About the question:
You will a cladogram in the attached files.
Answer:
lungs
Explanation:
A Cladogram is a tree-type graph based on cladistic analysis. It represents the common ancestral relationships among the involved groups.
• The tree-type graph is a ramified diagram that represents the relationship between the involved taxa.
• The cladistic analysis follows the maximum parsimony criterium. Explains the character state from the point of view of the fewest changes through history. Explains evolution with the minimal amount of evolutive changes. It recognizes the monophyletic groups as natural groups. These groups are the clades, and their classification -sequencing- represents their phylogeny.
• The sequencing term refers to lists of groups according to their relation. One group is the brother-group of the following one.
So the cladogram represents the relationship between groups according to a derived character.
The derived character is any trait that a group passes to the descendants. Through evolution, the characters change, and new changes are added. When referring to a derivate character, we mean that all the subsequent species in the cladogram carry the trait.
A cladogram provides an image of how new species keep characters that were inherited from older species.
In the attached cladogram, you can see that the lungs are the derived character that distinguishes the salamander from the perch.
Claws or nails separate salamander from lizards.
Fur separates birds and reptiles from mammals.
Jaws separate hagfish from perch.
Mutations occurred in evolution producing new traits, and these traits also appear in posterior groups. So, after the hagfishes emerged the jaws, and all the animals that followed the hagfishes have jaws.
Lungs appeared after the perch and before salamander, so salamander, and all the posterior animals, have lungs. And so on.
