Term
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Definition
-no natural populations can maintain exp. growth indefinitely
-population density is typically constant
-resources become limiting |
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Term
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Definition
The maximum population size an environment can support
-K varies
-Population growth rate (r)
-Pop growth slows as its density approaches |
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Term
| Logistic Growth Model on Natural Populations |
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Definition
-very small organisms fit well
-most pop. don't stabilize at K
-Predictions only correct when environment is constant, no predators, no competition |
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Term
| Why doesn't logistic curve fit natural populations? |
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Definition
Assumptions: 1) Each individual added to the population has same negative effect on population growth
-examples: isolated plants and flamingos, chance events
2) Population approaches (K) smoothly
3) Populations are large and density is important in regulation |
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Term
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Definition
| Any essential resource that is in short supply can limit population growth |
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Term
| Density-Dependent Control |
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Definition
Factors that alter per capita birth or death rates in a population are dependent on population density (can stabilize population density)
Ex: Parasitism, predation, competition |
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Term
| Density-independent Control |
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Definition
Factors that alter per capita birth or death rates in a population are independent of population density
Ex:Physical/chemical factors: weather, drought, freezes, flood and fire |
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