Homology

Homology refers to similarities in structures or features shared by different species because they originated from a common ancestor. These homologous traits may have different functions now, but their underlying anatomy reveals a shared evolutionary history. For example, the forelimbs of humans, whales, and bats look different and serve different purposes, yet they share similar bones, indicating they all descended from a common ancestor. Homology helps scientists understand how species are related and how traits have evolved over time through common ancestry.