Question

Differentiate between primary and secondary succession and provide one example of each.

Answer 1

Hint: Ecological succession is the process of evolution of structure of the biological species. It is a gradual change. It is a predictable and inevitable process of nature.

Complete Answer:

PRIMARY SUCCESSION	SECONDARY SUCCESSION
This type of succession begins in new habitats or lifeless areas.	This type of succession begins in the areas which were previously inhabited.
The plants and animals first colonize a lifeless habitat such as the areas which are devoid of soil.	The plants and animals recolonize a habitat after a disturbance like landslide, wildfire etc.
There is absence of humus as there is no soil in starting.	Presence of humus due to previous occupied place.
Takes `1000 years or more	Takes around 50-200 years.
An unfavourable environment since starting	From beginning the environment is favourable
Occurs in an area without any initial vegetation	Occurs in an area with initial vegetation.
This type of succession is initiated either by biological factor or an external agent.	This type of succession is initiated by an external factor.
The pioneer species in primary succession are mostly lichens followed by algae, fungi.	The pioneer species in this succession is mostly grasses.
No previous community is present.It takes a longer time.Examples- bare rock, ponds, deserts. Formation of new ecosystem after volcano, nuclear explosion.	Previous community is present.It takes a shorter time.Examples- the succession after fire, harvesting or the renewal after disease outbreak.

Note:There are two types of succession- primary and secondary succession. The secondary succession follows a major disturbance such as fire or flood. When succession reaches a climax which produces a stable community. This state of equilibrium is called a climax community.