How does natural selection lead to evolution?

Natural selection is a key mechanism of evolution that describes how certain traits become more common in a population over time. It operates on the principle that individuals with traits better suited to their environment have a higher chance of surviving and reproducing. This process favors individuals with advantageous traits, which increases their frequency in the gene pool of the population.

For example, in a population of birds where some have slightly longer beaks, those with longer beaks might be more successful at accessing food that shorter-beaked birds cannot reach. As a result, the longer-beaked birds are more likely to survive and reproduce, passing on their advantageous trait to the next generation. Over many generations, these advantageous traits become more prevalent in the population, driving the evolution of the species.

This process does not involve the elimination of all weaker organisms nor does it directly cause genetic mutations. Instead, it works on existing genetic variation within a population, selecting for traits that offer survival or reproductive benefits. Additionally, evolution does not ensure that all species remain constant; rather, it leads to changes and adaptations over time in response to environmental pressures.