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Why reptiles became the first successful land animal |
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Answer» Reptiles arose about 310–320 million years ago during the Carboniferous period. Reptiles, in the TRADITIONAL sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled EGGS, and possess ectothermic metabolisms. So defined, the group is paraphyletic, excluding endothermic animals like birds and mammals that are descended from early reptiles. A DEFINITION in accordance with phylogenetic nomenclature, which rejects paraphyletic groups, includes birds while excluding mammals and their synapsid ancestors. So defined, Reptilia is identical to Sauropsida. |
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