Phylogeny Practice Test Practice

The root marks the most recent common ancestor of all the taxa shown in the tree. From that ancestral point, all the lineages split and extend to the tips, which represent the living species or groups included. It’s a hypothetical ancestral lineage used to orient time and descent; it isn’t a specific living species today, and it isn’t about body size or the total number of taxa. The tips are the present-day lineages, not the root.