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Populations Have a Minimum Viable Size

Populations Have a Minimum Viable Size - where conditions...

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Populations Have a Minimum Viable Size Even if a number of individuals survive, the population size may become too small for the species to continue. Small populations may have breeding problems. They are susceptible to random environmental fluctuations and genetic drift to a greater degree than are larger populations. The chance of extinction increases exponentially with decreasing population size. The minimum viable population (MVP) is the smallest population size that can avoid extinction by the two reasons listed above. If no severe environmental fluxes develop for a long enough time, a small population will recover. The MVP depends heavily on reproductive rates of the species. Range and Density | Back to Top Populations tend to have a maximum density near the center of their geographic range. Geographic range is the total area occupied by the species. Outlying zones,
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Unformatted text preview: where conditions are less optimal, include the zone of physiological stress (where individuals are rare), and eventually the zone of intolerance (where individuals are not found). The environment is usually never uniform enough to support uniform distribution of a species. Species thus have a dispersion pattern. Three patterns found include uniform, clumped, and random. Geographic ranges of species are dynamic, over time they can contract or expand due to environmental change or human activity. Often a species will require another species' presence, for example Drosophila in Hawaii. Species ranges can also expand due to human actions: brown trout are now found worldwide because of the sprerad of trout fishing....
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