Exam 21: The Evolution of Populations

If the original finches that flew over to the Galápagos Islands from South America had already been genetically different from the parental population of South American finches,even before adapting to the Galápagos,this would have been an example of

In seedcracker finches from Cameroon,small- and large-billed birds specialize in cracking soft and hard seeds,respectively.If long-term climatic change resulted in all seeds becoming hard,what type of selection would then operate on the finch population?

Recent research investigating variation in human height have found that a variety of genes at different loci,as well as early nutrition,especially that of the mother during gestation (the period of time during development of a fetus)and childhood years,influence height.Given this information,which of the following is correct?

The Hardy-Weinberg equation p² + 2pq + q² = 1 allows you to calculate

Swine are vulnerable to infection by bird flu virus and human flu virus,which can both be present in an individual pig at the same time.When this occurs,it is possible for genes from bird flu virus and human flu virus to be combined.If the human flu virus contributes a gene for Tamiflu resistance (Tamiflu is an antiviral drug)to the new virus,and if the new virus is introduced to an environment lacking Tamiflu,then what is most likely to occur?

If you assume that Hardy-Weinberg equilibrium applies to the population of colonists on this planet,about how many people will have attached earlobes when the planet's population reaches 10,000?

Please use the following information to answer the questions below. HIV's genome of RNA includes the code for reverse transcriptase (RT),an enzyme that acts early in infection to synthesize a DNA genome off an RNA template.The HIV genome also codes for protease (PR),an enzyme that acts later in infection by cutting long viral polyproteins into smaller,functional proteins.Both RT and PR represent potential targets for antiretroviral drugs.Drugs called nucleoside analogs (NA)act against RT,whereas drugs called protease inhibitors (PI)act against PR. -Which of the following represents the treatment option most likely to avoid the production of drug-resistant HIV (assuming no drug interactions or side effects)?

Please use the following information to answer the questions below. A large population of laboratory animals has been allowed to breed randomly for a number of generations.After several generations,25% of the animals display a recessive trait (aa),the same percentage as at the beginning of the breeding program.The rest of the animals show the dominant phenotype,with heterozygotes indistinguishable from the homozygous dominants. -What proportion of the population is probably heterozygous (Aa)for this trait?

Over time,the movement of people on Earth has steadily increased.This has altered the course of human evolution by increasing

Again,if this population were in equilibrium,and if the sickle-cell allele is recessive,what proportion of the population should be susceptible to sickle-cell disease under typical conditions?

Please use the following information to answer the questions below. A large population of laboratory animals has been allowed to breed randomly for a number of generations.After several generations,25% of the animals display a recessive trait (aa),the same percentage as at the beginning of the breeding program.The rest of the animals show the dominant phenotype,with heterozygotes indistinguishable from the homozygous dominants. -What is the most reasonable conclusion that can be drawn from the fact that the frequency of the recessive trait (aa)has not changed over time?

"Until the agricultural revolution 10,000 years ago,people used to live in small populations with little gene flow between them.That is the best situation for rapid evolution," said Sewall Wright,one of the founders of population genetics.This conclusion on gene flow conflicts with the Hardy-Weinberg equilibrium,which states that no gene flow means

Whenever diploid populations are in Hardy-Weinberg equilibrium at a particular locus,

A mutation that is neither harmful nor beneficial is termed a

Which one of the genetic drift effects would limit natural selection?

If the nucleotide variability of a locus equals 0%,what is the gene variability and number of alleles at that locus?

Please use the following information to answer the questions below. You are studying three populations of birds.Population A has 10 birds,of which 1 is brown (a recessive trait)and 9 are red.Population B has 100 birds,of which 10 are brown.Population C has 30 birds,and 3 of them are brown. -Which population is most likely to be subject to the bottleneck effect?

The sickle-cell allele is pleiotropic (i.e. ,it affects more than one phenotypic trait).Specifically,this allele affects oxygen delivery to tissues and affects an individual's susceptibility to malaria.Under conditions of low atmospheric oxygen availability,individuals heterozygous for this allele can experience life-threatening sickle-cell "crises." Such individuals remain less susceptible to malaria.Thus,pleiotropic genes/alleles such as this can help explain why

Natural selection changes allele frequencies because some ________ survive and reproduce more successfully than others.

If four of the original colonists died before they produced offspring,the ratios of genotypes could be quite different in the subsequent generations.This would be an example of