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Published byFrank Benson Modified over 9 years ago
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Evolution
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What is it? Changes that occur in a population over time, in response to the environment.
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Lamarck Acquired characteristics can be passed down form generation to generation Organisms evolve over time due to the impact of the environmental factors acting on them
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Darwin Natural Selection: organisms best suited to survive will pass their traits down 1.Survival of the fittest 2.Struggle for existence (competition for resources, produce more young than can survive) 3.Variation and adaptation
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The Giraffe, Darwin and Lamarck LamarckDarwin Use and disuse Passing on of acquired characteristics Increasing complexity No extinction Variation Inheritance Differential Survival Extinction Lamarck: long necks of giraffes due to reaching for higher levels…offspring would inherit the trait… Darwin: longer necks were a result of adapting to the environment…short neck giraffes died off
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BREED ORGANISMS FOR PARTICULAR TRAITS Selective Breeding
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Fossils The preserved remains of plants and animals
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Aging a Fossil Carbon dating Measure the amount of C-14 (an isotope of Carbon) remaining in the fossil Calculate according to half life ( the time it takes for half the amount of a substance to degrade)
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Vestigial Organs Served a prior purpose Organism has evolved and no longer serves a purpose Example: human tail bone, snakes have tiny pelvic bones with limb bones, blind salamanders having eyes
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Vertebrates All vertebrates shared a common ancestor. How do we know this? What evidence is there for this? They have evolved from common ancestry, sharing certain inheritable traits. The backbone is the most evident.
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Mutation Permanent changes to the DNA sequence resulting in structural changes in a gene Peppered Moths: occurred over last two hundred years
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