bio ch 14 quiz

Which scenario describes an example of the bottleneck effect?

Cheetahs almost went extinct approximately 10,000 years ago during a mass die‑off of large mammalian species. Very few cheetahs survived, leaving the population with little genetic diversity.

Which statements correctly describe gene flow?

Gene flow can occur when pollen from one population of a plant species is dispersed by the wind to another nearby population of the same plant species. Gene flow is defined as the movement of genes from one population to another.

Select the statements that accurately describe the effect of natural selection on genetic equilibrium.

It can cause an allele to become more abundant in a population if it provides a survival advantage over other alleles for that trait. It can cause a dominant allele for a gene to become less abundant in a population. It is an evolutionary force that prevents natural populations from being in genetic equilibrium.

Darwin's finches came from a mainland species where some individuals were able to move to the islands and then spread from one island to another. Is the genetic diversity of the new population of finches on the Galápagos increased or decreased in relation to the population on the mainland, and what is this an example of?

It increased their genetic diversity because it represents an example of gene flow.

Which scenario describes an example of genetic drift?

Many of the brown, black, and white mice living in a coastal town are killed when a storm causes prolonged flooding. By chance, the small number of mice with brown fur are the only individuals to survive.

Which scenario describes an example of founder effect?

Members of a brown‑winged finch species from the mainland fly to an island that is otherwise uninhabited by finches. They establish a new population with different allele frequencies than the original population.

Which of the statements regarding gene flow are true?

Migration out of a population can result in changes in allele frequencies in the population. A vast desert can act as a barrier to gene flow.

In a hypothetical population of butterflies, a dominant mutation in an allele that controls wing color has resulted in purple spots developing on the wings. The genetic change is heritable such that the offspring of butterflies who inherit at least one mutated allele will develop purple spots. The population of butterflies inhabits a windy field that contains many purple flowers. Individuals with purple spots are so well camouflaged on the purple flowers that they are eaten less frequently by predators. There are other fields with populations of the same species of butterfly nearby, but purple flowers are less prevalent in these nearby habitat areas. There are no borders between these fields and it is common for individuals from one population to be blown into another population by the wind. Despite the advantage the mutated allele confers to the butterflies in the field with many purple flowers, the mutated allele never occupies 100%100% of the gene pool and the population of butterflies always contains a mix of individuals with and without purple spots. What is the most likely explanation for why this trait does not spread entirely throughout the population?

Outside alleles enter the population through gene flow.

Which scenario describes an example of gene flow?

Some of the rare, red‑winged finches from a small island fly to a nearby island to feed. They mate with the native brown‑winged finches, which results in an increase in the red‑wing allele frequency on the new island.

How might gene flow between two duck populations impede each population's ability to be best adapted to its local environment?

The alleles brought into a population may produce traits that are not beneficial to the ducks living in that particular habitat.

You examine a population and note that its allele frequencies for a particular gene are p = 0.55 and q = 0.45. If you came back and examined the population after several generations and found that the values for p and q had not changed, which statement would be true for this gene?

The population is not undergoing drift.

Two hypothetical populations of rabbits live on a mountain, one at low elevation and the other at high elevation. Rabbits at the low elevation experience a mild climate and have short fur, whereas rabbits at the high elevation are exposed to cold conditions and have long fur. There are no geographic barriers separating the ranges of the two populations. An ecologist finds that in both the low and high elevation populations, there are a few rabbits that have intermediate fur length. She notes that the rabbits with intermediate fur length can successfully mate and produce offspring with rabbits that have short or long fur. What is the most likely explanation for why some rabbits have intermediate fur length?

There is gene flow between the low and high elevation populations.

A population of organisms is said to be in Hardy-Weinberg equilibrium if it is not evolving. In a population that is not evolving, the frequency of alleles, genotypes, and phenotypes remains stable over generations. There are several assumptions that must be true for a population to be in Hardy-Weinberg equilibrium. Select all of the statements that are assumptions of a population in Hardy-Weinberg equilibrium.

There is no net mutation of genes. There is no migration in or out of the population. Random mating occurs within the population.

What is inbreeding depression?

a decrease in fitness of a population as a result of related individuals breeding

The proportion of alleles present in a gene pool is called the _______ and is an important tool in measuring evolutionary changes.

allele frequency

The collection of __________ in a population constitutes that population's gene pool.

alleles

If a small population of people from sub-Saharan Africa move to eastern Europe, which term would best describe this movement?

gene flow

The complete collection of genes and their variants within a population is called the population's

gene pool.

Inbreeding can lead to a decrease in genetic diversity and _________.

inbreeding depression

Imagine a population of beetles. Some black beetles move into and start mating with a population of yellow beetles. This increases the frequency of genes for black coloration in the yellow beetles' population. Which evolutionary process does this scenario describe?

migration

According to the biological species concept, what is the definition of a species?

organisms that can interbreed in nature to produce healthy offspring

Which term describes the study of the distribution of genetic traits and the allelic changes that occur within a population?

population genetics

What is reproductive isolation?

prevention of gene flow between two populations due to physical or behavioral barriers

According to the biological species concept definition of a species, what characteristics do individuals belonging to the same species share?

reproduce under natural conditions produce viable offspring

What is inbreeding?

the mating of two genetically similar individuals to produce offspring