Oxygen YoYos and Wings
Molecular oxygen: you can’t live with it, and you can’t live without it. We breathe it in constantly or else we would turn blue and die within minutes. Yet we take antioxidants because of the harm that oxygen radicals can wreak in our cells. Like fire, it is a useful substance, but only when tightly controlled. In addition, in its O3 form of ozone, it is part of our planetary protection system from harmful ultraviolet rays. Evolutionists presume there was no oxygen on the early earth. Indeed, the presence of oxygen would have brought chemical evolution to a halt. How and when did oxygen enter the geosphere and biosphere safely, and what effects do variations in oxygen have on life? That was the subject of some recent science news articles.
EurekAlert reported on a Carnegie Institution study that upsets a previous evolutionary belief about the early earth. Oxygen did not suddenly appear when organisms “invented” photosynthesis and started giving off oxygen as a “waste product,” but probably increased gradually 300 million years earlier than expected. Since Archaen organisms could not have survived with oxygen around, the article is entitled, “Learning to live with oxygen on early Earth.”
James Kasting also reported on this subject in Nature last week.1
The ancient rise of atmospheric oxygen is of great interest because of its close relationship with evolution, but the geological evidence for this is indirect and subject to interpretation. The consensus for more than 30 years has been that atmospheric oxygen first reached appreciable levels around 2 billion to 2.4 billion years ago, an occasion known as the great oxidation event (GOE). But doubters of this event have remained.
After presenting the evidence for an earlier oxygen increase given by Goldblatt et al in the same issue,2 Kasting considered pros and cons of the interpretation of the carbon isotope evidence. He listed other interpretations, including the “yo-yo atmosphere theory” that oxygen levels fluctuated over time.
But this would still leave some unexplained observations. For example, the Witwatersrand gold deposits in South Africa contain detrital minerals that were washed down streams between 2.8 billion and 3.0 billion years ago. In the presence of oxygen, these minerals should have become oxidized and dissolved. So, either the oxygen levels were never high enough for that, or they repeatedly went up and came back down very quickly. Or perhaps oxygen concentrations did not increase at all, and the low-MIF anomaly seen in post-GOE rocks was produced by some entirely anoxic mechanism, such as the shielding of solar ultraviolet rays by an organic haze.
Clearly the air is hazy on this issue. “The jury is still out,” he ends, “but all these contradictory observations are stimulating a lot of creative thinking. Let us hope that this will lead to a more unified understanding of a fascinating era in Earth’s history. The ancient atmosphere may have had a more complex evolution than we imagined.”
Jumping ahead millions of years in the evolutionary scheme, when oxygen was here to stay, the amount of oxygen in the atmosphere could have varied considerably. What does this do to organisms? EurekAlert reported another study from the American Physiological Society, that “Giant insects might reign if only there was more oxygen in the air.” In fact, insects were giants in past eras. Paleozoic strata show some dragonflies had wing spans of 2.5 feet. Paleontologists figure that the oxygen had 35% oxygen then, compared to 21% now. In fact, the size of today’s insects is limited by our relatively low oxygen budget, the researchers estimated. A bigger bug needs more oxygen, but the size of the tracheae (tubes that let in the air) are limited by the leg joints. Giantism could arise, because “when the oxygen concentration in the atmosphere is high, the insect needs smaller quantities of air to meet its oxygen demands.”
1James Kasting, “Earth sciences: Ups and downs of ancient oxygen,” Nature 443, 643-645(12 October 2006) | doi:10.1038/443643a; Published online 11 October 2006.
2Goldblatt, Lenton, and Watson, “Bistability of atmospheric oxygen and the Great Oxidation,” Nature 443, 683-686(12 October 2006) | doi:10.1038/nature05169.
What needs a Great Oxidation Event is the air in the Darwin Party Castle. It is so stuffy in there it’s stifling. Maybe science would take on giant new wings in a less suffocating environment.
It is an observational fact, though, that giant insects did once inhabit the earth. It’s interesting to study what environmental conditions allowed for giantism, not only in insects, but in other organisms, including mammals, and what the hazards might have been: e.g., more wildfire? Or was the oxygen increase also moderated by higher humidity? Some of these factors can be tested by observational lab science. The interpretation of past events, though, and when they occurred, as shown in the first article, is a yo-yo pastime. “The ancient atmosphere may have had a more complex evolution than we imagined,” Kasting said, using evolution in the equivocal sense of “change over time.” But when your clock is broken, and your data are contradictory, and your assumptions are circular, maintaining dogmatic allegiance to Darwinism could be called ear-aversable complicity.