Final answer:
Natural selection is a key mechanism of evolution where organisms with beneficial inherited traits are likelier to survive and reproduce, leading to populations better adapted to their environments over time. Darwin and Wallace outlined this principle, noting that while it does not create new traits, it selects from existing genetic variations for evolution to occur.
Step-by-step explanation:
Natural Selection Explained
Natural selection is a fundamental mechanism in the process of evolution. It describes how individuals in a population who inherit advantageous traits are more likely to survive and reproduce than those without these traits. Over time, this results in populations that are better adapted to their environments. Charles Darwin and Alfred Russel Wallace independently observed this pattern and developed the concept to explain biological diversity.
Natural selection operates on the principle that more offspring are produced than can possibly survive. This leads to a struggle for existence where only those with beneficial traits, which are inherited, will have a better chance to survive and pass those traits on to their offspring. The concept of "survival of the fittest" does not imply an ideal state of existence but rather refers to the reproduction of individuals with traits that favor survival within a particular environment.
However, natural selection has limitations. It cannot produce new traits but instead selects from existing genetic variations within the population. The existence of variations, new alleles emerging by mutation, and gene flow are essential for natural selection to bring about evolutionary change. Ultimately, natural selection results in species becoming more adapted to their local environments, leading to the evolutionary process Darwin referred to as "descent with modification".