Theories Of Evolution

Evolution: The development of complex organisms from simple celled organisams by a process of natural selection over millions of years

Larmarck's Theory: If an animal used a body part, it would get bigger and the bigger organ would be passed on to its offspring

Darwin's Theory: All species of living things have evolved from simple life forms that first developed millions of years ago

Darwin's Observations:

  • Living things produce offspring, many of which die before reaching adulthood
  • There is variation between the same species
  • Variation allows some individuals to survive better when conditions change
  • Those with advantageous adaptations are more likely to survive and reproduce, passing on the characteristic. The better genes ( alleles) become more common
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Darwin's Theory // Mutations

Darwins ideas weren't accepted: 

  • Most people were religious & Darwin's theory opposed the idea that God created everything
  • No-one knew about genes & DNA etc. and so found his ideas difficult to believe
  • There was insufficient evidence that Darwin was right so scientists weren't convinced



  • Happen randomly, to any cells
  • Occurs when cells are multiplying
  • Can make an organism survive better OR worse
  • Some mutations are passed on because they help the organism survive better in its environment
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Studying the similarities and differences between organisms helps us classify them into catergories and understand their ecological and evolutionary relationships

All organisms are either animals, plants or micro-organisms

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