What is required for natural.selection to occur population?

For natural selection to occur in a population, there must be variation in traits among individuals, differential survival and reproduction based on those traits, and heritability of the advantageous traits. This means that individuals with traits better suited to their environment are more likely to survive and reproduce, passing those traits to the next generation. Over time, this process can lead to changes in the population's genetic makeup, promoting adaptation to the environment.