Humans are the large-brained, allegedly sentient species that dominates Earth, and humans have greatly altered evolutionary processes, down to “engineering” the DNA of organisms. We have a “nature” and multi-billion year heritage, as any organism does. How much have we changed ours, and how much do our natures really matter? Can we consciously change our natures or overcome them? The nature/nurture debate is quite old, and as the domestication of plants and animals has demonstrated, or the , nurture can nature by selective breeding at the least. The , as an experiment, and the changes were dramatic. There is plenty about humanity that is nature at work, such as a child's acquisition of language or the urge to procreate (and the related ). Also, a great deal is socially learned. At least half of the variance in human traits such as intelligence and personality has been attributed to genetics, and nearly all the rest is socialization by the peer group (I believe that the , and the guiding role, but that is not scientifically demonstrable, at least today). But few of those scientific findings regarding human nature, if any of them, are relevant to why imperial "entertainment" is no longer . The improvement in standard of living due to increased energy consumption has precipitated many changes in what was once considered human "nature," such as . In a , would the dominant ideologies exalt and ?
As my fellow travelers and I have pursued FE, the nearly universal reactions to our efforts were denial and fear, which often led to our being attacked. Denial is a fear reaction, so we always found the barrier to be fear. If people got past denial and fear of “,” then greed and megalomania usually destroyed the efforts. Greed is the fear of never having enough, and megalomania is due to fear of inadequacy, so once again, fear defeated the effort. Those reactions usually happened long before organized suppression was applied. When the agents of organized suppression arrived, they almost effortlessly defeated the efforts by using people’s fear and greed against them. When I , I initially refused to believe it. We made the GCs’ task easy. They easily . The opposite of fear is love, which has always been the crux of this conundrum and will be addressed later. This chapter is about what life looks like after we get over the hump; I honor , but they can be addressed.
Many into their structures. also incorporate silica, and those are among the few life forms that use silicon, although it is one of . Diatoms seem to gain , and plants seem to have structural advantages, but it is thought that plants also used silica for a defensive measure, as it helps make plants unpalatable. Eating plants full of silica structures, called , is like chewing sand. This is particularly true with grasses, as phytoliths make chewing them a tooth-wrecking process, particularly for ruminants and their thorough chewing. Grazing herbivores have heavily enameled hypsodont teeth (also called high-crowned teeth) to . In North America, hypsodont herbivores proliferated while those without that heavy enamel (also called low-crowned teeth), which were browsers instead of grazers, declined. By about nine mya, North American browsers had largely vanished and grazers dominated the new grasslands. Earth kept cooling and drying, and fewer than seven mya, steppe vegetation began replacing savanna-like grasslands, and forests were decimated. This led to the greatest mass extinction in pre-human North America in the Cenozoic Era, as many species of horses, mastodonts, bears, dogs, and small predators went extinct, as well as mice, beavers, and moles. Asia and Africa were hit similarly, although not quite as hard as North America seemed to be, but South America and Australia hardly seemed affected at all. New Zealand’s surrounding seafloor changed from warm-water communities to the Southern Ocean communities that it has today.
When that likely human ancestor made the , it was the culmination of a process of increasing encephalization and manipulative ability that probably began its ascent with and accelerated when humanity’s ancestors became . and applying those findings to humanity’s ancestors is problematic, but there has probably not been significant evolution in great apes since they descended from the last common ancestor that they shared with humans, particularly chimpanzees. About one mya, and became a separate species, but for many years scientists did not realize it. Another chimpanzee split about 1.5 mya created east and west chimp species that are virtually indistinguishable today. It is widely considered to be very likely that the last common ancestor of chimps and humans looked like a chimp.
The invasion of North America from Asia (with a little migration from North America to Asia), while important, was not as dramatic as what happened in Africa a few million years later. About 24 mya, Africa and the attached Arabian Peninsula began colliding with Eurasia. The once-vast Tethys Ocean had finally been reduced to a strait between the continents, and one of Earth’s most dramatic mammalian migrations began. By about 18 mya, proboscidean had migrated from Africa and they reached North America by 16.5 mya. An left Africa but stayed in Asia. As with the North American interchange with Asia, however, the greater change came the other way. Rodents, deer, cattle, antelope, pigs, rhinos, giraffes, dogs (including the ), and cats came over, along with small insectivores and shrews. Most of the iconic large fauna of today’s African plains originated from elsewhere, particularly Asia. Asian animals invaded and dominated Europe and Africa, and became abundant in North America. In general, Asia had more diverse biomes and was the largest continent, so it developed the most competitive animals. That principle, which Darwin remarked on, became very evident when the British invaded Australia in the 18th century: imports such as rabbits and foxes quickly prevailed, and . The most important Miocene development for humans was African primate development, but that is a subject for a later chapter.
People are usually surprised to hear that grass is a relatively recent plant innovation. and only became common in the late Cretaceous, along with flowering plants. With grass, some , and grazers have been plentiful Cenozoic herbivores. According to , carbon dioxide levels have been falling nearly continuously for the past 150-100 million years. Not only has that decline progressively cooled Earth to the point where we live in an ice age today, but is currently considered the key reason why complex life may become extinct on Earth in several hundred million years. In the Oligocene, between 32 mya and 25 mya some plants developed a during photosynthesis known as . It allowed plants to adapt to reduced atmospheric carbon dioxide levels. C4 plants became in the Miocene, and grasses are today’s most common C4 plants and . The rest of Earth’s photosynthesizers use or , which is a water-conserving process used in arid biomes.
Among herbivores, their mode of digestion was important. attained the , and elephants, rhinos, and horses have that digestive process. Cattle, camels, deer, giraffes, and many other herbivorous mammals are foregut fermenters and many are , which have four-chambered stomachs, while the others . While foregut fermenters are more energy efficient, hindgut fermenters can ingest more food. Hindgut fermenters gain an advantage when forage is of low quality. What they . There are drawbacks to that advantage, however, such as when there is not much forage or its quality is poor, such as dead vegetation. A cow, for instance, digests as much as 75% of the protein that it eats, while a horse digests around 25%. Live grass contains about four times the protein as dead grass. Cattle can subsist on the dead grass of droughts or hard winters and horses cannot, which was a tradeoff in pastoral societies.
Huge mammals persist to this day, although the spread of humans was coincident with the with the exception of those in Africa and, to a lesser extent, Asia. The five-to-seven-metric-ton browser formed a guild common to dinosaurs mammals, and is probably related to metabolic limits and the relatively low calorie density that browsing and foraging affords. Sometimes, the similarity between dinosaurs and mammals could be eerie, such as and , which is a startling example of , which is the process by which distantly related organisms develop similar features to solve similar problems. They were even about the same size, at least for the most common ankylosaurs, which were about the size of a car. Ankylosaurs appeared in the early and succeeded all the way to the Cretaceous’s end. Glyptodonts appeared in the and prospered for millions of years.
The process of transforming requires millions of years. When organic sediments are buried, most of the oxygen, nitrogen, hydrogen, and sulfur of dead organisms is released, leaving behind carbon and some hydrogen in a substance called , in a process that is . Plate tectonics can subduct sediments, particularly where oceanic plates meet continental plates. There is an “oil window” roughly between 2,000 and 5,000 meters deep; if kerogen-rich sediments are buried at those depths for long enough (millions of years), (which produce high temperature and pressure) break down complex organic molecules and the result is the hydrocarbons that comprise petroleum. If organic sediments never get that deep, they remain kerogen. If they are subducted deeper than that for long enough, bonds are broken and the result is , which is also called . Today, the geological processes that make oil can be reproduced in industrial settings that can in a matter of hours. Many hydrocarbon sources touted today as replacements for conventional oil were never in the oil window, so were not “refined” into oil and remain kerogen. The so-called and are made of kerogen ( is soluble kerogen). It takes a great deal of energy to refine kerogen into oil, which is why kerogen is an inferior energy resource. Nearly a century ago in it took less than one barrel of oil energy to produce one hundred barrels, for an energy return on investment ("EROI" or "") of more than 100, in the Golden Age of Oil. Global EROI is declining fast and will fall to about 10 by 2020. The EROIs of those oil shales and oil sands are less than five and as low as two.
So far in this essay, mammals have received scant attention, but the mammals’ development before the Cenozoic is important for understanding their rise to dominance. The , called , first , about 260 mya, and they had key mammalian characteristics. Their jaws and teeth were markedly different from those of other reptiles; their teeth were specialized for more thorough chewing, which extracts more energy from food, and that was likely a key aspect of success more than 100 million years later. Cynodonts also developed a secondary palate so that they could chew and breathe at the same time, which was more energy efficient. Cynodonts eventually ceased the reptilian practice of continually growing and shedding teeth, and their specialized and precisely fitted teeth rarely changed. Mammals replace their teeth a . Along with tooth changes, jawbones changed roles. Fewer and stronger bones anchored the jaw, which allowed for stronger jaw musculature and led to the mammalian (clench your teeth and you can feel your masseter muscle). Bones previously anchoring the jaw were no longer needed and . The jaw’s rearrangement led to the most auspicious proto-mammalian development: . Mammals had relatively large brains from the very beginning and it was probably initially . Mammals are the only animals with a , which eventually led to human intelligence. As dinosaurian dominance drove mammals to the margins, where they lived underground and emerged to feed at night, mammals needed improved senses to survive, and auditory and olfactory senses heightened, as did the mammalian sense of touch. Increased processing of stimuli required a larger brain, and . In humans, only livers use more energy than brains. Cynodonts also had , which suggest that they were warm-blooded. Soon after the Permian extinction, a cynodont appeared that may have ; it was another respiratory innovation that served it well in those low-oxygen times, functioning like pump gills in aquatic environments.