Here's a simplified explanation of how natural selection works:
Variation: Within a population, individuals exhibit variation in their traits. This variation can be due to genetic differences, mutations, or environmental influences.
Selection: The environment exerts selective pressures on individuals based on their traits. Organisms with traits that are beneficial in their specific environment, such as better camouflage or efficient energy metabolism, have a higher chance of surviving and reproducing. This is known as survival of the fittest.
Adaptation: Individuals with favorable traits are more likely to pass those traits on to their offspring through reproduction. Over many generations, this leads to the accumulation of beneficial traits in the population, making it better adapted to its environment.
Reproductive success: Organisms that are better adapted to their environment tend to have higher reproductive success, meaning they produce more offspring that survive and reach reproductive age. This further increases the frequency of beneficial traits in the population.
Isolation: Geographical isolation, reproductive isolation, or other barriers to gene flow between populations can lead to the divergence of populations over time. This can contribute to the formation of new species.
Speciation: Over long periods of time, the accumulation of genetic changes and adaptations can result in the emergence of new species. These species are reproductively isolated from one another, meaning they cannot successfully mate and produce fertile offspring.
It's important to note that natural selection acts on existing genetic variation within a population. It does not directly create new traits or introduce entirely new genetic material. Instead, it favors the survival and reproduction of individuals with advantageous traits, leading to the gradual evolution of species over generations.