The Real World Has a Complex Interaction of Population Controls

The Real World Has a Complex Interaction of Population Controls

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The Real World Has a Complex Interaction of Population Controls Natural populations are not governed by a single control, but rather have the combined effects of many controls simultaneously playing roles in determining population size. If two beetle species interact in the laboratory, one result occurs; if a third species is introduced, a different outcome develops. The latter situation is more like nature, and changes in one population may have a domino effect on others. Which factors, if either, is more important in controlling population growth: physical or biological? Physical factors may play a dominant role, and are called density independent regulation, since population density is not a factor The other extreme has biological factors dominant, and is referred to as density dependent regulation, since
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Unformatted text preview: population density is a factor. It seems likely that one or the other extreme may dominate in some environments, with most environments having a combination control. Pollution Pollutants generally are (unplanned?) releases of substances into the air and water. Many lakes often have nitrogen and phosphorous as limiting nutrients for aquatic and terrestrial plants. Runoff from agricultural fertilizers increases these nutrients, leading to runaway plant growth, or eutrophication. Increased plant populations eventually lead to increased bacterial populations that reduce oxygen levels in the water, causing fish and other organisms to suffocate....
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This note was uploaded on 11/29/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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