Question

The rate of secondary succession is faster than primary succession because.
A. Soil or sediment is already present
B. Water is available in large quantity
C. Climax community is already present
D. pH of soil is favorable

Answer 1

Hint: The ecosystem constantly changes due to various factors. Environmental catastrophes like hurricanes, drought, and forest fires alter the communities existing in the ecosystem. Some environmental conditions like forest fires become necessary in some ecosystems which helps the soil to replenish nutrients and allows to get rid of debris built up.

Complete answer:
The change in an ecosystem that occurs due to the replacement of one community by the other through a series of systematic changes is known as ecological succession. The process of ecological succession occurring in any area or ecosystem may be due to the effects of the abiotic as well as the biotic components of the ecosystem.

Ecological successions are of two types which are the primary succession and the secondary succession. The primary succession takes place in an area which did not have any growth media or soil. In this type of succession, the substrate is unutilized by any type of organism. Primary succession is slow in nature and establishment of communities take a longer time. The lichens type of organism is the first organism to invade the area. They are known as the pioneer species. They complete their life cycle and depose forming the basic types of soil. After that some types of species also continue to remain and grow as well as decay in the area and finally a climax community is formed.

In the process of succession, environmental disturbances or catastrophes may cause to disrupt an already settled community. The changes brought about the ecological activities influence the organism as such several organisms may be wiped out. After these changes, some new types of species may invade the area. The plants are the pioneer species of these areas as soil is present already. Eventually, the species may form a stable community.

Secondary succession is faster than the primary succession as the growth media or the soil is already present which allows growth of the plants. The other factors such as the presence of few species also contribute towards the faster rate of growth in the secondary succession.

Hence, the correct answer is option (A).

Note: Ecological successions are affected by various factors and it is a complex process. The natural communities are constantly changing which brings about the process of succession. In a new area, the rate of succession will be much slower. In developed communities that had been disrupted by any changes, the rate of succession is faster and known as secondary succession.