What is ecological succession? Distinguish primary succession from secondary succession.

Explanation

It is the fairly and gradual replacement of species composition in an area Primary succession is also referred as ‘perisure’ and is a type of biotic succession that occurs on a substratum devoid of any previous life like bare rock, sand dunes, new islands exposer out of the sea etc. where there was previously no life.
Secondary succession is the biotic succession that occurs in an area, which had an existing biotic community and has become bare due to destruction by fire, landslide, earthquake etc.