Chapter 8

Question 1

Species richness

Answer 1

a combination of its number of different species.

Question 2

species evenness

Answer 2

the abundance of individuals within each of its species

Question 3

niche structure

Answer 3

the number of ecological niches, how they resemble or differ from each other, and how species interact with one another.

Question 4

species equilibrium model/theory of island biogeography

Answer 4

a balance between two factors determines the number of different species found on an island: the rate at which new species immigrate to the island and the rate at which existing species become extinct on the island.

Question 5

habitat islands

Answer 5

national parks surrounded by a sea of developed and fragmented land.

Question 6

native species

Answer 6

are those that normally live and thrive in a particular community.

Question 7

nonnative species/invasive species/alien species

Answer 7

others that evolved somewhere else and then migrate into or are deliberately or accidentally introduced into a community.

Question 8

indicator species

Answer 8

species that serve as early warnings of damage or danger to a community.

Question 9

fragmentation

Answer 9

the draining and filling of inland wetlands, deforestation, and development.

Question 10

keystone species

Answer 10

they have a much larger effect on the types and abundances of many other species in a community than their numbers would suggest.

Question 11

interspecific competition

Answer 11

Attempts by two or more organisms of a singe species to use the same limited resources in an ecosystem.

Question 12

resource partitioning

Answer 12

process of dividing up resources in an ecosystem so that species with similar needs (overlapping ecological niches) use the same scarce resources at different times, in different ways, or in different places.

Question 13

predation

Answer 13

situation in which an organism of one species captures and feeds on parts or all of an organism of another species.

Question 14

chemical warfare

Answer 14

some prey species discourage predators with chemicals that are poisonous, irritating, foul smelling, or bad tasting.

Question 15

parasitism

Answer 15

Interaction between species in which one organism preys on another organism, by living on or in the host.

Question 16

mutualism

Answer 16

type of species interaction in which both participating species generally benefit.

Question 17

commensalism

Answer 17

an interaction between organisms of different species in which one type of organism benefits and the other type is neither helped nor harmed to any great degree.

Question 18

ecological succession

Answer 18

process in which communities of plant and animal species in a particular area are replaced over time by a series of different and often more complex communities.

Question 19

primary succession

Answer 19

ecological succession in a bare area that has never been occupied by a community of organisms.

Question 20

secondary succession

Answer 20

ecological succession in an area in which natural vegetation had been removed or destroyed but the soil is not destroyed.

Question 21

pioneer species

Answer 21

first hardy species, often microbes, mosses, and lichens, that begin colonizing a site as the first stage of ecological succession.

Question 22

early successional plant species

Answer 22

plant species found in the early stages of succession that grow close to the ground, can establish large populations quickly under harsh conditions, and have short lives.

Question 23

mid successional plant species

Answer 23

grasses and low shrubs that are less hardy that early successional plant species.

Question 24

late succession

Answer 24

mostly trees that can tolerate shade and form a fairly stable complex forest community.

Question 25

disturbance

Answer 25

a discrete event that disrupts an ecosystem or community.