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Early Atmosphere components

Early Atmosphere components

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Early Atmosphere components

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  1. Early Atmosphere components • No ozone, so energy was created by lightening • Major Gases included: • carbon dioxide • Methane • NH3 • H20

  2. If there was just gas, where did the organic molecules on early earth come from?

  3. Oparin’s Hypothesis: Primordial Soup Model • 1920s- Primordial soup • Early earth’s oceans contained large amounts of organic molecules. So where did the organic molecules come from? • Gases of early atmosphere: CO2, H2O, NH3, CH4 • Chemical evolution- organic molecules formed spontaneously from inorganic molecules (gas) and energy (lightning)

  4. Miller + Urey • 1953- tested the primordial soup model (oparin’s hypothesis) • Put the gases they proposed had existed on early Earth in a beaker. • Stimulated lightning by using electrical sparks • Days later- Miller found a bunch of organic molecules • Amino acids • Fatty acids • Hydrocarbons (hydrogen and carbon) • Results supported Oparin’s hypothesis

  5. 4 steps to life (Miller + Urey) • 0. Inorganic matter • 1. Simple organic monomers • 2. Polymers • 3. Protocells (membrane bound) • 4. Cells (DNA present)

  6. Formation of Organelles • 1. Infolding of outer membrane to create endoplasmic reticulum, golgi body, vacoules • 2. Endosymbiosis: chloroplasts and mitochondria came from bacteria • A larger cell engulfes a small prokaryotic (bacteria) cell • The large and small cell work together to survive • Instead of being digested, the bacteria began to live inside the host cell where they performed either respiration (mitochondria) or photosynthesis (chloroplasts) • Mitochondria and chloroplasts have own DNA

  7. Miller + Urey demonstrate • Chemical evolution: organic molecules can be created from energy and gas molecules that exist on Early Earth

  8. No oxygen No ozone layer Lots of UV No land Lots of CO2 and ammonia Intense lightning storms Lots O2 Ozone layer Not much UV More land Less CO2 and ammonia Less lightning storms The AtmosphereEarly Modern

  9. Early life • Prokaryotic cells: no nucleus or cell organelles (bacteria) • Prokaryotic cells first appeared in 3.5 billion years ago • Eukaryotic cells have a nucleus enclosed by a membrane and has chromosomes (protists, fungi, plants, animals) • Eukaryotic cells first appeared 1.4 billion years ago

  10. Basic info of early life ---- Stromalites- fossilized mats of prokaryotic cells and sediment-- about 3.5 billion years ago (BYA) ---- First cells- heterotrophs (heterotroph hypothesis) • Heterotrophs annot make own food • This makes sense because there were lots of yummy organic molecules existing in puddles at the time

  11. The evolution of cells 1) Anaerobic heterotrophic prokaryotes- must have an environment without oxygen • Use and consume organic molecules • Amount organic molecules decrease and increase in competition 2) Autotrophic photosynthetic prokaryotes develop - able to make own food, do not compete with heterotrophs • Release oxygen which kills most anaerobic heterotrophs • Aerobic autotrophic prokaryotes- need oxygen in environment to survive • Aerobic heterotrophic prokayotes- heterotrophs that must have oxygen in the environment to survive • Eukaryotes • Multicellular organisms

  12. Autotrophs important because • They do not compete with anaerobic heterotrophs for food • They produced oxygen (bringing to current levels) • The oxygen they produce kills most anaerobic heterotrophs and only heterotrophs that were able to use oxygen survived and became the aerobic heterotrophs

  13. Plate Tectonics • According to this theory, the surface of the Earth is broken into large plates • The size and position of these plates change over time. • The edges of these plates, where they move against each other, are sites of intense geologic activity, such as earthquakes, volcanoes and mountain building

  14. Plate tectonics is… A combination of two earlier ideas, continental drift and sea-floor spreading. 1. Continental drift is the movement of continents over the Earth's surface and in their change in position relative to each other. 2. Sea-floor spreading: the plates move in a way that increases the size of the ocean floor

  15. Plate tectonics explain…. • How mountains form • Why Atlantic oean is getting larger • Movement of continents

  16. Continental Drift Proposed by Alfred Wegener in 1912. Evidence 1. The fit of the continents 2, The distribution of fossils • A similar sequence of rocks at numerous locations

  17. Fossils of the same species were found on several different continents.

  18. Rock sequences in South America, Africa, India, Antarctica, and Australia show remarkable similarities

  19. Law of SuperpositionRock LayersFossils found in sedimentary rock(sedimentation)

  20. Law of superposition • Approximate age of fossils is determined by where fossil lies in sediment. Lower layer indicates relatively older fossil • The lower the fossil is found (in a lower rock layer), the older it is • Fossils found closer to the surface are younger (more recent) in history

  21. Classification Why do we classify organisms? • To distinguish one organism from another • To determine relatedness of organisms • To compare similarities of organisms • To study evolutionary relationships of organisms • To create a common system of organization for scientists throughout the world

  22. Who classifies organisms? • Taxonomist: classifies organisms based on shared characteristics and genetic, biochemical, and embryological characteristics • Taxonomy: branch of biology concerned with classifying organisms • Carolus Linnaeus 1. Father of modern taxonomy 2. Gave organisms Latin names 3. Created hierarchy for all organisms General --> specific

  23. Seven hierarchial levels used today • Kingdom: Animalia • Phylum: Chlordata • Class: mammalia • Order: Primate • Family: Hominidae • Genus: Homo • Species: sapien King Phillip came over for green spaghetti

  24. What’s in a name? • All organisms referred to by their genus and species (bionomial nomenclature) • Rules for naming: capitalize Genus and lowercase species. Must underline or put scientific name in italics • Aminitamuscaria: white mushroom • Felisdomesticus: house cat • Pongopygmaeus: orangutan • Gorillagorilla: lowland gorilla

  25. Think about… • 1. Why are common names avoided? • 2. How can you tell if 2 organisms are related by their scientific name?