Thu January 24, 2013 By:

what is the relation between birds and reptiles?

Expert Reply
Wed January 30, 2013

It is a widely accepted notion that birds and reptiles share an ancestry. The leading theory in the evolution of modern reptiles and birds proposes that they descended from a common group of dinosaurs called theropods, which were carnivorous, bipedal (two-legged) dinosaurs that lived during the Triassic and Cretaceous periods.
In addition to sharing a common ancestry that predates the age of dinosaurs, birds and reptiles feature several similar attributes and physical characteristics.

Birds and reptiles are oviparous, meaning egg laying.

The bodies of birds and reptiles are covered entirely with different versions of scales that have developed over hundreds of thousands of years.

Birds and reptiles also share several skeletal and internal characteristics. Both have five fused bones in their jaws, a single middle ear bone and an almost identical nucleated red blood cell structure.

Reptiles and birds have a cloaca that serves as their body's only means of waste, reproductive and intestinal tract evacuations

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