Which statement best describes selective pressure?

• A. It is something that gives certain traits an advantage in a given environment.
• B. It is a random mutation introduced by the organism.
• C. It always leads to immediate speciation.
• D. It only affects nonliving factors.

Answer: (C)

Selective pressure is the environmental influence that makes certain heritable traits more advantageous for survival and reproduction. This means the environment favors individuals with those traits, so they leave more offspring and the trait becomes more common over generations. The statement that best captures this idea says that something in the environment gives certain traits an advantage in that setting. Mutations are the source of new variation, not the pressure itself. Speciation is not guaranteed to happen right away; selective pressure can drive adaptation, but it doesn’t ensure instant formation of new species. And selective pressures can involve both living and nonliving factors, not only nonliving ones. A classic example is the peppered moth, where darker-colored individuals were favored in polluted environments because they were better camouflaged from predators, illustrating how the environment shapes which traits are advantageous.