Evolution

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  • Evolution
    • More then 3 billion years ago, life on earth began as simple organisms from which all the more complex organisms evolved (rather than just popping into existence)
      • Animals move about the place and cant make their own food
      • Plants make their own food by photosynthesis and are fixed to the ground
      • Microorganisms are different to plants and animals eg bacteria are single celled
    • Natural selection
      • Mutation
        • This is a change in the organisms DNA
          • Most of the time mutations have no affect but sometimes they can be beneficial eg help with surviving or breeding
            • If so, the beneficial mutation is more likely to be passed on to the future generation by natural selection
              • Over time the beneficial mutation will accumulate in a population
    • Why people question evolution?
      • Darwin couldn't give a good explanation about how new characteristics appeared as genes and mutations wernt discovered til 50 years later
      • There wasn't enough evidence  to convince many scientists
      • It went against common religious beleifs about how the earth developed-first plausible explanation for exsistence without God.
    • Lamarcks theory
      • He argued that if a characteristic was used a lot by an organism then it would become more developed during its lifetime
        • He believed this would then be passed on to the next generation
      • This has now been rejected because if you dye an animals hair pink its offspring will still be born with the natural fur colour

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