Question 1

Which of the following best defines an ecological community?

Accepted Answer

A group of interacting species that occur together in the same place at the same time.

Question 2

Which method of subdividing a community focuses on organisms that make their living in similar ways, regardless of their taxonomic relationships?

Accepted Answer

Guilds

Question 3

A researcher is studying a coral reef and groups all nitrogen-fixing organisms together, even though they are not closely related taxonomically. This is an example of subdividing a community by:

Accepted Answer

Functional type

Question 4

Which of the following is a limitation of using stomach content analysis to construct food webs?

Accepted Answer

It requires large sample sizes and is destructive to the organism.

Question 5

In a food web, what does the thickness of the line between two species typically represent when biomass is included?

Accepted Answer

The flow of energy between the species.

Question 6

Which of the following best describes an interaction web?

Accepted Answer

A diagram that includes both trophic and non-trophic interactions among species.

Question 7

A scientist removes a predator species from an intertidal zone and observes a large increase in the abundance of its prey. What does this indicate about the predator's interaction strength?

Accepted Answer

The predator has a strong interaction strength.

Question 8

Which of the following is an example of an indirect positive effect in a mutualistic interaction web?

Accepted Answer

An ant protects an acacia tree from herbivores, benefiting the acacia.

Question 9

In exploitation competition, how do two species indirectly affect each other?

Accepted Answer

By reducing the shared resource, making less available for the other species.

Question 10

If the population of snails increases in a community where both snails and clams are preyed upon by octopuses, what is the likely indirect effect on the clam population?

Accepted Answer

Clam population will decrease due to increased predation.

Question 11

Which of the following best describes a guild in an ecological community?

Accepted Answer

A group of organisms that exploit the same class of environmental resources in a similar way.

Question 12

Which of the following is NOT a common way to subdivide a community for ecological study?

Accepted Answer

By reproductive rate

Question 13

Which of the following statements about food webs is TRUE?

Accepted Answer

Food webs can include both species and functional groups as nodes.

Question 14

A researcher uses stable isotopes to study the diet of a predator. What is a limitation of this method?

Accepted Answer

It can be ambiguous due to overlapping isotope signatures.

Question 15

Which of the following best describes the process for experimentally quantifying interaction strength between two species?

Accepted Answer

Measure the abundance of the target species, remove the interactor species, and measure the target abundance again.

Question 16

Which of the following scenarios best illustrates interference competition?

Accepted Answer

Two bird species directly fight over nesting sites.

Question 17

In the experiment with Pisaster sea stars and mussels, what was the observed effect of removing Pisaster from the intertidal zone?

Accepted Answer

A large increase in mussel abundance.

Question 18

Which of the following is a real-world example of a natural experiment affecting community structure?

Accepted Answer

Sea star wasting disease reducing Pisaster populations on the West coast.

Question 19

Which of the following statements about the boundaries of ecological communities is correct?

Accepted Answer

Community boundaries can be defined by physical or biological factors, but are often difficult to determine in nature.

Question 20

Which of the following best explains why ecologists often subdivide communities for study?

Accepted Answer

To make ecological tests more manageable by focusing on specific groups of species.

7.1 Community Ecology: Structure, Subdivision, and Species Interactions

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