00:01
Why are birds considered a separate class from reptiles? a.
00:05
They are of sufficient morphological difference to the reptile ancestors.
00:09
They are closely related to dinosaurs.
00:12
Birds are not a paraphyletic taxon.
00:15
D, birds and crocodilians are archosaurs.
00:19
Or e, birds are derived from reptile ancestors.
00:23
Okay, so the correct answer here is a.
00:25
And i'm going to start by drawing a rough diagram of the biolognae.
00:31
So we have reptiles and we get a structure, something like this.
00:38
So it's something like, we have other reptile groups like lizards, these are tortoises or turtles.
00:47
And then over here we have crocodiles and we have other birds.
00:52
So this is what the phylogeny kind of looks like.
00:57
So birds make up this region here and they are monologna.
01:08
So they are not paraphyletic, as c is true.
01:16
Remember that monophyletic means it includes the common ancestor and all descendants.
01:26
However, reptiles are paraphyletic.
01:29
Reptiles are paraphyletic, which means it includes the common ancestor, but not all the descendants.
01:40
So reptiles include all of this tree except for birds...