But the branch of the that readers might find most interesting led to humans. Humans are in the phylum, and the last common ancestor that founded the Chordata phylum is still a mystery and understandably a source of controversy. Was our ancestor a ? A ? Peter Ward made the case, as have others for a long time, that it was the sea squirt, also called a tunicate, which in its larval stage resembles a fish. The nerve cord in most bilaterally symmetric animals runs below the belly, not above it, and a sea squirt that never grew up may have been our direct ancestor. Adult tunicates are also highly adapted to extracting oxygen from water, even too much so, with only about 10% of today’s available oxygen extracted in tunicate respiration. It may mean that tunicates adapted to low oxygen conditions early on. Ward’s respiration hypothesis, which makes the case that adapting to low oxygen conditions was an evolutionary spur for animals, will repeatedly reappear in this essay, as will . Ward’s hypothesis may be proven wrong or will not have the key influence that he attributes to it, but it also has plenty going for it. The idea that fluctuating oxygen levels impacted animal evolution has been gaining support in recent years, particularly in light of recent reconstructions of oxygen levels in the eon of complex life, called and , which have yielded broadly similar results, but their variances mean that much more work needs to be performed before on the can be done, if it ever can be. Ward’s basic hypotheses is that when oxygen levels are high, ecosystems are diverse and life is an easy proposition; when oxygen levels are low, animals adapted to high oxygen levels go extinct and the survivors are adapted to low oxygen with body plan changes, and their adaptations helped them dominate after the extinctions. The has a pretty wide range of potential error, particularly in the early years, and it also tracked atmospheric carbon dioxide levels. The challenges to the validity of a model based on data with such a wide range of error are understandable. But some broad trends are unmistakable, as it is with other models, some of which are generally declining carbon dioxide levels, some huge oxygen spikes, and the generally relationship between oxygen and carbon dioxide levels, which a geochemist would expect. The high carbon dioxide level during the Cambrian, of at least 4,000 PPM (the "RCO2" in the below graphic is a ratio of the calculated CO2 levels to today's levels), is what scientists think made the times so hot. (Permission: Peter Ward, June 2014)
Could this essay's first half be considered an indulgence of my childhood fascination with nature? That argument could have merit, but I have always been a "big picture" kind of thinker, even as a teenager. I am writing this essay primarily to help manifest FE technology in the public sphere and help remedy the deficiencies in all previous attempts that I was part of, witnessed, heard of, or read about. The biggest problem, by far, was that those trying to bring FE technology to the public had virtually no support from the very public that they sought to help. My journey's most important lesson was that , and an egocentric humanity living in scarcity and fear is almost effortlessly manipulated by the social managers. John Q. Public is only interested in FE technology to the extent that he can immediately profit from it. Otherwise, he goes back to watching his favorite TV show. It took many years of disillusionment for that to finally become clear to me. While this essay and all of my writings are provided for free to humanity and anybody can read them, I intend to only reach a very tiny fraction of humanity with my writings, but that tiny fraction will be sufficient for my plan to succeed. The readers that I seek have a formidable task ahead of them, but nothing less is required for my approach to have any hope of bearing fruit. This essay and my other writings are intended as a course in (also called "big picture") thinking. Studying the details deeply enough to avoid misleading superficial understandings is also a key goal. I am an accountant by profession, but one of the world's leading paleobiologists surprisingly read an early draft of this essay and informed me that it was one of the best efforts that he ever saw on the journey of life on Earth. There was nobody on Earth whose opinion I would have respected more than his, so I do not think that I am asking readers of this essay's first half to humor me. Every sentient being on Earth should know the rudiments of what this essay's first half covers.
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