New animal forms developed, too. The cephalopods became the dominant predators of this period. Cephalopods are a group of mollusks that are related to octopus and squid.The orthoceras was a straight-shelled cephalopod that lived in the largest open end of its shell. Its feet came out of its head! They could rise and fall in the ocean water like a submarine. The siphuncle was a tube in the center of the animal. When filled with air, the animal’s body floated upward. A burst of air out the back end of the siphuncle pushed the animal forward.
Cephalopods are the most intelligent, most mobile, and the largest of all molluscs. Squid, octopuses, cuttlefish, the chambered nautilus, and their relatives display remarkable diversity in size and lifestyle with adaptations for predation, locomotion, disguise, and communication. These "brainy" invertebrates have evolved suckered tentacles, camera-like eyes, color-changing skin, and complex learning behavior. Their lengthy evolutionary history spans an impressive 500 million years and the abundant fossils they've left behind (mostly shelled nautiloids and ammonoids) record repeated speciation and extinction events. From myths about their enigmatic fossilized remains to fantastic accounts of tentacled sea monsters, cephalopods also figure prominently in the literature and folklore of human societies around the world. Today, biologists and paleontologists continue to captivate the human mind and imagination with details of these molluscs' behavior, natural history, and evolution.
Cephalopods are the most intelligent, most mobile, and the largest of all molluscs. Squid, octopuses, cuttlefish, the chambered nautilus, and their relatives display remarkable diversity in size and lifestyle with adaptations for predation, locomotion, disguise, and communication. These "brainy" invertebrates have evolved suckered tentacles, camera-like eyes, color-changing skin, and complex learning behavior. Their lengthy evolutionary history spans an impressive 500 million years and the abundant fossils they've left behind (mostly shelled nautiloids and ammonoids) record repeated speciation and extinction events. From myths about their enigmatic fossilized remains to fantastic accounts of tentacled sea monsters, cephalopods also figure prominently in the literature and folklore of human societies around the world. Today, biologists and paleontologists continue to captivate the human mind and imagination with details of these molluscs' behavior, natural history, and evolution.
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