The separation of a population by physical barriers such as mountains, rivers, or large bodies of water can lead to the independent evolution of that population. For example, a species of finch isolated on an island archipelago may develop distinct beak shapes adapted to the specific food sources available on each island, differing from their mainland ancestors. Over time, these differences can become so pronounced that new species arise.
This process is a key driver of biodiversity. It allows populations to adapt to unique environments, generating a wider array of life forms. Understanding this process is crucial for conservation efforts, as it helps identify populations that are particularly vulnerable to environmental changes or human activities. The study of isolated populations has played a significant historical role in developing evolutionary theory, providing tangible evidence for the power of natural selection.