Evolution

Evolution

Theories
1. Darwin's
  1. Based on Natural Selection
  2. Individuals compete for resources
    1. Those with characteristics best suited survive
      1. These individuals reproduce to produce more well-suited individuals
    2. Random mutations cause variation in the species
      1. This idea was found after Darwin's time
        It was the evidence he needed
  3. People objected at first
    1. Theory goes against story of creation
    2. Not enough evidence
    3. No evidence of inheritance or variation
2. Lamarck's
  1. If characteristic used a lot, that would improve over generations
  2. If characteristic not used a lot, eventually disappear
  3. Usually dismissed today
    1. Species would become more complex
      1. There are still simple organisms around today
3. Darwin's is most trusted today
Example
1. The Peppered Moth
  1. Random mutation caused variation - some dark, some light
    1. Tree surfaces are dark due to pollution
      1. Dark moth less likely to be seen and eaten
        Dark moths survive and breed
        Dark characteristics repeated over generations
Classification
1. Organisation of living things according to their similarities
2. E.g. Animal and Plant Kingdoms
  1. Smallest - species
Rapid Mutation of TB
1. 1. TB infects someone. The variation in the TB due to random gene mutations means that some bacteria are resistant to antibiotics
2. 2. After a course of antibiotics, all bacteria are killed except the resistant ones. This is through survival of the fittest and is Natural Selection
3. 3. These reproduce, passing on the resistant gene, keeping the patient ill
4. 4. So, a new drug has to be found that they are not resistant to.

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	Created by lauren_morris over 11 years ago