What is the main outcome of natural selection?

The primary outcome of natural selection is indeed the survival and reproduction of the fittest individuals, which is a fundamental principle of evolutionary biology. Natural selection operates on the basis that individuals within a population exhibit variations in traits, and those traits can affect their ability to survive and reproduce in a given environment.

The individuals who possess favorable traits—those best suited to their environment—are more likely to survive and produce offspring. Over time, these advantageous traits become more common within the population, leading to evolutionary change. This process is gradual and often results in adaptations that enhance the species' chances of survival in changing environments, illustrating how natural selection shapes the direction of evolutionary pathways.

In contrast, while an increase in biodiversity can be a long-term effect of natural selection, it is not the direct outcome of the process itself. Random changes, such as mutations, can influence genetic variation, but they do not specifically describe the selection process. Immediate adaptation is a misconception; adaptations occur over many generations as a result of natural selection, rather than instantaneously in response to environmental changes.