[1] As with all areas of Earth's distant past, there is plenty of debate and conjecture about all early events.  That all early life forms appeared to be heat-loving extremophiles leads to the idea that the increased energy available for chemical reactions (hotter temperatures make most chemical reactions easier to attain) is why life initially evolved in hot environments.  However, recent research suggests that the oceanic volcanic vents were fertile because of the dynamic interface between Earth's interior and the oceans and the rich chemical brew that it afforded.  See Nick Lane's Life Ascending, p. 17.  Because of certain aspects shared by all life forms today (right-handedness of all chiral molecules in all life forms, the use of DNA and certain biochemicals), it is also theorized that life came into being only once, and that all life on Earth today descended from that initial life form.  See Nick Lane's Oxygen, pp. 147-170. 

[2] Today, the prevailing theory is that all chloroplasts on Earth descended from a single instance of a photosynthetic bacterium being enveloped into a eukaryotic cell, by either predation or colonization.  See Oliver Morton's Eating the Sun, p. 206.  Mitochondria are thought to be the result of a bacterium being similarly enveloped.  A prominent theory (of several that have been proposed) posits that the envelopment of a hydrogen-producing bacterium into a hydrogen-respiring archaean cell gave rise to eukaryotic cells (called the hydrogen hypothesis), with the archaean “host” becoming the cell, and the enveloped bacterium becoming the mitochondria.  Also, this union is currently believed to have happened only once (see Nick Lane’s Power, Sex, Suicide; Mitochondria and the Meaning of Life, p. 25, and on the archaean/bacterial union that led to eukaryotic cells, see pp. 38-64), which was the ancestor of all complex life on earth.  According to that theory, the offspring of that original union eventually learned to respire oxygen, which was rising in the atmosphere due to the activities of photosynthetic bacteria.  It was earlier thought that the global oxygen event was one of Earth's mass extinction events that killed off most life forms, which were anaerobic at the time.  However, recent research has cast doubt on the extinctions associated with the Great Oxygenation Event, although it remains an area of healthy debate.  See Nick Lane's Oxygen, pp. 16-75.  All of those events that are believed to have only happened once (life appearing, chloroplasts and mitochondria appearing, and even the suitability of Earth to host complex life (see Ward and Brownlee's Rare Earth, for instance)) lead to the impression that there was some divine intervention or that complex life on Earth is a miracle of chance. 

Even for a materialist, it is easy to suspect that all those seemingly "coincidental," "accidental" miracles that led to today's situation are just a little too fortuitous, and that something else is happening besides all of those happy accidents.  On the evolution versus creation debate, the “skeptics” who battle the creationists, such as Michael Shermer, are not very representative of professional scientists, but are part of the scientific establishment’s politically active arm.  Andrew Knoll wrote in his Life on a Young Planet that scientists see the ancient religious texts as parables, and that, “Science’s creation story accounts for process and history, not intent” (p., 245).  On science and religion, Knoll wrote, “That these two ways of comprehending should be confused in either form or purpose strikes me as both absurd and unfortunate.”  Shermer states, “Just as one would not say, ‘I believe in gravity,’ one should not proclaim, ‘I believe in evolution.’”  (In Donald Prothero’s Evolution: What the Fossils Say and Why it Matters, p. xi).  That style of argumentation epitomizes the approach of organized skepticism.  I am experiencing gravity as I write this, as does every awake human on earth.  There is nothing to believe about it.  But nobody experienced speciation today.  The dismissal of human experience is a hallmark of organized skepticism.

[3] I have read many books on energy, Earth and humanity in the past several years, and perhaps the most succinct summary of Earth and humanity’s energy revolutions is Frank Neil’s Energy: Engine of Evolution, published by Shell Global Solutions; an oil company deserves some credit in the discussion.  In none of the energy books that I read did I see any mention of free energy as a potential solution to our current energy problems, other than Richard Heinberg’s facile semi-ridicule and subsequent dismissal of the entire milieu. 

[4] In 2009, Richard Wrangham published Catching Fire; How Cooking Made us Human.  His audacious and compelling hypothesis is that the ability to control fire may have led to the appearance of homo erectus almost two million years ago.  Fire allowed our ancestors to sleep on the ground, and cooking food may well have led to many of the evolutionary changes that mark the journey from upright ape to human.  In the end, it is a story of using fire energy to create more readily digestible food.  Wringing more calories out of cooked food for less effort was an evolutionary advantage, and the less energy devoted to digestion meant that the brain could use it, which led to the rapidly increasing brain size of the human lineage.  Works such as Wrangham’s are hallmarks of the increasingly multidisciplinary nature of recent scientific inquiry, and they are rolling back the frontiers of science.  While the less processed the food the better, I consider the “Cooking Hypothesis” to be a strong one.

[5] This note is from my upcoming anthropology essay, and is a preview of the material in my upcoming essays.  Of all of anthropology’s controversial topics, the debate regarding the megafaunal extinction events is one of the fiercest.  Paul Martin first proposed the “overhunting” hypothesis in 1967 for explaining the Quaternary extinction event.  The hypothesis was first applied to the extinction of North American megafauna soon after humans first migrated from eastern Asia.  Martin’s theory coincided with a cultural awakening in the USA, particularly regarding how the rise of the United States was accomplished by dispossessing American Indians of their lands. 

American Indian scholars, with Vine Deloria prominent, have strenuously disputed that American Indians contributed to the extinction of the Western Hemisphere’s megafauna.  They partly saw that theory as enhancing the European rationale for conquest: if the American Indians’ settling of the Americas was so destructive to native life forms, then the European conquest and settlement of the Americas is more “natural” than it might otherwise seem, and the Indians might not have quite the heritage of revering the environment that is popularly imagined.  I am sympathetic to the American Indians’ plight and ashamed of my ancestors’ behavior.  The first century of Europe’s conquest of the Americas is history’s greatest demographic catastrophe, and is arguably a genocide that continued for centuries until there were no more Indian lands remaining to steal/conquer.  Those denying or minimizing humanity’s role usually attributed the mass extinctions to climate change, diseases, or catastrophic celestial events.  There is evidence for “super-Tunguska” events in the North Hemisphere, with prominent proponents including being Victor Clube and Bill Napier, who have argued since the 1982 publication of The Cosmic Serpent that cometary debris impacted Earth during the Holocene, particularly the North Hemisphere, which may have precipitated the megafaunal extinctions of North America and northern Asia.  The works of Emanuel Velikovsky (a psychiatrist and Biblical catastrophist), Clube and Napier agree that such events could be the root of humanity’s long-standing fear/worship of comets and other celestial objects. 

However, in the years since the “overkill” hypothesis was posited, evidence has been amassed from across the planet, and whether it was fifty thousand years ago in Australia, in all of its wet, dry, hot and cold environments, or ten thousand years ago in South America (neither continent had continental ice sheets during the Pleistocene epoch), or the Pacific islands, including New Zealand, during the more recent Polynesian Expansion, the arrival of humans closely coincided with the extinction of all large mammals and birds.  The decimation of Earth’s species continues to this day. 

The only continent that retained a significant portion of its megafauna was Africa.  The leading theory for why some African megafauna survived while the megafauna quickly went extinct on other continents (Asia also kept some) is that the African megafauna evolved alongside humans and learned to fear people (and to a lesser extent, Asia).  Wherever humans arrived as they migrated across the planet, the native megafauna either had no natural predators or the few they had bore no resemblance to the bipedal, weapon-bearing newcomers, and they did not learn to avoid humans before becoming extinct.  They comprised the easy meat that sustained the hunter-gatherer lifestyle during its “golden age.”  There is impressive evidence for that theory; some is in the records of European encounters with animals with no previous human contact, as Europe conquered Earth.  The North Atlantic had a penguin-like bird known today as the great auk.  While they had been eaten by Neanderthals and other Continental humans, when European sailors found them on North Atlantic islands that humans had not yet visited, those great auks had no fear of people and were easily killed and herded aboard ships for slaughter.  They never feared humans and became extinct around 1850.  The dodo of Mauritius is another instance of the quick extinction of a meaty animal with no previous exposure to humans; Europeans discovered uninhabited Mauritius in the 1500s, and the Dutch began colonizing it in 1638.  In the first ten years of Dutch colonization, the dodo was rendered virtually extinct, and the last dodo was seen in 1662.  Even today, Antarctic penguins and Galapagos Islands animals are unafraid of humans. 

Robust evidence strongly contradicts the cometary/asteroidal and climate change theories of North America’s extinction event: mammoths and mastodons are the signature species of mass-extinction events, and survived on islands isolated from humans for thousands of years after their continental counterparts became extinct; they lived on Wrangell Island, in the Arctic Ocean, until less than four thousand years ago, and on Saint Paul Island, in the Aleutian island chain, until eight thousand years ago.  Island populations are far more vulnerable than continental ones, and those populations would not have been sheltered from climate changes or bolide events, but they were sheltered from humans for thousands of years longer than their continental counterparts were.  Also, elephants thrived in the Western Hemisphere’s tropics; the cuvieronius and the stegomastodon lived in South America for more than a million years until the arrival of humans, whereupon they quickly became extinct.  Other megafaunal island populations survived longer than their continental brethren: in the Caribbean, the ground sloth survived until less than five thousand years ago, its extinction again closely following the arrival of humans.  Virtually all large mammal species surviving in North America today migrated from Asia, where they evolved alongside humans.  Also, virtually all species that suddenly became extinct following the arrival of humans survived during many dramatic climate changes during the interglacial periods of the past million years, changes at least as drastic as what initiated the Holocene epoch.  Humans are the consistent variable in all extinctions of large animals during the past fifty thousand years.  Today’s theories are generally more complex than simply hunting every last animal to extinction.  In a study published in July 2010 (William Ripple and Blaire Van Valkenburgh, in the journal BioScience), evidence was presented that the introduction of a new super-predator into the ecosystem initiated cascading “trophic” failures, which drove both the megafaunal herbivores and their predators to extinction.  In 2009, Ripple produced a study which provided evidence that when the top-level predators are removed, lower-level predators thrive and the situation leads to ecosystem collapse.  This situation could help explain why many smaller mammals also died off when the megafauna did in North America.  Gifford Miller presented evidence in 1999 that the Australian megafaunal extinctions, which closely correlated with human arrival, may have been due to anthropogenic burning of the vegetation, an over-burning that quickly drove all megafauna to extinction. 

The seemingly hidden undercurrent in denying the anthropological aspect of the megafaunal extinctions is the human ego.  People are understandably reluctant to admit that their distant ancestors destroyed so many species, especially those that capture the imagination as the megafauna can.  Also, today’s societies, particularly the industrialized ones, are far more capable of destroying environments and species than humans with stone weaponry and fire-making skills could.  If humans caused the megafaunal extinctions, then we might need to become more introspective and change our destructive ways. 

[6] "Mode of production" is a concept introduced by Karl Marx.  Although my early writings were disparaged as "Marxist" by some, I had not read any of his work until recently.  I went to business school during the Cold War, and Marx was a reviled, even demonized, figure during my college years, as I was regaled with the wonders of capitalism.  It was not until I began reading excellent, multidisciplinary works where the authors openly acknowledged their debt to Marx (Mike Davis's Late Victorian Holocausts and Eric Wolf's Europe and the People Without History, for instance), that I began developing an interest in reading his work.  I am currently reading Marx's The Communist Manifesto, accompanied with scholarly analysis of it (A Norton Critical Edition, edited by Frederic L. Bender).  There is a lot to write about Marx and Marxian analytics, but not here.  Future essays will discuss his neglected work, his multidisciplinary approach and the failings of the materialistic perspective (it tends to advocate violence - which means that it misses the big picture). 

[7] In Earl Cook’s Man, Energy, Society, p. 186, he wrote: “Perhaps in no other way are the differing social gradations of low energy and high energy societies so clearly calibrated as in the status and appearance of women.”