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AP BIO
CH 54
Question | Answer |
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community | populations of different species living close enough to interact with each other |
interspecific interactions | relationship between individuals of two or more species in a community |
interspecific competition | competition for resources between individuals of two or more species when resources are in short supply |
competitive exclusion | when populations of two similar species compete for same limited resources, the one that uses the resources more efficiently will have a reproductive advantage and eliminate the other population |
ecological niche | the sum of a species use of the biotic and abiotic resources in its environment |
resource partitioning | division of environmental resources by coexisting species where the niche of each species differs by one or more significant factors from those of all the coexisting species |
character displacement | the tendencies for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species. |
aposematic coloration | bright warning coloration of many animals with effective physical or chemical defenses |
cryptic coloration | camouflage that makes a potential prey difficult to spot against its background |
Batesian mimicry | harmless species looks like a species that is poisonous or otherwise harmful to predators |
Mullerian mimicry | reciprocal mimicry by two unpalatable species |
herbivory | interaction in which an organism eats part of a plant or alga |
symbiosis | an ecological relationship between organisms of two different species that live together in direct and intimate contact |
parasitism | a symbiotic relationship in which one organism, the parasite, benefits at the expense of the other, the host, by living either within or on the host |
parasite | an organism that feeds on the cell contents, tissues, or body fluids of another species |
endoparasite | a parasite that lives within a host |
ectoparasite | a parasite that feeds on the external surface of a host |
mutualism | a symbiotic relationship in which both participants benefit |
obligate mutualism | mutualistic relationship in which at least one species has lost the ability to survive on its own |
facultative mutualism | mutualistic relationship in which both species can survive alone |
commensalism | a symbiotic relationship between two species that benefits one while the other is neither harmed nor helped |
facilitation | an interaction in which one species has a positive affect on the survival and reproduction of another species without the intimate association of a symbiosis |
species diversity | the variety of different kinds of organisms that make up a community |
species richness | a component of species diversity describing the number of different species in the community |
relative abundance | a component of species diversity that describes what percent or proportion each species represents of all individuals in the community |
Shannon diversity | an index of community diversity |
biomass | the total mass of all organisms in a habitat |
invasive species | a species often introduced by humans that takes hold outside its native range |
trophic structure | the different feeding relationships in an ecosystem |
food chain | path along which food energy is transferred from trophic level to trophic level, beginning with producers |
food web | interconnected feeding relationships in an ecosystem |
energetic hypothesis | concept that the length of a food chain is limited by the inefficiency of energy transfer along the chain |
dominant species | the species in a community that are the most abundant or have the highest biomass |
keystone species | a species that is not necessarily the most abundant, but which exerts strong control on the community structure due to its ecological role or niche |
ecosystem engineers | an organism that influences community structure by causing physical changes in the environment |
bottom-up model | model of community organization in which nutrients influence community organization by controlling plant or phytoplankton numbers, which in turn control herbivore numbers, which in turn control predator numbers |
top-down model | model of community organization in which predation influences community organization by controlling herbivore numbers, which in turn control plant or phytoplankton numbers, which in turn control nutrient levels; also called the trophic cascade model |
biomanipulation | an approach that applies the top-down model of community organization to alter ecosystem characteristics |
disturbance | a natural or human-caused event that changes a biological community and usually remove organisms from it; it can play a pivotal role in the structure of many communities |
nonequilibrium model | a model that maintains that communities change constantly after being buffeted by disturbances |
intermediate disturbance hypothesis | concept that moderate levels of disturbances can foster greater species diversity than low or high levels of disturbance |
ecological succession | `transition in the species composition of a community following a disturbance; establishment of a community in an area virtually barren of life |
primary succession | type of ecological succession that occurs in an area where there were originally no organisms present and where soil has not yet formed |
secondary succession | type of ecological succession that occurs in a community that has been cleared by some disturbance that leaves the soil barren |
evapotranspiration | the total evaporation of water from an ecosystem, including water transpired by plants and evaporated from a landscape, usually measured in mm and estimated for a year |
species-area curve | the biodiversity pattern that shows that the larger the geographic area of a community is, the more species it has |
pathogens | an organism or virus that causes disease |
zoonotic pathogens | a disease-causing agent that is transmitted to humans from other animals |
vector | organism that transmits pathogens from one host to another |