By reference to the tree above which of the following is an

By reference to the tree above, which of the following is an accurate statement of depicted evolutionary relationships? Explain your reasoning.

1) A crocodile is more closely related to a lizard than to a bird

2) A crocodile is more closely related to a bird than to a lizard

3) A crocodile is equally related to a lizard and a bird

4) A crocodile is related to a lizard, but is not related to a bird

Solution

Hi, let me try to explain this.

By reference to the above tree, it can be observed that statement 1 ((1) A crocodile is more closely related to a lizard than to a bird) is accurate.

A Phylogenetic tree usually used to represent the evolutionary patterns and to show the relationships among various species.

Any phylogenetic tree shows the evolutionary patterns from bottom to top.

Looking at this tree, it can be observed that in the evolutionary line, all the four species, lizard, crocodile, dinosaur and bird had a common ancestor. Up the line, lizards have branched out on the basis of certain charecterstics. similarly, crocodiles, dinosaurs and birds also branched out.

However, dinosaurs and birds still share a common ancestor when compared to the other species. so, dinosaur and bird are sister taxa with the most common features.

On this note, crocodiles and birds will be like third cousins (:-)) compared to dinosaurs and birds because they shared a common ancestor 2 evolutions back.

similarly, lizards and crocodiles are the sister taxa and have shared a common ancestor 1 evolution back and are relatively closer compared to crocodiles and birds.