Darwin and Evolution

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Darwin and Evolution

• What is unusual about the insect in the picture?
• How would this be beneficial to the organism?

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• What is a theory?
• a well-supported testable explanation of
  phenomena that have occurred in the natural world

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Darwins Big Idea (Evolution)

• Charles Darwin came up with the theory of
  evolution
• He sailed on the H.M.S. Beagle In 1831
• Darwin observed plants and animals around the
  world and collected evidence on his trip

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Darwin's Observations

• Patterns of Diversity
• Organisms are well adapted to the Environment
• How did this happen?

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Darwin's Observations

• Darwin observed living organisms and collected
  fossils
• What do fossils tell us?

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Darwin's Observations

• Galapagos Islands
• Many different species of land tortoises,
  iguanas, finches
• Different traits were found in the tortoises on
  different islands finch beaks varied

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Darwin Asked Why?
Why are there different forms of organisms?
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Ideas that shaped Darwins Thinking

• James Hutton (1785)- Proposed that the earth is
  much more than 1000 years old. It is shaped by
  geological forces that took place over extremely
  long periods of time.
• Thomas Malthus (1798)- Predicted that the human
  population will grow faster than the space and
  food supplies needed to sustain it.

Hutton
Malthus
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Ideas that shaped Darwins Thinking

• Jean-Baptiste Lamarck- First to propose that
  species change over time.
• (!!!Species do change over time but this but not
  this way)

Lamarck
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• His exact theory of use was wrong
• Proposed that by selective use or disuse of
  organs, organisms acquired or lost certain traits
  during their lifetime.
• These traits could be passed onto their
  offspring.
• Over time this process led to change in a
  species.

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Ideas that shaped Darwins Thinking

• Charles Lyell-
• Proposed that processes occurring now have shaped
  earths geological features over a long period of
  time.
• Stated you can actually observe these processes
  today. Earths layers are rising and falling with
  volcanic activity etc.

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Alfred Wallace-

• Wrote to Darwin in 1858 speculating evolution by
  natural selection, based on his studies of plants
  and animals

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Vocabulary

• Evolution- change in a kind of organism over
  time process by which modern organisms have
  descended from ancient organisms.
• Theory- well-tested explanation that unifies a
  broad range of observations
• Fossil- preserved remains or evidence of an
  ancient organism

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• natural variation- differences among individuals
  of a species
• artificial selection- selection by humans for
  breeding of useful traits from the natural
  variation among different organisms
• struggle for existence- competition among members
  of a species for food, living space, and the
  other necessities of life

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• Fitness- ability of an organism to survive and
  reproduce in its environment
• Adaptation- inherited characteristic that
  increases an organisms chance of survival
• survival of the fittest- process by which
  individuals that are better suited to their
  environment survive and reproduce most
  successfully also called natural selection

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• natural selection- process by which individuals
  that are better suited to their environment
  survive and reproduce most successfully also
  called survival of the fittest
• descent with modification- principle that each
  living species has descended, with changes, from
  other species over time