Which are the most successful animals on earth?

There are several species that have remained fairly similar for huge amounts of time. Sharks and alligators for instance though there are also many insects too.

Sharks are the most successful. They evolved before there was any life on land. They evolved 200 million years befor the dinosaurs and crocodiles. They evolved 150 million years before insects. They are the only animal that have reached the end of evolution and have stopped evolving. They evolved in the late Ordivician period and became sharks we know in the Silurain period, 400 million years ago. They are the perfect predator.