Question

The horizontal axis of the cladogram depicted below is a timeline that extends from 100,000 years ago to the present; the vertical axis represents nothing in particular. The labeled branch points on the tree (V-Z) represent various common ancestors. Let's say that only since 50,000 years ago has there been enough variation between the lineages depicted here to separate them into distinct species, and only the tips of the lineages on this tree represent distinct species. 100,000 Prese ale Which of the five common ancestors, labeled V-Z, is the common ancestor of the greatest number of species, both living and extinct?

A) V
B) W
C) Y
D) Z

Answer 1

Without seeing the specific cladogram, one cannot definitively identify which ancestor is the common ancestor of the greatest number of species. Typically, the common ancestor labeled at the base or root would have the most descendants, but without the diagram, it's impossible to say for certain.

Step-by-step explanation:

The question asks which common ancestor, labeled from V to Z, is the ancestor of the greatest number of species on a phylogenetic tree. Because a phylogenetic tree can be read like a map of evolutionary history with rooted trees showing a single ancestral lineage, the common ancestor with the greatest number of descendant species would be the one that appears earliest in the tree and thus has the most branches extending from it after divergence events. Without the specifics of the cladogram, answer cannot be determined without further information. However, by concept, since lineage V would be at the base and root of the tree in a typical orientation, it would generally represent the common ancestor from which all other lineages stem, making it the ancestor of the greatest number of species.