Question

Natural selection is best defined as occurring when the environment causes

• A. differential mortality
• B. assortative mating
• C. a reduced gene pool
• D. differential success in reproduction

Answer 1

The correct option is D differential success in reproduction

• Differential reproductive success is a term used to compare the successful reproduction rates of two groups of individuals in the same generation of a species population, each exhibiting a different genetically determined characteristic or genotype- in other words, how many offspring each group of individuals is able to leave behind.
• Natural selection—the cornerstone principle of evolution is best defined as occurring when the environment causes differential success in reproduction.
• If individuals exhibiting variation A of a trait are demonstrated to show a higher reproductive success rate compared to individuals with variation B of the same trait, we can infer that natural selection is at work and that variation A is advantageous at the time. Those individuals with variation A will deliver more genetic material for that trait to the next generation, making it more likely to persist and carry on to future generations. Variation B, meanwhile, is likely to gradually vanish. This is how evolution works.
  
• So the correct option is D.