BIO topic 4

• theory of natural selection by evolution
• how does bacteria develop resistance to antibiotics

  1. By NATURAL SELECTION
  2. mutation in the bacteria causes there to be variation in the resistance of the bacteria
  3. only the most resistant survive antibiotic treatment
  4. they reproduce + pass on the beneficial characteristics to their offspring
• Darwin's theory of natural selection by evolution

  HOW WELL SPECIES ARE ABLE TO ADAPT TO AND SURVIVE DIFF SELECTION PRESSURE

  1)there's variation in organisms due to mutation

  2) selection pressures cause competition to survive

  3) those w/ adapted characteristics survive + they reproduce and pass down the beneficial characteristics to their offspring
• what does evolution show

  how selection pressures create variation
• natural selection = survival of the fittest
• evidence for evolution

  1. bacteria
  2. fossils
  3. stone tools
• how long ago was ardi

  • 44 mil years ago
• Ardi's brain is same size as chimpanzee
• Ardi is 44 million years old
• lucy's brain is bigger than ardi's
• Leaky found the fossil hominid- Turkna Boy 1.6 million years ago
• Homo erectus found 1.6 million years ago
• Turkna Boy had more human like feet which suggested he was very adapted to walking upright
• lucy's features

  • arched feet
  • arm + legs both ape and human like
  • bigger brain then ardi
• Stone tool evolution

  2. Scrape meat off

  3. Crack bones

  4. Sculpted rocks

  5. Hunting axes
• Stone tools show evolution before getting more complex
• Homo erectus used wood spears
• Neanderthal tools are 300,000 years old
• Flint tools used by Homo sapiens 200,000 years ago
• Darwin made the Theory of Evolution
• Wallace helped develop the Theory of Evolution
• Warning colours used to deter predators is an example of evolution by natural selection
• Evolution has influenced antibiotic resistance, classification of organisms, and conservation of species
• Fossil dating methods


  1. Seeing the complexity of the fossil

  2. Stratigraphy

  3. Carbon dating
• Pentadactyl limb is evidence we evolved from a common ancestor
• Domains


  • Archaea
  • Bacteria
  • Eukarya
• Kingdoms


  • Animals
  • Plants
  • Fungi
  • Protists
  • Prokaryotes
• Genetic analysis has led to the 3 domains
• Archaea


  No nucleus, no unused sections of DNA
• Bacteria


  No nucleus, no unused sections of DNA
• Eukarya


  Nucleus, unused sections of DNA
• Selective Breeding


  1. Select animals with desired characteristic

  2. Breed them

  3. Select best offspring and breed

  4. Continue until desired trait is strengthened
• what does selective breeding do ?

  • Improves yield for farmers
  • Useful for medical research
• Selective breeding can lead to reduced gene pool and inbreeding problems
• Selective breeding can make organisms less resistant to new diseases
• Tissue Culture


  use of plants to create clones using artificial growth medium
• Tissue Culture


  1. Select plant to clone

  2. Remove tissue

  3. Sterilise

  4. Put in growth medium

  5. Grow roots and shoots
• Tissue Culture


  • Can be done on a large scale all year round
  • Requires little space
• Genetic Engineering


  Modifying genome of bacteria to give it desirable characteristics
• example of genetic engineering

  • Insulin - Bacteria can be genetically modified to contain the human insulin gene
  • GM crops