- 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.