Smithsonian National Museum of Natural History Geologic Time The Story of a Changing Earth
Presented by the Department of Paleobiology.
The Proterozoic
Contents
Eon Overview
Earth's Crust as a Platform for Prokaryotic Life
Eukaryotes and the First Multicellular Life Forms
Changes in the Earth's Atmosphere
Proterozoic Mountains and Glaciers
Evidence
Rangea from the Ediacaran Fauna, Namibia.
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sample
First eukaryotes
Ediacaran Fauna 1
Ediacaran Fauna 2
Ediacaran Fauna 3
Ediacaran Fauna 4
Banded Iron Formations
Stromatolites
references and links
Foundational Concepts
Dating Methods
Earth Processes
Life Processes
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Earth’s Crust as a Platform for Prokaryotic Life
For much of the history of living things, organisms were exclusively primitive, single-celled forms such as bacteria and cyanobacteria. Then as now, these simple prokaryotic cells lacked a nucleus and were relatively small, but they already contained the same basic hereditary materials found in all life today—DNA and RNA. Many of these early life forms relied on chemosynthesis for their energy, deriving it from the chemicals around them instead of from sunlight or other organisms. Some inhabited environments that seem hostile, such as deep-sea hydrothermal vents.



Eon Overview | Earth's Crust as a Platform for Prokaryotic Life | Eukaryotes and the First Multicellular Life Forms | Changes in the Atmosphere | Proterozoic Mountains and Glaciers



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