Succession is the universal process of change in community composition over an ecological time scale. It is a unidirectional change.

Selection pressure has been categorized by the process of growth pattern, i.e., r-selection and k-selection. R-selection applies in early stage while k-selection in late stage.

Entropy measures the degree of randomness. Early stage has high entropy while late stage has low entropy.

Succession happens in a bare area where no community existed before is known as a primary, community and the succession which is followed by the destruction of primary community is called secondary succession.

Nudation is the first stage of succession where there is a development of the bare area by several external factors takes place.