The other critical innovation was the modern steam engine, which was intimately related to coal. Burgeoning coal mines quickly exhausted deposits above the water table and began digging deeply into the earth, and water in the mines became a great problem. Not only were floods killing miners, but standing water made mines inoperable. Romans pumped water from their mines (). So did British mining operations, and around 1710, combined the ideas of a and an to make the , to pump water from coal mines. In a parallel case of using coal for smelting, the coal-fired Newcomen engine was . It was the first of its kind, primitive compared to later engines, and its spread was gradual. . He eventually invented an improved version with a that was . The steam engine that powered the Industrial Revolution was thus born, although, as with coal, its spread was gradual, and wind and water power were competitive with coal for nearly a century. The hydrocarbon-fueled steam engine was the key to the Industrial Revolution, in which the energy of ancient sunlight was exploited to generate previously unimaginable power. A steam locomotive of 1850 roaring through the English countryside would have been inconceivable to an English peasant of 1500. From a to to to less than five hundred years, the duration of each Epochal Event continued to shrink as levels of energy use increased dramatically and with each event.
In 1750, only 5% of England’s pig iron was produced with coke, but by 1800, with and the continuing rising price of charcoal, British pig iron production was 150,000-200,000 metric tons annually, and almost all was coke-smelted. It was ten times greater than annual production in the 18th century’s first half, and the steep ascent began in the 1770s. In the first decade of the 19th century, it doubled again. During the 18th century, British coal production increased five-fold, to more than 15 million metric tons, and it doubled again by 1830. It took ten times its weight in fuel to produce ten tons of iron, and twenty times for copper. One reason for iron’s relative “cheapness,” energy-wise, is that life processes into oxides. In 1900, the British produced five million tons of pig iron annually, the USA produced twice as much, and Germany produced more than six million tons. In 2011, the UK produced only seven million tons of pig iron, China produced nearly a hundred times as much, and , which was several thousand times what England, the early leader in industrialization, produced two centuries earlier. In 2008, global coal production was estimated at 5.8 billion metric tons, which was nearly 400 times what the UK mined in 1800.
So far, this essay has dealt lightly with regional differences and largely confined the discussion to polar, temperate, and tropical conditions in the seas, and rainforest versus dryer conditions on land. While existed, barriers to species diffusion on land were relatively modest, hence dominance. But at the Triassic’s end, and continental differences in plants and animals often became significant in later times. Although the formation of Pangaea had profound impacts, because land life was relatively young, the differences and resultant changes due to the removal of oceanic barriers were less spectacular than would happen in the distant future, such as when .
The Golden Age of before it was displaced by , and diapsids, particularly , began displacing therapsids early in the Triassic. A descendant, , burrowed and was possibly a direct ancestor of mammals. If it was not our direct ancestor, it was a to it. Proto-mammals were displaced and largely driven underground during the Triassic, and many of them About 225 mya, which was about halfway through the Triassic, , although there is plenty of fierce controversy over exactly which animal could be called a mammal. But reptiles starred in the Mesozoic’s tale, dinosaurs in particular. Mammals were small, marginal creatures, and until the late Mesozoic, they only emerged from their burrows at night to feed.
The Triassic began hot and ended hot, and the Jurassic and Cretaceous were also hot, so staying warm was not a significant issue for dinosaurs. stayed cool by becoming aquatic, and for land-based dinosaurs, features such as plates apparently replaced the sails of for both heating and cooling, and like the synapsid sail, those plates may have also been used for display. Also, like the cliché, many large herbivorous dinosaurs lived near cooling swamps, although the issue has been controversial. Cooling swamps and protective water holes that we see in the tropics today were a major aspect of Mesozoic landscapes. But the thermoregulatory aspect that most work is directed toward today is how dinosaurs kept warm. There is compelling evidence that dinosaurs regulated their body temperature in myriad ways, including internal chemistry. All bipedal animals today are endotherms and they all have four-chambered hearts, as dinosaurs did. , dinosaurs living near the poles (, ), and of dinosaur bones all support the idea that , but one of the more intriguing areas is that of . Like tree rings, bones have seasonal growth rings and they have been read for many dinosaur fossils. They have been used to determine dinosaurian life expectancies. could live to be about 30, giant could live to be 50, and smaller dinosaurs, as with smaller mammals, lived shorter lives. The tiny ones only lived three-to-four years and the mid-sized ones lived seven-to-fifteen years. Growth rates also provide thermoregulation evidence. Tyrannosaurs had juvenile growth spurts and largely stopped growing as adults, and sauropods had growth rates equivalent to today’s whales, which are Earth’s fastest growing animals. But there is also evidence of ectothermic dynamics. The great size of dinosaurs would have led to relatively easy ways to stay warm, as large animals have a greater mass-to-surface area ratio, like the way in which . Also, in the generally hot Mesozoic times, staying warm would have been fairly easy, particularly for huge dinosaurs.
In his , Charles Darwin sketched processes by which species appear and disappear, today called speciation and extinction. is a landmark in scientific history and is still immensely influential. But it was also afflicted by false notions that are still with us. Europe’s emergence from dogma and superstition has been a long, fitful, only partially successful process. In the 1500s, Spanish mercenaries to the unfortunate Indians that they conquered and annihilated that stated that Creation was about five thousand years old, as scholars of the time simply added up the “begats.” The is filled with tales of genocide, miracles, and disasters, with a global flood that the faithful survived. As geology gradually became a science and processes such as erosion and sedimentation were studied, the Judeo-Christian belief of Earth's being five thousand years old and the concept of arose in Europe.
In the early 19th century, a dispute was personified by , a British lawyer and geologist, and , a French paleontologist. Their respective positions came to be known as and . Just as , so did uniformitarianism prevail in scientific circles. Under the comforting uniformitarian worldview, there was no such thing as a global catastrophe. Changes had only been gradual, and only the present geophysical, geochemical, and biological process had ever existed. The British Charles Darwin explicitly made Lyell’s uniformitarianism part of his evolutionary theory and he proposed that extinction was only a gradual process. Cuvier was , which contradicted the still-dominant Biblical teachings, even in the . Although Cuvier did not subscribe to the , his catastrophic extinction hypothesis was informed by his fossil studies. But Lyell and Darwin prevailed. Suggesting that there might have been catastrophic mass extinctions in Earth’s past was an invitation to be branded a pseudoscientific crackpot. That state of affairs largely prevailed in orthodoxy until the 1980s, after the was posited for the dinosaurs’ demise. An effort led by a scientist publishing outside of his field of expertise (a ) removed from its primacy. Only since the 1980s have English-speaking scientists studied mass extinctions without facing ridicule from their peers, which has never been an auspicious career situation. Since then, many and mass extinction events have been studied, but the investigations are still in their early stages, partly due to a dogma that prevailed for more than a century and a half, and Lyell’s uniformitarianism is influential. The ranking of major mass extinctions is even in dispute, , and a was recently .
For this essay’s purposes, the most important ecological understanding is that the Sun provides all of earthly life’s energy, either (all except nuclear-powered electric lights driving photosynthesis in greenhouses, as that energy came from dead stars). Today’s hydrocarbon energy that powers our industrial world comes from captured sunlight. Exciting electrons with photon energy, then stripping off electrons and protons and using their electric potential to power biochemical reactions, is what makes Earth’s ecosystems possible. Too little energy, and reactions will not happen (such as ice ages, enzyme poisoning, the darkness of night, food shortages, and lack of key nutrients that support biological reactions), and too much (such as , ionizing radiation, temperatures too high for enzyme activity), and life is damaged or destroyed. The journey of life on Earth has primarily been about adapting to varying energy conditions and finding levels where life can survive. For the many hypotheses about those ancient events and what really happened, the answers are always primarily in energy terms, such as how it was obtained, how it was preserved, and how it was used. For life scientists, that is always the framework, and they devote themselves to discovering how the energy game was played.
Speciation has probably been more controversial than extinction. To be fair to Darwin, genetics was not yet a science when was published in 1859. It was not until the by Silesian friar Gregor Mendel that the science of genetics began, but Mendel’s work was until the 20th century. Darwin went to his grave unaware of Mendel’s work. Today, speciation is primarily considered to be a genetic event. But similar to how that dictate their function, and that appear at higher levels of complexity, the DNA code by itself does not explain life, although the popular frames life and evolution as a .
Biologists consider extinctions to be due to failure to adapt to environmental changes, and the “environment” includes other organisms. Exactly how species go extinct is still poorly understood, but the idea that the battle for survival is a common understanding among biologists, and ecosystems . makes the relationship explicit. There are many interacting variables, including those environmental nutrients, both inorganic and those provided by life forms. The ability of an organism or species to adapt is partly dependent on how specialized it is and how unique its habitat is. Absolute numbers, geographic distribution, position in the food chain (higher in the food chain is riskier), mobility, and reproductive rates all impact extinction risk. During the , about 80% of all animals were immobile. Today, 80% of all animals are mobile. The immobile animals were at higher extinction risk, for obvious reasons.