Photosynthesis (Process that changed history)

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Photosynthesis(Process that changed history)

• Light energy CO2 H2O ? glucose O2
• IMPORTANT POINTS
• ? Example of 1st Law of Thermodynamics (E
  conservation)
• Radiant energy (light) ? chemical energy
  (glucose)
• ? Carbon from atmosphere locked into an organic
  molecule (glucose) Carbon fixation! (This
  point covered for Test IV)
• ? Water molecules split ? O2 gas is released!

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Evolution of the Earths Atmosphere

• The Continuing Story

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• Major Episodes in the History of Life

Millions of years ago
Major Episode
475 570 1,000 1,700 2,500 3,500 4,500
Plants and fungi colonize land All major animal
phyla established First multicellular
organisms Oldest eukaryotic fossils Accumulation
of atmospheric 02 Oldest prokaryotic
fossils Origin of Earth
Visual Summary 15.1
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4.5 BYA

• Earth FormedWhat was original atmosphere like?

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3.5 BYA

• Life appeared! (Prokaryotic)
• Q Did these organisms need oxygen to live?
• Then some New guys appeared

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Cyanobacteria or blue-green algae
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2.5 BYA

• Significant build up of oxygen gas in Earths
  atmosphere (Due to photosynthesis!)
• Many original inhabitants die due to this
  Pollution Crises!
• Some organisms adapt use O2 to release stored
  energy of food.

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1.7 1.5 BYA

• The Rise of Eukaryotes!
• First Protists ?plants, animals, fungi
• 1.0 BYALife experiments with multi-cellularity!

9
½ BYA

• (570mya)
• CAMBRIAN EXPLOSION!
• All major animal phyla established!
• ( 470 mya)
• ? Terrestrial life appears(First Fungi plants,
  then animals)? What was necessary for
  terrestrial life?

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OZONE!

• O2 O2 O2 2 O3
• Why is Ozone so important?