After I first published this essay in September 2014, I read Paul Boyer's , which surveyed the reactions of Americans to dropping atom bombs on Japan. I read it in relation to my studies regarding the , but what struck me was how similar the reactions to the bombs were to how people view FE today. The primary difference, of course, is that everybody acknowledges that nuclear bombs exist and have been used, while almost nobody acknowledges today that FE technology exists, through , , or . Another obvious difference is that the first use of atomic energy was vaporizing a couple of cities. While the initial American reaction was celebratory and euphoric, it quickly became evident that the USA would not hold a monopoly on nuclear weapons forever, and fears of nuclear attack became part of the fabric of American consciousness, and by 1946, nearly half of Americans were amenable to the idea of a world government that could prevent a nuclear holocaust.
As will become a familiar theme in this essay, the rise and fall of species and ecosystems is always primarily an energy issue. The Ediacaran extinction is a good example: Ediacaran fauna either an energy source for early Cambrian predators, ran out of food energy, ran out of the oxygen necessary to power their metabolisms, or lacked some other energy-delivered nutrient. After the extinction events, biomes were often cleared for new species to dominate, which were often descended from species that were marginal ecosystem members before the extinction event. They then enjoyed a of relative energy abundance as their competitors were removed via the extinction event.
SAVE THE TREES - Essay, Article
When humans began to raze forests and use the resultant soils to raise crops, they were working their way down through the food chain, no longer harvesting ecosystem detritus but destroying entire ecosystems literally at their roots for short-term human benefit. That practice eventually turned forest ecosystems into deserts. As this essay will survey, that was a rampant problem in all early civilizations. Eventually, humans learned to reach even further back into the ecological horizon as they began burning energy stores that were hundreds of millions of years old; was first and second. They were burned a million times as fast as they were created. In all instances, humans were releasing sunlight energy that had been captured and stored by organisms. In the 20th century, when humans began using nuclear fission, they were going even further back in time and harvesting energy stored via billions of years ago. With each new energy source, humans were harvesting older, more concentrated energy sources, which released far more energy than the previously used source. In each instance, humans plundered the energy source to exhaustion. Humans have not lived in “harmony” with nature since they learned to control fire.
Al Gore: Climate of Denial - Rolling Stone
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.
Can science and the truth withstand the merchants of poison?
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)