Which statement is an accurate description of natural selection?

Which statement is an accurate description of natural selection?

• A. It happens randomly with no relation to survival
• B. It always produces perfect adaptation
• C. It only affects physical traits, not behavior
• D. It describes differential survival and reproduction based on heritable variation

Answer: (D)

Natural selection is the mechanism by which differences in survival and reproduction, driven by heritable variation, lead to changes in a population over generations. The statement that fitness differences arise because some heritable traits give individuals a better chance to survive and leave offspring is the accurate description, because it captures how advantageous traits increase in frequency over time. This process isn’t random with respect to who survives; while new variation comes from mutations, which are random, the success of individuals depends on how well their heritable traits match the environment. Natural selection also doesn’t guarantee perfect adaptations, since it works with existing variation and is shaped by environmental constraints, and it can involve behavioral traits as well as physical ones.

Natural selection is the mechanism by which differences in survival and reproduction, driven by heritable variation, lead to changes in a population over generations. The statement that fitness differences arise because some heritable traits give individuals a better chance to survive and leave offspring is the accurate description, because it captures how advantageous traits increase in frequency over time. This process isn’t random with respect to who survives; while new variation comes from mutations, which are random, the success of individuals depends on how well their heritable traits match the environment. Natural selection also doesn’t guarantee perfect adaptations, since it works with existing variation and is shaped by environmental constraints, and it can involve behavioral traits as well as physical ones.