
that match their homozygous theoretical parents and will mate them, and then be responsible for two generations of flies. Their
duties will include feeding and caring for the flies during non-mating times. When a generation is complete, they will remove all
flies and count them, noting their relevant characteristics. After the second generation has been counted, they will compile their
data and analyze it using the Chi squared statistical analysis.
Additionally, performing a similar experiment using plants (may require dividing the lesson into two phases/parts to observe
offspring), students will perform a cross with pea plants. Following a brief history lesson on Gregor Mendel, the class will be
introduced to Mendel’s Laws of segregation and independent assortment. Different plants will produce different results, pending
on the parent generation’s genotype. This further demonstrates that a genotype is different than a phenotype, and that simply
because an organism displays a trait, does not necessarily mean it passes that trait along to its offspring. We could do a similar
demonstration using roses, as cross between a red rose and a white rose will produce pink offspring. This provides a perfect segue
into the notion of codominance. When referring to codominance, it would also open up the classroom to a discussion on skin color
especially in a diverse setting (despite the complications of having several genes used to determine skin color, this would still be an
excellent opportunity for the purpose of demonstration).
Several worksheets will be handed out for practice purposes. They will help the students begin to see the patterns that occur in
nature. These worksheets do not need to necessarily be graded, but are important in practicing the skills needed for the more
complicated statistical analysis. At the end of the unit, a summative exam will be given, example questions can be seen below.

1: If the P1 cross is Tt x tt, what percentage of the offspring will express the recessive trait?
       a) 25%
       b) 50%
       c) 75%
       d) 100%
2: Which of the following could NOT be possible following this cross... TT x Tt?
     a) A heterozygous genotype
     b) Expression of the dominant genotype
     c) Carrier of the recessive allele
     d) Expression of the recessive phenotype
     e) None of the above, ALL are true.

3: Which example demonstrates genetic recombination?
     a) Two tall giraffes mating, and producing taller offspring
     b) A brown eyed person and a blue eyed person mating to produce a green eyed person
     c) Salmon offspring with strong swimming muscles making it farther upstream to spawn
     d) Small eared rabbits mating to produce a rabbit with large ears

4. Why is one male born with hemophila (bottom row), but not his brothers or sisters? (Essay)


Examples of Formative Assessment: (In the form of “Morning Warm-ups”)
      1: Show all possible crosses of a brown eyed person (BB or Bb) and a blue eyed person (bb).
      2: A student notices that in his garden of red and white tulips, there are a select few tulips which are pink. The student never
              planted any pink tulips, and is very confused. Why did this happen?
      3: Why are there two parts to each allele? Why does the offspring only get one of those?
      4: Explain the difference between genotype and phenotype.

Synthesized Unit           Summative Assessment                   Formative Assessment            Major Activity
Objectives                                                                                        (Include whether it will be
                                                                                                                     Inquiry or Application)
Students will be able to         Cumulative Exam                              Teacher can see the results of the      Fly lab - Application
perform and follow statistically Example Question: See number 2 above         students’ analysis of their theoretical
a homozygous cross for at least                                               cross during the lab preparation.
two generations                  Worksheets
Students will be able to identify Example Question: See numbers 1 and 3       Through use of practice worksheets, Worksheets and in class discussion -
how alleles combine to express above                                          teacher can see how well the students inquiry
dominant or recessive traits                                                  understand the concept.
Students will be able to draw Example Question would include a picture        The worksheets will demonstrate        Worksheets - Inquiry
and label chromosomes and         of a chromosome that the student would be   their ability on this concept.
how cell division occurs.         required to label.
Students will be able to identify Example question would be along the lines   Using discussions in class and         In class discussion and worksheets -
different forms of dominance of number 2 as well.                             worksheets completed, the teacher      Inquiry
and predict how crosses will                                                  can get a feel for how well the
                                                                              students can identify the various

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