Comment on Birbs & Dinos
logicbomb@lemmy.world 2 days ago
In evolutionary taxonomy, reptiles are gathered together under the class Reptilia (/rɛpˈtɪliə/rep-TIL-ee-ə), which corresponds to common usage. Modern cladistic taxonomyregards that group as paraphyletic, since genetic and paleontological evidence has determined that crocodilians are more closely related to birds (class Aves), members of Dinosauria, than to other living reptiles, and thus birds are nested among reptiles from a phylogenetic perspective. Many cladistic systems therefore redefine Reptilia as a clade (monophyletic group) including birds, though the precise definition of this clade varies between authors.
Hawke@lemmy.world 2 days ago
I kinda know what some of those words mean.
Can I get a picture?
pruwybn@discuss.tchncs.de 2 days ago
Image
chonglibloodsport@lemmy.world 2 days ago
Which is especially weird if you’ve ever held a bird in your hands and looked at its feet up close: birds are scaly!
TheTechnician27@lemmy.world 2 days ago
Any particular words you don’t know? Probably the most likely ones are para- and monophyletic. For a taxon (scientific grouping) to be valid, it needs to be monophyletic, meaning it contains the most recent common ancestor of the group’s other members and all known descendants of that common ancestor. Paraphyletic, by contrast, means not all the descendants are in there. For example, imagine if the mammals just randomly excluded the bears – that would be paraphyletic, because the bears also share a common ancestor with the other mammals.
Hawke@lemmy.world 2 days ago
That was a brilliant explanation, thank you.
para- and mono-phyletic were indeed the problem words. I can tell they are related to phylum but “phylum” doesn’t mean much to me except to know that it’s a word for some grouping of species.
The other part where I was snagged is the significance of cladistics and the new/old classification methods. I knew both terms as “words for groups of species and hadn’t dug further.
Between the family tree example and the diagram — got it, thanks to you and your sibling reply.