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Altering Population Growth

Altering Population Growth - Lake Erie and lake trout...

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Altering Population Growth Human action is causing the extinction of species at thousands of times the natural rate. Extinction is caused by alteration of a population's environment in a harmful way. Habitat disruption is the disturbance of the physical environment of a species, for example cutting a forest or draining wetlands. Habitat disruption in currently the leading cause of extinction. Changes in the biological environment occur in three ways. 1. Species introduction: An exotic species is introduced into an area where it may have no predfators to control its population size, or where it can gratly out compete native organisms. Examples include zebra mussels introduced into
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Unformatted text preview: Lake Erie, and lake trout released into Yellowstone Lake where they are threatening the native cutthroat trout populations. 2. Overhunting: When a predator population increases or becomes more efficient at killing the prey, the prey population may decline or go extinct. Examples today include big game hunting, which has in many places reduced the predator (or in this case prey) population. In human prehistory we may have caused the extinction of the mammoths and mastodons due to increased human hunting skill. Secondary extinction: Loss of food species can cause migration or extinction of any species that depends largely or solely on that species as a food source...
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