[Jess Kitting]

According to evolutionary theory, did mammals develop from reptiles, from birds, or from something else?

Just curious.

[Soliton]

According to evolutionary theory, did mammals develop from reptiles, from birds, or from something else?

My post was about birds evolving from dinosaurs. It didn't mention mammals. However, I would be interested in seeing any scientific evidence you have that would suggest that one kind of oxygen/CO2 exchange system can't possibly evolve into another.

[Soliton]

According to evolutionary theory, did mammals develop from reptiles, from birds, or from something else? Just curious.

Mammals evolved during the Triassic period, about the same time that the first dinosaurs appeared. The earliest mammals were tiny, shrew-like mammals. The long line of animals leading to the mammals includes: Jawless fish (Cambrian period-mid Ordovician periods) Bony fish (mid Ordovician period-late Devonian period) Amphibians (late Devonian period-early Carboniferous period) Reptiles (late Carboniferous period) Pelycosaurs ("mammal-like reptiles") (late Carboniferous period to very early Triassic period) Mammals (mid-Triassic period to today). M/p>

[Non-Sequitur]

According to evolutionary theory, did mammals develop from reptiles, from birds, or from something else?

The believed progression was fish to amphibians; amphibians to reptiles; reptiles to mammals and birds.