What is natural selection?

• A. Random mating changes allele frequencies in a population.
• B. The constant survival of all individuals regardless of variation.
• C. Differential survival and reproduction due to heritable variation.
• D. Acquired traits being inherited.

Answer: (C)

Natural selection is the process by which certain heritable traits become more common in a population because individuals with those traits tend to survive longer and/or leave more offspring. Variation exists among individuals, and some of that variation is genetic. The environment favors individuals with advantageous traits, so their genes are passed on more often, shifting allele frequencies over generations and leading to adaptation.

For example, when coloration improves camouflage in a given environment, those individuals leave more offspring, increasing the frequency of alleles for that beneficial color. If everyone survived and reproduced equally, there would be no change in trait frequencies. If acquired traits could be inherited, then life experiences could shape populations in ways natural selection doesn’t actually do, but inherited genetic variation is what selection acts upon.