(a) What is ecological succession?

Explanation

The occurrence of relatively definite sequence of communities over a long period of time in the same area resulting in establishment of stable or climax community is known as ecological or biotic succession. Primary Succession : * It is also referred as .perisere. and is a type of biotic succession that occurs on a substratum devoid of any previous life,like bare rock, sand dunes, new islands exposed out of the sea etc. where there was previously no life. * Primary succession takes a very long time (more than thousands of years in case of climac forest on bare rock). Process of primary succession occurs through a number of sequential steps,which follow one another. Thet are nudation,invasion,migration,ecesis,aggregarion,competition,reaction,and stabilization. Secondary successions : * It 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. * The sequence of successional stages is called .suvsere. and time required for the completion of sere is much shorter than for primary succession.