chapter 20

Question 1

what is a community

Answer 1

consists of two or more populations of different species, living in the same geographic area and interacting with one another

Question 2

what is mutualism, what are some examples

Answer 2

an interaction between two species in which both species benefit
[shrimp shares its burrow with golby for protection; insects receive food from plants while spreading pollen from plant to plant; bacteria digest the cellulose in termites while living in digestive track] plus//plus

Question 3

what is predation, what are some examples

Answer 3

an interaction between species in which one species eploits another living species for food [hare and lynx] plus//minus

Question 4

what are keystone predators

Answer 4

not necessarily abundant in a community, but they exert as strong effect on the community structure [sea star]

Question 5

what are some prey defenses

Answer 5

camouflage, hiding, running away, gathering in large numbers, weaponry, chemical defenses, warning coloration

Question 6

what is parasitism, what are some examples plus//minus

Answer 6

an interaction between species in which the parasite benefits at the expense of the host by living either within or on the host
[fungus & American elm] if too successful, leads to extinction
[rabbits & viruses in Australia] coevolution of both parasite and host

Question 7

what is biological control

Answer 7

using one organism to control the numbers of another

Question 8

what is competition, what is competitive exclusion – what are some examples minus/minus*

Answer 8

an interaction between populations living in a common environment and sharing a limited resource minus//minus

Question 9

distinguish between habitat and niche

Answer 9

—>habitat – place where an organism lives

—>niche – the role than an organism plays in the place where it lives

Question 10

distinguish between a fundamental niche and a realized niche

Answer 10

—>fundamental niche – the physical limits of tolerance of the organism

—>realized niche – that portion of the fundamental niche which is actually utilized, determined by the physical factors and competition

Question 11

what is resource partitioning

Answer 11

closely related species avoiding excessive competition while sharing the same resource in different ways, areas or times

Question 12

distinguish between interspecific competition and intraspecific competition

Answer 12

—>intraspecific – within a single species

—>interspecific – between different species

Question 13

what is territoriality

Answer 13

individual or groups that claim a geographic area by defending it against intruders intraspecific competition

Question 14

what is ecological succession

Answer 14

the slow process whereby one community of plants and animals replaces another —- typically very slow process

Question 15

distinguish between primary succession and secondary succession

Answer 15

—>primary succession – establishes new communities in new previously unoccupied surfaces [bare rock, sand, bare soil]

—>secondary succession – the recovery of a once-vegetated area as it grows again towards climax [forest fires, volcanic eruptions]

Question 16

what are the stages of invasion in ecological succession

Answer 16

migration —>establishment —>aggregation —>competition

Question 17

what is a climax community

Answer 17

the terminal stage to which a plant community develops under a stable climate

Question 18

what is the climax community of this region

Answer 18

oak, hickory, beech, maple

Question 19

what is an ecosystem

Answer 19

community of plants and animals plus their non-living environment through which energy flows and minerals cycle

Question 20

what are the abiotic components of an ecosystem

Answer 20

water, oxygen, carbon dioxide, minerals, continuous supply of energy

Question 21

what are the biotic components of an ecosystem

Answer 21

producers, consumers, primary consumers, secondary consumers, tertiary consumers, and decomposers(detritivores)

Question 22

what is a food chain,

Answer 22

series of organisms, each of which is eaten by the next

Question 23

what is a food web

Answer 23

interconnected with one another in an overall pattern

Question 24

what is a trophic level

Answer 24

the feeding level in a food chain to which an organism belongs

Question 25

why are energy conversions in an ecosystem never 100% efficient

Answer 25

the amount of energy at each level that is available to be passed on is reduced because large amounts of energy loss [wastes; heat energy] therefore, there is not enough left to be passed on

Question 26

what limits the number of trophic levels in an ecosystem

Answer 26

limited amount of energy, not all food in one trophic is eaten and not all eaten food is useful [nutrients] [**on average, animals convert only 10% of energy they consume into new animal growth**]

Question 27

what is a pyramid of energy

Answer 27

the flow of energy through an ecosystem

Question 28

what is productivity

Answer 28

the amount of organic matter produced by the members of a given trophic level during a given period pf time

Question 29

which ecosystem contributes the most to the Earth’s net primary productivity

Answer 29

open oceans

Question 30

what are biogeochemical cycles

Answer 30

the movement of nutrient elements through an ecosystem by physical and biological processes

Question 31

what are the two general types of biogeochemical cycles

Answer 31

-->sedimentary –major reservoir is some sedimentary material such as soil, rocks or water -->atmospheric(gaseous) – major reservoir is the atmosphere

Question 32

describe three examples of biogeochemical cycles

Answer 32

carbon cycle, nitrogen cycle [**Hubbard Experimental Forest, forest cutting experiment**] water cycle, & phosphorus cycle

Question 33

why are decomposers important in the biogeochemical cycles

Answer 33

they are responsible for the breakdown and return of nutrients back into the environment

Question 34

what do scientists think is the main cause of global warming

Answer 34

(humans) pollution of nitrogen oxides in the atmosphere

Question 35

describe the water cycle, what are the three phases of the water cycle

Answer 35

evaporation, precipitation, runoff

Question 36

what is acid rain

Answer 36

sulfur and nitrogen mixed compounds (sulfuric acid) with water in the atmosphere

Question 37

what is pollution

Answer 37

wastes that are not destroyed as fast as they are produced or cannot be bio-degraded by the decomposers

Question 38

distinguish between primary productivity and secondary productivity

Answer 38

primary productivity – rate at which energy is stored in organic matter by photosynthesis in producers *gross primary productivity minus respiration = net primary productivity secondary productivity – rate of formation of new organic matter by heterotrophs