7th Grade Science – Unit 2 – Genetics WWE #7
Name:
WWE #7: Due Friday 10/24
This WWE is a review of what we’ve learned about Genetics so far.
Through this WWE you will demonstrate your understanding of:
Punnett Squares
Pedigree Charts
Genotypes
Phenotypes
Heterozygous
Homozygous
Dominant Traits
Recessive Traits
Incomplete Dominance
Co-dominance
Mutations
You are a botanist studying a new type of plant. This plant has only been found on the sides of a
mountain in Spain. The locals call it Spyra. The locals have only found Spyra plants with
flowers that are orange or red. Fascinated by this new plant that has never been genetically
tested, you fly to Spain to experiment with it.
1. First you want to determine which flower color is dominant. You fertilize the seeds of a
Spyra with red flowers with the pollen of a Spyra with orange flowers. Assuming that
both are homozygous, make a Punnett Square to show the possible genotypes of the
offspring. Use the letters O for orange and R for red, since you are not yet sure of
dominance.
2. Next you decide to analyze the offspring of two of these generation 2 plants. To do so
you create a Punnett square for each possible dominance, then compile the data in a
table. (Hint: The parents will be the same each time, as each of the above offspring in
generation 2 have the same genotype.)
7th Grade Science – Unit 2 – Genetics WWE #7
Name:
a. Dominant color: Red (R), Recessive color: Orange (r)
Genotype
Predicted
Phenotype if
Red is
Dominant
Genotype
Predicted
Phenotype if
Orange is
Dominant
Genotype
Predicted
Phenotype if
Incomplete
dominance
b. Dominant color: Orange (O), Recessive color: Red (o)
c. Incomplete dominance: Orange (O) Red (R)
7th Grade Science – Unit 2 – Genetics WWE #7
Name:
d. Co-dominance: Orange (O) Red (R)
Genotype
Predicted
Phenotype if
Incomplete
dominance
Write or type your answers to questions 3 and 4 on a separate sheet of paper and attach it
to this packet.
3. You end up with 200 generation 3 plants! Of these 200 plants, 54 of them have red
flowers, 46 have orange flowers and 98 have red flowers with orange splotches. You can
now determine the dominance of the Spyra plant. Provide a written explanation, at least
1 paragraph long, detailing which color trait is dominant. Use evidence from your
experiment to support your conclusion.
4. You may have noticed that there are two plants not included in the above information.
That’s because these plants had white flowers! Explain in detail how this could have
happened. Your explanation needs to be at least a paragraph long.