Lecture 2 Notes BILD 3

• Evolution


  A pattern and a process
• Evolution as a pattern


  1. Descent with modification

  2. Divergence
• Evolution as a process involves random processes such as mutation and genetic drift, and natural selection
• Natural selection relies on variation, where some traits are more helpful (fit) than others
• Not all individuals have an equal chance of surviving and reproducing
• Traits that affect survival


  • Speed
  • Colour
  • Size
  • Immune system
• Natural selection


  Occurs when a particular version of a trait makes the individuals who have it more likely to survive or reproduce
• Natural selection happens whenever there is variation in a trait that affects survival and/or reproduction
• Histograms


  • Smooth curve
  • Variation in number of visits to natural area
  • No variation in number of rabbits
• Natural selection reduces the number of individuals with less fit traits