Another evolutionary concept is that all changes had mechanical reasons for happening (again, today’s science has ), and each mechanical change required some purpose in improving an organism’s chances of surviving to reproduce, or at least not have unduly impaired it. As evolution progressed, for each species, it was like taking a road, and the farther down the road a species went in its development, the “lifestyle” opportunities that its biological operation created precluded other kinds of styles. For instance, trees will never become . Trees went down the path of roots, , growing taller than their neighbors, and the like. A plant cannot choose locomotion as a way of life. It does not generate enough energy for it, for one thing. Animals went down a very different evolutionary path than plants did, and muscles, brains, livers, and the like have no analogy in plants and, by themselves, plants will not grow muscles or brains anytime soon, although humans have been making radical changes in animals over brief periods of time, such as the many breeds of dog.
Because of early Eocene Arctic forests, animals moved freely between Asia, Europe, Greenland, and North America, which were , and great mammalian radiations occurred in the early Eocene. Many familiar mammals first appeared by the mid-Eocene, such as , elephants, , and . The may have first appeared in Asia and migrated to India, Africa, and the Americas. Europe was not yet connected with Asia, however, as the separated them. Modern observers might be startled to know where many animals originated. and lived there for more than 40 million years, until humans arrived. Their only surviving descendants in the Western Hemisphere are . As with , or , or , or Eocene mammalian migrations via polar routes, the migrants often involuntarily “sailed” on vegetation mats that crossed relatively short gaps between the continents. Such a migration depended on fortuitous prevailing currents and other factors, but it happened often enough.
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The energy from controlled fire allowed humans to , , and socially organize in new ways. Humans commandeered energy that otherwise and used it for immediate human benefit. It was also the first great human robbery. All heterotrophs “” energy from other life forms to live. The primary exception is the symbiosis that . But no animal had ever robbed energy from ecosystems on that scale before. By making fires, humans were liberating many times the energy that their biological processes used - energy that could have fed forest ecosystems. While humans were only using deadwood, it was the least destructive to forest ecosystems. But when humans began burning forests to flush out animals to kill and make biomes suitable for animals to hunt, they were destroying and altering ecosystems on a vast scale. A cord of wood provides about four years of the calories that fuel a human adult’s body, and one hectare can provide a sustainable annual harvest of about ten years of human calories. A family of four using a hectare for firewood on a sustainable basis would be using more than twice their caloric intake for burning wood. Very little of that released energy would benefit humans if they burned it over a campfire, as humans did for the entire epoch of the hunter-gatherer; that liberated energy largely went straight into the sky. The direct benefit to humans would be the energy that went into cooking food, what warmed human flesh, what was used to make tools, and the benefits of scaring off predators and providing light at night. More indirect benefits would have been ecosystem changes to provide human-digestible calories, such as American Indians burning the woodlands and plains to make environments conducive to animals that they could easily hunt. In , the earliest epochs are the most uncertain, but saying that hunter-gatherer humans used 2.5 times their dietary calories in their economy is probably, perhaps greatly, understating the case. That 5% efficiency number is also a rough estimate, and both numbers could be refined by a scientifically performed effort. Maybe somebody has already done it. The numbers in that table for subsequent epochs are more accurate, and the most accurate of all are those for , and I live in one. The increases in efficiency became more modest with each epoch as the limits of were approached.
Jan 14, 2013 · Conclusion
The Nile River's valley made the rise of Egyptian civilization possible, and it had the Old World’s most reliable food supply. Even today, half of Egypt’s population lives on the Nile’s delta. Annual floods brought silt from deforestation and erosion from the highlands to the delta, which kept the fields fertile. Unlike the Mesopotamian disaster, salination was not a major problem for Egyptians, except at and irrigated areas above the flood line. The Egyptian and Harappan civilizations were not pristine, as they were beneficiaries of Fertile Crescent innovations, and arose from hunter-gatherer societies that did not pass through the learning and evolutionary curve for domesticating their plants and animals. Those may have been the only places on Earth where civilization first appear. If not for those regions where people domesticated plants, humanity might still be living like aboriginal Australians did for nearly 50,000 years.
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Europe was a crucible for violence probably ever since the human conquest of Neanderthals, and evidence for warfare and mass violence increases as the timeline progressed from then. But going back to those , violence is not instinctual as much as calculated, and is a response to economic scarcity above all else. However, those early religious rituals were not only a method to form group cohesion; they were also a way to condition men to throw their lives away while trying to take the lives of others. The rituals and rites of passage for men were often extremely painful ordeals that conditioned them for the short life of a warrior, and forming highly contrasting in-group/out-group beliefs that facilitated killing other people. The portion of the human brain where emotions appear to be seated, in the , is no larger than in our great ape cousins. It is well-known that fear shuts down the neocortex, as animals prepare for fight-or-flight responses, and it is no different with humans. However, the response is much more dramatic with humans, with their huge neocortexes and frontal lobes. So the human response to fear is losing much of what makes humans seemingly sentient. Those religious rituals seem designed to bypass the neocortex and form a bridge to the limbic system where emotions rule. Religion seems to have arisen as a to warfare, but that will be explored in the next chapter, which covers the civilizing of humanity, which is the .