Question 1

The most common cause of extinction is:

Accepted Answer

Habitat change, primarily caused by human activities such as development, deforestation, and climate change, is the most common cause of extinction. Overspecialization and limited species range can also contribute to extinction, but these are less common factors. Asteroid impacts and interactions with other species can cause mass extinctions, but they are not the most common cause of individual species extinctions.

Question 2

The parasitic Rhagoletis flies that show a preference for either hawthorn or apple trees and are no longer interbreeding populations illustrate what type of speciation?

Accepted Answer

The parasitic Rhagoletis flies that show a preference for either hawthorn or apple trees and are no longer interbreeding populations illustrate sympatric speciation. This is because the two populations are in the same geographic location (sympatric), but have evolved distinct preferences for different host plants, which has caused reproductive isolation and prevented interbreeding.

Question 3

The immediate cause of most extinctions is:

Accepted Answer

Environmental change, such as climate change or habitat destruction, is the primary immediate cause of most extinctions. Overspecialization and hybridization can also contribute to extinctions, but are not the most common cause. Genetic drift and wide distribution are not immediate causes of extinction.

Question 4

Which statement BEST describes how overspecialization can affect a species?

Accepted Answer

If a species is highly specialized and the environment around it changes, the species may not be able to adapt quickly enough to survive, increasing the likelihood of extinction. Therefore, highly specialized adaptations can actually be a disadvantage for a species in a rapidly changing environment.

Question 5

The introduction of a new species into an area that has several differing habitats and very rich resources but no predators will likely lead to:

Accepted Answer

The introduction of a new species into an area with diverse habitats and abundant resources but no natural predators can lead to adaptive radiation. This is because the absence of predators allows the species to occupy multiple niches without competition or predation pressure, leading to the evolution of different adaptations and new species. Extinctions can also occur if the new species outcompetes or preys upon native species, but adaptive radiation is a more likely outcome. Mechanical incompatibility, limited speciation, and temporal isolation are not relevant to this scenario.

Question 6

The organisms most likely to undergo sympatric speciation by polyploidy are:

Accepted Answer

Polyploidy is more common in plants than in animals. This is because plant cells are able to tolerate multiple sets of chromosomes, whereas animal cells typically cannot handle the disruption in the balance of genetic material. Insects may also undergo polyploid speciation, but it is less common than in plants. Mammals, birds, and protists are unlikely to undergo polyploid speciation.

Question 7

The origins of 300 or more species of cichlid fish in Lake Malawi can BEST be explained by:

Accepted Answer

The fact that there are over 300 species of cichlid fish in Lake Malawi suggests that a single ancestral species rapidly diversified into many different species with adaptations to different ecological niches, which is a hallmark of adaptive radiation.

Question 8

A horse has a diploid number (2n)of 64 and a donkey has 2n = 62. The hybrid of these two species, mules, have 2n = 63 and are sterile. Why are mules sterile?

Accepted Answer

Mules have an odd number of chromosomes (63) because the horses and donkeys have a different number of chromosomes. During meiosis, one chromosome fails to pair and divide properly, leading to the production of non-functional gametes in mules. This results in mules being sterile as they are unable to produce viable offspring.

Question 9

When a species invades a new habitat and evolves rapidly into several new species to better exploit new resources, what has occurred?

Accepted Answer

Rapid evolution into several new species to better exploit new resources is characteristic of adaptive radiation.

Question 10

Which species is least likely to become extinct?

Accepted Answer

The answer of Which species is least likely to become...

Question 11

A single species of finch from South America was displaced to a new habitat in the Galápagos Islands and evolved rapidly into several new species as it exploited the new resources. What occurred in these Darwin's finches?

Accepted Answer

The evolution of multiple new species in a relatively short amount of time to exploit new resources is characteristic of adaptive radiation, which occurred with Darwin's finches in the Galápagos Islands. Phyletic speciation occurs when a species gradually transforms into a new species over a long period of time without a major event such as a migration or habitat change. Divergent speciation occurs when populations of a species become physically separated and evolve independently, resulting in distinct species. Stabilizing selection occurs when individuals with intermediate phenotypes have higher fitness than those with extreme phenotypes, resulting in a narrowing of the range of variation over time. Polyploidy is a type of genetic mutation where an organism has multiple sets of chromosomes, which can lead to reproductive isolation and speciation, but this is not what happened with Darwin's finches.

Question 12

Hybridization may lead to the extinction of a species because:

Accepted Answer

The answer of Hybridization may lead to the extinction of...

Question 13

What is the BEST explanation for the origin of the unique species recently found in the Annamite Mountains of Vietnam?

Accepted Answer

The unique species in the Annamite Mountains likely originated through allopatric speciation, where geographic isolation led to the divergence of species.

Question 14

Which statement BEST describes the reproductive isolation between populations of Rhagoletis flies found on apple and hawthorn trees?

Accepted Answer

Apple-liking males are more likely to encounter apple-liking females than hawthorn-liking females, leading to behavioral isolation based on host preference.

Question 15

Which of the following is the most prevalent immediate cause of extinction?

Accepted Answer

Environmental change is considered the most prevalent immediate cause of extinction due to factors such as climate change, habitat destruction, and pollution. While the other options can also contribute to extinction, they are not as widespread and immediate as environmental change.

Question 16

Which of the following is an example of adaptive radiation?

Accepted Answer

Adaptive radiation refers to the diversification of a single ancestral species into a variety of differently adapted descendants. Darwin's finches are an example of adaptive radiation as they are a collection of species that evolved from a common ancestral species and have diversified into different beak shapes and sizes based on their feeding habits and environments.

Question 17

Which species is MOST likely to become extinct?

Accepted Answer

Kirtland's warbler is at a higher risk of extinction because it has a small breeding range and its habitat is declining due to human activities such as logging and development. The other species mentioned have larger ranges and are not currently considered endangered.

Question 18

The introduction of a few individuals into a new habitat that is unoccupied by other members of the species is a(n):

Accepted Answer

The introduction of a few individuals into a new habitat that is unoccupied by other members of the species is a founder event. This is because these individuals become the founders of a new population in the new habitat.

Question 19

In northern Minnesota, the lynx (Lynx Canadensis)habitat overlaps the bobcat (Lynx rufus)habitat. The two can breed and produce healthy, fertile offspring, which could lead to:

Accepted Answer

The production of fertile offspring between two species can lead to increased competition for resources, potentially resulting in the extinction of one or both species due to hybridization and loss of distinct species characteristics.

Question 20

Overspecialized adaptations:

Accepted Answer

Overspecialized adaptations are the result of natural selection, as they evolve to suit specific environmental conditions. However, they do not necessarily promote adaptability to changes or independence from other species.

Quiz 16: The Origin of Species