Chris Jags

So I have a question about evolution.

If, say, in the case of T-Rexes evolving into chickens (and if that isn't correct, I'm just using it as an example, apply your own more correct example), at what point do we say that T-Rexes went "extinct"? Because they kinda didn't, or at least there's no hard line where they did...?

#extinction #evolution

May 27 at 11:22pmWeb
Show threadSteven D. Brewer 🏳️‍⚧️3d ago
@ChrisJagged In evolution, what you generally talk about is shared common ancestry. That's what phylogenetic trees and cladograms show. It's closer to say that chickens and particular dinosaurs shared a common ancestor. We consider the T-Rex extinct because they weren't the ancestor of any extant species today.
Show threadChris Jags3d ago

@stevendbrewer

Thanks. So if an animal could provably have a *direct* lineage from an ancestor which is no longer with us, what is that ancestor considered?

Show threadSteven D. Brewer 🏳️‍⚧️3d ago
@ChrisJagged When you're dealing with fossil evidence, it's hard to establish those kinds of relationships that clearly. It's usually not a whole species that is ancestral to another: you have founder effects or genetic drift that causes some sub-population to become reproductively isolated and diverge. Where you can track those kinds of relationships a lot more clearly with things like viruses.
Show threadChris Jags3d ago

@stevendbrewer

Thanks for the info. Even that divergence doesn't feel like extinction of the original group to me, just an evolution thereof, but fortunately science isn't based around my feelings 😄