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		Geological Time Scale     Eon Era Period Epoch Notable Events Phanerozoic "Visible Life" Organisms with skeletons or hard shells. 540 million years ago through today. Cenozoic "The Age of Mammals" 65 million years ago through today Quaternary Period "The Age of Man" 1.8 million years ago to today Holocene 11,000 yeras ago to today Human civilization Pleistocene The Last Ice Age 1.8-.011 million years ago The first humans (Homo sapiens) evolve. Mammoths, mastodons, saber-toothed cats, giant ground sloths, and other Pleistocene megafauna. A mass extinction of large mammals and many birds happened about 10,000 years ago, probably caused by the end of the last ice age. Tertiary Period 65 to 1.8 million years ago Neogene 24-1.8 million years ago Pliocene 5-1.8 million years ago First hominids (australopithecines). Modern forms of whales. Megalodon swam the seas Miocene 24-5 million years ago Increase in mammals, including horses, dogs and bears. Modern birds. South American monkeys, apes in southern Europe, Ramapithecus. Paleogene 65-24 million years ago Oligocene 38-24 million years ago Starts with a minor extinction (36 million years ago). Many new mammals (pigs, deer, cats, rhinos, tapirs appear). Grasses common. Eocene 54-38 million years ago Mammals proliferate. Rodents appear. Primitive whales appear. Paleocene 65-54 million years ago First large mammals and primitive primates, plesiadapiforms. Mesozoic Era "The Age of Reptiles" 248 to 65 million years ago Cretaceous Period 146 to 65 million years ago Upper 98-65 million years ago High tectonic and volcanic activity. Primitive marsupials develop. Continents have a modern-day look. Minor extinction 82 million years ago. Ended with large extinction (the K-T extinction) of dinosaurs, pterosaurs, ammonites, about 50 percent of marine invertebrate species, etc., probably caused by asteroid impact or volcanism. Lower 146-98 million years ago The heyday of the dinosaurs. The first crocodilians, and feathered dinosaurs appear. The earliest-known butterflies appear (about 130 million years ago) as well as the earliest-known snakes, ants, and bees. Minor extinctions at 144 and 120 million years ago. Jurassic Period 208 to 146 million years ago Many dinosaurs, including the giant Sauropods. The first birds appear (Archaeopteryx). The first flowering plants evolve. Many ferns, cycads, gingkos, rushes, conifers, ammonites, and pterosaurs. Minor extinctions at 190 and 160 million years ago. Triassic Period 248 to 208 million years ago The first dinosaurs, mammals, and crocodyloformes appear. Mollusks are the dominant invertebrate. Many reptiles, for example, turtles, ichthyosaurs. True flies appear. Triassic period ends with a minor extinction 213 million years ago (35% of all animal families die out, including labyrinthodont amphibians, conodonts, and all marine reptiles except ichthyosaurs). This allowed the dinosaurs to expand into many niches. Paleozoic Era 540 to 248 million years ago Permian Period "The Age of Amphibians" 280 to 248 million years ago Amphibians and reptiles dominate. Gymnosperms dominant plant life. The continents merge into a single super-continent, Pangaea. Phytoplankton and plants oxygenate the Earth's atmosphere to close to modern levels. The first stoneflies, true bugs, beetles, and caddisflies, The Permian ended with largest mass extinction. Trilobites go extinct, as do 50% of all animal families, 95% of all marine species, and many trees, perhaps caused by glaciation or volcanism. Carboniferous Wide-spread coal swamps, foraminiferans, corals, bryozoans, brachiopods, blastoids, seed ferns, lycopsids, and other plants. Amphibians become more common. 360 to 280 million years ago Pennsylvanian Period 325 to 280 million years ago First reptiles. Many ferns. The first mayflies and cockroaches appear. Mississippian Period 360 to 325 million years ago First winged insects. Devonian Period "The Age of Fishes" 408 to 360 million years ago Fish and land plants become abundant and diverse. First tetrapods appear toward the end of the period. First amphibians appear. First sharks, bony fish, and ammonoids. Many coral reefs, brachiopods, crinoids. New insects, like springtails, appeared. Mass extinction (345 million years ago) wiped out 30% of all animal families) probably due to glaciation or meteorite impact. Silurian Period 438 to 408 million years ago The first jawed fishes and uniramians (like insects, centipedes and millipedes) appeared during the Silurian (over 400 million years ago). First vascular plants (plants with water-conducting tissue as compared with non-vascular plants like mosses) appear on land (Cooksonia is the first known). High seas worldwide. Brachiopods, crinoids, corals. Ordovician Period 505 to 438 million years ago Primitive plants appear on land. First corals. Primitive fishes, seaweed and fungi. Graptolites, bryozoans, gastropods, bivalves, and echinoids. High sea levels at first, global cooling and glaciation, and much volcanism. North America under shallow seas. Ends in huge extinction, due to glaciation. Cambrian Period "The Age of Trilobites" 540 to 500 million years ago "Age of Trilobites" -The Cambrian Explosion of life occurs; all existent phyla develop. Many marine invertebrates (marine animals with mineralized shells: shell-fish, echinoderms, trilobites, brachiopods, mollusks, primitive graptolites). First vertebrates. Earliest primitive fish. Mild climate. The supercontinent Rodinia began to break into smaller continents (no correspondence to modern-day land masses). Mass extinction of trilobites and nautiloids at end of Cambrian (50% of all animal families went extinct), probably due to glaciation. Proterozoic Eon 2.5 billion years ago to 540 million years ago Neoproterozoic era Ediacaran 635 to 540 Million Years Ago Vendian biota (Ediacaran fauna) multi-celled animals appear, including sponges. A mass extinction occurred. The continents had merged into a single supercontinent called Rodinia. Cryogenian 850 to 635 million years ago Extensive glaciation, crash in acritarch (single-celled organisms, especially the planktonic algae) populations. Tonian 1000 to 850 million years ago Events leading to the breakup of supercontinent Rodinia started in this period. The first radiation of acritarchs (single-celled organisms, especially the planktonic algae) occurred Mesoproterozoic era Stenian 1200 to 1000 million years ago The supercontinent Rodinia assembled during this period. Ectasian 1400 to 1200 million years ago Evidence of an eucaryote, red algae Bangiomorpha pubescens has been identified from ca. 1200 million years ago, old rocks in Hunting Formation (Somerset Island, Canada). It is the oldest known sexually reproducing organism and therefore the earliest known complex multicellular organism.. Calymmian 1600 to 1400 million years ago Expansion of existing platform covers, or by new platforms on recently cratonized basements. The supercontinent Columbia broke up during the Calymmian some 1500 million years ago Paleoproterozoic era Statherian 1800 Ma to 1600 Ma (million years ago First complex single-celled life appeared. The period is characterized on most continents by either new platforms or final cratonization of fold belts. The supercontinent Columbia formed at the beginning of this period. Orosirian 2050 to 1800 million years ago Latter half of the period was an episode of intensive orogeny on virtually all continents. Probably during this period Earth's atmosphere changed to oxygen-rich due to photosynthesis of cyanobacteria. Two largest known impact events on Earth occurred during the Orosirian. At the very beginning of the period, 2023 million years ago, a large asteroid collision created the Vredefort impact structure. The event that created the Sudbury Basin structure occurred near the end of the period, 1850 millions years ago. Rhyacian 2300 to 2050 million years ago The Bushveld Complex and other similar intrusions formed during this period. Huronian glaciation period ended in late Rhyacian 2100 million years ago. Siderian 2500 to 2300 million years ago Abundance of banded iron formations (BIFs) peaked early this period. BIFs were formed as algae produced waste oxygen, which combined with iron forming magnetite (Fe3O4, an iron oxide). This process cleaned the oceans from iron and formerly greenish seas become clear. Eventually the process created the oxygen-rich atmosphere of today. Huronian glaciation began in the Siderian 2400 million years ago and ended in the late Rhyacian 2100 million years ago. Archeozoic Eon (Archean) 3.9 to 2.5 billion years ago Neoarchean 2800 to 2500 million years ago Mesoarchean 3200 to 2800 million years ago Fossils from Australia show that stromatolites have lived on Earth since the Mesoarchean. Paleoarchean 3600 to 3200 million years ago The oldest ascertained life form (Well-preserved bacteria older than 3460 million years found in Western Australia is from this era. Eoarchean 3800 to 3600 million years ago Hadean Eon 4.6 to 3.9 billion years ago "Rockless Eon" - The solidifying of the Earth's continental and oceanic crusts.