Chapter 16

Question 1

Intraspecific competition

Answer 1

competition among individuals of the same species.

Question 2

Interspecific competition

Answer 2

competition among individuals of different species.

Question 3

Resource

Answer 3

anything an organism consumes or uses that causes an increase in population growth rate when it becomes more available.

Question 4

Renewable resources

Answer 4

resources that are constantly regenerated (e.g., seeds, sunlight).

Question 5

Nonrenewable resources

Answer 5

resources that are not regenerated (e.g., space).

Question 6

Leibig’s law of the minimum

Answer 6

law stating that a population increases until the supply of the most limiting resource prevents it from increasing further.

Question 7

Competition coefficients

Answer 7

variables that convert between the number of individuals of one species and the number of individuals of the other species.

Question 8

α

Answer 8

competition coefficient for species 1, which converts individuals of species 2 into the equivalent number of individuals of species 1.

Question 9

β

Answer 9

competition coefficient for species 2, which converts individuals of species 1 into the equivalent number of individuals of species 2.

Question 10

Zero population growth isocline

Answer 10

population sizes at which a population experiences zero growth.

Question 11

Coexistence of two species is most likely when…?

Answer 11

interspecific competition is weaker than intraspecifc competition (i.e., when α and β are less than 1).

Question 12

Competitive exclusion principle

Answer 12

two species cannot coexist indefinitely when they are both limited by the same resource.

When two species are limited by the same resource, one species is often a better competitor survives better when resources are scarce.

Question 13

Darwin’s thoughts on competition: related species

Answer 13

Darwin suggested that competition is most intense between related species because they have similar traits and consume similar resources.

For related species that compete strongly, natural selection should favor differences in habitat use.

Question 14

Which organisms are often the most susceptible to predation or herbivory?

Answer 14

the most competitive organisms

Question 15

Exploitative competition

Answer 15

competition in which individuals consume and drive down the abundance of a resource to a point that other individuals cannot persist.

Exploitative competition is considered indirect competition because it occurs through a shared resource.

Question 16

Interference competition

Answer 16

when competitors do not immediately consume resources but defend them; considered direct competition.

Question 17

Apparent competition

Answer 17

when two species have a negative effect on each other through an enemy—including a predator, parasite, or herbiviore.

Question 18

Allelopathy

Answer 18

a type of interference competition that occurs when organisms use chemicals to harm their competitors.

Allelopathy can be an effective strategy for invasive plants.