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Theories of evolution

Theories of evolution

Charles Darwin is famous for his theory of evolution, but he was not the only person to develop such a theory.

Darwin’s theory

Photograph of Charles Darwin

Charles Darwin (1809 - 1882)

Charles Darwin was an English naturalist. He studied variation in plants and animals during a five-year voyage around the world in the 19th century. He explained his ideas about evolution in a book called On the Origin of Species, which was published in 1859.

Darwin's theory caused controversy among his contemporaries and his ideas were only gradually accepted, although some people still do not believe them today. The reasons for skepticism include:

  • Darwin’s theory conflicted with religious views that God had made all the animals and plants on Earth
  • Darwin did not have enough evidence at the time to convince many scientists
  • it took 50 years after Darwin’s theory was published to discover how inheritance and variationvariation: Difference between individuals; distance from the norm worked.

Lamarck’s theory

Jean-Baptiste Lamarck was a French scientist who developed an alternative theory of evolution at the beginning of the 19th century. His theory involved two ideas:

  1. A characteristic which is used more and more by an organism becomes bigger and stronger, and one that is not used eventually disappears
  2. Any feature of an organism that is improved through use is passed to its offspring.

However, we now know that in most cases this type of inheritance cannot happen.

Lamarck's theory cannot account for all the observations made about life on Earth. For instance, his theory implies that all organisms would gradually become complex, and simple organisms disappear. On the other hand, Darwin's theory can account for the continued presence of simple organisms.

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