What does 'survival of the fittest' mean in terms of natural selection?

The phrase "survival of the fittest" in the context of natural selection refers to the idea that it is not merely physical strength that determines an organism's ability to survive and reproduce, but rather the overall fitness in relation to the specific environment. This fitness is defined by how well an organism can adapt to its surroundings, utilize resources, evade predators, and successfully reproduce.

Being "best suited to the environment" means that certain traits, which may be physical, behavioral, or physiological, give individuals an advantage in accessing food, avoiding dangers, or coping with disease. These advantageous traits are more likely to be passed on to the next generation because those organisms that possess them are more likely to survive and reproduce.

This concept encapsulates the essence of natural selection, highlighting that it is the combination of traits that align with environmental demands that enhances survival and reproductive success, not just sheer strength or chance.