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Amniotes Emerge: Amniotic Eggs

By Michael Alan Prestwood

Sun 31 Mar 2024
Published 2 years ago.
Updated 4 days ago.
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Corn snake hatching, Pantherophis guttatus guttatus, also know as red rat snake
The amniotic egg evolved in the first amniotes, which evolved into today's reptiles, birds, and mammals.

Amniotes Emerge: Amniotic Eggs

340 Million years ago (+/- 10 million)
Ancestor or reptiles, birds, and mammals.

Around 340 million years ago, the next major leap in egg evolution came with the first amniotes, not reptiles specifically. These animals evolved the amniotic egg, with protective membranes and, in many lineages, a shell that supported development away from open water. That innovation helped free reproduction from aquatic settings and later passed into both the synapsid line, which led to mammals, and the sauropsid line, which led to reptiles, dinosaurs, pterosaurs, and birds.

— map / TST —

Michael Alan Prestwood
Author & Natural Philosopher
Prestwood writes on science-first philosophy, with particular attention to the convergence of disciplines. Drawing on his TST Framework, his work emphasizes rational inquiry grounded in empirical observation while engaging questions at the edges of established knowledge. With TouchstoneTruth positioned as a living touchstone, this work aims to contribute reliable, evolving analysis in an emerging AI era where the credibility of information is increasingly contested.
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