00:01
Hello everyone, in this question we need to construct a phylogenetic tree and we have been said that on this tree put a square around the branches that include the lizard and crocodiles and their common ancestors and we need to tell about the monophyletic, paraphyletic and polyphyletic taxons.
00:24
So, in the monophyletic taxons these are the ones which have a single common ancestor and all its descendants.
00:34
Here the shared derived characters and shared ancestral characters are seen.
00:39
Then in the paraphyletic it does not include all the descendants of the common ancestor and in the polyphyletic groups here if group includes some or all of its descendants but these does not include the common ancestors.
01:01
So here let us make the phylogenetic tree.
01:05
So all we will see lamb prey which will be our out group as after that there will be divergence based on the lungs, based on the jaws.
01:19
This here is the common ancestor and now based on the jaws here we will have the perch and then the divergence will be on the basis of lungs and here we will see salamander and then the divergence will be on the basis of claws or nails and a small divergence will be seen here on the basis of the scale and due to which here will be the lizard formed and then the divergence will be on the basis of gizzard and here we will see crocodile and then here the divergence will be on the basis of feather and we will see the pigeon here.
02:08
Now the divergence due to claws and nails here will diverge it further and then the divergence will be on the basis of the mammary gland.
02:20
So here we will have the chimpanzee and the mouse.
02:25
So here the lizard and crocodile will be here in the box with their common ancestor that will be from this, that will be from this scale here because this here is the example of the paraphyletic group because they have evolved from the same ancestor.
02:49
Here the pigeon also arrived as well but here the pigeon has the feather and due to which it has diverged further.
03:00
So here we have not taken all the descendants but we have taken the descendants which have the common features.
03:06
So that is why here we have put the crocodile as well as the lizard in the box.
03:12
The feather here is the shared derived character in the bird and there is no homoplasty seen in the bird.
03:24
So we have been asked is the above text on a clade.
03:29
So basically clade is a grouping that includes the common ancestor and all the descendants of that ancestor.
03:37
So here we can say that all of the organism on the pruned branch make up the clade.
03:48
Then what is the shared derived trait? so that we have already discussed that feather is the shared derived character of the bird and keratinous scale is the shared ancestral character for crocodile, pigeon and lizard and here no homoplasty is seen.
04:08
And now we have been given a table.
04:12
So in this table basically these 1, 2, 3, 4 numbering can be taken as the characters...