![]() |
![]() |
|||
![]() ![]() ![]() ![]() ![]() ![]() |
||||
![]() |
||||
|
Population Regulation |
|||
|
![]() |
![]() |
||
There are four basic processes that regulate the size of populations: births and immigration (both of which cause an increase in population) and death and emigration (which result in a decrease in population). These processes are mostly restricted to mobile creatures, like animals. When resources are plentiful, more individuals will be attracted to the area, and there will be more births. If times are not so good, however, no new individuals will be attracted to the area and many will disperse in search of a new and better place. As a result, there will also be a decrease in the birth rate. As a population increases in size, there is a corresponding increase in competition for resources such as food, water, nutrients and even space. The resulting decrease in available resources slows down the population growth either through a decrease in the birth rate, an increase in the death rate, or a combination of both. Eventually, however, the birth and death rates will even out so that the population can successfully survive on the available resources.
As a population grows, overcrowding becomes a major problem for the
species at hand. Not only does overcrowding cause increased competition for resources as discussed above, it causes other imbalances that can be even more detrimental to the population. Disease becomes a major problem when a group of animals are in close proximity to each other. Just as the bubonic plague
spread very rapidly through the cities of Europe, diseases are passed along very easily when there is not enough room for a population to spread out. Some diseases, if fatal, can cause
population numbers to drop rapidly. Other diseases can debilitate the entire population, causing a decrease in the birth rate through different means, such as sterility. |
||||
Updated August 13th, 2001 by AB |