Question

The cladistic principle of monophyly would suggest that: Select one: a. All apes are hominins. b. Outgroups are unhelpful in deciding what species constitute natural groups. c. Birds are reptiles. d. Species boundaries are fuzzy. e. None of the above is correct.

Answer 1

c. Birds are reptiles

Step-by-step explanation:

Phylogeny studies the bonds among the members of a group. The monophyletic groups include the common ancestor and all the descendants. The paraphyletic groups include the ancestor and only a few descendants (not all of them). And the polyphyletic groups include descendants that do not share the same ancestor.

In the exposed example, option C -Birds are reptiles- is the one that describes a monophyletic group. Dinosaurs are reptiles, and birds evolved from them. So, according to the cladistic principle, dinosaurs are the common ancestors of all reptiles, and birds are one of the descendants. The group reptilia include the dinosaurs and all their descendants, and reptilia would not be a monophyletic group unless they include birds among them. As birds evolved from dinosaurs, they are reptiles.