AQA GCSE Biology B1.7 Evolution

Lamarck
1. Suggested a theory called 'the inheritance of acquired characteristics'
  1. Theory stated that characteristics which develop during an organism's lifetime can be passed on to the next generation
    1. People found this difficult to believe
Darwin
1. Suggested the theory of 'natural selection'
  1. Theory stated that small changes in an organism took place over a very long time and all organisms in a species vary and therefore some are more likely to survive. Those that are best adapted breed and pass on characteristics
    1. The theory of natural selection was only very gradually accepted as:
      1. It challenged the theory of creationism
        Insufficient evidence at the time
        The mechanism of variation and inheritance was not known until 50 years later
Natural Selection
1. Evolution occurs via natural selection
  1. Individuals in a specific species may show a wide range of variation due to differences and mutations in their genes
    1. Individuals with the characteristics best suited to the environment in which they live are more likely to survive
      1. They are therefore more likley to breed successfully and pass on the genes to their offspring
  2. Where new forms of a gene result from mutation, there may be a rapid change in a species if the environment changes.
Classification
1. Studying the similarities and differences between organisms allow us to classify organisms into animals, plants and microorganisms, and helps us to understand evolutionary and ecological relationships
  1. Models allow us to suggest relationships between organisms.
    1. Evolutionary trees are an example of these.

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AQA GCSE Biology B1.7 Evolution

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