ecological communities consistent all interacting species populations with any legal system most species populations within an established community such as the African savanna have interacted with one another over a long period of time the interactions that occur between populations in the community fall in to three major categories competition in which populations compete for limited resources predation in which orgenisms have one species kill and eat those of another and symbiosis in which two species populations live together in close association with one another
to the benefit of one or both of the species all these interactions act as forces have natural selection on the species populations involved bus populations are given biological community are intertwined with one another in it intricate coevolutionary process however these self-sustaining balance communities developed through gradual changes occurring over long periods of time during these periods of change one type a community gives way to another until a balanced self-sustaining community is established for example none of the earth's majestic forests originally began as forest up huge trees rather the land they now cover was initially inhabited by lichen washes grasses and low-growing shrubs it was only after a long period of time that the established forest ecosystems we see today we're formed the process by which ecosystems slowly change into balanced self-sustaining communities is called succession what's now take a closer look at the selective forces of competition predation and symbiosis as well as how self-sustaining communities are created through succession each species in the community a unique ecological niche them compasses all aspects that species way of life the concept of the ecological niche not only includes a species physical home or habitat one also it's food requirement behavior and predators