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Evolution and the Origin of Life

Evolution and the Origin of Life

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Evolution and the Origin of Life

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  1. Evolution and the Origin of Life

  2. What is the Relationship between behavior and survival? • How did this dictate the diversity of organisms? • Do these diverse organisms have anything in common with me?

  3. What was the early Earth like and how did life come about?

  4. Big Bang:The beginning of the universe began with an explosion that sent energy and matter in all directions. (1927 Belgian Priest Georges Lemaître)

  5. Formation of Earth • 4.6 billion years ago • Established age through radiometric dating • Half Life: period of time it takes unstable atoms undergoing radioactive decay to decrease by half • Radiometric dating: Uses radioactive decay of isotopes by calculating half life

  6. Radioactive Decay Which isotope would best be measured for radiometric dating of the oldest rock on Earth? Which isotope would best be used for dating a mammoth Tusk that was 30,000 years old?

  7. Early Earth Q: Could we have survived in the Early Earth? A: NO!! Very harsh conditions

  8. Primitive Atmosphere • Composed of hydrogen (H2), nitrogen (N2), carbon dioxide (CO2), water vapor (H2O) and carbon monoxide (CO) • Maybe even some ammonia (NH3) and methane (CH4) • Oxygen (O2), is not present in a free form!!

  9. Harsh Conditions • Anaerobic = no O2 • Interior of the Earth was very hot = many active volcanoes • High amounts of the sun’s UV light covered the Earth = harmful to DNA • Intense lightning

  10. Where did life come from? Some theories… • Divine Creation: Life on Earth was put here by some divine force commonly thought of as God or gods. • Extraterrestrial Origins:Life came from someplace outside of Earth, such as a fallen meteorite or asteroid.

  11. In the soup hypothesis, all the elements needed for • the construction of nucleic acids were drifting around in • the early waters—primordial soup—and atmosphere of • earth. • The addition of energy, in the form of lightning, • catalyzed the chemical reaction that joined them together.Theories of How Life Began: Did the First Cells Form in a Soup, Sandwich, or Pizza? • Primordial soup theory:

  12. Life came from a number of chemical reactions starting from nonliving matter or chemicals

  13. Non-living Chemicals to Organic Molecules • First hypothesized by Russian Scientist A.I. Operin. • Energy from volcano eruptions, lightning and solar radiation allowed for chemical reactions and formation of new organic macromolecules • Miller-Urey experiment helped show that this was possible.

  14. Miller-Urey experiment gasses from primitive atmosphere introduced to electrical sparks (lightning). Electrons jump forming organic molecules

  15. Genetic Information • “RNA world” • Can form spontaneously • Can replicate itself • Catalyzed the formation of protein synthesis

  16. Cellular Organization • Small cellular looking formations called microspheres • Made from the joining of organic molecules • Have selectively permeable membranes • Store and release energy

  17. First Cells • Anaerobic, heterotrophic Prokaryotes. • Why would autotrophs eventually have an advantage over these heterotrophs?

  18. Autotrophs make an appearance… • Archaea, unicellular organisms, undergo chemosynthesis obtaining energy from the oxidation of sulfur.

  19. First Eukaryotes Endosymbiosis • Around 2 billion years ago, a small aerobic • prokaryote was engulfed by a larger, • Anaerobic prokaryote making the eukaryote. • The environment was beneficial for both.

  20. To sum it up… • The universe is between 10 and 20 billion years old, and the common accepted age is 15 billion years. This is a very long time. To appreciate its depth, we'll map the history of the universe into one of our twelve-month calendar years. Our cosmic year begins with the formation of the universe at midnight. Although a lot goes on in the first few months, our galaxy, the Milky Way, doesn't form until May 1 and our solar system is absent until around September 9. Earth forms on September 14 and life originates in late September or early October. The Eukaryotes, the first cells with nuclei, are flourishing by mid-November but most of what we know about the history of life occurs in December. • December opens with an increase in oxygen in our atmosphere, a by product of oxygen-producing algae that destroy themselves by overproducing oxygen. The first worms appear in mid-December, and plants begin colonizing the land around December 20. Life enters middle age on Christmas and dinosaurs dominate the next few days. The first primates appear on December 29th but the first humans don't develop until late evening on the last day of the year, near 10:30 PM. Agriculture is invented with just 40 seconds before midnight, Rome falls with three seconds remaining, and recent history makes up the last second. We are beginning the second year as newcomers to the universe. •

  21. References • •