natural selection and genetic modification

• Natural selection

  Survival of the fittest - animals that are better suited to the environment survive and those that are not die off
• Stages of natural selection

  1. Variation

  2. Natural selection

  3. Inheritance

  4. Evolution
• Variation

  • Naturally occurring differences within a species due to genetics and environment
• Evolution

  • Animals not suited to the environment die off, leaving the adapted ones to survive and reproduce
• Darwin and Wallace

  Scientists who came up with the theory of evolution
• Evidence for evolution

  • Bacteria developing antibiotic resistance
  • Human fossils showing gradual change
  • Pentadactyl limb in different animals (turtles, dolphins, humans)
• Five kingdoms to classify living things

  • Animals
  • Plants
  • Fungi
  • Prokaryotes
  • Protists
• Three domain system

  More broad classification of organisms based on genetic analysis - Archaea, Bacteria, Eukarya
• Selective breeding

  Breeding parents with desired characteristics to produce offspring with those traits
• Selective breeding can reduce the gene pool and cause health problems
• Genetic modification

  Combining genes from different organisms to create a new organism with desired traits
• Steps in genetic modification

  1. Extract insulin gene from human DNA

  2. Insert into bacterial plasmid (vector)

  3. Insert recombinant DNA into cell

  4. Cell produces insulin
• Genetic modification is fast and easy but expensive, and the modified genes could spread to the environment