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History of Life on Earth

History of Life on Earth. January 12, 2009. What is the age of the Earth?. 4,500 years old 4,500,000 years old 4,500,000,000 years old 4,500,000,000,000 years old. Miller-Urey Experiment. Showed that, under certain conditions, organic compounds could form from inorganic molecules

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History of Life on Earth

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  1. History of Life on Earth January 12, 2009

  2. What is the age of the Earth? • 4,500 years old • 4,500,000 years old • 4,500,000,000 years old • 4,500,000,000,000 years old

  3. Miller-Urey Experiment Showed that, under certain conditions, organic compounds could form from inorganic molecules The experiment

  4. Life’s Building Blocks • Hydrothermal Vents: energy from the vents could have fueled chemical reactions and the depth of the sea would have offered protection from solar radiation • Space: some meteorites that have hit the Earth’s surface contain amino acids

  5. Really, Mrs. G? Space?? http://www.nmnh.si.edu/rtp/students/2007/schedule07_mineral_tour_photo_meteorites.html

  6. What process is used to estimate the age of fossil within strata, or layers of the Earth? • half-life • radioactive decay • radiometric dating • relative dating Copralite = Dinosaur dung http://i.livescience.com/images/ig25_dinosaur_dung_09.jpg

  7. What has shaped the geologic time scale of the Earth? • earthquakes • the formation of the Earth • floods • mass extinctions

  8. What do some scientists think provided the energy for chemical reactions that produced the first biological molecules? • meteors • heat from hydrothermal vents • ribozymes • microspheres

  9. The First Cells • Lipids make up cell membranes • Lipids do not mix with water • In water, lipids can form tiny spheres called microspheres. • Microspheres may have been the first step towards cellular organization

  10. Endosymbiosis • A mutually beneficial relationship in which one organism lives within another • Larger cells engulfed smaller cells, which then began to live inside larger cells

  11. Evidence for Endosymbiosis • Size and structure: mitochondria are the same size as most bacteria • Genetic material: both chloroplast and mitochondria contain their own DNA that is different from the DNA of their host cells • Ribosomes: both have ribosomes • Reproduction: Like bacteria, chloroplasts and mitochondria reproduce by simple fission

  12. Which were the first animals to evolve and successfully live on land? • arthropods • reptiles • amphibians • mycorrhizae

  13. Tapping Timeline

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