What is the definition of extinction in evolutionary terms?

The definition of extinction in evolutionary terms refers specifically to the complete loss of a species. This occurs when there are no living individuals left that can reproduce and pass on their genetic material. Extinction can happen due to a variety of factors including environmental changes, loss of habitat, predation pressures, and competition with other species.

When a species is fully extinct, it means that it has failed to adapt to its changing environment or has been outcompeted, leading to its disappearance from the planet. This concept is crucial in evolutionary biology because it highlights the dynamics of species survival and the factors that can lead to the loss of biodiversity in ecosystems.

Other options, while related to extinction in some manner, do not encapsulate the definition as precisely. The gradual loss of populations might indicate trends leading to extinction but does not capture the finality of the extinction process itself. The reduction of biodiversity refers more broadly to the decline in the variety of life but does not specifically define extinction. Lastly, the emergence of new species pertains to speciation, which is a process opposite to extinction, emphasizing the continuity of life and evolution rather than its cessation.