Darwin's theory

  • Created by: EmilyAlys
  • Created on: 24-05-18 11:09
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  • Darwin's theory
    • During the 18th century, people started to accept that organisms slowly evolve into others.
      • Two scientists, Charles Darwin (1890-1882) and Alfred Russel Wallace.
        • These two scientists came up with essentially the same idea about how this happened.
          • The first book about this idea was written by Darwin and published in 1859.
    • We think about Darwin's idea as a series of stages as follows.
      • Genetic Variation: the characteristics individuals vary (due to differences in genes).
        • Environmental change: conditions in an area change.
          • For example: the lack of a resource (such as food) causes more competition between organisms.
            • Natural selection: by chance, the variations of some individuals make them better at coping with the change than others, and more likely  to survive.
              • Also called "survival of the fittest".
                • Inheritance: the survivors breed and pass on their variations to their offspring. So the next generation contains more individuals with the 'better-adapted variations'.
                  • Evolution: If the environmental conditions remain changed, natural selection occurs over and over again, and a new species evolves with all the individuals having the 'better-adapted variations'
                    • Woolly mammoths and elephants evolved from the same animal. This means they have a common ancestor.
                      • In colder climate the mammoth would have evolved to have thicker hair to cope with the environment.

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