RGNatural Selection

• What does natural selection increase?

  Advantageous alleles in a population
• What sometimes result in the formation of a new allele?

  Randomly- occuring mutations

  • this can be harmful = mutated allele dies out quickly
  • Some mutations can produce alleles that are beneficial to n organism = helps organism survive in certain environments
• When the allele codes for a characteristic that increases chances of an organism surviving, what can happen?

  Its frequency within the population can increase. THIS PROCESS = NATURAL SELECTION
• what are 2 key factors in evolution?

  Adaptation and selection
• What is definition of evolution?

  The gradual change in species over time
• What has evolution led to?

  The huge diversity of living organisms on Earth
• What does natural selection lead to?

  Populations being better adapted
• What do adaptations do?


  Help organisms survive in their environment
• 3 types of adaptations?

  Behavioural, physiological, anatomical
• What are behavioural adaptations?

  Ways an organism acts that increase its chance of survival and reproduction
• Example of a behavioural adaptation?


  Possums sometimes play dead if they are being threatened by a predator to escape attack
• Definition of physiological adaptations?

  Processes inside an organism's body that increases its chance of survival
• Example of physiological adaptation?


  Brown bears hibernate over WINTER

  • lowered rate of metabolism
  • = this conserves energy = they do not need to look for food in the months when it is scarce
• Definition of anatomical adaptations?

  Structural features of an organism's body that increases its chance of survival
• Example of anatomical adaptations?


  Whales have a thick layer of blubber which helps them keep warm in cold sea