Evolution of Evolutionary Thought

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Evolution of Evolutionary Thought

• SB5a. Trace the history of the theory.
• SB5d. Relate natural selection to changes in
  organisms.

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Jean Baptiste Lamarck (1744-1829)

• Theory of evolution in 1809 (before Darwin)
• Two Ideas about Evolution
• Use Disuse- if you dont use a part, you lose
  it. The parts you use the most get stronger.
• Inheritance of Acquired Traits- the
  characteristics acquired by an organism during
  its lifespan are passed onto its offspring.
• Does an organism acquire characteristics?
• NO an organism is BORN with characteristics they
  dont grow them during a lifespan.
• Ex A giraffes neck grows longer to reach
  higher leaves.
• Older idea- no longer accepted

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Alfred Russell Wallace(1823-1913)

• Wrote Darwin letters that prompted Darwin to
  finish his book- had same basic ideas as Darwin.
• Did his research on Malay Archipelago
• Sometimes called Father of Biogeography
• Verified Darwins ideas on struggle for
  existence

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Charles Darwin(1809-1882)

• Naturalist on HMS Beagle for 4 years.
• Collected many fossils and animal species from
  Africa and South America.
• Most famous research done on Galapagos Islands
  off coast of S. America.
• Did not publish until 20 years after his return
• Was completing research and collecting evidence.
• Published Origin of Species in 1859- book that
  described natural selection evolution.

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• Origin of the Species
• Had 2 points
• Descent with modification-
• Most organisms are descended from a common
  ancestor
• History of life is like a tree, with multiple
  branchs from a common trunk.

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2. Natural Selection

1. Individuals within a population vary in their
   traits.
2. More offspring are produced than can survive.
   Many will get eaten or will not be able to
   compete for resources.
3. There is competition for limited resources that
   creates a struggle for existence.
4. Individuals with advantageous traits will survive
   and reproduce. Those with bad traits will die,
   taking those bad traits with them. (Survival of
   the Fittest)

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Kettlewells Peppered Moth Experiment
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What is EVOLUTION?

• Evolution is the gradual change in a POPULATION
  over a long period of time.
• Natural Selection leads to EVOLUTION.

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Galapagos Tortoises
The saddleback tortoise lives on an island with
little vegetation, high branches, no grasses.
Shell is taller and has neck notch so can reach
food sources higher up.
The dome tortoise lives on an island with lots of
vegetation, low hanging branches, and grasses.
Shell is flatter and no neck notch.
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Pete and Rosemary Grant researched ground finches
in Galapagos during the 1970s and 1980s. Write
a paragraph that describes how the finch
populations changed over time. Look back at
Darwins four postulates for help.