B13: variation and evolution

• Nature


  Our genes
• Nurture


  Our environment
• Nature and nurture are battling at the same time to control our characteristics
• Characteristics controlled by genes

  • Eye color
  • Hair color
  • Skin color
• Characteristics controlled by environment

  • Hair length
  • Scars
  • Tattoos
• Height and weight


  Controlled by both genes and environment
• Natural selection


  1. Random mutation

  2. Successful mutation

  3. Reproduction

  4. Gene passing on
• Natural selection in geckos

  • Green gecko in rainforest
  • Brown gecko in desert
• Selective breeding


  Picking desirable characteristics and breeding to strengthen the gene pool
• Selectively bred animals


  • Greyhounds
  • Racehorses
  • Pugs
• Risks of selective breeding

  • Narrowing gene pool
  • Genetic disorders passed down
  • Slower adaptation to environment
  • Easier disease spread
• Genetic engineering


  Modifying genes of plants and animals
• Genetically engineered products


  • Salmon with more pink color
  • Larger salmon
  • Bacteria producing human insulin
• Concerns with genetic engineering

  • Uncontrolled release into environment
  • Lack of research on safety
  • Reducing genetic variation
  • Expensive process
• Embryo cloning


  Splitting an embryo to create multiple identical offspring
• Adult cell cloning


  Using the nucleus of an adult cell to create a clone
• Cloned animals


  • Dolly the sheep