Lamarck

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The History of Evolution
Darwin
Lamarck
Cuvier
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Species
lion

• Species group of organisms that can interbreed
  and produce fertile offspring
• Different species rarely breed
• Interspecies breeding often results in sterile
  offspring
• Ex Horse x Donkey Mule
• Ex Lion x Tiger Liger
• New species when unable to successfully
  reproduce
• Are horses donkeys a different species even
  though they can produce offspring?

tiger
liger
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horse
donkey
mule
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Jean Baptiste de Lamarck

• Acquired Inheritance Early theory where
  organisms could acquire and pass traits after
  birth
• Cause environmental changes forced individuals
  to change
• Problem Traits acquired after fertilization
  cannot be passed to offspring
• Early Belief Giraffes Long Necks
• Long necks are result of stretching to reach
  leaves
• Extra length was passed on to offspring

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Geologic Change

• Early belief
• Earth 6,000 years old
• Life remained unchanged
• New Observations
• Rock layers (strata) contained differing fossils
• Deeper fossils (older) less complex
• Environmental changes thought to affect life
  characteristics
• Uniformitarianism geologic processes that shape
  earth are uniform

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Charles Darwin

• Observed
• Organisms have variations based upon environment
• Similarities between extinct fossils modern
  life
• Marine fossils atop mountains
• Natural Selection Process where organisms with
  favorable traits survive and reproduce
• Major concept in biology published in The Origin
  of Species (1859)

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Adaptation Variation

• Variation Inherited traits that make an
  individual different from others
• Green, flat wings of the insect above
• Adaptation Variation increases the chance of
  survival
• Ability to blend with environment

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Butterflies won't lay eggs on plants with fake
egg spots
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Can you find the geckos?
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Gross....bird poop...or is it???
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Causes of Genetic Variation

• Genetic variation increases chances some survive
  changing environments
• Gene Pool All alleles within a population
• Two main causes of genetic variation
• 1) Mutations Random genetic changes may affect
  phenotypes
• 2) Recombination During meiosis, genes recombine
  in varying patterns

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Variation 4 Different Gametes
Chromatids copied
Crossing- over
Crossing- Over finished
Genetic variation! Four differing chromatids
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Quick Review

• Features of a species can evolve, or change over
  time
• Natural selection is when favorable traits allow
  survival reproduction
• Variations allow an organism to be better suited
  to its environment