What does evolution describe in the context of biology?

Evolution describes changes in populations over time, focusing on the genetic alterations that occur across generations. It is a fundamental concept in biology that explains how species adapt to their environments and how new species can arise from common ancestors. This process involves mechanisms such as natural selection, genetic drift, and mutation, which collectively influence the frequency of traits within a population.

By emphasizing populations rather than individual organisms, the definition captures the essence of how traits can become more or less common over time as a result of various selective pressures. For example, in a population undergoing evolutionary change, individuals with advantageous traits may survive and reproduce more successfully, leading to those traits being passed on to subsequent generations.

In contrast, individual development of organisms refers to ontogeny, which is unrelated to the evolutionary processes that shape populations over time. Similarly, while the survival of specific individuals can be a part of natural selection, it does not encompass the broader understanding of evolution. Lastly, immediate adaptations are often physiological or behavioral responses to environmental changes, which may occur within an individual's lifetime, but evolution focuses on long-term genetic changes at the population level.