Chapter 5

Question 1

Predation

Answer 1

occurs when a member of one species

the predator) feeds directly on all or part of a member of another species (the prey

Question 2

Parasitism

Answer 2

occurs when one organism (the para-
site) feeds on another organism (the host), usually by
living on or in the host.

Question 3

Mutualism

Answer 3

is an interaction that benefits both spe-
cies by providing each with food, shelter, or some
other resource.

Question 4

Commensalism

Answer 4

is an interaction that benefits one

species but has little or no effect on the other.

Question 5

Resource partitioning

Answer 5

occurs when species
competing for similar scarce resources evolve specialized
traits that allow them to share resources by using parts
of them, using them at different times, or using them in
different ways.

Question 6

Coevolution

Answer 6

When populations of two different species interact in such a way over a long period of time, changes in the gene pool of one species can lead to changes in the gene
pool of the other. Such changes can help both sides to become more competitive or to avoid or reduce competition.

Question 7

Population

Answer 7

is a group of interbreeding individuals

of the same species

Question 8

Age structure

Answer 8

its distribution of individuals among various age groups—can have a strong effect on how rapidly it increases or decreases in size.

Question 9

Range of tolerance

Answer 9

Every species has a range of tolerance to different changes in its ecosystem before dying

Question 10

Limiting factors

Answer 10

A number of physical or chemical factors can help to determine the number of organisms in a population. Sometimes one or more factors, known as

Question 11

Limiting factor principle

Answer 11

Too much or too little of any physical or chemical factor can limit or prevent growth of a population, even if all other factors are at or near the optimal range of tolerance.

Question 12

Environmental resistance

Answer 12

the combination of all factors that act to limit the growth of a population.

Question 13

Population crash

Answer 13

When a species shoots over an environment’s carrying capacity and can no longer sustain itself

Question 14

Population density

Answer 14

is the number of individuals in a

population found in a particular area or volume.

Question 15

Ecological succession

Answer 15

The normally gradual change in species

composition in a given area is called

Question 16

Interspecifc competition

Answer 16

occurs when members
of two or more species interact to gain access to the
same limited resources such as food, water, light,
and space.

Question 17

Primary ecological succession

Answer 17

involves the gradual establishment of biotic communities in lifeless areas where there is no soil in a terrestrial ecosystem or no bottom sediment in an aquatic ecosystem. Examples include bare rock exposed by a retreating glacier (Figure 5-19), newly cooled lava, an abandoned highway or parking lot, and a newly created
shallow pond or reservoir. Primary succession usually takes hundreds to thousands of years because of the need to build up fertile soil or aquatic sediments to provide the nutrients needed to establish a plant community.

Question 18

Secondary ecological succession

Answer 18

in which a series of communities or ecosystems with different species develop in places containing soil or bottom sediment. This type of succession begins in an area where an ecosystem has been disturbed, removed, or
destroyed, but some soil or bottom sediment remains.

Question 19

Inertia or persistence

Answer 19

the ability of a living system such as a grassland or a forest to survive moderate disturbances

Question 20

Resilience

Answer 20

the ability of a living system to be

restored through secondary succession after a more severe disturbance.