Wednesday, October 24, 2007

Community Ecology





A community consists of all the organisms that live together in one place. To be a community these organisms have to interact with one another. Whether its by competition or predation. Community ecology by it self is the study of interactions among all populations in one area.


A common mistake made is the confusion between a niche and a habitat. So what exactly is the difference? A habitat is the place in which an organism lives. On the other hand a niche is the specific job that an organism does within a habitat.





In the diagram above it shows competition within a niche. If the species on the bottom was removed then the smaller (darker species in the picture) species on top will take over and occupy the entire tidal zone. Although at lower depth the species on the bottom will out -compete the species on the top excluding it from the niche.


  • Competitive exclusion is when no two similar species can occupy the same niche during the same time (as shown in the diagram above).

  • For example: This is why lions and tigers do not occupy the same habitat as one another. Because they both have the same niche.

















A micro habitat is a small habitat within a much lager one... for example, in the rain forest each lizard has the same niche. But because they live in different levels of the rain forest there is no competitive exclusion occurring.

There are four different types of symbiotic interactions within a habitat. These interactions affect what goes on in the ecological community. These are the four symbiotic interactions:

  1. Competition-(-/-)

  2. Predation/ Parasitism

  3. Mutualism

  4. Commensalism

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