Question 1

Evolution results from

Accepted Answer

Evolution results from a combination of all the listed factors: mutations introduce genetic variation, natural selection acts on that variation to determine which traits are favorable, genetic drift can randomly change the frequency of certain traits in a population, and gene flow introduces new genetic material from other populations.

Question 2

All of the following conditions are included in the Hardy-Weinberg equilibrium principle except

Accepted Answer

The Hardy-Weinberg equilibrium principle assumes random mating, meaning that individuals mate with each other regardless of their genotype. Non-random mating, such as assortative mating where individuals preferentially mate with others of the same genotype, violates this assumption and can lead to changes in allele frequencies in a population. Therefore, non-random mating is not included in the Hardy-Weinberg equilibrium principle.

Question 3

For thousands of years, humans have bred domesticated plants and animals to produce and maintain desirable traits, such as large fruits. Darwin used which term to describe this

Accepted Answer

The term Darwin used to describe the process of humans selecting desirable traits in plants and animals is artificial selection. This is a form of selective breeding that has been used for thousands of years to improve desirable characteristics in domesticated species.

Question 4

Which of the following correctly describes the Hardy-Weinberg equilibrium equation?

Accepted Answer

The Hardy-Weinberg equilibrium equation is represented as $p^2 + 2pq + q^2 = 1.0$, where $p$ and $q$ are the frequencies of the two alleles, and $p^2$, $2pq$, and $q^2$ represent the frequencies of the homozygous dominant, heterozygous, and homozygous recessive genotypes, respectively. Option D correctly matches this formula.

Question 5

What results could Clausen, Keck, and Hiesey have expected to see if alpine, mid-elevation, and lowland populations of sticky cinquefoil (Potentilla glandulosa) were not genetically different?

Accepted Answer

If the populations were not genetically different, then there would be no selective advantage for any particular elevation. As a result, all plants would be expected to grow equally well at all elevations. Therefore, choice E is the best answer.

Question 6

The Hardy-Weinberg principle states that

Accepted Answer

The Hardy-Weinberg principle states that allelic frequencies within a population will not change unless certain conditions are met. These conditions include: no mutation, no gene flow (i.e. migration), random mating, no genetic drift, and no natural selection. If these conditions are met, then the allelic frequencies within a population will remain the same from generation to generation.

Question 7

In a population of birds, the average beak size is selected against and the large and small sized beaks are selected for. This is an example of

Accepted Answer

Disruptive selection occurs when extreme traits are favored over intermediate traits, leading to a bimodal distribution of traits. In this case, the extreme traits are large and small beak sizes, which are selected for, while the intermediate trait (average beak size) is selected against. This is different from directional selection where one extreme trait is favored over the other, and stabilizing selection where intermediate traits are favored over both extremes. Natural selection is the process by which certain traits become more or less common in a population based on their impact on survival and reproduction. Balanced polymorphism occurs when multiple alleles for a gene are maintained in a population at relatively stable frequencies.

Question 8

Research on soapberry bugs (Jadera haematoloma) supports all of the following results except

Accepted Answer

The other choices are all supported by research on soapberry bugs: beak length positively correlated with fruit diameter (B), genetic differences observed between populations (C), natural selection occurred (D), and developmental changes occurred without genetic changes and beak length positively correlated with fruit diameter (E). However, choice A is not supported by the research, as there were observed genetic changes between populations.

Question 9

Locally adapted and genetically distinctive populations within a species are referred to as

Accepted Answer

Locally adapted and genetically distinctive populations within a species are referred to as ecotypes.

Question 10

Within a population, if the average is selected for and the two opposing extremes are selected against, this is an example of

Accepted Answer

Stabilizing selection favors the average phenotype and selects against extremes, leading to a reduction in phenotypic variation within a population. The other options (A: directional selection, B: disruptive selection, D: natural selection, and E: balanced polymorphism) either do not specifically describe selection for the average and against extremes, or do not accurately reflect the scenario described in the question.

Question 11

Evolution can be defined as

Accepted Answer

Evolution refers to a change in gene frequencies within a population over time, which can lead to adaptation and the emergence of new species. It does not necessarily favor the average phenotype, increase individual size, or eliminate "bad" traits. The extent to which phenotypic variation is due to genetic variation is a related concept, but not the same as evolution.

Question 12

Which of the following is not part of Darwin's theory of natural selection?

Accepted Answer

Darwin's theory of natural selection actually posits that more offspring are produced than can be supported by the environment, leading to competition for resources. This is contrary to choice C, which incorrectly states that fewer offspring are produced each generation than can be supported.

Question 13

Which of the following are conditions necessary to maintain Hardy-Weinberg equilibrium?

Accepted Answer

All of the choices are necessary to maintain Hardy-Weinberg equilibrium. If any of these conditions are not met (mutations occur, population size is small, fitness is not equal, or mating is non-random), the genetic frequencies of the population will change over time and the population will not be in Hardy-Weinberg equilibrium.

Question 14

Adaptation to the environment by a population does not include

Accepted Answer

Adaptation to the environment by a population always includes A, B, C, and D, so none of the choices are correct.

Question 15

In a population of lizards, the average and long length tails are selected against and the short tails are selected for. This is an example of

Accepted Answer

Directional selection occurs when selection favors one extreme phenotype over the other. In this case, the short-tailed lizards are being favored while the long-tailed lizards are being selected against, leading to a shift in the population towards the shorter-tailed phenotype.

Question 16

Over time, average phenotypes become less common and the population becomes phenotypically more diverse as a result of ________ selection.

Accepted Answer

Disruptive selection favors extreme phenotypes over intermediate phenotypes, which leads to a decrease in the frequency of intermediate phenotypes and an increase in the frequency of extreme phenotypes. This results in a more diverse population where the average phenotype becomes less common.

Question 17

Research conducted on the Glanville fritillary butterfly (Melitaea cinxia) can be summarized in all of the following statements except

Accepted Answer

Research on the Glanville fritillary butterfly has shown that inbreeding, smaller meadow sizes, and a decrease in heterozygosity can contribute to local extinctions. However, there is no direct evidence from this research that specifically links an increase in predation to local extinctions of this species.

Question 18

For a population in Hardy-Weinberg equilibrium, in a situation where there are only two alleles at a particular locus, the proportions of genotypes are: SS = 0.64, Ss = 0.32, and ss = 0.04. Calculate the allele frequency for the recessive allele.

Accepted Answer

According to the Hardy-Weinberg equilibrium equation, p² + 2pq + q² = 1, where p and q are the frequencies of the dominant and recessive alleles, respectively. The genotype frequencies given in the question can be used to solve for q² (the frequency of the homozygous recessive genotype):

ss = q² = 0.04

Taking the square root of both sides gives the frequency of the recessive allele, q:

q = sqrt(0.04) = 0.2

Therefore, the answer is B.

Question 19

Populations of field crickets (Teleogryllus oceanicus) native to Australia, but now found on the Hawaiian islands have decreased genetic diversity when compared to source populations. This is a result of

Accepted Answer

The decrease in genetic diversity can be attributed to genetic drift, which occurs in small populations and can lead to the random loss of certain alleles over time. Stabilizing selection could potentially maintain genetic diversity, and an increase in genetic diversity within populations would not result in a decrease in overall diversity. Large population sizes are usually associated with greater genetic diversity, so this cannot explain the observed phenomenon. Therefore, D is the best choice.

Question 20

Darwin is often considered the father of evolutionary thought. Which of the following terms is/are not part of Darwin's analysis?

Accepted Answer

While gene frequencies are a component of evolution and genetics, Darwin did not specifically analyze them in his work on natural selection and evolution through adaptation and fitness.

Quiz 4: Population Genetics and Natural Selection