Chemical Evolution

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Chemical Evolution

• From Compounds to Life

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Origin of Universe

• The Big Bang
• 15-18 billion years ago- all matter was in one
  condensed mass
• Explosion caused matter and energy in universe
• Earth formed 4.6 billion years ago
• Early Earth
• Hot when formed, volcanoes, crust formed and
  cooled over hot interior
• Primitive atmosphere N2, CO2, H2O, H2, CO, NH3,
  CH4 (no free O2)
• No ozone layer- energy came from UV rays to make
  bigger compounds amino acids and RNA.

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Miller-Urey Experiment

• conducted in 1953 by Stanley Miller with Harold
  Urey
• the first experiment to about the evolution of
  prebiotic chemicals and the origin of life on
  Earth
• mixture of methane, ammonia, hydrogen, and water
  vapor introduced into a 5-liter flask (simulate
  the Earth's primitive, reducing atmosphere)
• energized by an electrical discharge apparatus to
  represent ultraviolet radiation from the Sun
• products were allowed to condense and collect in
  a lower flask which modeled a body of water on
  the Earth's surface

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Miller-Urey Experiment

• heat supplied to this flask recycled the water
  vapor just as water evaporates from lakes and
  seas, before moving into the atmosphere and
  condensing again as rain
• after a day of continuous operation
• a thin layer of hydrocarbons on the surface of
  the water
• after about a week of operation
• a dark brown scum had collected in the lower
  flask and was found to contain several types of
  amino acids, including glycine and alanine,
  together with sugars, tars, and various other
  unidentified organic chemicals

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Heterotroph Hypothesis

• Primitive atmosphere gases UV radiation ?
• Early organic compounds ?
• Organic compounds in oceans ?
• Pre-cells formed ---- anaerobic processes for
  energy ?
• Photosynthesis cells formed, better able to
  survive, produced free O2 as waste
• 6. Atmosphere formed ozone layer

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Oxygen Importance

• Huge electron acceptor
• Highly reactive
• Has an ability to make a lot of ATP which equals
  energy
• If it were there evolution would have sped up so
  fast there would be no variety

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Origin of Life

• Aristotle (350 BC)
• decaying material could be transformed by the
  Spontaneous Action of Nature' into living animals

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Biological Evolution

• First- Coacervates- cell like structures empty
  membranes
• RNA-Self replicating molecules and other
  compounds were added to membranes
• Together with mineral clays (catalytic
  environment) the first self replicating life
  system A Prokaryotic Cell

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Evolution of First Life

• Essential functions of Life
• acquisition of energy from the environment
• use of energy to synthesize molecules
  metabolism
• information transfer to succeeding generations
  genetics

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Types of Organisms

• Prokaryotic Kingdom single-celled organisms
  containing no internal structures surrounded by
  membranes (therefore there is no nucleus)
• Monera bacteria and cyanobacteria

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Endosymbiotic Theory
Chloroplast
Plants and plantlike protists
Aerobic bacteria
Ancient Prokaryotes
Photosynthetic bacteria
Nuclear envelope evolving
Mitochondrion
Primitive Photosynthetic Eukaryote
Animals, fungi, and non-plantlike protists
Primitive Aerobic Eukaryote
Ancient Anaerobic Prokaryote
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Endosymbiotic Theory

• Proposed by Lynn Margulis in 1953
• Explained how eukaryotes evolved
• During the time that prokaryotes were evolving,
  the ozone layer stopped the Uvs from making new
  compounds, a cannibalistic society probably
  resulted
• Some prokaryotes became symbiotic instead of
  being ingested.

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Types of Organisms

• Eukaryotic Kingdoms all organisms consisting of
  cells which contain membrane-bound nuclei
• Protista - mostly one-celled organisms have
  characteristics of all three other Eukaryote
  Kingdoms
• Fungi - organisms which decompose stuff
• Plantae - organisms which use photosynthesis to
  make their own food
• Annuals complete life cycle in one season
• Perennials live for more than one season
• Animalia - organisms which must get organic
  compounds from food they eat - most are able to
  move
• Invertebrates no backbone
• Vertebrates Fish, Amphibians, Reptiles, Birds
  and Mammals