Cope’s rule in the evolution of marine animals
In: Science (Washington). American Association for the Advancement of Science: New York, N.Y. ISSN 0036-8075; e-ISSN 1095-9203, more
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| Authors | | Top |
- Heim, N.A.
- Knope, M.L.
- Schaal, E.K.
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| Abstract |
Cope’s rule proposes that animal lineages evolve toward larger body size over time. To test this hypothesis across all marine animals, we compiled a data set of body sizes for 17,208 genera of marine animals spanning the past 542 million years. Mean biovolume across genera has increased by a factor of 150 since the Cambrian, whereas minimum biovolume has decreased by less than a factor of 10, and maximum biovolume has increased by more than a factor of 100,000. Neutral drift from a small initial value cannot explain this pattern. Instead, most of the size increase reflects differential diversification across classes, indicating that the pattern does not reflect a simple scaling-up of widespread and persistent selection for larger size within populations. |
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