why are there a huge amount of different insect varieties, like in ants, but only a small amount of different varieties in animals such as crocodiles?
In: Biology
I think a more relevant answer:
There actually used to be hundreds if not thousands of crocodilans (species) in the past and todays crocs/alligator are just the last survivors of an ancient lineage that was just outcompeted by other more evolved competition. They survived by being a niche animal that survives by filling a very very specific role (passive ambush predator in shallow water) that they fit very well. Outside of this role they are easily out-competed by other animals more evolved, this is why even if a larger variation of crocodile evolved it would die out because say wolves or lions would just be better at the role of land hunter.
Many insects like ants however are generalists that dominate in the insect world, because of this when they evolve into new variations those variations are able to compete with other animals already in that field. Another good example is cats and dogs, there used to be a lot of other large predators like Terror birds, but eventually these two species alone came to dominate the field worldwide (bears being the only real exception) and from their gradually evolve new variations like small fox’s and giant tigers etc.
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