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)
With the advent of television, war propaganda and reporting went through a considerable evolution from the Korean War, to Vietnam, to the Oil Wars in the Middle East. Many have claimed that the relative freedom of journalists to report on the Vietnam War turned public opinion against the administration of Lyndon Johnson and Richard Nixon. Never again! Beginning with the Gulf War (1991), news coverage of international conflicts to domestic audiences was strictly censored and shaped by the military in a series of press conferences and news releases. "Surgical bombing" and "collateral damage" were euphemisms describing tremendous infrastructure damage and dead civilians, and illustrated with remote aerial shots devoid of human casualties. During the War on Iraq, embedded journalists were required to report only what their military chaperones throught suitable, and any news stories or images broadcast on CNN--if not censored by the Pentagon--went through a rigorous process of "analysis." A new style of television coverage--"Happy Talk"--emerged during the Vietnam War to place the disturbing news of conflict into a convivial atmosphere of newsroom banter, pundit speculation, and bracketing stories about the weather, sports, or human interest. As Clark comments, "This style reduces any potential sense of critical disruption in social affairs by integrating disturbing pictures and information within a contrived atmosphere of normality" (117).
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.
Rockefeller became a robber baron extraordinaire with the rise of oil in transportation. In the USA in 2011, more than 90% of all transportation energy was provided by oil, and the proportion is about the same for global industrial transportation. In the West, nearly all coal is used to produce electricity. A watershed event in oil’s use in transportation was when Winston Churchill, after in 1911, . The UK did not have domestic sources of oil as the USA did, and thus began the West’s domination of the oil-rich Middle East, which continues into the 21st century. By 1920, against the peoples of what became Iraq, as the UK secured the region for oil interests, and before World War II was over, Churchill called for the complete genocide of the Japanese people, , , and his , . His , but he is primarily remembered in the West as the great statesman who stood up to Hitler. Similarly, , the historical figure that and whose , is for .