Final answer:
Natural selection is the process by which organisms with advantageous traits have a better chance of survival and reproduction. It operates on phenotypic variations within populations, leading to the more frequent occurrence of beneficial traits, a process known as adaptive evolution. Essentially, it contributes to organisms developing adaptations for survival and reproductive success in their given environments.
Step-by-step explanation:
How Natural Selection Works
Natural selection is a fundamental concept in evolutionary biology and a major mechanism that drives the evolution of species. It acts on the phenotypic variations in populations, influencing the frequency of traits that affect survival and reproduction. Organisms possessing advantageous traits have a higher likelihood of surviving and reproducing, thereby passing these traits on to their offspring. Over time, these advantageous traits become more common in the population.
For instance, a population of beetles might include individuals with varying colors. In a particular environment, darker colored beetles might be less visible to predators than lighter colored ones. Consequently, dark-colored beetles have a better chance of surviving and reproducing. As a result, the frequency of the dark color trait increases within the population, demonstrating the natural selection process. This leads to adaptive evolution, where beneficial alleles become more prevalent due to their contribution to an organism's fitness in a specific environment.
Importantly, natural selection operates on the entire organism, not just individual alleles. If an organism carries both a beneficial trait and a deleterious mutation, the overall fitness of the organism in its environment determines its reproductive success. In summary, natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is crucial for the development of adaptations that assist in the survival and reproductive capacity of organisms.