Chapter 6

Question 1

Population

Answer 1

composed of all individuals that belong to the same species and live in a given area at a particular time

Question 2

Community

Answer 2

incorporates all of the populations of organisms within a given area

Question 3

Population Ecology

Answer 3

the study of factors that cause populations to increase or decrease

Question 4

Population Size

Answer 4

the total number of individuals within a defined area at a given time

Question 5

Population Density

Answer 5

the number of individuals per unit area (or volume, in the case of aquatic animals) at a given time

Question 6

Population Distribution

Answer 6

a description of how individuals are distributed with respect to one another

Question 7

Sex Ratio

Answer 7

a population is the ratio of males to females

Question 8

Age Structure

Answer 8

a description of how many individuals fit into particular age categories

Question 9

Density-Dependent Factors

Answer 9

influence an individual’s probability of survival and reproduction in a manner that depends on the size of the population

Question 10

Limiting Resource

Answer 10

a resource that a population cannot live without and which occurs in quantities lower than the population would require to increase in size

Question 11

Carrying Capacity

Answer 11

a limit to how many individuals the food supply could sustain

Question 12

Density-Independent Factors

Answer 12

have the same effect on an individual’s probability of survival and amount of reproduction at any population size

Question 13

Growth Rate

Answer 13

the number of offspring an individual can produce in a given time period, minus the deaths of the individual or its offspring during the same period

Question 14

Intrinsic Growth Rate

Answer 14

under ideal conditions, with unlimited resources available, every population has a particular maximum potential for growth

Question 15

Exponential Growth Model

Answer 15

Nt = Noen

Question 16

J-Shaped Curve

Answer 16

a growth exponential growth model

Question 17

Logistic Growth model

Answer 17

describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the evn

Question 18

J-Shaped Curve

Answer 18

a growth exponential model when graphed

Question 19

Logistic Growth model

Answer 19

describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment

Question 20

S-Shaped Curve

Answer 20

the logistic growth model when graphed

Question 21

Overshoot

Answer 21

becoming larger than the carrying capacity

Question 22

Die-Off

Answer 22

population crash

Question 23

K-Selected Species

Answer 23

species that exceed the carrying capacity

Question 24

Selected Species

Answer 24

species that have a high intrinsic growth rate because they produce often and produce large numbers of offspring

Question 25

Survivorship Curves

Answer 25

species that have distinct patterns of survival over time

Question 26

Corridors

Answer 26

Strips of habitat that connect the separated populations

Question 27

Metapopulation

Answer 27

a group of spatially distinct populations that are connected by occasional movements of individuals between them

Question 28

Community Ecology

Answer 28

the study of interactions with other species that determine the survival of a species in a habitat

Question 29

Competition

Answer 29

the struggle of individuals to obtain a limiting resource

Question 30

Competitive Exclusion Principle

Answer 30

two species competing for the same limiting resource cannot coexist

Question 31

Resource Partitioning

Answer 31

when two species divide a resource based on differences in the species’ behavior or morphology

Question 32

Predation

Answer 32

refers to the use of one species as a resource by another species

Question 33

True Predators

Answer 33

typically kill their prey and consume most of what they kill

Question 34

Herbivores

Answer 34

consume plants as prey

Question 35

Parasites

Answer 35

live on or in the organism they consume, referred to as their host

Question 36

Pathogens

Answer 36

parasites that cause disease in their host

Question 37

Parasitoids

Answer 37

organisms that lay eggs inside other organisms

Question 38

Mutualism

Answer 38

benefits two interacting species by increasing both species’ chances of survival or reproduction

Question 39

Commensalism

Answer 39

a type of relationship in which one species benefits but the other is neither harmed nor helped

Question 40

Symbiotic

Answer 40

the relationship of two species that live in close association with each other

Question 41

Keystone Species

Answer 41

a species that plays a role in its community that is far more important than its relative abundance might suggest

Question 42

Predator-Mediated Competition

Answer 42

when a keystone species is reduced or increased, the other species in the ecosystem are equally as effected

Question 43

Ecosystem Engineers

Answer 43

a keystone species may create or maintain habitat for other species

Question 44

Ecological Succession

Answer 44

the predictable replacement of one group of species by another group of species over time

Question 45

Primary Succession

Answer 45

occurs on surfaces that are initially devoid of soil

Question 46

Primary Succession

Answer 46

occurs on surfaces that are initially devoid of soil

Question 47

Secondary Succession

Answer 47

occurs in areas that have been disturbed but have not lost their soil

Question 48

Pioneer Species

Answer 48

species that are the first to occur in an area where the soil has been previously disturbed

Question 49

Theory of Island Biogeography

Answer 49

demonstrates the dual importance of habitat size and distance in determining species richness