Amniotic Archosaur Ancestors of Dinosaurs and Birds
This chapter focuses on the amniotic archosaur ancestors of dinosaurs and birds. Amphibians, reptiles, monotremes, and birds—frog, alligator, platypus, and chicken—all hatch from eggs and all boast backbones. Yet the eggs of amphibians, and many of their traits, are significantly different from those of others. Leo Lionni's story, An Extraordinary Egg, hides some fascinating evolutionary twists linking these creatures together while defining their differences. In between the lines lurks the incipient origin of earth's most monstrous creatures: the dinosaurs. This chapter first examines the ancestry of archosaurs before discussing prominent inherited traits that define subgroups within the amniotes such as crocodiles. It also considers the bone anatomy that provides the clues to the close relationship between birds and dinosaurs; the “dinochicken,” Tyrannosaurus chickensis, reconstructed from imaginary fossil evidence; and whether dinosaurs are not truly extinct, but only evolved to become smaller and more feathery than in the past.
Cornell Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.
If you think you should have access to this title, please contact your librarian.
To troubleshoot, please check our FAQs, and if you can't find the answer there, please contact us.