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Works Cited
- The early life forms in the Archean Eon laid the foundation for subsequent evolutionary developments, including the emergence of eukaryotic cells, multicellularity, and the diverse array of life forms that we see today. (Windley 2023)
- There was no multicellular life in the Archean Eon! All that existed as far as life goes are single-celled organisms. (Windley 2023)
- We know that Earth was bombarded by asteroids especially towards the end of the Archean Eon. (Windley 2023)
- Archean oceans were likely created by the condensation of water from the gas of many volcanoes (Windley 2023)
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Time Span: 2.5 to 4 Billion Years Ago
Fun Facts:
There were several major events during the Archean Eon, such as the appearance of the proto-crustt and photosyntthetic organisms.
Major Events
The Archean Earth was full of exciting things! Click here to find out more.
What Was the World Like?
THE ARCHEAN EON
Lepot, Kevin. “Signatures of Early Microbial Life from the Archean (4 to 2.5 Ga) Eon.” Earth-science reviews 209 (2020): 103296–. Web. Schopf, J. William. “Fossil Evidence of Archaean Life.” Philosophical transactions of the Royal Society of London. Series B. Biological sciences 361.1470 (2006): 869–885. Web. Brian Frederick Windley. “Archean Eon.” Encyclopædia Britannica Online 2020: n. pag. Print.
Works Citetd
Oceanic and atmospheric chemistries were largely controlled by extreme volcanic activity, and altered Earth’s early crust, both before and during the Archean Eon. During this time, major changes to geodynamics, or the forces of earth. These changes would eventually affect the chemistry of Earth’s surface and eventually, evolution of life. Oxygen was likely produced by photosynthesis as early as the Mesoarchean, but did not rise in the atmosphere until the end of the Archean Eon.
Archean Earth, Cont.
The Archean Eon saw the growth of the juvenile continental crust with an increase in of the necessary components in an “proto-crust.” It also likely saw the onset of plate tectonics. Large subaerial igneous provinces appeared toward the end of the Archean. (Schopf)
Some Major Events
During the Archean Eon, there were rocks that include evidence of some of the oldest traces of life. (Lepot 2020) Even with the presence of a young sun, the Archean climate is generally classified as temperate to hot. The atmosphere, and also likely the surface, saw an intense UV flux during this time. (Lepot 2020) Because of this, the atmosphere would have displayed concentrations in CO2, CH4 and H2 much higher than those of today, and may have allowed high-altitude nonliving formation of oxygen.
The Archean World
More Major Events
Early Life
Most Archean life lived in extreme environments, where high temperatures or intense radiation were common. These early life forms are often referred to as extremophiles because they could tolerate these very harsh conditions.Some scientists believe that photosynthetic organisms may have evolved during the late part of the Archean Eon. They used different pigments than most modern photosynthetic organisms and likely produced oxygen.
Most Archean life lived in extreme environments, where high temperatures or intense radiation were common. These early life forms are often referred to as extremophiles because they could tolerate these very harsh conditions.(Schopf)
