AP Bio Study Guide

Big Idea 1.A

What are the main principles of Darwin's theory of natural selection?

  • Populations tend to grow exponentially and overpopulate, exceeding their resources.
  • Overpopulation results in competition and a struggle for survival.
  • In any population, there is variation and an unequal ability of individuals to survive and reproduce. (The source of this "variation" is genetics).
  • Only the fittest individuals survive and pass their traits on to the offspring.
  • Evolution occurs as advantageous traits accumulate in a population.