Chapter 4: Populations and Communities

Question 1

Population

Answer 1

Members of the same species that live in the same area

Question 2

Community

Answer 2

Different species that all live in the same area

Question 3

Population growth

Answer 3

A change in populaion size

Question 4

Equilibrium

Answer 4

(births + immigration) = (deaths + emigration)

Question 5

Population Growth Rate

Answer 5

Amount the population has changed divided by the time it had to change

Question 6

Exponential Growth

Answer 6

Growth at a constant rate of increase

Question 7

Population Explosion

Answer 7

Results from exponential growth

Question 8

J-curve

Answer 8

the curve of exponential growth

Question 9

Logistic Growth

Answer 9

Some process slows growth so it levels off near carrying capacity

Question 10

Carrying Capacity (K)

Answer 10

the maximum population of a species a habitat can support without being ruined

Question 11

S-curve

Answer 11

Results from logistic growth

Question 12

Biotic potential

Answer 12

The number of offspring produced under ideal conditions

Question 13

Environmental Resistance

Answer 13

The biotic and abiotic factors that limit a population’s increase

Question 14

K-strategists

Answer 14

Lower biotic potential

1. care for and protect young
2. live in stable environment
3. larger, longer lived, well-adapted to normal environmental fluctuations
4. populations fluctuate around carrying capacity
5. equilibrian species

Question 15

R-strategists

Answer 15

Produce lots of young, but leave their survival to nature

1. low recruitment
2. rapid reproduction/movement/life span
3. adapted to changing environment
4. “boom-and-bust”

Question 16

3 Survivorship curves

Answer 16

Type 1 Survivorship: low mortality in early life
Type 2 Survivorship: Intermediate survivorship pattern
Type 3 Survivorship: many offspring that die young

Question 17

Population Density

Answer 17

Number of individuals per area

Question 18

Density-Dependent Factor

Answer 18

Increases with increased population density

Question 19

Density-Independent Factor

Answer 19

Its effects are independent of the density of the population

Question 20

Top-Down Regulation

Answer 20

Control of a population

Question 21

Bottom-Up Regulaion

Answer 21

Control of a population occurs as a result of scarcity of a resource

Question 22

Critical Number

Answer 22

the minimum population base allowing the survival and recovery of a population

Question 23

Threatened Species

Answer 23

populations are declining rapidly

Question 24

Endangered Species

Answer 24

Populations are near critical number

Question 25

Predator

Answer 25

The organism that does the feeding

Question 26

Prey

Answer 26

the organism that is fed upon

Question 27

Parasite

Answer 27

An organism that feeds on its "prey," usually without killing it

Question 28

Host

Answer 28

The organism that is being fed upon

Question 29

Herbivory

Answer 29

Eating plants

Question 30

Keystone Species

Answer 30

Play a crucial role in maintaining ecosystem biotic structure

Question 31

Intraspecific Competition

Answer 31

Competition between members of the same species for resources

Question 32

Territory

Answer 32

An area defended by an individual or group

Question 33

Territoriality

Answer 33

Reduces intraspecific fighting, which ensures adequate resources for some

Question 34

Interspecific competition

Answer 34

Fighting between different species in the same area

Question 35

Competitive Exclusion Principle

Answer 35

Species can't survive if they compete directly in many respects

Question 36

Resource Partitioning

Answer 36

The dividion of a resource and specialization in different parts of it

Question 37

Mutualism

Answer 37

Both species benefit

Question 38

Commensalism

Answer 38

one species benefits but the other is unaffected

Question 39

Amensalism

Answer 39

One species is harmed while the other in unaffected

Question 40

Symbiosis

Answer 40

A relationship between two organisms

Question 41

Selective Pressures

Answer 41

Environmental resistance factors that affect survival and reproduction

Question 42

Natural Selection

Answer 42

The process of specific traits favoring survival of certain individuals

Question 43

Biological Evolution

Answer 43

Modification of the gene pool of a species by natural selection over generations

Question 44

Fitness

Answer 44

An individual's average contribution to the gene pool of the next generation

Question 45

Reproduction Isolation

Answer 45

The original populations separate into two populations

Question 46

Plate Tectonics

Answer 46

Populations becaome isolated through the slow movement of Earth's continents

Question 47

Tectonic Plates

Answer 47

Huge slabs of rock in the Earth's crust that float on an elastic layer beneath them