But even though they were “regular” on the geologic time scale, driven by , there would have been nothing “regular” about them to evolving humans. When ice sheets advanced, global climate became cooler and dryer; rainforests shrank and deserts expanded. Human adaptations to those changes, which could even be discerned in one human lifetime, must have had profound impacts on the human journey. In short, humans had to readily adapt to rapidly changing conditions, and rapid adaptation would have had selective effects on burgeoning human intelligence and problem-solving ability; those that adapted, survived. Also, scientists think that the rapidly oscillating climate resulted in migrations and pockets of isolated members of species that then underwent rapid evolutionary adaptation, the kind that leads to speciation. This may have been partly responsible for the relatively rapid evolution of the human line, particularly in the past million years.
Did the control of fire to , ? Or did merely use it to begin dominating the world? Was cooking the seminal event in the appearance of humans? Those questions may not be definitively answered in my lifetime, and led to the somewhat uncertain title of this chapter. Highly transformative developments coincided with the appearance and dispersal of , which was a radical break from all that came before – biologically, technically, and culturally – and strongly implies great cognitive enhancements. I believe that the control of fire and cooking would leave deep cultural and biological impacts on the human journey, and because barely changed during its nearly two-million year tenure on Earth, both in biology and in Acheulean artifacts, I favor Wrangham’s hypothesis, at least until the Next Big Finding. Just as Einstein said that and that his theories would one day become obsolete, but that their best parts would survive in the new theories, I suspect that significant aspects of Wrangham’s hypothesis will live on in successor hypotheses, and other scientists have been following Wrangham’s lead.
I am taking some liberties in calling Turkana Boy a ; he is technically a member of , which is often considered ancestral to , which is the Asian variant’s name. There is great debate regarding how the human family tree branches between and . Some call the various -type species all subspecies of , while others argue for several distinct species. I will not stray far from the orthodox narrative here, for good reason. The reconstructed early human tale is based on very limited evidence, but that evidence will only grow over time, and the tools and techniques for using them will become more sophisticated. Although there may be some upcoming radical changes in the view of the early human journey, efforts of countless scientist and fossil hunter lifetimes support the narrative that this essay sketches, and I respect their findings and opinions, even though I acknowledge many limitations. The human ego, it seems, becomes more involved as the story of life on Earth moves closer to its human chapters.
led to more involved mammalian parenting behaviors and increased female participation, in addition to the great investment that females have in gestating offspring. Larger simian males are more likely to become dominant, and dominant males often get the most and best food and have enhanced reproductive rights, as females are attracted to them. Virtually all monkey and ape societies are male-dominated, and the modern ideal of human females freely choosing their mates (or, perhaps more importantly, non-dominant males choosing their mates, if they get to mate at all) is rarely in evidence in monkey and ape societies, and is a new phenomenon for humans. The phenomenon of attractive women mating with rich and powerful men has deep roots in the simian evolutionary journey.
Did the larger brain lead to the behaviors, or did the behaviors lead to the larger brain? If other evolutionary trends have relevance, they mutually reinforced each other and provided positive feedbacks; down one evolutionary line it reached conditions that led to the human brain. The initial behavior was probably the use of a body part (the brain) for a new purpose, and its success led to selective advantages that led to mutual reinforcement. Although it is by no means an unorthodox understanding, I think that the likely chain of events was walking upright freed hands for new behaviors, which led to new ways of making and using tools, which enhanced food acquisition activities. This allowed the energy-demanding brain to expand, as well as related biological changes, which led to more complex tools and behaviors that acquired and even more energy. That, in short, defines the human journey to this day, which the rest of this essay will explore. There has never been and probably never will again be an energy-devouring animal like humanity on Earth, unless it is a human-line descendant.
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.
So far, this essay has dealt lightly with regional differences and largely confined the discussion to polar, temperate, and tropical conditions in the seas, and rainforest versus dryer conditions on land. While existed, barriers to species diffusion on land were relatively modest, hence dominance. But at the Triassic’s end, and continental differences in plants and animals often became significant in later times. Although the formation of Pangaea had profound impacts, because land life was relatively young, the differences and resultant changes due to the removal of oceanic barriers were less spectacular than would happen in the distant future, such as when .
The heart became steadily more complex during complex life’s evolutionary journeys. have one pump and two chambers. Amphibians , wherein oxygenated and deoxygenated blood are not structurally separated but mix. That arrangement is obviously not as energy-efficient as separating oxygenated and deoxygenated blood. Some later reptiles evolved four-chambered hearts, which their surviving descendants, and , possess, and somewhere along the line, also evolved four-chambered hearts, perhaps before they became mammals.
Perhaps the most damaging deficiency in FE efforts, after self-serving orientation, was that the participants and their supporters were scientifically illiterate and easily led astray by the latest spectacle. Scientific literacy can help prevent most such distractions. While writing this essay, I was not only bombarded with news of the latest FE and alternative energy aspirants' antics, but I had to continually field queries regarding whether Peak Oil and Global Warming were conspiratorial elite hoaxes (or figments of the hyperactive imaginations of environmentalists and other activists), for two examples that readily come to mind. Digesting this essay's material should have those questions answered as mere side-effects. Far from being a hoax or imaginary, Peak Oil was and , and it is all downhill from there, and conventional oil will be almost entirely depleted in my lifetime. , although both were heavily promoted in the USA in 2014. In every paleoclimate study that I have seen, so-called greenhouse gases have always been considered the primary determinant of Earth's surface temperature (after the Sun), and carbon dioxide is chief among them. The radiation-trapping properties of carbon dioxide are not controversial in the slightest among scientists, and after the Sun's influence (which is exceedingly stable), declining carbon dioxide levels are considered to be the conditions that have dominated Earth for the past 35 million years. Humanity's increasing the atmosphere's carbon dioxide content is influencing the cause of Icehouse Earth, and , and are merely proximate causes. Increasing carbon dioxide can turn the global climate from an to a Greenhouse Earth, and the last time that happened, Earth had its . But have purposefully confused the issues, and a scientifically illiterate public and have played along, partly because believing the disinformation seems to relieve us all of any responsibility for our actions. Although scientific literacy can help people become immune to the disinformation and confusion arising from many corners, and reading this essay's first half can help people develop their own defense from such distractions, my goals for this essay's first half are far greater than that.
As will be explored in this essay, all of the marine life have anoxia as a suspected contributing cause, so oxygen is a major area of interest among extinction specialists. Whether oxygen levels were also significant contributing causes of evolutionary innovation is another area of interest today. Again, to food chains. Even if the first animals did not respire anaerobically, they adapted to aerobic respiration early on and then became dependent on it. There would be no going back for animals; all except those few adapted to and anoxic environments went “all in” with aerobic respiration.
This essay presents a , and nearly half of the events happened during the timeframe covered by this essay's first half, which includes almost the entirety of Earth's history. Humanity's tenure amounts to a tiny sliver of Earth's history, and surveying pre-human events was partly intended to help readers develop a sense of perspective. We are merely Earth's latest tenants. We have unprecedented dominance, but we are quickly destroying Earth's ability to host complex life. As my astronaut colleague openly wondered, is ? Is our path of destruction inevitable, as we plunder one energy resource after another to exhaustion? Will depleting Earth's hydrocarbons be the latest, greatest, and perhaps final instance?