What is carrying capacity? Why do populations fluctuate around some estimated value of K?

Answer 1

As population density increases, birth rates decrease and death rates increase. The carrying capacity is at the point when these two rates are equal.

Fluctuations may happen when the food availability; water supply; environmental conditions; and space change..

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Answer 2

Carrying capacity is the theoretical maximum population that a particular habitat can support. This is why predation (and hunting) is so necessary: to thin the herd. Otherwise, excess individuals will die either from starvation and disease, from intraspecies conflict, or end up destroying the habitat. When a population crashes after exceeding K, it usually rebounds even stronger, showing exponential growth, until K is exceeded again, and another decline occurs.

This is not true of human activity though, because the calculation of K ALWAYS fails to account for the benefits of technological advances, such as improved agricultural methods. This is why "environmentalists" are always so wrong with their predictions.

Answer 3

Carrying capacity is the "maximum population size that a particular environment can support." K varies because the amount of "limiting resourses" (food, water, shelter, etc.) changes from season to season and from year to year.