Download Activity 54 • Investigating Human Traits 1. For each of the six

Activity 54 • Investigating Human Traits
1. For each of the six characteristics you studied, how many versions, or traits, are observed in your class?
2. Which of the traits you investigated—for eye color, tongue rolling, PTC tasting, crossing all your fingers,
height, and arm span—do you think people inherit from their biological parents?
Explain.
3. If a trait is not inherited, what else might cause it? Explain, or give some examples.
4. If you studied more people in your community, would you expect to find more traits for each characteristic?
Explain your answer.
Activity 55 • Plants Have Genes, Too!
1.Record in your science notebook your prediction for the color or colors of the plants that will grow from the
seeds. You may make more than one possible prediction, but be sure to indicate which you think is most likely
to happen.
2. What are your reasons for each.prediction you proposed for Question 1? Explain.
Joe’s Dilemma • Activity 56
1. What are the signs that suggest a person may have the Marfan syndrome?
2. What causes the Marfan syndrome?
3. Can you “catch” the Marfan syndrome from another person, the way you can catch the flu? Explain.
4. What effect can the Marfan syndrome have on a person’s life?
5. Look back at the questions you wrote in your science notebook for Step 2 of the Procedure.
a. Were any of your questions answered? Record the new information you learned from the video.
b. What new questions would you want to ask a doctor or genetic counselor?
6. Reflection: How would you behave toward a fellow student whom everyone suspects has the Marfan
syndrome?
Copycat • Activity 57
1. Classify each of the following as either sexual or asexual reproduction. Explain each answer.
a. An orange cat is bred with a black cat, in hopes of producing a tortoiseshell cat.
b. A cutting is taken from a red-flowered geranium and placed in water to develop roots. Once roots
have grown, the new plant is placed in soil and grows to produce another red-flowered geranium.
c. A red-flowered geranium with dull leaves is bred with a white-flowered geranium with shiny
leaves, with a goal of producing a redflowered geranium with shiny leaves.
d. A male fish releases sperm cells into the water. One of the sperm unites with an egg from a female
fish to form a new cell that grows into a new fish.
e. A small worm that lives in water splits in two and each half grows to normal size. The head end
grows a tail, and the tail end grows a head.
f. Sheep reproduce only by sexual reproduction in nature. Using modern technology, a clone of an
adult sheep is produced.
2. Reflection: If you were given an opportunity to clone yourself, would you do it? Explain.
Activity 58 • Creature Features
1. Based on the breeding results and your simulations, which hypothesis do you think best fits the evidence?
Explain your answer.
2. Reflection: You have used models to investigate several scientific questions in Science and Life Issues.
What are the trade-offs of using models to investigate the real world?
Activity 59 • Gene Combo
1. What is the ratio of blue-tailed to orangetailed critter pups? Use the class data to answer this question:
a. Divide the number of blue-tailed offspring by the number of orange-tailed offspring. ratio of tail
colors = number of blue-tailed offspring number of orange-tailed offspring
b. Round this value to the nearest whole number. Then express it as a ratio by writing it like this:
____________________: 1
(whole number)
c. Express this ratio as a pair of fractions, so that you can use them to complete the following
sentence: “About ____ of the offspring have blue tails, and about ____ of the offspring have orange tails.”
d. Explain why the class obtained such a large ratio. For example, why isn’t the ratio of blue to
orange tails 1:1, that is, 1/2 blue and 1/2 orange?
2. You and your partner are about to toss two coins 100 times. Predict about how many times the outcome
would be:
a. heads-heads
b. heads-tails
c. tails-heads
d. tails-tails
3. How sure are you that you will get exactly the results you predicted for Question 3? Explain your answer.
4. Look back at Activity 58, “Creature Features.” Do the results of the coin-tossing model match the
Generation Three critter data? Explain.
5. Try to write your own definition of the phrase dominant trait as it is used in genetics. Hint: Does it mean
that every time any pair of critters mates, most of the offspring will have blue tails? Why or why not?
Activity 60 • Mendal, First Geneticist
1. Based on Mendel’s results, what trait for each pea characteristic is dominant? Make a table of the dominant
and recessive alternatives for each characteristic in Table 1. Add an extra column to your table; you will use it
to record your answers to Question 2a. See Table 1 below.
2.
a. Calculate to the hundredths place the ratio of dominant to recessive for each characteristic in the
third generation. Record the ratio for each characteristic in the table you prepared for Question 1.
b. Why are the ratios not exactly 3:1?
3. Look at Figure 1, which shows the ratio of green-seeded to yellow-seeded offspring. Explain why a 1:3 ratio
of green-seeded plants to yellow-seeded plants is the same as a fraction of 1/4 green-seeded plants.
4. Mendel performed his experiments on more characteristics than the four shown in Figure 1. Why was it
important for him to look at more than one characteristic?
5. Reflection: People often think of mathematics as important to physics and chemistry, but not to life science
(biology). What is your opinion?
Activity 61 • Gene Squares
1. Compare the results of your Punnett square for Problem 1 on Student Sheet 61.1 with the results of the
Ocean/Lucy cross in Activity 59, “Gene Combo.” Why are they similar?
2. Refer to the table of Mendel’s results in Activity 60, “Mendel, First Geneticist,” on page D- 36.
a. What are the traits for pea flower color? Suggest letters you might use to represent the alleles for
flower color.
b. What are the traits for seed surface? Suggest letters you might use to represent the alleles for seed
surface.
3. Review your results on Student Sheet 61.1. Why is it impossible for offspring to show the recessive trait if
one parent is homozygous for the dominant trait?
4. A scientist has some purple-flowered pea plants. She wants to find out if the pea plants are homozygous for
the purple flower color.
a. What cross will be best to find out if the purpleflowered peas are homozygous?
b. Use Punnett squares to show what will happen if the plants are crossed with white-flowered
plants and
i. the purple-flowered plants do not have an allele for the white trait.
ii. the purple-flowered plants do have an allele for the white trait.
Analyzing Genetic Data • Activity 62
1. Look back in your science notebook for the prediction you made in Activity 55. Was your prediction
correct? Explain.
2. Compare the class’s results for seedling color to Mendel’s results for various pea plant traits. Why are they
similar? What do they suggest about the inheritance of the pale yellow and green Nicotiana traits?
3. Do each group’s results fit Mendel’s model? Explain.
4. When you first set out these seeds to germinate, you were told that they were all the offspring of two green
parent plants. You were also told that each of the green parents had one green parent and one yellow parent.
a. Based on the class’s results, what can you conclude about the color alleles of each of the green
parents of your seedlings?
b. How is this breeding cross similar to the one you modeled in Activity 59, “Gene Combo”? Explain.
5. Construct a Punnett square to show what will happen if one of the green parent-generation Nicotiana
plants is crossed with a pale yellow plant. Explain the results.
Show Me the Genes! • Activity 63
1.Draw a flow diagram (a series of pictures) such as the one below that shows the locations and relative sizes
of DNA, genes, chromosomes, and cells in a human body. Write a paragraph to explain your diagram.
Activity 64 • Nature and Nurture
1. Was your hypothesis correct? Explain.
2. What effect did heredity have in determining the color of the seedlings?
3. What effect did the environment have in determining the color of the seedlings?
4. Can heredity alone ensure an organism will grow well and be healthy? Explain.
5. Can the environment alone ensure an organism will grow well and be healthy? Explain.
6. Reflection: What role do you think genes and the environment play in human development and health?
Explain your thinking and give some examples.
Breeding Critters—More Traits • Activity 65
1. Look at the other critters made by your classmates. They are all siblings (brothers and sisters). What are
their similarities and differences?
2. Which characteristics show a simple dominant/ recessive pattern like tail color? List them in a table and
indicate which version is dominant and which is recessive for each trait. Hint: Look at Table 1 to see which
traits have this pattern.
3. For which characteristic do some offspring have traits in between Skye’s and Poppy’s traits? Explain. (For
example, in some plants, a cross between a red- and white-flowered plant will give pink-flowered offspring.
This is called incomplete dominance.)
4. For which characteristic do some offspring have both Skye’s and Poppy’s traits? Explain. (For example, in
humans, a person with type A blood and a person with type B blood can have a child with type AB blood. This
is called co-dominance, as both traits appear in the offspring.)
5. Which critter trait is affected by an environmental factor, such as light, temperature, or diet? Explain.
6. Consider the pattern for sex determination.
a. How is a critter’s sex determined?
b. Whose genetic contribution—Ocean’s or Lucy’s—determines the sex of the offspring?
7. Who does your critter most look like—Skye, Poppy, Ocean, or Lucy? On which traits did you base your
choice?
8. Draw a critter with all recessive traits. Assume the recessive trait for spikes is no spikes.
Patterns in Pedigrees • Activity 66
1. The following pedigrees represent the blood types in four unrelated families. In each case, the parents have
Type A and Type B blood.
a. Which of the 8 parents are definitely heterozygous for the Type O allele? Explain.
b. Which of the 8 parents are probably not heterozygous for the Type O allele? Explain.
c. Can you be certain that the parents you named in response to Question b do not have a Type O
allele? Explain.
2. The pedigree shown on the next page represents a genetic condition. Use the information it provides to
answer the questions below. Use Student Sheet 66.1 (page 3) to try out allele combinations for related
individuals.
a. Is the condition most likely a dominant or a recessive trait? Explain your reasoning.
b. Is Jan most likely to be homozygous dominant, heterozygous, or homozygous recessive?
3. The pedigree shown below represents another genetic condition.
a. Is the condition most likely a dominant or a recessive trait? Explain your reasoning.
b. Is Marcus most likely to be homozygous dominant, heterozygous, or homozygous recessive?
4. The pedigree shown below represents a third genetic condition.
a. Is the condition most likely a dominant or a recessive trait? Explain your reasoning.
b. Is Sophia most likely to be homozygous dominant, heterozygous, or homozygous recessive?
5. The term carrier is used very differently in genetics than in the study of diseases.
a. What is being “carried” by a genetic carrier? What is being “carried” by a disease carrier?
b. How does transmission occur for genetic conditions? How does transmission occur for infectious
diseases?