Natural selection and genetic engineering

• The stages of natural selection are:

  • variation
  • selection pressure
  • survival of the fittest
  • reproduction
  • inheritance
• Natural selection leads to antibiotic resistance by;

  • variation- some bacteria are more resistant to antibiotics and some are less resistant
  • selection pressure- people do not finish their course of antibiotics
  • survival of the fittest- bacteria with high resistance to antibiotics survive and bacteria with low resistance dies
  • reproduction - bacteria with high resistance reproduce
  • inheritance - the allele / gene for high antibiotic resistance is passed onto the offspring
• Fossils are evidence for human evolution because:

  • Ardi fossil aged 4.4 million years ago
  • lucy fossil aged 3.2 million years ago
  • The turkana boy fossil ages 1.6 million years ago
  • Fossils show skull size increased which means brain size increased and species became more intelligent
  • stone tools became more sophisticated over time showing species become more intelligent
• The 3 domain classification system was developed for genetic analysis
• to date fossils:

  • compare them with fossils that have already been dated
  • from the layer of the rock they are found in
• The benefits of selective breeding:

  • produce more food
  • improve food quality
• The risks of selective breeding:

  • genetic diseases, reduces genetic variation
• The stages of selective breeding:

  • select organisms with desired characteristics
  • breed them together
  • select offspring’s with desired characteristics and breed together
  • repeat over many generations until all of the offspring have the desired characteristics
• The term genetically modified organism is an organism that has had its genome changed by inserting a gene from another organism
• benefits of genetic engineering

  • produces more food
  • improves food quality
• Risks of selective breeding:

  • genetic diseases, reducing genetic variations