A Revolution Beneath the Seas

Life in the seas appeared 380 billion years ago. In the Cretaceous period, many species of marine life emerged, and some organisms ceased to evolve. During this fascinating period, the seas were the battlefield of an evolutionary revolution.

Molluscs began the attack by developing tools to pierce through shells. Crabs, lobsters, crawfish and other modern crustaceans reached their full development and continued the assault. Sharks, which appeared over 400 million years ago, underwent their greatest evolution ever. Entire families of marine organisms were threatened with extinction as bony fish (teleosts) diversified and predatory reptiles emerged.
Canadian Heritage Information Network
Canadian Heritage Information Network, Canadian Museum of Nature, Musée du Séminaire de Sherbrooke, Royal Tyrrell Museum

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