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385
The first four-legged animals, or tetrapods, evolve from intermediate species such as Tiktaalik, probably in shallow freshwater habitats.
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Mar 16, 900
The first multicellular life develops around this time.
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May 1, 1500
Eukaryotic cell organisms develop
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The oldest fossils of single-celled organisms date from this time.
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Beginning of photosynthesis by blue-green algae which releases oxygen molecules into the atmosphere and steadily works to strengthen the ozone layer and change the Earth's chemically reducing atmosphere into a chemically oxidizing one
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The Earth's crust solidifies--formation of the oldest rocks found on Earth
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Formation of the approximately homogeneous solid Earth by planetesimal accretion
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Archaeozoic (Archean) era
3.5 Billion