Why are there so many species?

Answer 1

There are many environmental conditions - hot,cold. fry, wet - each supporting various plant ecosystems which are each designed to exploit specific conditions in the local environment. These many species are tasty, good protective cover and good breeding ground for species which are adapted to specific conditions of periods of productivity. Each of these species living on the plants is in turn tasty to some other omnivorous or carnivores species. As a result there are many niches to be filled in the ecosystem.