Female cardinals select male mates in part based on their bright red color. What effect would this have on a cardinal population that was in Hardy-Weinberg equilibrium?

Question

A.  The red allele frequencies would decrease because of equilibrium.
B.  The frequency of red alleles would be less than those predicted by Hardy-Weinberg equilibrium.
C.  The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium.
D.  The frequency of red alleles would be equal to those predicted by Hardy-Weinberg equilibrium.
E.  The red allele frequencies would remain unchanged because of equilibrium.

Clarify Question
· What is the key concept addressed by the question?
· What type of thinking is required?
· What key words does the question contain and what do they mean?

  Gather Content
· What do you already know about the Hardy-Weinberg principle? How does it relate to the question?

Consider Possibilities· What other information is related to the question? Which information is most useful?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?

Answer 1

C.  The frequency of red alleles would be greater than those predicted by Hardy-Weinberg equilibrium.

Clarify Question
· What is the key concept addressed by the question?
        o This question is asking you to predict what will happen to allele frequencies if female cardinals select male mates based upon their red color.
· What type of thinking is required?
        o You are being asked to take what you already know and use, or apply, it to the concept of sexual selection to the Hardy-Weinberg principle.
· What key words does the question contain and what do they mean?
        o Hardy-Weinberg equilibrium, which refers to populations whose genotype frequencies do not change from generation to generation.
        o Frequency, which refers to the number of times a particular event occurs in a sample.
        o Allele, which refers to a version of a gene.

  Gather Content
· What do you already know about the Hardy-Weinberg principle? How does it relate to the question?
        o The Hardy-Weinberg principle states that the original proportions of the genotypes in a population will remain constant from generation to generation, as long as the following assumptions are met:
            1. No mutation takes place.  
            2. No genes are transferred to or from other sources.
            3. Mating is random.
            4. The population size is very large.
            5. No selection occurs.
        o The question stem violates one of the five assumptions. Which assumption is violated and how will this violation influence changes in the allele frequency?

Consider Possibilities· What other information is related to the question? Which information is most useful?
        o The question states that female cardinals will select male mates based upon a characteristic they possess. If a male does not possess that characteristic, then they will not be able to find a female to mate with and thus their fitness will decrease. What would happen to the frequency of alleles that do not code for bright red color?
 
Choose Answer
· Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer?
        o To answer this question, you may choose to identify the Hardy-Weinberg condition that is not being met and then identify how that condition may influence allele frequency in a population. In this specific example, female cardinals prefer to mate with bright red males. How will this influence the frequency of the allele that codes for the bright red color?

Reflect on Process
· Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
        o This question asked you to determine the effect selection would have on Hardy-Weinberg equilibrium.
        o Answering this question correctly depended on your ability to use the Hardy-Weinberg principle in a new situation.
        o If you got the correct answer, excellent! If you got an incorrect answer, where did the process break down? Did you remember the five assumptions for Hardy-Weinberg equilibrium, or that selection for a certain phenotype can influence an allele’s frequency? Did you have trouble extending how a phenotype is tied to a set of alleles?