The maximum likelihood tree (the tree with the clades numbered) constructed for the mammals in the figures shown supports which of the following hypotheses for the evolutionary relationships among mammalian groups?
A) The maximum likelihood tree supports the Marsupionta hypothesis.
B) The maximum likelihood tree supports the Theria hypothesis.
C) The maximum likelihood tree supports both the Marsupionta and the Theria hypotheses.
D) The maximum likelihood tree supports neither the Marsupionta nor the Theria hypotheses.

Question

The maximum likelihood tree (the tree with the clades numbered) constructed for the mammals in the figures shown supports which of the following hypotheses for the evolutionary relationships among mammalian groups?  
A) The maximum likelihood tree supports the Marsupionta hypothesis. 
B) The maximum likelihood tree supports the Theria hypothesis. 
C) The maximum likelihood tree supports both the Marsupionta and the Theria hypotheses. 
D) The maximum likelihood tree supports neither the Marsupionta nor the Theria hypotheses.

Quizplus · Accepted Answer

The maximum likelihood tree shows two major clades: one containing marsupials (represented by the opossum) and one containing placental mammals (represented by all other taxa). This supports the Theria hypothesis, which proposes that all living mammals can be divided into two groups: those that have a placenta and those that do not. The tree does not support the Marsupionta hypothesis, which proposes that marsupials and placentals share a common ancestor that was separate from that of monotremes (represented by the platypus).

The Maximum Likelihood Tree (The Tree with the Clades Numbered)