BIOL 214 | Final Exam | With 100% accurate solutions + rationales 2026-Case Western Reserve University

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BIOL 214 Final Exam With 100% accurate
solutions + rationales 2026
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In May 2017, a black flamingo was observed among a population of pink flamingos in a salt lake at the
Akrotiri Environmental Centre on the southern coast of Cyprus. The flamingo is thought to have a condition
that causes it to over produce the pigment melanin, turning it dark rather than the usual pink color. The
over production of melanin is thought to be the result of a malfunctioning regulatory gene that controls
the expression of the TYR, TYRP1 and TYRP2 genes that code for the enzyme tyrosinase. Tyrosinase
catalyzes the production of melanin.

The short answer questions are all based on this observation

1. Melanism can help some species of birds blend into their surroundings, making it a useful anti-predator
͘
ĚĞĨĞŶƐĞƵƚƐŝŶĐĞĂĚƵůƚĨůĂŵŝŶŐŽƐĚŽŶ ͛ƚŚĂǀĞmany natural predators in the region, the black flamingo's
feathers are not likely to lead to a higher risk of predation.

a. Define evolution.


b. What are the necessary conditions for evolution by natural selection?



c. Following this initial observation in 2017, the number of black flamingos in the population increased to
6 in 2018, but then decreased to 3 in 2019, and has was zero in 2020. What does this tell you about the
fitness of the black flamingo?
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2. Some researchers proposed the problem with the tyrosinase regulatory protein was the result of a
mutation in the DNA sequence. In an attempt to locate and characterize the mutation, data on the
nucleotide sequence, mRNA, tRNA, and amino acid sequence for a section of the tyrosinase regulatory
protein were collected and analyzed. Fill in the table below.


G

DNA double helix
A G T

G G U mRNA transcribed
Appropriate tRNA
A C G
anticodon
Amino acids
Met incorporated into
protein


3. Other researchers proposed the problem with the tyrosinase regulatory protein was due to a splicing
mutation. How would a splicing mutation lead to a malfunctioning regulatory protein?




4. There is agreement among researchers that the black flamingo is the result of a malfunctioning regulatory
protein that controls the expression of the TYR, TYRP1, and TYRP2 genes.

a. Diagram and label the regulation of the TYR, TYRP1, and TYRP2 genes as they would exist in a normal
(pink) flamingo.

b. Describe (no need to redraw) how the diagram would be different in the black flamingo.
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5. In attempt to determine the inheritance pattern of black feathers, researchers tracked the reproductive
activity of the black flamingo (which was female) during the 2017 breeding season. After one mating, she
produced two chicks that were pink males, two pink females, one black male, and one black female.

a. Is the condition of black feathers autosomal or sex linked?




b. What is the dominant/recessive relationship between the pink and black alleles?




c. What are the genotypes of the parental flamingos?




6. The appearance of the black flamingo sparked interest in pink flamingos in general. For instance, some
flamingos were found to have brittle feathers, a recessive condition. In an attempt to determine the
frequency of the brittle feather allele in a population of pink flamingos, 426 were identified with normal
feathers and 6 were shown to have brittle feathers.

a. What are the frequencies of the normal and brittle feather alleles in this population?




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