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Published byLucas Lane Modified over 9 years ago
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Evolution Genetic change in a species over time
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Charles Darwin 1831- Ship’s doctor, HMS Beagle Travelled around the world observing species and collecting specimens
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3 Darwin Left England in 1831 Darwin returned 5 years later in 1836
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Darwin was influenced by: 1.James Hutton – geologist The same geologic processes have occurred throughout Earth’s history 2. Charles Lyell – geologist Earth’s surface has changed over time, Earth is millions, not thousands of years old 3. Thomas Malthus – economist if unchecked, human population will double every 25 years (the struggle for survival prevents this)
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1859 Book: Origin of Species Theory: Natural Selection 1.Overproduction occurs in all species 2.Variations occur in all species 3.Struggle for survival- resources are limited, not all born will survive 4.Survival of the fittest- those best adapted to their environment will survive and reproduce.
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Fitness: ability of an individual to survive and reproduce - central to the process of Evolution - individuals with low fitness either die or produce few offspring
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Adaptation: Inherited characteristic that increases an organisms chance for survival Adaptations Can Be: Physical - Speed, Camouflage, Claws, Quills, etc. Behavioral - Solitary, Herds, Packs, Activity, etc.
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Evidence of Evolution 1.Fossils 2.Comparative Embryology 3.Homologous structures 4.Vestigial Organs 5.Biogeography 6.Biochemistry
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9 Fossil Record Earth is Billions of Years Old Fossils in different layers of sedimentary rock show evidence of gradual change over time
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10 Evidence for Evolution - Comparative Embryology Embryonic Development: similarities indicate a common ancestor
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11 Homologous Structures Ex: Forelimbs of mammals have the same bones
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Vestigial Organs not used by us, used by related species Ex: appendix (koalas need theirs) Ex: Human coccyx (tailbone) Ex: hip bones in snakes
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13 Geographic Distribution of Living Species Unrelated animals on different continents have similar adaptations to similar environments. Ex: deer, kangaroo – eat the same food, have same skull and jaw
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Biochemistry – similar DNA and amino acid sequences indicate a common ancestor
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15 Evolution of pesticide resistance in response to selection
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16 Key Concept Over time, Natural Selection results In changes in the inherited characteristics of a population. These changes increase a species fitness in its environment
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