What does the "natural selection theory" describe?

The natural selection theory describes the concept of "survival of the fittest," illustrating how species adapt over time based on the advantageous traits that enhance their survival and reproductive success in a given environment. This concept emphasizes that those individuals within a species who possess traits that give them a better chance at surviving and reproducing will pass those traits to the next generation.

Over time, this leads to changes in the population as advantageous traits become more common, while less advantageous traits diminish. This process is not random; it is driven by an organism's interactions with its environment and the challenges it faces, ensuring that only those best suited for survival thrive in their ecological niches.

The idea is foundational in understanding evolution, as it explains how species evolve through gradual changes that improve their adaptation to their surroundings over generations. This is distinct from the idea of random survival or immediate structural changes, which do not accurately capture the gradual and selective process central to natural selection.