This refers to the progressive changes that happen to the biological structure of an ecological community.
Over time, there are changes that take place in the composition of species that constitute an ecological community.
In the case of primary succession, a region that is uninhabited by any species gets occupied by a few species over a period of time.
In other cases, a preexisting group of species is replaced by a new group of species, a process called secondary succession.
As a general rule, it is believed that ecological communities move from possessing very little species diversity to a more stable state where they house an array of species.
