Early Atmosphere components

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Early Atmosphere components

• No ozone, so energy was created by lightening
• Major Gases included
• carbon dioxide
• Methane
• NH3
• H20

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If there was just gas, where did the organic
molecules on early earth come from?
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Oparins Hypothesis Primordial Soup Model

• 1920s- Primordial soup
• Early earths 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)

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Miller Urey

• 1953- tested the primordial soup model (oparins
  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 Oparins hypothesis

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4 steps to life (Miller Urey)

• 0. Inorganic matter
• 1. Simple organic monomers
• 2. Polymers
• 3. Protocells (membrane bound)
• 4. Cells (DNA present)

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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

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Miller Urey demonstrate

• Chemical evolution organic molecules can be
  created from energy and gas molecules that exist
  on Early Earth

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The AtmosphereEarly Modern

• 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

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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

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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

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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

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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

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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

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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

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Plate tectonics explain.

• How mountains form
• Why Atlantic oean is getting larger
• Movement of continents

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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

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Fossils of the same species were found on
several different continents.
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Rock sequences in South America, Africa, India,
Antarctica, and Australia show remarkable
similarities
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Law of SuperpositionRock LayersFossils found
in sedimentary rock(sedimentation)
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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

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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

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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 --gt specific

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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

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Whats 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
• Aminita muscaria white mushroom
• Felis domesticus house cat
• Pongo pygmaeus orangutan
• Gorilla gorilla lowland gorilla

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Think about

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