if dinosaurs were reptiles and cold blooded, what would cause the evolutionary step to become warm blooded and birds as it’s said that birds are the closest living relatives of dinosaurs.

Question

if dinosaurs were reptiles and cold blooded, what would cause the evolutionary step to become warm blooded and birds as it’s said that birds are the closest living relatives of dinosaurs.

In: Biology

Answer 1

Many dinosaurs (and all birds) are thought to have been warm blooded. From the wikipedia article on dinosaurs, “Birds belong to the dinosaur subgroup [Maniraptora](https://en.wikipedia.org/wiki/Maniraptora), which are [coelurosaurs](https://en.wikipedia.org/wiki/Coelurosauria), which are theropods, which are saurischians.”. There are several existing branches of reptiles of which one gave rise to the dinosaurs and birds and another gave rise to the mammals. Warm-bloodedness arose several times throughout the history of life. In additions to (many) dinosaurs, birds, and mammals, many sea reptiles are thought to have been warm-blooded ([ichthyosaurs](https://en.wikipedia.org/wiki/Ichthyosaur), [pterosaurs](https://en.wikipedia.org/wiki/Pterosaur), [plesiosaurs](https://en.wikipedia.org/wiki/Plesiosaur)). See https://en.wikipedia.org/wiki/Dinosaur_renaissance. Also see [https://en.wikipedia.org/wiki/Mammaliamorpha](https://en.wikipedia.org/wiki/Mammaliamorpha) and [https://en.wikipedia.org/wiki/Evolution_of_mammals](https://en.wikipedia.org/wiki/Evolution_of_mammals) for the mammal lineage.