Answer:
They are similar in that both involve the growth of new organisms in an environment. However they differ in that primary succession occurs in a place where no life had been before, while secondary succession occurs in place where life had been before, but was destroyed.
Some examples of primary succession include the formation of a new ecosystem after a volcano, glacier outbursts, or a nuclear explosion. Some examples of secondary succession include succession after fire, harvesting, logging, or abandonment of land or the renewal after a disease outbreak.