BSC 2010 Chapter 15 Quiz

Suppose the size of a population of mustard plants is 6,000. According to genetic drift theory, what is the probability that a newly-arisen mutation will become fixed in this population?

1/12,000

The frequency of an allele in a population of manatees is 0.15. If the population is at Hardy-Weinberg for this locus, what number of 600 individuals should be homozygous for this allele?

13.5

You discover a population of seals and find it to be at Hardy-Weinberg equilibrium with respect to the A locus. Suppose that there are two alleles at this locus and the frequency of one of those alleles (the a-6 allele) is 0.4. Of the individuals that carry at least one a-6 allele, what percent are homozygotes?

25

The Hardy-Weinberg equilibrium is not applicable under which condition?

Asexual reproduction

Which statement about selection is true?

Dispruptive selection is the only type of selection that can produce a bimodial distribution.

Which evolutionary process adapts populations to their environments?

Natural selection

Which phenomenon is not an evolutionary mechanism?

Random mating

Which observation would most seriously challenge the hypothesis that most non-coding DNA is slightly deleterious?

Species with larger population sizes have more non-coding DNA.

_______ selection operates if individuals within a population with the smallest and largest body sizes have fewer offspring than those of average body size.

Stabilizing

The frequency of one allele for a given gene locus with two alleles (A at frequency p and a at frequency q) in a population is known. Assume Hardy-Weinberg conditions hold true. Which statement is false?

The frequency of heterozygotes is given by (p + q)/N, where N is the number of individuals in the population.

Which statement about the genomes of organisms is false?

The total size of the genome of eukaryotes varies little from organism to organism.

Which statement about synonymous mutations is true?

They do not change the phenotype.

Sexual recombination

can result in the elimination of harmful mutations.

In explaining what we now call evolution, Darwin often used the phrase "descent with modification." Fundamental to this idea is that

divergent species share a common ancestor.

Gene families are groups of _______ genes that arose by _______ and _______.

homologous; gene duplication; sequence evolution

A neutral mutation

is fixed in a population at a rate equal to the mutation rate.

A gene involved in neural development shows three times as many synonymous site substitutions than non-synonymous ones. A likely explanation is that this gene

is under purifying selection

Mistakes in the replication of DNA

provide genetic variation