What is the main difference between adaptive radiation and other forms of speciation? adaptive radiation is a mechanism for evolution. adaptive radiation happens over a relatively short time. adaptive radiation requires a founding population. adaptive radiation occurs only on islands.

The correct answer would be "Adaptive radiation happens over a relatively short time".

Adaptive radiation refers to the process of evolution in which ancestor organisms diversify rapidly into a wide variety or new forms as a result of environmental changes, availability of new resources, availability of new niches, or new challenges.

Accumulation of adaptive radiations over a long period of time results in speciation.

For example, Darwin's finches adapted according to their feeding behavior.