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Earth's Oxygen History Could Explain "Darwin's Dilemma" In Evolution
TaleSlinger (3080869) writes Scientists following two different lines of evidence have just published research [Here's the abstract to the paywalled Science paper] that
may help resolve "Darwin's dilemma," a mystery that plagued the father of evolution until his death more than a century ago. Life appeared when the earth was tens of millions of years old, but evolution didn't go into high gear until the "Cambrian Explosion", nearly a billion years later. The two papers propose complementary theories that help explain this. The first suggests that scientists have long overestimated the amount of oxygen in the earth's atmosphere in the pre-Cambrian era just before the "explosion." The second suggests suggests that very dramatic changes driven by the tectonic breakup of the so-called "supercontinents" of the pre-Cambrian era could have caused an extraordinary leap in oxygen levels of both the ancient oceans and the earth's atmosphere. These two studies fit neatly together, suggesting that a world deprived of oxygen could have changed relatively quickly into an incubator for new life in shallow ponds spread across the continents and fed by waters rich in nutrients. Perhaps that set the stage for the explosion, which may have been five times the evolutionary rate seen today.
Second lack of evidence is not the evidence of lack. Before the Cambrian "explosion" the organisms had not developed bones and shells that would fossilize. It is very hard for soft bodies to fossilize and for the indirect evidence to stick around. There are very few places where the original primordial earth crust still survives without change. Almost the entire seafloor is new. Constantly being melted into the magma in the subduction zones and being reformed in the expansion zones. No evidence of anything would survive that. So it is totally incorrect to say that earth was not teeming with life or that the competition was absent.
Today multi-trillion cell agglomerations are sitting on keyboard and typing follow up responses to pointless postings in slashdot. Many trillion cell colonies of micro organisms live symbiotically with these agglomerations which call themselves human. Trillions of these cells commit suicide promptly when the signal arrives, to be replaced by new copies. They know they are not in the gonad and they will never reproduce. Still they all tick along doing their stuff. The foundations for such a way of life for these cells were laid down before the Cambrian "explosion".
And we become time traveling mind readers and state confidently "Darwin was plagued by the mystery...". Darwin was constantly complaining of so many illnesses he was such a strain on Emma. He had lot more than a mystery plaguing him.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
The problem with The Magic Soup theory is that over time, all closed systems tend to disorder ...
The "Magic Soup" theory that you're trying to strawman is NOT a closed system. Energy that comes in from sunlight or even just heat = not a closed system. The rest of the post isn't even worth replying to.