The dilemma of the jet set
THE LARGE animals in the sea are almost all vertebrates: fish, turtles and whales. Only one group of invertebrates has produced creatures of comparable size and activity. These are the molluscs, on the face of it an unlikely group to have given rise to some of the ocean’s most outstanding athletes....
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| Format: | Article in Journal/Newspaper |
| Language: | English |
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Reed Business Information
1990
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| Online Access: | https://oceanrep.geomar.de/id/eprint/37815/ https://oceanrep.geomar.de/id/eprint/37815/1/2638.pdf |
| Summary: | THE LARGE animals in the sea are almost all vertebrates: fish, turtles and whales. Only one group of invertebrates has produced creatures of comparable size and activity. These are the molluscs, on the face of it an unlikely group to have given rise to some of the ocean’s most outstanding athletes. Yet it did. The cephalopods, a class of animals that includes the squids, cuttlefish and octopuses, are indisputably molluscs. They share a common body plan with clams and snails, but are greatly modified to allow them lifestyles comparable with those of the vertebrates. Between them, the cephalopod molluscs, the fish and the toothed whales constitute a formidable assemblage of predators, eating each other and anyone else available as a source of protein in the sea. The molluscs established themselves as predators of the midwater zone before the fish. The cephalopods apparently arose from small limpet-like animals that crawled on the seabed. These primitive forerunners of today’s sophisticated predators disputed possession of the late Cambrian sea floor with a range of other animals, most of them armoured, and many, we may safely assume, predatory. What distinguished the early protocephalopod from the rest of the mob was a capacity to secrete gas into the apex of its shell. |
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