35. What is Ecological Succession? Distinguish between Primary succession and Secondary succession.

Ans: The sequential, gradual and predictable changes in the species composition in an area are called succession or ecological succession.

Primary succession:

It begins in areas where no living organisms ever existed. Therefore, the establishment of a biotic community is very slow.

e.g., newly cooled lava, bare rock, newly created pond or reservoir.

Secondary succession: It begins in areas where natural biotic communities have been destroyed.

e.g., abandoned farm lands, buried or cut forests. Since soil is available, it is a faster process.