Hey student,

I hope you are doing good.

PRIMARY SUCCESSION:

• Primary succession is a type of ecological succession that takes place in an environment that is recently formed and lacks habitable soil but then is colonized for the first time by living organisms.
• Primary succession takes a longer time to complete.
• Some examples of primary succession include the formation of a new ecosystem after a volcano, glacier outbursts, or a nuclear explosion.

SECONDARY SUCCESSION:

• Secondary succession is a type of ecological succession that occurs in an environment with an already established ecosystem that gets disruption due to some events like fire or hurricane and is then re-colonized by other organisms.
• Secondary succession takes a shorter time to complete.
• Some examples of secondary succession include succession after fire, harvesting, logging, or abandonment of land or the renewal after a disease outbreak.

I hope it helps.