Mammal Tree

Two cladograms derived from different scientific interpretations of evolutionary relationships of mammals based on morphological and and genetic characters of species.  Trends in Ecology and Evolution. 19: 430-438.

The left hand cladogram is based on evidence from morphology, while the right hand one is based on evidence from genetics. The two trees are similar, but they are not identical. See if you can identify how many ways these two cladograms differ. This is one of the main difficulties of phylogenetic systematics. The “true” evolutionary tree is lost in the distant past and all that scientists can do is find evidence for the best evolutionary hypothesis. Sometimes different data sets do not give the exact same results. Although we will never know for certain what the true evolutionary tree of any particular clade is the correct one, probability suggests that as more and more evidence is collected the resulting cladograms are closer and closer to the truth.