ecology2

Question 1

number of organisms of one species that an environment can support indefinitely; populations below this tend to increase; those above this tend to decrease.

Answer 1

carrying capacity

Question 2

simple model that shows how matter and energy move through an ecosystem.

Answer 2

food chain

Question 3

a stable, mature community that undergoes little or no change in species over time.

Answer 3

climax community

Question 4

any biotic or abiotic factor that restricts the existence, numbers, reproduction, or distribution of organisms.

Answer 4

limiting factor

Question 5

all the living organisms that inhabit an environment.

Answer 5

biotic factors

Question 6

nonliving parts of an organism’s environment, air currents, temperature, moisture, light, and soil are examples.

Answer 6

abiotic factors

Question 7

growth pattern where a population grows faster as it increases in size; graph of a exponentially growing population resembles a J-shaped curve.

Answer 7

exponential growth phase

Question 8

layer of the atmosphere that helps to protect living organisms on Earth’s surface from damaging doses of ultraviolet radiation from the sun.

Answer 8

ozone layer

Question 9

organism that represents a feeding step in the movement of energy and materials through an ecosystem.

Answer 9

trophic level

Question 10

rain, snow, sleet, or fog with a pH below 7; causes the deterioration of forests, lakes, statures, and buildings.

Answer 10

acid precipitation

Question 11

colonization of barren land by pioneer organisms.

Answer 11

primary succession

Question 12

sequence of changes that take place after a community is disrupted by natural disasters or human actions.

Answer 12

secondary succession

Question 13

model that shows all the possible feeding relationships at each trophic level in a community.

Answer 13

food web

Question 14

a symbiotic relationship in which both species benefit.

Answer 14

mutualism

Question 15

animals that feed on animals that have already died.

Answer 15

scavengers-detrivores

Question 16

collection of several interacting populations that inhabit a common environment.

Answer 16

community

Question 17

limiting factors such as disease, parasites, or food availability that affect growth of a population.

Answer 17

density-dependent factors

Question 18

factor such as temperature, storms, floods, drought, or habitat disruption that affects all populations, regardless of their density.

Answer 18

density-independent factor

Question 19

group of ecosystems with the same climax communities; on land are called terrestrial , those in water are called aquatic .

Answer 19

biome

Question 20

group of organisms all of the same species, which interbreed and live in the same place at the same time.

Answer 20

population

Question 21

interactions among populations in a community; the community’s physical surroundings, or abiotic factors.

Answer 21

ecosystem

Question 22

orderly, natural changes, and species replacements that take place in communities of an ecosystem over time.

Answer 22

succession

Question 23

organisms that cannot make their own food and must feed on other organisms for energy and nutrients.

Answer 23

heterotrophs

Question 24

organisms that use energy from the sun or energy stored in chemical compounds to manufacture their own nutrients.

Answer 24

autotrophs

Question 25

organisms, such as fungi and bacteria, that break down and absorb nutrients from dead organisms.

Answer 25

decomposers

Question 26

permanent, close association between two or more organisms of different species.

Answer 26

symbiosis

Question 27

place where an organism lives out its life.

Answer 27

habitat

Question 28

portion of Earth that supports life; extends from high in the atmosphere to the bottom of the oceans.

Answer 28

biosphere

Question 29

role or position a species has in its environment; includes all biotic and abiotic interactions as an animal meets its needs for survival and reproduction.

Answer 29

niche

Question 30

scientific study of interactions between organisms and their environments.

Answer 30

ecology

Question 31

small organisms that drift and float in the water; includes both autotrophic and heterotrophic organisms, their eggs, and the juvenile stages of many marine animals.

Answer 31

plankton

Question 32

symbiotic relationship in which one organism benefits at the expense of another, usually another species.

Answer 32

parasitism

Question 33

symbiotic relationship in which one species benefits and the other species is neither harmed nor benefited.

Answer 33

commensalism

Question 34

the disappearance of a species when the last of its members dies.

Answer 34

extinction

Question 35

the total mass or weight of all living matter in a given area.

Answer 35

biomass

Question 36

variety of life in an area; usually measured as the number of species that live in an area.

Answer 36

biodiversity