By Scott Kaelen

Scott Kaelen – Flogging a World of Dead Horses

Note: This is an extraordinary opportunity for us, here at Modern Atheist .org, to make available to our readers this remarkably detailed timeline – of some 80 seminal benchmarks to the initial rise of life, and its subsequent evolution – over the 4 and a half billion year history of planet Earth. And touching on the earliest fossil evidence for religious observances – in pre-human burial rituals, as well. And also introduce you to a talented and insightful new voice.

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The Earth was formed 4.54 billion years ago. Current studies propose the earliest life on Earth began during the infernal Hadean Eon, the earliest proposals suggesting a mere 0.14 billion years after the formation of our planet.

Here is my chronological compilation of all major events of life on Earth, and the emergence of religions.

After the Hadean Era came the Eoarchaen Era, when the molten Earth cooled sufficiently to form the beginnings of a crust. During this era, 3.7bya, the earliest known biogenic graphite existed. Evidence was found in the Isua Greenstone Belt in Western Greenland. The graphite contained the earliest pre-DNA biological evidence in the form of RNA (ribonucleic acid). 3.5bya, still during the early Archaean Era, 0.2 billion years after the earliest biogenic graphite), the earliest microbial mat organisms existed in the form of bacteria and archaea, and the split between the two occurred during this time. Evidence was found at the Strelley Pool Formation in Western Australia. The microbial mat is known as the Last Universal Ancestor of all current life on Earth. During the Proterozoic Era, 2.5bya, the first molecules that constituted the earliest cells underwent a slow process of evolution, organizing into molecular systems with properties of biological order, such as amino acids. Oxygenic photosynthesis began at around this time, but it would be another billion years until the appearance of dioxygen in the atmosphere as a result of biologically-induced photosynthesis by bacteria known as cyanobacteria. This gave rise to the Great Oxygenation Event – the first massive extinction event that wiped out almost all anaerobic (non-breathing) life on Earth. The GOE triggered a glaciation event as a result of oxygen reacting with atmospheric methane. Gradually, aerobic organisms began to evolve and begin to bring equilibrium to the atmosphere. Complex cells known as eukaryotes – organisms with a nucleus and other structures within membranes – came into existence during this time, and the earliest evidence of this dates back to 1.85bya. The eukaryotes began using oxygen in their metabolism. 1.7bya saw the beginnings of the first multicellular organisms. A particular type of cell division began, known as meiosis, which led to the first known occurences of sexual reproduction among simple eukaryotes. 1.1bya the first formations of marine plankton began. 1bya saw the beginnings of the first algae in the form of vaucheria. 750 million years ago saw the rise of slightly more complex life in the form of the first protozoa, such as melanocyrillium. 600mya the accumulation of oxygen in the atmosphere gave rise to the formation of an ozone layer. The Ediacaran Period saw the first large, complex multicellular organisms known as Ediacara biota, which were tubular or frond-shaped. They flourished during the Avalon Explosion. 560mya the first fungi began to appear. Mere tens of millions of years after the Avalon Explosion came the Cambrian Explosion, beginning about 542mya during the Cambrian Period. This explosion of life on Earth saw the beginnings of the body formation of metazoans – multicellular eukaryotic organisms known as Animals. This lasted for about 20 million years, and the following 70 – 80 million years saw a drastic increase in evolution accelerated by a great order of magnitude. Such life as existed at this time included: sponges, slug-like animals, molluscs, worms, jellyfish and the first arthropods – notably the diverse trilobytes. The first fossil evidence for jellies, sponges, anemones and corals dates back to 550mya. Along with trilobytes, other animals such as crustaceans, molluscs and brachiopods thrived in the oceans. The first known fossil evidence for land exploration by marine animals dates back to 530mya, possibly predating the first terrestrial plants. 525mya saw the emergence of the first vertebrates (animals with backbones) in the form of jawless fish. 434mya saw algae and fungi living along the edges of lakes evolve into the first primitive land plants. 420mya came the first primitive scorpions and arachnids on land. 410mya the first toothed fish evolved. Life on land and in the water continues to diversify, bringing rise to the first insects and tetrapods (four-legged animals). By 360mya some insects had evolved wings and taken to the skies. The land was covered in vegetation including seed-bearing plants. The first sharks had evolved in the seas. All life continued to diversify, particularly amphibious life. 320mya, in the late Carboniferous Period, reptilian life diversified until a distinct branch evolved known as Synapsids, which were the precursor to mammalian life. 275mya, synopsids diversify further, branching off into therapsids, a closer ancestor of mammalian life. 251mya the Permian-Triassic Extinction Event wiped out 90 – 95% of all marine life. Terrestrial life was not so unlucky, though the event struck the ecosystem a critical blow, resulting in more diversification, especially in the oceans where the new balance of power demanded more versatility, including the first ichthyosaurs. During the Early Triassic Period, the first dinosaurs walked the Earth in the form of early plateosaurids, and during the Late Triassic Period the first true mammals evolved, such as adelobasileus. In the oxygen-rich environment, herbivores grew to immense sizes to accommodate for the large guts needed for digesting the nutrient-poor plants. By 170mya, at the height of the Jurassic Period, life was beginning to more closely resemble species extant to today, including newts and salamanders and early ancestors of alligators. The first flying reptiles, pterosaurs such as pterodactyls, evolved some 163mya. 155mya, archaeopteryx took to the skies as possibly the ancestor of modern birds. 130mya, early in the Cretaceous Period, came the emergence of first freshwater turtles. 115mya monotremes – egg-laying mammals – evolved. 100mya the first bees entered the evolutionary chain. 90mya the ichthyosaurs became extinct, and the first snakes appeared. 80mya came the first ants. 68mya gave the first fossil records for triceratops and tyrannosaurus. 2 million years later came the Cretaceous-Paleogene Extinction Event that marked the beginning of the Cenozoic Era, wiping out roughly half of all animal species including all the dinosaurs, except for those that had taken to the skies – the ancestors of birds. Conifers and ginkgo trees spread across the higher climes, and mammals became the dominant species. Carnivorous mammals known as creodonts evolved, and would become the dominant predators for many millions of years until dying out some 35mya. 60mya saw the beginnings of the earliest true primates. Bird groups continue to diversify, some becoming flightless and land predators, others evolving into modern birds such as parrots, woodpeckers and swifts. Mammals such as sea cows and armadilloes begin to appear in the diversification of life. 52mya sees the evolution of the first bats. 50mya sees rhonoceroses, camels and horses enter the evolutionary chain, and early primates continue to diversify. 40mya, modern butterflies and moths enter the timeline. Many species beame extinct, and many others came into existence from the great diversity of life. The first eagles and hawks appeared, as well as sloths and dogs, and many grasses evolved from the flowering plants. 30mya saw the earliest pigs and cats. 25mya were the first deer. 20mya, early in the Miocene Epoch, came the first bears, hyenas and giraffes. 15mya the first kangaroos appeared. 7mya was the time of the Chimpanzee-Human Last Common Ancestor, when the diversity of primates gave rise to the earliest of hominins – sahelanthropus and early australopithecines. 5mya the Pliocene Epoch began, and the evolution of animals such as the hippopotamus, elephant, zebra and lion, as well as the woolly mammoth shortly afterwards. 4mya early hominin australopithecus enters the fossil record. The Pleistocene Epoch began some 2.6mya. The smilodon – sabre-toothed cats – entered the fossil record 2.5mya. 2 million years ago the first members of the genus Homo appear in the fossil record in Africa, H habilis and later H erectus being the most prominent. Also the ancestor of modern cattle evolves in India. Australopithecus becomes extinct. 1.2mya Homo antecessor emerges in Spain. Roughly 1mya saw the emergence of the hominid Gigantopithecus, the giant ancestor of modern apes, across Asia. 600,000 years ago Homo heidelbergensis entered the timeline in Africa, Europe and Wesetern Asia, dying out some 200-250,000 years ago. 350,000 years ago Neanderthals evolved. Anatomically modern humans, known collectively as Homo sapiens, and including the only sub-species Homo sapiens idaltu and Homo sapiens sapiens – evolved 200,000 years ago. Worth noting is that the Neanderthals and Gigantopithecus were both still alive long after the emergence of humans, but were gradually replaced by Homo sapiens to the point of extinction. 223,000 – 100,000 years ago shows evidence of ancient hominins disposing of their dead in mass graves. Also evident is that Neanderthals buried their dead in simple graves, occasionally with blocks of limestone that may denote grave markers, perhaps indicating the earliest signs of pseudo-religion having not begun with humans, but with a completely separate species. Homo sapiens idaltu dies out some 160,000 years ago, leaving Homo sapiens sapiens as the only extant species of Homo. 100,000 years ago Gigantopithecus died out in Asia, after up to 900,000 years of existence. Neanderthals begin stripping the flesh from their dead prior to burial. 40,000 years ago in Europe, the Neanderthals became extinct after some 310,000 years of existence. Also at this time came the first evidence for human cremation, discovered in the dry Lake Mungo in Australia. Homo sapiens sapiens survives all other hominins as the only extant species on the planet. 38,000 years ago the oldest known zoomorphic and semi-anthropomorphic sculpture was made, showing the first indications of Homo sapiens giving human characteristics to animals, perhaps representing a deity, and providing further possible evidence of emerging religion. 30,000 years ago shows the first evidence of humans burying their dead along with apparent personal artifacts and tools, including figurines of women, some of which had been purposefully broken or repeatedly stabbed. Such burials may indicate a concern for what happens to the body after death. Also 30,000 years ago, an ancient place of worship existed in Botswana, at the World Heritage Site known as Tsolido. 25,000 years ago, evidence of burials is found across Eastern Europe, Iberia and Wales, including a more varied range of artifacts including shells, ivory beads, pendants, ivory blades and dolls. From 21,000 years ago, there begins a lack of evidence for the continuation of burial activity. Such evidence resumed roughly 8,000 years later, 13,000 years ago. With a gap in time of almost 10,000 years, the practice of burial resumes. Men, women and children in Italy were buried in the same place as their ancestors from 10,000 years earlier. The same burial practices also resume, burying the dead with the same artifacts and tools as their ancestors. Now the dead are buried side by side, just as in modern cemetaries. In 9831BC the Neolithic Revolution began, marking a distinct change in humans from hunting and gathering to settlements and agriculture. Humans became sedentary, non-nomadic, beginning the practises of irrigation and deforestation, division of labour, economy and trade, architectural art, administration and political structures, hierarchical ideologies, and ownership of property. Several pine posts are erected at the site that would later become Stonehenge, in Wiltshire, England. Over the next few centuries, many shrines are constructed, along with other places of worship. Wall art consists of phallic symbols, feminine figures and scenes of hunting. Possessions are left at the places of worship. The Proto-Indo European people developed religion that focused on sacrificial ideology similar to previous practises among earlier shrines. This religion left offerings in the form of food, objects and animal sacrifices. These practises pointed further at humans worshipping a higher purpose, and possibly a higher entity or a divine being, heavily influencing future Indo-European cultures and their religions. In 5,000BC structures were built which were used for human sacrifices. Other evidence shows a shift in human thinking and perception, indicating a growing presence of religion. According to the Judeo-Christian-Islamic scriptures, which would not be written for another 2,000 years, 4,100 years and 4,570 years respectively, the Earth was created by Yahweh/Jehovah(God)/Allah in 4,000BC. In 3750BC, the Proto-Semitic people developed a set of proto-languages and religions across the Middle East. Those languages would develop into the Semitic languages known as Amharic, Tigrinya, Arabic, Aramaic, and Hebrew. The proto-religions evolved into the Abrahamic religions, focusing on the figure of Abraham and beginning with Judaism, which was founded by Moses. No historical evidence exists to support the historicity of Moses existence, though he is purported to have been born in 1393BC, some 800 years after Abraham is written to have existed. Christianity emerged late in the 1st century AD, following some decades after the purported life of Jesus, who spread word of Judaism and its prophets including Abraham, Moses and Noah. Approximately 570AD, the prophet Muhammad was born. A century after his death, the Judeo-Christian faith was used as a basis for a new religion known as Islam. The rest, as they say, is history. A history that would become the bloodiest the Earth had ever seen in its 4.54 billion years.