How can natural selection be defined?

Natural selection can be defined as the differential survival and reproduction of individuals based on their phenotypic differences. This process is rooted in the idea that certain traits confer advantages in a given environment, allowing individuals with those traits to survive longer and reproduce more effectively than those without them. Over time, these advantageous traits become more common in the population as those individuals pass on their genes to future generations.

The mechanism of natural selection operates on existing variation within a population, where individuals with traits better suited to their environment are more likely to survive and reproduce. For instance, in an environment where food sources are scarce, individuals with traits that enable them to find food more effectively will have a better chance of living long enough to reproduce, thus passing those beneficial traits to their offspring.

Understanding natural selection is crucial as it explains how species adapt over time through the gradual shift in the composition of traits within a population, leading to evolutionary change. This definition highlights the role of phenotypes, which are observable characteristics that arise from the interaction of an organism's genetic makeup and its environment.