a-dinosaur-a-day:

shadybacon:

a-dinosaur-a-day:

shadybacon:

a-dinosaur-a-day:

aquaticpaleo:

harmalite:

CLADISTICS ruined my life

yall joke but this is actually a serious conundrun with cladistic-based classification

The choice is this: 

Birds are reptiles 

Or crocodilians (and probably turtles) ARENT 

That’s it, that’s the choice 

What if
Bird and reptiles are two different things
that came from the same thing

Nope 

Because you can’t group (lizards, snakes, tuatara, turtles, crocodilians) without also including (birds) 

So if you don’t want to include birds in reptiles then you have to leave out some things we’ve called reptiles 

birds are dinosaurs though, full stop. we’ve already defined what a dinosaur is and it includes birds. but reptiles isn’t really defined so much as thrown against a wall angrily. 

But don’t turtles and alligators have more in common with modern reptiles than modern birds have in common with modern reptiles?

I’m not trying to contradict, I’m trying to understand. Mammals and reptiles have a common ancestor as well, but we do not make them the same group.

It’s not about having things in common. It’s about common ancestry, which is how we classify animals in light of extinct species, which defy trait-based classification. 

And, the common ancestor of [lizards, snakes, tuatara, turtles, crocodilians] by definition is also the common ancestor of birds. It is NOT the common ancestor of mammals. 

So, either we decide that Tuatara Lizards and Snakes are the only reptiles, or we include birds as reptiles. Or we just decide reptiles are no longer a thing. 

i say we allow birds to be classified as reptiles. i wanna live in a society where we complain about sea reptiles swooping in and stealing our fries