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E and K Selection

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Submitted By shamin195
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Species in the environment, r and K selection
K and r selection: * r - the intrinsic rate of increase * K - the carrying capacity for the organism in that environment * r and K selection was an early attempt to identify life-history distinctions * r-selected species do well at low population density, and are at an advantage in frequently disturbed habitats * K-selected species do well at high population density and are at an advantage in constant or predictable habitats * Heuristically very useful as it allows use to predict the types of species likely to occur under different disturbance regimes
R selection: * r-selected species have a rapid rate of population increase. * This is typical of species that colonise short-lived environments or of populations that undergo large fluctuations * Eg. Weeds, aphids, bacteria

K selection: * K - selected species have superior competitive ability in stable environments where rapid population growth is unimportant as the population is maintained near K

Ways to categorize/class species: * By biome or community type * By life history strategy * By life reproductive strategy * By basic approach to the environment
What governs the distribution of species? * Evolutionary factors populations separated on to geographically distinct regions have different evolutionary trajectories * Dispersal constraints species may not have reached all suitable areas * Abiotic constraints all species have a range of physical (climatic) or chemical (e.g. substrate type) tolerances * Biotic constraints interactions with other species may exclude or include species from a community * Human influences recently species have been deliberately or inadvertently transported from one region to another
The species pool concept

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