University of Michigan - Department of Astronomy

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Natural Selection

Worksheet

Part 1: Prey

Paper type: _______________

Generation 1: Before Foraging

Total Number of Prey:__
400______            Total Number of Prey Alleles: ___800____

Genotype Frequncy:

AA: ___0.25___             AB: __0.5_____                        BB: ___0.25___

 

Phenotype Numbers:

Type of Prey

Number of Prey in Gen. 1

Number eaten from Gen. 1

Number of Survivors of Gen 1

Black Bean  (AA)

100

 

 

Mottled Bean (AB)

200

 

 

White Bean (BB)

 

100

 

 

 

Total prey remaining: ___________                        Alleles remaining: ________

Prey allele frequencies (show your work)

 

                        A: p =

 

                        B: q =

 

Prey Punnet Square (fill in p’s and q’s with calculated allele frequencies):

 

A

p=

B

q=

A

p=

freq. of AA=p*p

 

 

freq. of BA=p*q

 

B

q=

freq. of AB=p*q

 

 

freq. of BB=q*q

 

 

Genotype frequency:

AA: ___________                        AB: ____________                        BB: ______________

 


Generation 2:

 

# of Prey:____________                         # of alleles: _____________

 

Phenotype Numbers:

Type of Prey

Number of Prey in gen. 2

Number eaten from gen. 2

Number of Survivors of gen. 2

Black Bean  (AA)

 

 

 

Mottled Bean (AB)

 

 

 

White Bean (BB)

 

 

 

 

 

Total prey remaining: ___________                        Alleles remaining: ________

Prey allele frequencies (show your work)

 

                        A: p =

 

                        B: q =

 

Prey Punnet Square (fill in p’s and q’s with calculated allele frequencies):

 

A

p=

B

q=

A

p=

freq. of AA=p*p

 

 

freq. of BA=p*q

 

B

q=

freq. of AB=p*q

 

 

freq. of BB=q*q

 

Genotype frequency:

AA: ___________                        AB: ____________                        BB: ______________

 

Generation 3:

 

# of Prey:____________                         # of alleles: _____________

 

Phenotype Numbers:

Type of Prey

Number of Prey in Gen. 3

Number eaten from Gen 3

Number of Survivors of Gen 3

Black Bean  (AA)

 

 

 

Mottled Bean (AB)

 

 

 

White Bean (BB)

 

 

 

 

 

Total prey remaining: ___________                        Alleles remaining: ________


Prey allele frequencies (show your work)

 

                        A: p =

 

                        B: q =

 

Prey Punnet Square (fill in p’s and q’s with calculated allele frequencies):

 

A

p=

B

q=

A

p=

freq. of AA=p*p

 

 

freq. of BA=p*q

 

B

q=

freq. of AB=p*q

 

 

freq. of BB=q*q

 

Genotype frequency:

AA: ___________                        AB: ____________                        BB: ______________

 

Generation 4:

 

# of Prey:____________                         # of alleles: _____________

 

Final Numbers:

Type of Prey

Number of Prey in Gen 4

Genotype frequency of Gen. 4

Black Bean  (AA)

 

 

 

Mottled Bean (AB)

 

 

 

White Bean (BB)

 

 

 

Part 1 Questions:

1.     Why are the genotype frequencies of genration 4 the same as the genotype frequencies of the survivors of generation 3?

 

 

 

 

2.     Did the total number of alleles increase, decrease or stay about the same?

 

 

 

3.     Did the genotype frequency change significantly for any of the genotypes?  If so, which one(s)? 

 

 

 

 

4.     Look at the data on the board for the other groups.  What group (paper type) had the bggest change in the number of alleles?  Did it increase or decrease?  By what factor?

 

 

 

 

 

5.     What group (paper type) had the biggest change in the genotype population?  What genotype changed the most?  Did it increase or decrease?

 

 

 

 

 

6.     How would you explain the changes in prey population for the different groups?

 

 

 

 

 

 

 

Part 2: Predators

 

Utensil type: _________________

 

Generation 1:

 

# of predators: ___________            # of Alleles: ___________

 

Genotype Numbers

 

Starting number

Surviving number

Fingers AA

 

 

 

Fingers Aa

 

 

 

Utensil aa

 

 

 

 

My genotype: ____                        My kills: ______             (I was the controller ____)

 

Largest number of beans eaten: ________

 

Number of survivors: _______                        Surviving alleles: _______

 

Allele Frequency (show your work)

 

                        A: p =

 

                        B: q =

 

 

Punnet Square (fill in p’s and q’s with calculated allele frequencies):

 

A

p=

a

q=

A

p=

freq. of AA=p*p

 

 

freq. of aA=p*q

 

a

q=

freq. of Aa=p*q

 

 

freq. of aa=q*q

 

Genotype frequency:

 

AA: ________                        Aa: ________                        aa: __________

Phenotype frequency:

 

Fingers: ____________                        Utensil: ___________

 

Generation 2:

Number of predators: ___________            Number of Alleles: ___________

 

Genotype Numbers

 

Starting number

Surviving number

Fingers AA

 

 

Fingers Aa

 

 

Utensil aa

 

 

 

My genotype: ____                        My kills: ______             (I was the controller ____)

 

Largest number of beans eaten: ________

 

Number of survivors: _______                        Surviving alleles: _______

 

Allele Frequency (show your work)

 

                        A: p =

 

                        B: q =

 

Punnet Square (fill in p’s and q’s with calculated allele frequencies):

 

A

p=

a

q=

A

p=

freq. of AA=p*p

 

 

freq. of aA=p*q

 

a

q=

freq. of Aa=p*q

 

 

freq. of aa=q*q

 

Genotype frequency:

 

AA: ________            Aa: ________                        aa: __________

Phenotype frequency:

 

Fingers: ____________                        Utensil: ___________

Generation 3:

Number of predators: ___________            Number of Alleles: ___________

 

Genotype Numbers

 

Starting number

Surviving number

Fingers AA

 

 

Fingers Aa

 

 

Utensil aa

 

 

 

My genotype: ____                        My kills: ______             (I was the controller ____)

 

Largest numberof beans eaten: ________

 

Number of survivors: _______                        Surviving alleles: _______

 

Allele Frequency (show your work)

 

                        A: p =

 

                        B: q =

 

Punnet Square (fill in p’s and q’s with calculated allele frequencies):

 

A

p=

a

q=

A

p=

freq. of AA=p*p

 

 

freq. of aA=p*q

 

a

q=

freq. of Aa=p*q

 

 

freq. of aa=q*q

 

Genotype frequency:

 

AA: ________            Aa: ________                        aa: __________

Phenotype frequency:

 

Fingers: ____________                        Utensil: ___________

Generation 4:

Number of predators: ___________            Number of Alleles: ___________

 

Final Numbers

 

Number of predators

Genotype frequency

Fingers AA

 

 

Fingers Aa

 

 

Utensil aa

 

 

 


Part 2 questions

1.     Why weren’t half the predators given utensils to begin with if half the alleles code for a utensil?

 

 

 

 

 

2.     Did the total number of alleles increase, decrease or stay about the same?  Why?

 

 

 

3.     Which tool was more effective for your group, fingers or the utensil?  How do you know?

 

 

 

 

 

 

4.     Look at the data on the board for the other groups.  Which foraging tool was the most effective overal?  How can you tell from the data on the board?

 

 

 

 

 

 

 

Discussion Questions:

1.     Look at Tables 2 & 3 on Blood Groups in the appendix. 

  1. If one of the parents is type AB, what are the possible blood types of the child? 
  2. If both parents are type O, what will the child’s blood type be?
  3. Which blood type is most common for most populations?  Does this make sense?  Why?
  4. Does a frequency of 0 mean that that blood type doesn’t exist in that population?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.     Tay-Sachs is a fatal genetic disease which, when expressed, causes death before the age of reproduction. Why is this recessive gene still present in human populations?  Would it be present if it were a dominant gene?  Explain your answers.





 

 

 

 

 

 

 

 

 

3.     Imagine a mutation causes a change that gives an organism a significant advantage over its neighbors.  Based on your data from this lab, how many generations would it take for a new species to develop (the new trait becomes the dominant trait, disadvantageous traits vanish, and the two types or organisms cease to interbreed)?  Justify your answer.

 

 

 

 

 

 

 

 

 

 

 

4.     Based on your answer from the previous question, how many new species could develop over 1 million years from an organism with 20 years between generations (roughly average for current primate species)?  Show your work.  Why aren’t there this many species of primates on Earth now?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

5.     In this simulation pressure on prey and predator populations is primarily a function of the type of prey versus the type of predator. The first self-replicating molecules faced different pressures. What type of evolutionary pressures did they experience? Explain the role of natural selection for those early self-replicating molecules.













6.     Early self-replicating molecules developed pre-cell membranes. How could these pre-cell membranes have effected natural selection?














7.     Even though we don’t know about the chemistry of life on other worlds than the Earth, would you expect natural selection to play a role in the evolution of life elsewhere? Explain.