Question 1

In calculating alpha diversity, the Shannon diversity index measures

Accepted Answer

The Shannon diversity index measures the relative abundance of species in a community, taking into account both the number of species and their evenness. It does not measure absolute abundance, ecological or morphological diversity, or differences across habitats or communities.

Question 2

Following a severe ice storm in 1991 in Rochester, New York, the composition of the trees changed as the community recovered from the disturbance. This is an example of

Accepted Answer

Secondary succession is the process of ecological succession that occurs in areas that have been disturbed or disrupted, in this case, by the ice storm. As the community recovers from the disturbance, new species take over and the composition of the ecosystem changes.

Question 3

Sorenson's index measures _______ diversity.

Accepted Answer

Sorenson's index measures beta diversity, which is the difference in species composition between two communities or habitats. It takes into account both the number and relative abundance of species present in each community. Alpha diversity refers to the diversity within a single community, functional diversity relates to the variety of ecological functions performed by organisms, gamma diversity is the total diversity across multiple habitats or communities, and delta diversity is not a commonly used term in ecology.

Question 4

A study of diversity patterns in an agricultural area of southern England showed that rivers have _______ alpha diversity and _______ beta diversity.

Accepted Answer

Rivers typically have high alpha diversity due to the variety of habitats and niches they provide, but low beta diversity because the species composition is often similar across different river sites.

Question 5

According to the island biogeography model, _______ and _______ determine the number of species on an island.

Accepted Answer

The island biogeography model states that the number of species on an island is determined by the size of the island and its distance from the mainland. Larger islands closer to the mainland will have higher numbers of species, while smaller islands farther away will have lower numbers of species. This is because larger islands have more resources and can support larger populations, while islands closer to the mainland have more opportunities for colonization and gene flow.

Question 6

Which of the following is the correct chronological order (from youngest to oldest) for the succession of species in Glacier Park?

Accepted Answer

Lichens are pioneer species that colonize bare rock, followed by alders which improve soil conditions, and finally spruces which establish in the developed soil.

Question 7

One assumption of the theory of island biogeography is that _______ population sizes of species will _______.

Accepted Answer

The answer of One assumption of the theory of island...

Question 8

The island biogeography theory addresses

Accepted Answer

The island biogeography theory primarily addresses species-area relationships, explaining how the number of species on an island is related to the island's size and distance from the mainland.

Question 9

Which of the following would most likely be found late in succession?

Accepted Answer

As succession progresses, competition becomes more intense and plants may start producing chemicals that interfere with the growth of other plants. This is known as allelopathy, and it is more commonly found in later stages of succession.

Question 10

Which of the following is a hypothesis generated by biologists to explain species richness gradients?

Accepted Answer

Greater competition in the tropics leading to narrower niches is a hypothesis that explains why there might be more species in the tropics compared to other regions.

Question 11

Which of the following statements about the patterns of succession in moraines at Glacier Bay is true?

Accepted Answer

According to the passage, the youngest moraines at Glacier Bay are populated with bacteria, fungi, and photosynthetic microorganisms. There is no statement indicating that we know a great deal about the patterns of succession in moraines at Glacier Bay, or that the composition of the soil has remained constant over the past 200 years. Additionally, there is no information provided about the abundance of nitrogen in young moraines. Therefore, options A, C, and D are incorrect. Option E is incorrect because it includes option A, which is false.

Question 12

The plants that grow best on recently formed moraines at Glacier Bay are those that

Accepted Answer

Plants that form mutualisms with nitrogen-fixing bacteria can thrive in nutrient-poor soils, such as those found on recently formed moraines, by obtaining essential nitrogen through this symbiotic relationship.

Question 13

Which of the following statements about disturbances is false?

Accepted Answer

Disturbances can also be caused by abiotic factors, such as hurricanes, floods, fires, and earthquakes.

Question 14

Which of the following would be most useful for calculating alpha diversity?

Accepted Answer

The Shannon index is a commonly used measure of alpha diversity, which takes into account both species richness and evenness in a community. Sorenson's index is more commonly used to measure similarity between communities, while the other options (Spicoli index, species-area relationship, successional integral) are not commonly used measures of alpha diversity.

Question 15

In one community, 10 species of grasses are found. A nearby community has 15 species, and shares 6 of those species with the first community. What is Sorenson's index for these communities?

Accepted Answer

Sorenson's index can be calculated as:

Sorenson's index = (2 * number of shared species) / (number of species in community 1 + number of species in community 2)

In this case, the number of shared species is 6, the number of species in community 1 is 10, and the number of species in community 2 is 15.

Sorenson's index = (2 * 6) / (10 + 15) = 12 / 25 = 0.48

Therefore, the answer is C, 0.48.

Question 16

Daniel Simberloff and Edward Wilson tested the island biogeography theory by

Accepted Answer

Simberloff and Wilson tested the island biogeography theory by defaunating tiny islets of mangroves in the Florida Keys. They investigated how the size and distance of the islands affected the diversity and richness of the species present on the islands over time.

Question 17

Which of the following statements about species richness is true?

Accepted Answer

Species richness is highest in the tropics. This is because the tropics have a warm and stable climate throughout the year, which allows for high levels of productivity and diverse habitats to support a large number of species. Additionally, the tropics have a longer history of stable climate and geological conditions, allowing for the evolution and diversification of many species.

Question 18

Which of the following statements about island biogeography is false?

Accepted Answer

The theory of island biogeography is primarily concerned with predicting the number of species that will be found on an island based on its size and distance from the mainland. It is not primarily concerned with the identity of those species. Therefore, statement D is false.

Question 19

Three species of grasshoppers are found in a transect: 10 of species A, 15 of species B, and 25 of species C. What is the Shannon diversity index of this transect? (Note: * = times, and ln (x) is the natural logarithm of x.)

Accepted Answer

The answer of Three species of grasshoppers are found in...

Question 20

Which of the following statements about succession is false?

Accepted Answer

K-strategy plants are typically replaced by other K-strategy plants during succession, not r-strategy plants. R-strategy plants are typically successful in disturbed or recently cleared areas, whereas K-strategy plants are more competitive in stable, mature ecosystems.

Quiz 57: Community Ecology