Natural Selection

• What gives some organisms an advantage over others?

  Variation
• What does natural selection increase in a population?

  The proportion of advantageous alleles
• What can randomly-occurring mutations result in?

  A new allele being formed
• What usually happens to harmful mutated alleles?

  They quickly die out
• How can some mutations be beneficial to an organism?

  They produce better-functioning proteins
• What happens when an allele codes for a characteristic that increases survival chances?

  Its frequency can increase in the population
• What are the steps of natural selection?

  1. Differential reproductive success occurs.
  2. Individuals with advantageous alleles survive and reproduce.
  3. Next generation inherits beneficial alleles.
  4. Frequency of beneficial alleles increases.
  5. Leads to evolution over generations.
• What is evolution?

  The gradual change in species over time
• What are key factors in evolution?

  Adaptation and selection
• What are the types of adaptations in organisms?

  1. Behavioural adaptations
  2. Physiological adaptations
  3. Anatomical (structural) adaptations
• What are behavioural adaptations?

  Ways an organism acts to survive
• What are physiological adaptations?

  Processes inside an organism's body
• What are anatomical (structural) adaptations?

  Structural features of an organism's body
• How does a thick layer of blubber help whales?

  It keeps them warm in cold sea
• How do adaptations help organisms?

  They increase the chance of survival