Thomas Malthus

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Thomas Malthus

• 1798 published Essay on the
• Principle of Population
• Gave Darwin idea that populations produce more
  offspring than can survive because populations
  increase faster than earth can support
• This would mean that natural selection would be
  the survival of the fittest because there were
  not enough resources for every organism to
  survive.

2
Lamarck

• Lamarck published a theory of evolution in 1809
  (same year Darwin was born). He explained the
  mechanism of evolution with two principles.
• The use or disuse of body parts leads to their
  development or deterioration, acquired
  characteristics can be inherited.

3
Charles Lyell

• Proposed geological theory of uniformitarianism
  which is different from catastrophism.
• Uniformitarianism- the events in the past that
  formed the Earth are still at play today and are
  a gradual process
• Principles of Geology was published, Darwin read
  and agreed with the findings.

4
Charles Lyell Continued

• He studied sedimentary rock and how the layers
  (stata) of the Earth form.
• He said that these processes take thousands of
  years to occur.
• Darwin used this information to conclude that if
  the different layers of the Earth take thousands
  of years to form, then the different fossils
  found in each layer mustve taken thousands of
  years to change or evolve.

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Charles Lyell Cont.
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Voyage of the Beagle

• Darwin was 22 years old when he sailed from Great
  Britain on the H.M.S. Beagle in 1831.
• He spent the voyage collecting thousands of
  specimens of the fauna and flora, observing
  various adaptations of organisms. He was
  particularly struck by the uniqueness of the
  fauna of the Galapagos Islands

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Darwin and Wallace

• In the 1830s Darwin starts compiling his work
  and another scientist, Alfred Wallace, was also
  working on a theory of natural selection.
• Before publishing his findings, Wallace sends a
  copy of his work to Darwin in 1858.
• To Darwins surprise, Wallace has formulated a
  very similar theory!

8

• Both findings were presented to the Linnaean
  Society in 1858.
• Darwins Origin of Species was published in 1859
  (yes! 20 years after he wrote it!), Wallace will
  continue his travels and research
• Wallaces theory and name will forever stand in
  the shadow of Darwin and the theory of evolution

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Best Seller!

• Darwins book was a success, however, natural
  selection was still questioned even by Darwinist
• In 1865 Mendels findings on heredity were
  published
• However, it would take until the 1900s before
  the findings were revisited
• Charles Darwin dies in 1882 and is buried in
  Westminster Abbey