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Charles Darwin Born Feb 12, 1809
Same day as Abraham Lincoln H.M.S. Beagle - traveled around the world Galapagos Islands Looked at finches – a small song bird Also studied turtles on the different islands On trip home came up with his popular book “The Origin of Species”
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During his travels, Darwin made numerous observations and collected evidence that led him to propose a revolutionary hypothesis about the way life changes over time. That hypothesis, now supported by a huge body of evidence, has become the THEORY of Evolution.
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Darwinobserved that the characteristics of many animals and plants varied noticeably among the different islands of the Galapagos. See how the turtles are different on the three different islands.
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Did Darwin come up with Evolution?
NO!!! This theory had been thought of many hundreds of years prior to Darwin He did come up with the process that helps describe how evolution occurs though Natural Selection
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Evolution Natural Selection
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Evolution Evolution means a change over time or descent with modification It occurs in populations, not individuals in response to environmental pressures Natural selection is the mechanism of evolution (the way it happens)
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Natural Selection Natural selection happens because:
1. Overproduction – organisms produce more offspring than can survive Fun Facts: A fern plant may produce 50 million spores each year. If they all survived, in the second year they would nearly cover North America. An oyster may shed 114,000,000 eggs in a single spawning season. If they all survived, the ocean would be literally filled with oysters.
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Natural Selection 2. Variation – Within a population there are many differences between organisms. These differences are inherited. Examples: Color in flowers Length of antlers in elk Height in humans Shape of beak in birds
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Natural Selection 3. Struggle for existence – There are limited resources, so living things must compete against each other to stay alive 4. Survival of the fittest – Only the organisms best adapted to the environment will live
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Natural Selection 5. Populations evolve – Over time, the favorable adaptations are passed on and the entire population changes
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Artificial Selection Artificial selection occurs when humans select the best traits for plants and animals Examples: Disease-resistant crops Beefy cattle Cows that produce more milk
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Adaptations Adaptations are genetic changes that increase the survival of a population
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Types of Adaptations Mimicry – Organisms that copy the appearance of another species for protection
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Types of Adaptations Camouflage – When an organism blends in to its surroundings
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