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Natural Selection quiz #1

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Terms in this set (10)

  • What are the two main observations that form the basis of natural selection, and how do they lead to evolutionary change in populations?
    The two main observations are: (1) variation exists within populations and is inherited from parents to offspring, and (2) species tend to overproduce offspring, more than the environment can support. These lead to the inference that individuals with advantageous traits are more likely to survive and reproduce, causing those traits to become more common in the population over time, resulting in evolutionary change.
  • Why is existing variation within a population essential for natural selection to occur, and how does natural selection affect the frequency of traits?
    Existing variation is essential because natural selection can only act on differences that already exist within a population; it does not create new variation. Natural selection increases the frequency of traits that enhance survival and reproduction, making populations better adapted to their current environment.
  • What are the two main observations that form the basis of natural selection?
    The two main observations are that variation exists within populations and is inherited, and that species tend to overproduce offspring beyond what the environment can support.
  • How does overproduction of offspring contribute to natural selection?
    Overproduction means more individuals are born than can survive, leading to competition and selection for traits that enhance survival and reproduction.
  • Why is existing variation within a population essential for natural selection to occur?
    Natural selection can only act on differences that already exist within a population; it does not create new variation.
  • How does natural selection affect the frequency of traits in a population?
    Natural selection increases the frequency of traits that enhance survival and reproduction, making populations better adapted to their current environment.
  • In the example of snowshoe hares, how does coat color variation affect survival?
    Hares with coat colors that better match their environment (e.g., brown in less snowy years) are less likely to be caught by predators and more likely to survive and reproduce.
  • What does it mean to say that fitness is relative in the context of natural selection?
    Fitness is measured by an organism's reproductive success compared to others in the population, and it depends on the current environment.
  • Do individuals or populations evolve as a result of natural selection, and why?
    Populations evolve because the frequency of traits changes over generations, while individuals either survive and reproduce or they do not.
  • How does natural selection lead to adaptations in a population?
    Natural selection increases the number of traits that are well-suited to the current environment, resulting in populations that are better adapted over time.