Thing is, nothing, and I mean there is NO EVIDENCE that species can somehow start as a reptile and over time become mammalian, for example.
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Both are eukaryotes. Both are vertebrates. Both are tetrapods. They seem to have a lot in common.
But the fact is mammals didn’t evolve from reptiles. They have a common ancestor.
Why you would imply that evolution says mammals evolved from reptiles I don’t know for sure.
It posits that humans evolved from lower species. Full stop.
There’s no evidence to support it.