Which of the following situations will most directly lead to natural selection in a population?

• A. Individuals acquire a beneficial trait during their lifetime and pass that acquired trait to their offspring.
• B. Individuals vary in a heritable trait, and those with certain trait values survive and reproduce more than others in a given environment.
• C. A population experiences a sudden decrease in size due to a random natural disaster, changing allele frequencies by chance.
• D. All individuals have identical genotypes, and all survive and reproduce at the same rate regardless of the environment.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the concept of natural selection, which requires variation in traits among individuals in a population, heritability of those traits, and differential survival or reproduction based on those traits.
2. Step 2: Identify that natural selection acts on heritable traits, meaning traits must be passed genetically from parents to offspring, not acquired during an individual's lifetime.
3. Step 3: Recognize that random events like natural disasters causing changes in allele frequencies represent genetic drift, not natural selection, because they do not depend on trait advantages.
4. Step 4: Note that if all individuals have identical genotypes and survival rates, there is no variation or differential reproduction, so natural selection cannot occur.
5. Step 5: Conclude that the situation where individuals vary in a heritable trait and those with certain trait values survive and reproduce more than others directly leads to natural selection.