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Chapter 22 Notes: Introduction to Evolution

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Chapter 22 Notes: Introduction to Evolution Our planet is home to a huge variety of organisms (Scientists estimate 5-20 million species of organisms alive today!) – PowerPoint PPT presentation

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Title: Chapter 22 Notes: Introduction to Evolution


1
Chapter 22 Notes Introduction to Evolution
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  •  Our planet is home to a huge variety of
    organisms
  • (Scientists estimate 5-20 million species of
    organisms alive today!)
  •   Even more amazing is evidence of organisms
    that once lived on earth, but are now extinct

Dodo bird
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  •   Several hundred million species have come and
    gone during 4.5 billion years life is believed to
    have existed on earth
  •   Sowhere have they gone why have they
    disappeared?

4
  • TERMS TO KNOW!!
  •  EVOLUTION the process by which modern
    organisms have descended from ancient organisms.
  • (CHANGE OVER TIME)
  •  Central Idea organisms alive today have been
    produced by a long process of change over time.
  •   FITNESS refers to traits and behaviors of
    organisms that enable them to survive and
    reproduce

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  •  COMMON DESCENT species share common ancestors
  •  
  •  ADAPTATION any inherited characteristic that
    enhances an organisms ability to survive and
    reproduce
  • based on variations randomly inherited

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HOW DO WE KNOW THAT EVOLUTION HAS OCCURRED (and
is still happening!!!)???
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Lines of Evidence
  • 1.  So many species!
  • -at least 5 million species (250,000 beetles!)
  •  

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  • 2. Biogeography
  • -Distribution of plants and animals
  • -Example 13 species of finches on the 13
    Galapagos Islands
  • -57 species of Kangaroos all in Australia

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Lines of Evidence (cont.)
  • 3.  Age of Earth
  • - Rates of motion of tectonic plates
  • - Radioactive dating

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  • 4.  FOSSILS
  • - Evidence of once-living things(shells, casts,
    bones, teeth, imprints, preservation in ice,
    amber, tar or peat)
  • - Show a succession of forms through a vast span
    of time

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Lines of Evidence (cont.)
  • -We see progressive changes based on the order
    they were buried in sedimentary rock
  • Few fossils/species many
    fossils/species
  • Simple organisms complex organisms

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Lines of Evidence (cont.)
  • 5. Applied Genetics Artificial Selection
  • - We see DDT-resistant insects special crops

Insecticide applied
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  • 6. Homologies shared common anatomical or
    biochemical traits
  • - Forearm bones
  • - Embryos of vertebrates

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  • 7.  Vestigial Organs
  • - Leftovers from the evolutionary past
  • - Structures that no longer serve their purpose
  •  

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  • 8.  Molecular/Biochemical Homologies
  • - DNA is the universal genetic code or code of
    life
  • -Proteins (sequences of amino acids)

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  • ANALOGOUS STRUCTURES
  • NOT EVIDENCE!!
  • similar in function, but not in internal form
  • ex butterfly wing vs. bird's wing
  • VS.
  • both fly, but butterflies don't have bones so
    support their wing whereas birds do DNA
    instructions are different
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