Consider five species of toads (A-E).Species A and B are sister species.Species C and D are also sister species.The clade containing species A and B is a sister to the clade containing species C and D.Not counting the root as a node, how many nodes would be found in a phylogenetic tree of species A, B, C, D, and E?
A) One
B) Two
C) Three
D) Four
E) Five

Question

Quizplus · Accepted Answer

If we draw a phylogenetic tree of these five species, we can see that there are three nodes. The first node separates the clade containing species A and B from the clade containing species C and D. The second node separates species E from the rest of the tree. The third node separates species C and D from their common ancestor. Therefore, there are three nodes in the phylogenetic tree of these five species.

Consider Five Species of Toads (A-E)