In evolutionary biology, the term 'common ancestor' refers to what?

The term 'common ancestor' in evolutionary biology specifically refers to an ancestral species from which other species have descended. This concept is fundamental to the theory of evolution, which posits that all living organisms share common evolutionary pathways.

Through the process of divergent evolution, species evolve from a common ancestral lineage, resulting in the biodiversity we observe today. This common ancestor is not necessarily a single identifiable species but can represent a group that has given rise to multiple lineages. The connection between diverse species can often be traced back through fossil records, genetic similarities, and comparative anatomy, helping scientists understand evolutionary relationships.

In this context, while a species that no longer exists is indeed related to the concept of common ancestors, simply being extinct does not define the term. The most recent species to evolve is more specific and may not encompass the broader range of ancestral connections. Similarly, describing a type of extinct organism lacks the specificity needed to capture the essence of what a common ancestor represents in the evolutionary tree of life.