Write in what context did Darwin use the terms ' fitness', survival and selection while elaborating on the mechanism of evolution.

Explanation

The fitness , according to Darwin , refers ultimately and only reproductive fitness . Hence, those who are better fit in an environment , have more progeny than others . Therefore , will survive more and hence , are selected by nature . He called it natural selection and implied it as a machanism of evolution . Mutation , migration , genetic drift and natural selection result in evolution.