Chapter 54: Community Ecology

Front 1

community

Back 1

group of populations of different species living close enough to interact

Front 2

interspecific interactions

Back 2

interactions with individuals of other species in the community (competition, predation, herbivory, symbiosis-parasitism, mutualism, commensalism-and facilitation)

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competitive exclusion

Back 3

slight reproductive advantage in competition will lead to local elimination of the inferior competitor

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ecological niche

Back 4

sum of a species's use of the biotic and abiotic resources in its environment;a species's ecological role within the ecosystem

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resource partitioning

Back 5

differentiation of niches that enables similar species to coexist

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character displacement

Back 6

characteristics diverge more in geographically overlapping than in separate populations of two species

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predation

Back 7

+/- interaction between two species in which one species, the predator, kills and eats the other, the prey

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cryptic coloration (camouflage)

Back 8

makes prey difficult to see

Front 9

aposematic coloration

Back 9

in animals with effective chemical defenses; warning coloration (adaptive because predator avoid prey that have bright colors)

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batesian mimicry

Back 10

a palatable, harmless, species mimics an unpalatable one (mimicry involves behavior change)

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herbivory

Back 11

+/- interaction in which an organism eats parts of a plant or alga

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alga

Back 12

a plant or plantlike organism of any of several classes of chiefly aquatic organisms

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symbiosis

Back 13

individuals of two or more species live in direct and intimate contact with one another (can be help, harmful, or neutral)

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parasitism

Back 14

+/- interaction in which one organism(parasite) derives its nourishment from another organism

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endoparasites

Back 15

parasites that live within the body of their host

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ectoparasites

Back 16

parasites that feed on the surface of their host

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mutualism

Back 17

+/+ interaction in which interaction benefits both species

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commensalism

Back 18

+/0 interaction that benefits one species but neither helps nor harms the other

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facilitation

Back 19

+/+ or +/0 interaction where species can have positive effects on survival/reproduction of other species without living in direct or intimate contact

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species diversity

Back 20

the variety of different kinds of organisms that make up the community

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species richness

Back 21

number of different species in the community

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relative abundance

Back 22

proportion each species represents in the community

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Shannon Diversity (H)

Back 23

H= -(Pa x ln(Pa)) + (Pb x ln(Pb)) + (Pc x ln(Pc))... where a,b,c=species in a community, p=relative abundance

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invasive species

Back 24

organisms that become established outside their native range

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trophic structure

Back 25

feeding relationships between organisms; way organisms use food resources

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trophic level

Back 26

comprising of organisms that share the same function in the food chain and the same nutritional relationship to the primary sources of energy

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energetic hypothesis

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length of food chain is limited by inefficiency of energy transfer among chain

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biomass

Back 28

the total mass of all individuals in a population

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dynamic stability hypothesis

Back 29

proposes that long food chains are less stable than short chains

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dominant species

Back 30

most abundant species in a community or collectively have the highest biomass

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keystone species

Back 31

not usually abundant in a community; species that exert strong control by pivotal ecological roles

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ecosystems engineers

Back 32

organisms that exert control on a community by changing the environment

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bottom-up model

Back 33

postulates a unidirectional influence from lower to higher trophic levels (v to h)

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top-down model

Back 34

predation controls community organization because predators limit herbivores, which limit plants, which limit nutrient levels through uptake (p to v to h to n)

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disturbance

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event that changes a community by removing organisms from it or altering resource availability; keeps many communities from reaching a state of equilibrium in species diversity or competition

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non-equilibrium model

Back 36

describes most communities as constantly changing after being affected by disturbances