Let's study ID: just right oxygen (Introduction)

by David Turell , Sunday, July 24, 2022, 16:53 (636 days ago) @ David Turell

Michel Denton's view:

https://salvomag.com/post/burning-yet-not-consumed

"Denton explains that the level of oxygen in Earth’s atmosphere – 21 percent – is highly fine-tuned to allow both efficient respiration and combustion – the chemical reaction that allows humans to extract energy from burning fuels, which kickstarted our technical civilization. If the oxygen level were to fall much below 16 percent, human cognitive faculties would be severely compromised, migraines would come far too frequently, and even moderate physical activity would prove exhausting. What’s more, plant-based fuels would not stay alight. Below 12 percent, no combustion at all would be possible.

"With anything higher than 24 percent, however, forest fires would ravage vast swathes of the continental earth. In addition, elevated oxygen concentrations would generate much higher levels of what’s called reactive oxygen species (such as hydrogen peroxide) inside our cells, which would degrade biomolecules at dangerous rates. Furthermore, Denton also points out the extraordinary fire retarding properties of nitrogen, that all but inert gas which makes up 78 percent of the earth’s atmosphere, keeping oxygen’s vicious reactivity in check, allowing fires to burn, but not uncontrollably so.

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"Denton calls our attention to yet more life-affirming properties of oxygen. Consider, for example, the solubility of oxygen in water. If oxygen were just a little more soluble in water, the oceans would draw down too much of it from the atmosphere, stymying the progress of air-breathing land animals. If it were only slightly less soluble in water, the marine environment upon which human civilization depends, would collapse.

"Here again, the level of oxygen in the atmosphere, with its just-right solubility, allows for life to flourish on our planet. But if oxygen is not sufficiently soluble in water, how can enough of it reach the innermost recesses of the human body? It turns out that some unique properties of transition metals – iron in particular – are found at the heart of the myriad hemoglobin molecules packed inside our red blood cells. The chemical properties of iron make it possible to bind oxygen molecules just strongly enough to carry it to all cells of the human body, but weakly enough to have it released into the tissues of our bodies.

"In the upper atmosphere, ultraviolet light from the Sun breaks up oxygen molecules (O2) into single atoms. Then, an oxygen molecule can combine with an oxygen atom to create a gaseous substance called ozone (O3). Too much ozone is toxic to life, but the small amount created in the earth’s stratosphere helps protect life on land from the most damaging effects of ultraviolet light. Thus, in a splendid symmetry, we see the molecule of life also acting to protect life.

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"The unique properties of oxygen allowed our ancestors to tame a flame, but not just to keep warm and cook food, but also to use its unique properties to reduce metal ores of copper and tin using charcoal. Materials such as these launched the human technological revolution, with the creation of brand-new materials like bronze. Later, when humans learned how to create even hotter furnaces, the extraction of iron from its ore became possible, and just think how that metal has transformed the human world. Indeed, in a very real sense, we still live in the iron age. Similarly, the combustive properties of oxygen allowed humanity to roast limestone into lime, a key ingredient of concrete, as well as to exploit vast reserves of fossil fuels which launched the industrial revolution."

Comment: The just right level of oxygen evolved over time as cyanobacteria evolved to produce it in our atmosphere. Living organisms evolved using antioxidant molecules to protective themselves from the destructive effects of oxygen. How does a chance development of evolution choose such a dangerous gas to use as a basis of life? It doesn't. Design is required to carefuly put it all together.