Question 1

In many bird species, the number of eggs laid is negatively correlated with the survival of the young.At the extreme of very large clutch sizes, hardly any of the young survive.Clutch size variation is largely due to genetic factors.In light of this, which statement is most likely to be true?

Accepted Answer

The negative correlation between clutch size and survival of young suggests a trade-off between producing many offspring and investing resources in their survival. Genetic factors play a large role in determining clutch size, so there is potential for selection to act on these genes. However, favoring very large clutches would likely result in low survival rates, so intermediate-sized clutches that balance reproductive output with offspring survival are most likely to be favored by natural selection.

Question 2

Suppose the population size of a species of field mice is 2 million.It has a mutation rate of 2 × 10^-9, and its genome size is 3 billion bp.The number of new mutations that appear in this species would be about _______.

Accepted Answer

The answer of Suppose the population size of a species...

Question 3

Which statement about the neurotoxin tetrodotoxin (TTX) is false?

Accepted Answer

Tetrodotoxin (TTX) actually interferes with nerve conduction by blocking voltage-gated sodium channels, not glycolysis.

Question 4

Which would not be considered an example of a trade-off?

Accepted Answer

Trade-offs involve a balance between benefits and costs, often seen in adaptations where an advantage in one aspect leads to a disadvantage in another. Choice B describes a genetic predisposition to diseases without mentioning any benefit or advantage associated with having the e4 allele, thus it does not illustrate a trade-off.

Question 5

In scientific terms, the word "_______" refers to a significant body of factual evidence and its applications in a particular field of knowledge.

Accepted Answer

The answer of In scientific terms, the word "_______" refers...

Question 6

The differential contribution of offspring to the next generation by various genetic types belonging to the original population is known as _______.

Accepted Answer

The answer of The differential contribution of offspring to the...

Question 7

Suppose variants at a single locus affect wing length in a species of crickets, with homozygotes for the L allele having long wings, homozygotes for the l allele having short wings, and heterozygotes having wings of intermediate length.In one population of 500 individuals, 340 have long wings, 120 have intermediate-length wings, and 40 have short wings.The frequency of the L allele is _______.

Accepted Answer

The answer of Suppose variants at a single locus affect...

Question 8

The average size of downy woodpeckers in North America gradually increases as one moves north.What term best describes this phenomenon?

Accepted Answer

Clinal variation describes the gradual change in a trait along a geographic gradient. In this case, the gradual increase in downy woodpecker size as one moves north fits this description. The other options are unlikely to be at play in this scenario; directional selection implies that there is a selective pressure driving the evolution of larger downy woodpeckers, which is not mentioned in the question. Frequency-dependent selection refers to selection that depends on the relative abundance of different alleles in a population, and there is no indication that this is influencing downy woodpecker size. Muller's ratchet is a hypothesis that suggests that asexual populations will accumulate deleterious mutations over time, which does not seem relevant here. Genetic drift is a random process that can lead to the loss of genetic diversity in a population, but there is no mention of this in the question either.

Question 9

Studies of enzyme genotypes and flight in Colias butterflies showed that

Accepted Answer

The study found that males heterozygous for the PGI gene had greater mating success because they were able to fly farther in a broad range of temperatures. This suggests that genotypes for the PGI gene do affect flight ability and that heterozygous individuals have an advantage in this regard. The other choices are not supported by the study.

Question 10

Suppose that in a population of 1,400 individuals, 125 individuals are homozygous for allele A7 and 450 are heterozygous for the same allele.The frequency of the A7 allele is therefore _______.

Accepted Answer

The answer of Suppose that in a population of 1,400...

Question 11

If the frequency of an allele is 0.6, we would expect to find _______ copies of that allele in a population of 1,100 individuals.

Accepted Answer

The answer of If the frequency of an allele is...

Question 12

If the frequency of one allele at a locus with two alleles is 0.73, the frequency of the other allele must be _______.

Accepted Answer

The answer of If the frequency of one allele at...

Question 13

If there is only one allele at a locus in a particular population, that allele is said to be fixed and the locus is _______.

Accepted Answer

The answer of If there is only one allele at...

Question 14

The most likely reason that subpopulations often vary genetically from one another is that they

Accepted Answer

Subpopulations living in different environments may be subject to different selective pressures, resulting in differential survival and reproduction of individuals with certain traits. Over time, this can lead to genetic differences between subpopulations.

Question 15

The genome of a virus with 9,000 nucleotides has had 18 new mutations.The mutation rate is thus _______ percent.

Accepted Answer

The answer of The genome of a virus with 9,000...

Question 16

An allele in a population of oysters has a frequency of 0.21.Out of 600 oysters, _______ copies of the allele are present.

Accepted Answer

The answer of An allele in a population of oysters...

Question 17

Which of the following can act as a constraint on the evolutionary process?

Accepted Answer

All the options listed can act as constraints on the evolutionary process. The trade-off between the cost and benefit of an adaptation (A) can limit the development or persistence of certain traits. The occurrence of rare catastrophic events (B) can drastically alter the course of evolution by causing mass extinctions or changing environments. The fact that all evolutionary innovations are modifications of previously existing structures (C) means that evolution is constrained by an organism's existing anatomy and genetic makeup, limiting the directions evolution can take.

Question 18

The observation that females of a species of beetles prefer to mate with males with relatively rare color patterns would be an illustration of

Accepted Answer

Frequency-dependent selection occurs when the fitness of a phenotype depends on its frequency in the population. In this case, the rare color pattern of males is preferred by females, which increases the fitness of males with that phenotype. This creates a situation where the fitness of a phenotype depends on its frequency in the population, resulting in frequency-dependent selection.

Question 19

The table shows the average performance of different genotypes at the A locus for three different populations of lizards in two different environments.The number before the slash is for running speed (in meters per second), and the number after the slash is for relative strength.  In which population is there evidence of a trade-off between running speed and relative strength?

Accepted Answer

The answer of The table shows the average performance of...

Question 20

Charles Darwin and _______ independently articulated the concept of natural selection.

Accepted Answer

The answer of Charles Darwin and _______ independently articulated the...

Quiz 20: Mechanisms of Evolution