Question 1

Which combination of attributes of a community should result in the lowest species richness?

Accepted Answer

Low specialization of species across a narrow resource spectrum means that there is little competition for resources, which allows for a greater number of species to coexist.

Question 2

Refer to the table.
 Similar to Tilman's studies of coexistence using diatoms, a research team is now examining competitive outcomes between two species of bacteria, A and B, which vary in how they use silica and phosphorus. The team manipulated both silica and phosphorus and examined whether bacteria A or bacteria B won the competition, or whether there was co-existence between the two species (denoted as outcome C). The results are shown in the table. From these results, the team concludes that

Accepted Answer

The answer of Refer to the table.
 Similar to Tilman's...

Question 3

Consider two species in competition for shared resources, species 1 and species 2. If these species are coexisting, which statement must be true?

Accepted Answer

When two species coexist in competition for shared resources, neither species typically reaches its carrying capacity due to the limiting effects of competition.

Question 4

Consider two interacting beetle species in an environment which switches between one of two states: state 1, in which species 1 outcompetes species 2; and state 2, in which species 2 outcompetes species 1. The time spent in either state, as well as the degree to which one species outcompetes the other, is roughly the same. Thus, on average, species 1 and 2 are comparable in their competitive abilities. According to Hutchinson's model of coexistence, in which of the scenarios is competitive exclusion most likely to occur?

Accepted Answer

Competitive exclusion is most likely to occur when the environment remains in one state long enough for one species to outcompete the other, as in scenario D where the environment switches every five weeks, allowing enough time for competitive exclusion to occur in four weeks.

Question 5

In Sousa's study of succession in intertidal boulder fields in California, disturbance was _______ proportional to the size of the boulders. The highest level of species richness occurred when disturbance was _______.

Accepted Answer

Disturbance was inversely proportional to the size of the boulders, and the highest species richness occurred at an intermediate level of disturbance.

Question 6

According to the dynamic equilibrium model, species diversity is highest when disturbance is at _______ levels and competitive displacement is at _______ levels.

Accepted Answer

Species diversity is highest when both disturbance and competitive displacement are at low to intermediate levels, allowing for a balance between species colonization and extinction.

Question 7

Refer to the table.
 The table shows hypothetical data for a community of fungi. These data show that the community best fits the _______ model. Based on this, one would predict that the diversity of the community with a disturbance of 16 and a competitive displacement of 16 would have a diversity of _______.

Accepted Answer

The answer of Refer to the table.
 The table shows...

Question 8

Which of the following is not an assumption of a neutral model of species coexistence?

Accepted Answer

Species use resources in similar ways is not an assumption of a neutral model of species coexistence. Neutral models assume that all species are ecologically equivalent and that their coexistence is maintained by random chance.

Question 9

Refer to the table.
 The table shows six species of bacteria with their population growth rates (per day) and competitive interaction strengths. Given the data, which assemblage of species would most likely fit the assumptions of the lottery model?

Accepted Answer

The answer of Refer to the table.
 The table shows...

Question 10

The ability of a community to remain the same in terms of its structure and function despite some perturbation is known as

Accepted Answer

Community stability refers to the ability of a community to maintain its structure and function despite disturbances or changes.

Question 11

Which statement about the redundancy hypothesis, explaining the relationship between species diversity and community function, is false?

Accepted Answer

The redundancy hypothesis does not predict a linear relationship between species richness and community function. Instead, it suggests that the value of adding species decreases as species richness increases, due to overlapping ecological functions.

Question 12

The study of snails by Johnson et al. (2009) found that increasing species richness and

Accepted Answer

Increasing species richness and increasing population density can both decrease parasite transmission. This is because a more diverse community of snails is less likely to be infected with a particular parasite, and a higher population density of snails means that there are more potential hosts for the parasite, which can dilute the infection.

Quiz 19: Species Diversity in Communities

Which combination of attributes of a community should result in the lowest species richness?

Consider two species in competition for shared resources, species 1 and species 2. If these species are coexisting, which statement must be true?

In Sousa's study of succession in intertidal boulder fields in California, disturbance was _ proportional to the size of the boulders. The highest level of species richness occurred when disturbance was _.

According to the dynamic equilibrium model, species diversity is highest when disturbance is at _ levels and competitive displacement is at _ levels.

Refer to the table. The table shows hypothetical data for a community of fungi. These data show that the community best fits the _ model. Based on this, one would predict that the diversity of the community with a disturbance of 16 and a competitive displacement of 16 would have a diversity of _.

Which of the following is not an assumption of a neutral model of species coexistence?

Refer to the table. The table shows six species of bacteria with their population growth rates (per day) and competitive interaction strengths. Given the data, which assemblage of species would most likely fit the assumptions of the lottery model?

The ability of a community to remain the same in terms of its structure and function despite some perturbation is known as

Which statement about the redundancy hypothesis, explaining the relationship between species diversity and community function, is false?

The study of snails by Johnson et al. (2009) found that increasing species richness and