1. What is EVOLUTION?
An Introduction
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2. Where did the theory of evolution come from?
Ancient Greeks and Romans suggested
All living things are related
Living things had changed over time
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3. Then what?
In 1809, Jean Baptiste de Lamarck proposed that traits developed by a parent, during his or her lifetime, would be passed down to the offspring.
He was incorrect—there was no genetic change.
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4. Charles Darwin In 1831, Darwin sailed from England
on the H.M.S. Beagle
Explored the South American coast
Explored the wildlife of the Galapagos Islands
Observed 13 species of finches on the island that were similar to 1 species of finch he had seen on South America
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5. Galapagos Islands Martin
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6. Darwin’s Finches
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7. Darwin’s Conclusions
The finches on the Galapagos Islands evolved from one species
The finches must have competed for food
Finches with beak shapes that allowed them to eat survived longer and produced more offspring
After many years, the finches became separate species
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8. Darwin’s Book
On the Origin of Species by Means of Natural Selection, published 1859
Species were not specially created in their present forms, but evolved from ancestral forms
The mechanism for this evolution was natural selection
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9. Natural Selection
Organisms with traits best suited to their environment are more likely to survive and reproduce
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10. Principles of Natural Selection
1. Organisms produce more offspring than can survive
2. Differences, or variations, occur among individuals of a species.
3. Some variations are helpful. More individuals with these helpful variations survive and reproduce
4. Over time, the offspring of these individuals make up more of the species and eventually become a separate species
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11. Key Points
Natural selection acts on individuals, but INDIVIDUALS do NOT evolve.
Populations evolve.
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12. Populations evolve to adapt to a particular environment
Key Points
Populations evolve to adapt to a particular environment
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13. Key Points Selection act on inherited traits, not acquired traits
(Remember Lamarck was incorrect)
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14. Key Points
Genetic changes do NOT appear in response to the environment
Genetic changes are random
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15. Evolution A change in inherited characteristics over time
Archaeopteryx:
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