Transcript OL P4 - CCMI - Central Caribbean Marine Institute

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OCEAN LITERACY
OCEAN LITERACY
Essential Principles & Fundamental Concepts of Ocean Science
PRINCIPLE 4
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REVISION HISTORY
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Aug 25, 2010
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ESSENTIAL PRINCIPLE 4
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The ocean makes Earth habitable.
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4 | THE OCEAN MAKES EARTH HABITABLE
4(a) Most of the oxygen in the atmosphere originally came from the
activities of photosynthetic organisms in the ocean.
Atmospheric Oxygen From Oceanic Organisms
Most of the atmospheric oxygen originally came from photosynthetic
organisms in the ocean such as the blue-green bacteria and other
plant life.
Photosynthesis is the process by which organisms (e.g. blue-green
bacteria, green algae, and plants) use carbon dioxide, water and
sunlight to produce carbohydrates and oxygen.
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4 | THE OCEAN MAKES EARTH HABITABLE
4(b) The first life is thought to have started in the ocean. The earliest
evidence of life is found in the ocean.
Pre-Cambrian – 4,500 MYA To 543 MYA
By examining some of the oldest sedimentary rocks on Earth,
scientists have concluded that life on Earth started in the ocean.
The oldest fossils date to roughly 3,500 MYA and consist of bluegreen bacteria. In fact, all life on Earth for the next 1,000 million
years was probably bacterial. By about 2,500 MYA, abundant fossils
of living organisms, mostly blue-green bacteria, can be found. Then,
about 1,800 MYA, simple eukaryotic cells (cells with a nucleus)
started appearing.
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