What term is used to describe a group of organisms that have evolved from a common ancestor?

The term "clade" refers to a group of organisms that includes a common ancestor and all of its descendants. This concept is fundamental in the study of evolutionary biology, as it allows scientists to categorize organisms based on shared characteristics that arise from a common lineage. Clades can be identified through cladistics, a method that classifies organisms based on the branching of evolutionary lineages. The key point about clades is that they represent a complete branch on the tree of life, encompassing all organisms that share a specific evolutionary history.

In contrast, "species" refers to a specific group of organisms capable of interbreeding and producing fertile offspring, which does not necessarily represent common ancestry at a broader level. "Population" describes a group of individuals of the same species living in a specific area, focusing on demographic attributes rather than evolutionary relationships. The term "genus" is a taxonomic category that groups species together based on shared characteristics but does not indicate the broader evolutionary context of all descendants from a common ancestor. Thus, "clade" is the most accurate term when discussing organisms that have descended from a shared ancestor.