Applying Ideas

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Applying Ideas

This is an on-line version of the same Applying Ideas questions included at the end of the chapter in your textbook. Use this version to quickly and easily submit your work to your instructor or teaching assistant.

1. In humans, albinism is caused by loss-of-function mutations in genes involved in the synthesis of melanin, the dark pigment in skin. Only people homozygous for a loss-of-function allele have the phenotype. In Americans of northern European ancestry, albino individuals are present at a frequency of about 1 in 10,000 (or 0.0001). Knowing this genotype frequency, we can calculate the frequency of the loss-of-function alleles. If we let p₂ stand for this frequency, we know that p₂2 = 0.0001, so p₂= sq. root of 0.0001 = 0.01. By subtraction, the frequency of normal alleles is 0.99. If these loci conform to the conditions required by the Hardy-Weinberg principle, what is the frequency of "carriers"—or people who are heterozygous for the condition? Your answer indicates the percentage of Caucasians in the United States who carry an allele for albinism.
To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

2. The text contends that conservation managers frequently use gene flow, in the form of transporting individuals or releasing captive-bred young, to counteract the effects of drift on small, endangered populations. Explain how gene flow can also mitigate the effects of inbreeding.
To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

3. In 1789, a small band of mutineers led by Fletcher Christian took over the British warship HMS Bounty and fled to tiny Pitcairn Is land in the South Pacific. There the sailors joined a small population of native Polynesians, married, and raised families. All contemporary Pitcairn islanders can trace at least part of their family tree back to the colonization event. What evolutionary forces were at work in this small, isolated population before, during, and after the arrival of the mutineers?
To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.

4. Imagine that you are a conservation biologist charged with creating a recovery plan for an endangered species of turtle. The turtle’s habitat has been fragmented into small, isolated protected areas by suburbanization and highway construction. There is some evidence that certain populations are adapted to marshes that are normal, while others are adapted to acidic wetlands or salty habitats. Further, some populations number less than 25 breeding adults, making genetic drift and inbreeding a major concern. In creating a recovery plan, the tools at your disposal are captive breeding, capture and transfer of adults to create gene flow, or creation of habitat corridors between wetlands to make migration possible. Write a two-paragraph essay outlining the major features of your proposal.
To create paragraphs in your essay response, type at the beginning of the paragraph, and at the end.




1.	In humans, albinism is caused by loss-of-function mutations in genes involved in the synthesis of melanin, the dark pigment in skin. Only people homozygous for a loss-of-function allele have the phenotype. In Americans of northern European ancestry, albino individuals are present at a frequency of about 1 in 10,000 (or 0.0001). Knowing this genotype frequency, we can calculate the frequency of the loss-of-function alleles. If we let p₂ stand for this frequency, we know that p₂2 = 0.0001, so p₂= sq. root of 0.0001 = 0.01. By subtraction, the frequency of normal alleles is 0.99. If these loci conform to the conditions required by the Hardy-Weinberg principle, what is the frequency of "carriers"—or people who are heterozygous for the condition? Your answer indicates the percentage of Caucasians in the United States who carry an allele for albinism. To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.



2.	The text contends that conservation managers frequently use gene flow, in the form of transporting individuals or releasing captive-bred young, to counteract the effects of drift on small, endangered populations. Explain how gene flow can also mitigate the effects of inbreeding. To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.



3.	In 1789, a small band of mutineers led by Fletcher Christian took over the British warship HMS Bounty and fled to tiny Pitcairn Is land in the South Pacific. There the sailors joined a small population of native Polynesians, married, and raised families. All contemporary Pitcairn islanders can trace at least part of their family tree back to the colonization event. What evolutionary forces were at work in this small, isolated population before, during, and after the arrival of the mutineers? To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.



4.	Imagine that you are a conservation biologist charged with creating a recovery plan for an endangered species of turtle. The turtle’s habitat has been fragmented into small, isolated protected areas by suburbanization and highway construction. There is some evidence that certain populations are adapted to marshes that are normal, while others are adapted to acidic wetlands or salty habitats. Further, some populations number less than 25 breeding adults, making genetic drift and inbreeding a major concern. In creating a recovery plan, the tools at your disposal are captive breeding, capture and transfer of adults to create gene flow, or creation of habitat corridors between wetlands to make migration possible. Write a two-paragraph essay outlining the major features of your proposal. To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.

Chapter 22: Evolutionary Processes

Applying Ideas