it explains the unity and diversity of life theory of evolution is theory that explains how random changes in genetic material and competition for scarce resources causes species to change gradually it is a unifying theme in biology because without evolution biology has thousands of isolated and unrelated facts evolution ties those facts together into a single unified explanatory framework for example it can help explain why two rabbits which live in very different environments have so many characteristics in common it also tells us why they differ in certain specific ways.
