Final answer:
Ecological succession refers to the sequence of changes in a community after a disturbance; secondary succession is a type of such succession that occurs in previously colonized areas that got disturbed, leading to the replacement of species over time.
Step-by-step explanation:
The replacement of species that follows a disturbance in an already existing community is known as ecological succession. This process involves a sequence of changes that a community undergoes following a severe disturbance. In cases where the disturbance has occurred in areas already inhabited but affected by events such as natural disasters, the term secondary succession applies. Unlike primary succession which occurs on new, uncolonized land, secondary succession happens in environments where soil and some life forms already exist. Over time, the ecosystem sees several changes in the composition of plant and animal communities as new species move in and replace the previous ones, until a relatively stable, mature ecosystem is established.