Why Mammals Got Bigger

Saturday, February 4, 2012 - 09:40 in Paleontology & Archaeology

In evolutionary biology, Cope’s rule refers to the trend towards increasing body size in a lineage over geological time periods. Put simply, the rule says that members of a lineage get bigger over time. The rule has received mixed support, applying to some lineages (such as fossil mammals), but suffering from inconclusive evidence in others (Mesozoic birds, living mammals). To explain the occurrence of the trend in some lineages, two explanations can be put forward: A passive mechanism: body size evolution passively drifts away from a lower boundary, an idea favored by S.J. Gould, among others. read more

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