Question 1

The fossil record indicates that whales evolved from:

Accepted Answer

The fossil record indicates that whales evolved from land-dwelling mammals with hooves, specifically a group known as artiodactyls. This is supported by the similarities in bone structure between artiodactyls and whales.

Question 2

In pools below waterfalls,where predation is _____,male guppies are _____,whereas in pools above waterfalls where predation is ______,male guppies are ______.

Accepted Answer

C

Question 3

Choose the phrase that best represents microevolutionary change.

Accepted Answer

Changes in allele frequency in a population is the best choice for microevolutionary change. This refers to the small scale changes in a population's gene pool, such as the increased frequency of an advantageous trait due to natural selection or genetic drift. The other options represent macroevolutionary changes, such as speciation or extinction events that occur on a larger scale.

Question 4

The molecular evidence of how the cytochrome c gene changes with time suggests that this gene evolves:

Accepted Answer

The molecular evidence of how the cytochrome c gene changes with time suggests that this gene evolves at a constant rate.

Question 5

In a certain population,the frequency of a dominant allele is represented by p = 0.7,and the frequency of the recessive allele is represented by 0.3.What is the frequency of the heterozygous genotype?

Accepted Answer

The frequency of the heterozygous genotype can be calculated using the formula 2pq, where p is the frequency of the dominant allele and q is the frequency of the recessive allele. 
Therefore, the frequency of the heterozygous genotype is:
2 x 0.7 x 0.3 = 0.42.

Question 6

Sickle-cell anemia in humans is an example of:

Accepted Answer

Sickle-cell anemia is an example of stabilizing or balancing selection, as carriers of the sickle-cell allele have some resistance to malaria, while individuals with homozygous sickle-cell anemia have severe negative health effects. Therefore, the selection pressure balances between the negative effects of the disease and the positive resistance to malaria.

Question 7

In small populations,gene frequencies can change drastically by chance alone.This phenomenon is called:

Accepted Answer

Genetic drift refers to random fluctuations in gene frequencies that occur in small populations. This randomness can lead to the loss of certain alleles or fixation of others, which can have a significant impact on the genetic diversity of the population over time. Migration, density-independent effects, and density-dependent effects all play a role in shaping populations, but they are not specifically related to the chance fluctuations caused by genetic drift.

Question 8

In human infants,there has long been evolution toward having the highest survival rate at a 6-7 pound birth weight.This is an example of:

Accepted Answer

Stabilizing or balancing selection favors the intermediate traits over extreme traits. In this case, human infants with a birth weight of 6-7 pounds have the highest survival rate and therefore, are favored by natural selection. This selects against infants with extremely high or low birth weights, resulting in stabilizing or balancing selection.

Question 9

When selection operates to eliminate intermediate phenotypes,it is referred to as:

Accepted Answer

Disruptive selection specifically targets and eliminates intermediate phenotypes, favoring the extremes at both ends of the spectrum. This process increases the variance in the population by promoting phenotypic diversity.

Question 10

The Hardy-Weinberg equilibrium is based on a number of assumptions.Which of the following is NOT one of those?

Accepted Answer

The Hardy-Weinberg equilibrium assumes that mating occurs randomly and that there are no mating preferences or selective pressures.

Question 11

When only a very few individuals give rise to a new population in a new area of favorable habitat,they might differ in appearance from the other,larger population from which they separated.This effect is called the:

Accepted Answer

The founder effect occurs when only a few individuals establish a new population in a new area of favorable habitat. Due to the small number of individuals, there is a higher likelihood of genetic drift taking place, leading to differences in appearance and genetic makeup from the larger population they separated from. The mutation effect refers to the introduction of new mutations into a population. Inbreeding effect and outbreeding effect refer to changes in genetic composition due to mating patterns within a population.

Question 12

A population of frogs developing a slight difference in their mating calls is an example of:

Accepted Answer

A slight difference in mating calls is a small genetic change within a population, which is a characteristic of microevolutionary change. Macroevolutionary change refers to larger-scale changes over a longer period of time, such as the emergence of new species. Hardy-Weinberg equilibrium refers to a theoretical state where a population's genetic composition remains constant over time. Artificial selection involves intentional breeding for specific traits and is not relevant to this scenario.

Question 13

Most types of organisms evolve at about the same rate.

Accepted Answer

Different organisms can evolve at different rates depending on various factors such as selection pressure, genetic variability, and environmental changes. For example, bacteria can evolve rapidly due to their short generation time and high mutation rate, while some species of trees may evolve much slower due to their longer generation time and lower mutation rate.

Question 14

Biochemical changes that occur in organisms through time can help us:

Accepted Answer

The biochemical changes that occur in organisms through time can help us infer relatedness, construct molecular family trees, and understand how groups of organisms changed through time. Therefore, all of the choices are correct.

Question 15

The notion that organisms that are more distantly related should have time to accumulate more biochemical differences than those more closely related can best be illustrated using:

Accepted Answer

The concept of a molecular clock is based on the idea that mutations occur at a relatively constant rate over time, allowing researchers to estimate when two species diverged from a common ancestor. Therefore, a molecular clock can be used to illustrate the accumulation of biochemical differences between distantly related organisms over time. The other options, such as radioactive isotope dating, gel electrophoresis, and a geologic time scale, do not directly relate to comparing biochemical differences between organisms.

Question 16

Features that are similar in organisms that are not evolutionarily related are due to:

Accepted Answer

Features that are similar in organisms that are not evolutionarily related are due to similar selective pressures. This is known as convergent evolution, in which unrelated organisms develop similar adaptations to similar environments or ecological niches.

Question 17

Two populations of flowers are separated by a mountain range and would not be capable of interbreeding.This is an example of:

Accepted Answer

Geographical isolation refers to physical barriers between two populations that prevent or reduce gene flow, typically resulting in the evolution of distinct species. In this case, the mountain range is a physical barrier that prevents the two populations of flowers from interbreeding.

Question 18

________________ results from microevolutionary changes that increase the likelihood of survival and reproduction.

Accepted Answer

Adaptation results from microevolutionary changes that increase the likelihood of survival and reproduction. These changes can result from natural selection, genetic drift, or gene flow. Adaptations can be anatomical, physiological, or behavioral, and they allow organisms to better exploit their environment and avoid predation or competition.

Question 19

If two species of birds occur in the same area but occupy different habitats they do not mate.This is an example of:

Accepted Answer

This is an example of ecological isolation, as the two species do not mate due to occupying different habitats. Behavioral isolation refers to differences in courtship behaviors, mechanical isolation refers to physical differences preventing mating, and temporal isolation refers to differences in breeding times.

Question 20

Over time,the same bones in different vertebrates were put to different uses.This falls under the category of:

Accepted Answer

This concept is described by homologous structures, which are anatomical features in different species that have a similar form or function due to shared ancestry, but may be used differently across species.

Quiz 14: Evolution and Natural Selection