he grouped the types of creatures according to their similarities: animals with blood and animals without blood, animals that live on water and animals that live on land.
due to the finches' habitat and their how they have to adapt to it. if there were different ways of eating etc, they would have a different styled beak to suit that adaptation.
hope it .
activities of living organisms (animals, burrows, plant roots), pressure from overlying load/materials and atmospheric conditions.