Earth's early atmosphere had abundant oxygen

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Contents 1 Claim 2 Source 3 Responses 4 Fallacies contained in this claim 5 External Links 6 Related claims 7 See Also 8 Acknowledgments

Claim

If all kinds of organisms were present on the earth from its early history, earth's atmosphere must have had an atmosphere much like today's, with enough oxygen to support all kinds of life.

Source

• add source

Responses

1. Oxygen is one of the more chemically reactive elements. If the primordial atmosphere actually did start out with "abundant" free oxygen, those primordial oxygen molecules would have taken themselves out of circulation by reacting to form iron oxide, carbon dioxide, water, and other oxygen compounds -- and they would have done so rather quickly, on a geologic timescale. The free oxygen we have in the atmosphere today is mainly the result of photosynthesis, a process which continually acts to replenish the atmosphere's supply of free oxygen. Before photosynthetic plants and bacteria appeared, we would expect little oxygen in the atmosphere. The oldest fossils (over a billion years older than the banded iron formations and other evidence for a transition to an oxygen atmosphere described below) were bacteria; we don't find fossils of fish, clams, or other organisms that need oxygen in the oldest sediments.
2. The supposition that Earth had "all kinds of organisms" from its early history is not supported. Indeed there is much evidence to contradict this. Also, early organisms would have been anaerobic: not requiring oxygen for life.
3. Early Precambrian strata tend to contain unoxidized iron, which cannot coexist in a stable equilibrium with an atmosphere full of free oxygen.
4. Until 2005, it was thought that the source of the early earth's atmosphere was volcanic gas. However, late in 2005, Bruce Fegley, Ph.D., et al., have amassed evidence that due to the chondritic origins of the earth and outgassing experiments performed on chondrites (a type of meteor), the early earth atmosphere would have closely resembled the reducing atmosphere used in the original Miller-Urey experiment. (See "Reducing Early Earth," [1] Sep 11, 2005, "Astrobiology Magazine")
5. Earth's oxygen atmosphere is a consequence of, not a precursor to, prokaryotic life. Aerobic organisms (those organisms that require or tolerate the presence of oxygen) evolved in reaction to the environmental changes brought about by carbon dioxide-reducing prokaryotes, which produce molecular oxygen as a metabolic waste product. This is anecdotally referred to as the "Oxygen Holocaust" and is perhaps, by biomass, the largest extinction event in the history of Earth. Humans are used to thinking of oxygen as a boon to life because we breathe it, but oxygen is actually toxic to most forms of life, even today. It was even more true at the prokaryote-eukaryote transition.
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Fallacies contained in this claim

• Question Begging (It's not clear that all kinds of organisms were present from an early time)
• Appeal to Intuition (Intuition dictates life/earth has always been as it is today)
• Wrong Direction of Cause and Effect (Life caused oxygen, not vice versa)
• Suppressed Evidence (of nature of primitive life/atmosphere)

External Links

• Tamzek, Nic, 2002. Icon of Obfuscation. [2]
• Henke, Kevin R, More Errors On True.Origin: J. Sarfati's Support of Flood Geology [3]
• Kazlev, M. Alan (27 October 2002). The Oxygen Atmosphere. PALAEOS.

Related claims

• Early molecules would have decayed
• Early molecules would have been destroyed by UV light
• Miller's experiments had invalid assumption of type of atmosphere

See Also

Why is Creationism not a Scientific Theory?

Acknowledgments

• Cubist