Alice Clement

Research Associate in the College of Science and Engineering, Flinders University

Elia Pellegrini/Unsplash

If we go far enough back in time, we all share an ancestor. And some of the features found in our bones and bodies today are a testament to that.

Many of us are returning to work or school after spending time with relatives over the summer period. Sometimes we can be left wondering how on earth we are related to some of these people with whom we seemingly have nothing in common (especially with a particularly annoying relative).

However, in evolutionary terms, we all share ancestors if we go far enough back in time. This means many features in our bodies stretch back thousands or even millions of years in our great family tree of life.

In biology, the term “homology” relates to the similarity of a structure based on descent from a shared common ancestor. Think of the similarities of a human hand, a bat wing and a whale flipper. These all have specialist functions, but the underlying body plan of the bones remains the same.

This differs from “analogous” structures, such as wings in insects and birds. Although they serve a similar function, the wings of a dragonfly and the wings of a parrot have arisen independently, and don’t share the same evolutionary origin.[…]

Read more: We can still see these 5 traces of ancestor species in all human bodies today