What is natural selection often described as?

Natural selection is often described as "survival of the fittest" because it emphasizes how certain traits increase an organism's chances of surviving and reproducing in its environment. This concept, introduced by Charles Darwin, suggests that individuals with advantageous traits are more likely to survive and pass those traits on to their offspring, leading to a gradual change in the population over generations. The "fittest" in this context does not necessarily mean the strongest; instead, it refers to those best suited for their environment.

This phrase succinctly captures the essence of natural selection, where the pressure of environmental factors determines which traits are beneficial for survival. Over time, this leads to populations that are better adapted to their surroundings. While other processes, such as genetic mutation, play a role in diversity and evolution, they are not the main mechanism that drives the adaptation of species in the way that natural selection does.