Which set of conditions must be present for natural selection to occur in a population?

• A. Heritable variation exists among individuals, and individuals with certain traits leave more offspring than others (differential reproductive success).
• B. All individuals have identical phenotypes, and the environment does not affect survival or reproduction.
• C. Evolution occurs only through random changes in allele frequencies with no consistent fitness differences among traits.
• D. Acquired traits during an organism's lifetime are directly passed to offspring, regardless of genetic variation.

Answer: (A)

Verified step by step guidance

1. Understand that natural selection requires variation in traits within a population; this means individuals must differ genetically in ways that affect their traits.
2. Recognize that for natural selection to act, these trait differences must be heritable, meaning they can be passed from parents to offspring through genetic information.
3. Identify that individuals with certain heritable traits must have differential reproductive success, meaning they leave more offspring than others because those traits confer some advantage in survival or reproduction.
4. Note that if all individuals have identical phenotypes or if the environment does not influence survival or reproduction, natural selection cannot occur because there is no advantage to any trait.
5. Understand that natural selection is not about random changes alone or the inheritance of acquired traits; it specifically requires heritable variation and differential reproductive success to drive evolutionary change.