new The Great Story Timeline of the Epic of Evolution
   
Epic of Evolution
Timeline
   

This timeline was created by Connie Barlow and Michael Dowd in 2002 (with periodic updates). Click here to select from more Epic of Evolution Timelines created by others.

For a playful and experiential way to learn just the Life Story aspect of the Epic of Evolution, visit our "The River of Life".

Note: This Great Story timeline is entirely for community use. Enjoy it, modify it, update it, share it, teach it, ritualize it, play with it, create from it however and wherever you wish. Do let us know suggestions for improvements, and tell us about fun or poignant ways that the timeline and Great Story Beads enter your life and the lives of others. Please especially keep us abreast of ways that it is taken into educational or worshipful settings.

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Far more than merely a resource, this particular timeline of cosmic/Earth/life/human history is actually one of the most concise tellings of the Epic of Evolution in existence. It presents the sequence of major events in our 13.7 billion year common creation story, and it does so in 250 meaningful, science-based snapshots. Click on a time period in the table below, or scroll down to begin.

 
I. GREAT RADIANCE phase - 13.7 billion years ago
II. GALACTIC phase - 12 billion years ago
III. HADEAN Eon of early Earth - 4.6 billion years ago
IV. ARCHAEAN Eon of early life - 3.8 billion years ago
V. PROTEROZOIC Eon - 2 billion years ago
VI. PALEOZOIC Era begins - 540 million years ago
  540-500 mya CAMBRIAN
500-440 mya ORDOVICIAN
440-410 mya SILURIAN
410-360 mya DEVONIAN
360-290 mya CARBONIFEROUS
290-245 mya PERMIAN
VII. MESOZOIC ERA (Age of Dinosaurs) begins.
245-210 mya TRIASSIC
210-145 mya JURASSIC
145-65 mya CRETACEOUS
VIII. CENOZOIC Era (Age of Mammals and Birds) begins

NOTE: In this timeline, you will notice that we group events by geological time period, rather than listing specific dates, as science changes fast enough that it is safest to simply know whether something happened in, say, the Devonian period rather than in the Carboniferous. We also sometimes ignore first appearances of life forms, and simply wait to put a bead where the group suddenly takes off in diversity, size, etc. But that is a matter of taste.

You will see that the timeline carefully documents the major mass extinctions, along with the pulses of localized "extinctions of the massive" that mark the entry of humans into frontier lands all over the planet. (Connie learned a lot about these modern extinctions in the course of working on her 2001 book, The Ghosts of Evolution.)

Beginning in the Cenozoic, 65 million years ago, our particular timeline highlights events in the story as they play out on the continent of North America. We envision very different Cenozoic timelines being created by enthusiasts who live on other continents. North Americans can click for a more detailed North American Timeline (with beads photos) that Connie completed in July 2004. The human phase (Holocene epoch) notes major developments in non-indigenous religions and in western scientific and philosophical thought that contributed toward our present understanding of Reality and of ourselves as part of an emerging cosmos of nested creativity. In other words, we chose to tell the story of our species' coming to know and celebrate the Great Story (the Epic of Evolution). This works well for us, given who we are and what we have chosen to do with our lives. An entirely different cultural story may work better for you.

Each of us is an expression of the Great Story,
whether we are thirteen billion and 85 years old,
or thirteen billion and 4!

Information Sources

The sources we used for creating our timelines are varied, but we relied heavily on:

The Universe Story, by Brian Swimme and Thomas Berry (1992). This is the classic text for those of us involved in the Great Story movement. Tom and Brian include a detailed timeline that runs from the Fireball (Big Bang) through the human saga. Some of the dates for the natural history events have changed since they wrote their book, of course, as science moves on.

Life, by Richard Fortey (1997). The subtitle of this highly acclaimed book is "A Natural History of the First Four Billion Years of Life on Earth." It is beautifully written by a senior paleontologist at the British Museum of Natural History. Intended for luscious reading, not as a reference text, the chapters have no subheadings within, so you cannot easily peruse.

Ancestor's Tale, by Richard Dawkins (2004). Imagine starting back on a journey through time, as if flowing down a watershed all the way to the Ocean of Origin. Other streams join ours, one by one, by measure of their life forms' relatedness to us. Because all the mollusks and arthropods and worms join together well upstream of meeting our branch of the river, they all join our current (rather, we joint THEM, as there are more of them than us at that point) as one vast group all together. For this reason, there are only 40 such "confluences" in The River of Life journey, and thus only 40 beads need to be selected and strung. Visit/download Connie Barlow's curriculum based on this book, "River of Life".

The Evolutionary Biology of Plants, by Karl Niklas (1997). This is a technical book, well written and with excellent illustrations. Here we learn, for example, that plant speciation and extinctions followed a timeline distinct from the "mass extinctions" that set the pace for animal evolution.

Aquagenesis, by Richard Ellis (2001). Subtitled "The Origin and Evolution of Life in the Sea," it is very well written by a marine biologist and artist at the American Museum of Natural History, and easy to use as a reference guide. Because Ellis is primarily an illustrator and writer of popular science, you can trust him to present all credible sides of scientific controversies. For example, his portrayal of the range of interpretations of the ediacaran creatures that lived just before the Cambrian "explosion" of animal evolution is superb.

The Eternal Frontier, by Tim Flannery (2001). This is an ecological, evolutionary story (a wondrous story, not just a series of facts) of the North American continent during the last 65 million years -- the entire Cenozoic Era. Plants, animals, geological features, landscapes: all are in here. As with Fortey's Life, it is not intended as a reference tool but for full-out reading. Connie is in awe of this book, and has used it as the scientific grounding for a slide show presentation on the North American story that she created. Flannery's book was also the scientific source for developing our own Coming Home to North America ritual.

"Life's Top Ten Greatest Inventions", multi-author 2005. Published in the 9 April 2005 issue of New Scientist magazine, this is a terrific and short overview of some of life's greatest achievements: multicellularity, the eye, the brain, language, photosynthesis, sex, programmed cell death, parasitism, superorganisms, symbiosis. Access the article online at:
http://www.newscientist.com/article/mg18624941.700

A Briefer History of Time, by Eric Schulman (1999). This paraody on Steven Hawking's international bestseller, A Brief History of Time, tells "the history of the universe in 100 words or less" and expounds on what he considers the 50 major moments of cosmic transformation in profoundly delightful and humorous ways.


I. Great Radiance
(Use small transparent beads for spacers.)

  • THE GREAT MYSTERY wholly beyond human language and understanding. That ULTIMATE REALITY which brings all things into existence, sustains all things, is revealed in all things, and draws all things unto Itself.

  • ALL OF HUMANITY'S VARIOUS NAMES, IMAGES, AND METAPHORS FOR ULTIMATE REALITY: GOD / GODDESS / GREAT SPIRIT / CREATOR / LORD / THE ALMIGHTY / YAHWEH / ALLAH / THE IMPLICATE ORDER / UNMOVED MOVER / ORIGINATING POWER / SOURCE / GROUND OF BEING / BUDDHA NATURE / BRAHMAN / INDRA'S NET / HIGHER POWER / THE TAO / THE UNIVERSE / KOSMOS / THE ONE / THE GREAT SELF / ETC.

Each metaphor for ULTIMACY becomes its own lens through which Reality is experienced. Thus, while each image or name can be understood as pointing to an essential aspect of Reality as a whole, it would not be accurate to say that these are simply different names for the same thing. Just as each and every life form reveals something unique about the nature of ULTIMATE CREATIVITY, so too does each name or metaphor for THE WHOLENESS OF REALITY distinguish something unique and important about its nature.

  • 13.7 bya THE GREAT RADIANCE / BIG BANG / PRIMORDIAL FLARING FORTH. This includes the phases of Cosmic Fluctuation (10 to the minus 43 seconds after BB), Inflation (10 to the minus 37 seconds after BB), and Expansion (10 to the minus 32 seconds after BB).

  • EMERGENCE OF THE FOUR FUNDAMENTAL FORCES (From 10 to the minus 32 to 10 to the minus 10 seconds after BB): Gravity, Electromagnetism, Strong Nuclear Force, Weak Nuclear Force.

  • PARTICLE AND ANTIPARTICLE ANNIHILATION (1 second after BB): All the antiparticles in the universe annihilate almost all the particles, creating a cosmos made up of matter and photons. By this time, the temperature had fallen to about 10 billion degrees Celsius, and the density of the universe was about 100,000 times that of the Earth. One teaspoon of matter would have weighed about 1.5 tons.

  • DEUTERIUM AND HELIUM NUCLEI PRODUCTION (1 minute after BB): protons and neutrons emerge and form the nuclei of simplest chemical elements: heavy hydrogen (deuterium), helium, and traces of lithium.

  • RECOMBINATION / FIRST ATOMS (300,000 years after BB): Electrons combine with hydrogen and helium nuclei, producing the first neutral atoms.

II. Galactic phase
(Use small gold beads for spacers.)

  • 12 bya PROTOGALACTIC CLOUDS of hydrogen form; the Universe differentiates into vast clumps of gaseous matter.

  • 11 bya GALAXIES emerge — producing the large-scale structures of the Universe.

  • 11 bya Gravity draws hydrogen into dense spheres of gas, sprinkled throughout each galaxy. At a threshold pressure, nuclear fusion begins: this is the birth of STARS. Let there be Light!

  • 11 bya to present GALAXIES INTERACT: some collide and are engulfed; others pass through one another, usually with tremendous gravitational impact to both.

  • 10 bya to present SUPERNOVAS forge COMPLEX ELEMENTS (atoms heavier than helium; i.e., carbon, nitrogen, oxygen, calcium, iron, gold, etc.). These elements are born in the fiery bellies of stars at least 8 times more massive than our sun. The created elements enrich the galaxies when the stars explode as supernovas.

  • 5 bya A SHOCK WAVE from a nearby supernova or gravitational density wave energizes the enriched gas cloud that will become our swirling solar system.

  • 5 bya the SUN ignites.

III. Hadean Eon of early Earth
(Use small red beads for spacers.)

  • 4.6 bya EARTH and other planets form by aggregating space debris in their orbital paths.

  • 4.5 bya the MOON is carved out of Earth by a huge impact; its orbit around Earth gradually becomes more distant through time.

  • 4.1 bya the Great Bombardment ends; RAIN falls upon a cooling Earth for first time.

  • OCEANS form.

IV. Archaean Eon of early life
(Use small copper beads for spacers)

  • 3.8 bya the first LIFE (Archaea) evolves in a very hot environment, possibly at great depth within Earth's crust or at hydrothermal fissures in the floor of the deep oceans.

  • NITROGEN FIXATION: Life copes with a nitrogen shortage by learning how to break the triple bond of nitrogen (N2) molecules that make up the bulk of the atmosphere, and to affix nitrogen atoms onto hydrogen atoms for fertilizer; biomass increases yet again.

  • Closed-cycle metabolisms of GAIA are now fully in place. Life mediates crucial links in the biogeochemical cycles of carbon, nitrogen, and oxygen, thereby maintaining an endless re-supply of Earth's finite reserves of elements vital for life.

  • 2.15 bya water-based PHOTOSYNTHESIS is invented by blue-green cyanobacteria to cope with a shortage of hydrogen atoms, previously scavenged from volcanic gases: pure hydrogen and hydrogen sulfide. The energy in sunlight is used to break apart water (H2O) molecules, thus opening up a virtually unlimited supply of hydrogen atoms crucial for building proteins, fats, and carbohydrates. Biomass increases as a result. [Note: 2.1 by date is new in 2008; see article in New Scientist.]
  • 2.1 bya marine iron rusts into RED BEDS from oxygen released during photosynthesis. When geology can no longer soak up oxygen, the OXYGEN CRISIS threatens microbial life, but it is also an opportunity because (1) an ultraviolet-absorbing OZONE SHIELD is formed in the upper atmosphere, and (2) bacterial precursors of mitochondria evolve a way to use gaseous oxygen for a high-energy-yielding form of RESPIRATION — without which self-aware consciousness might never have evolved.

    V. Proterozoic Eon
    (Use small orange or yellow beads as spacers.)

  • 2 bya EUKARYA arise via symbiogenesis (in response to Oxygen Crisis and possibly a shortage of phosphorus?); life becomes nested, one center of creativity within another, as oxygen-using mitochondria and photosynthesizing plastids cooperate with the larger host cells.

  • 1.5 bya MEIOTIC SEX emerges in eukarya, which is the first step in what will eventually evolve into a mode of reproduction that entails egg and sperm.

  • 1.2 bya the geological activity of MARS freezes up, thus foreclosing full geophysical cycling of chemical elements that could be vital to life.

  • 1 bya single-celled creatures invent PREDATION by developing flexible amoeba-like pseudopods that can surround a "prey" and secrete enzymes into that enclosed space (vacuole).

  • 565-543 mya the GARDEN OF EDIACARA is the time when the first multicellular life forms in the sea evolve differentiated body forms. Multicellularity is an innovation in which the offspring of dividing cells stay in bonded association with one another, resulting in synergies of community. These synergies include (1) the ability of individual cells to specialize in different tasks, and (2) the presence of new pattern and structure at the group level that brings forth emergent properties (as in the possibilities of a fin or an eye). The first multicellular creatures are soft-bodied ediacarans, which may be neither animals nor algae but something unique. Thus the microcosm expands into a mesocosm, with fossils (some as long as 3 feet) that a human eye can easily see.

  • EXTINCTION. All the ediacarans go extinct, possibly because of the evolution of hard parts by animal predators that ate the ediacarans. Predation intensifies and is now part of the mesocosm. The peaceable garden is ended.

  • Phanerozoic Eon begins, which includes the Paleozoic, Mesozoic, and Cenozoic Eras.


    • VI. Paleozoic Era begins
    (Use small blue beads as spacers, with different hues of blue for each of the
    six geological periods within the Paleozoic).

    540-500 mya CAMBRIAN Explosion

    • First true animals, including jellyfish and SPONGES.

    • Intensification of life interactions as multicellular predators invent hard parts for teeth and drills and claws, prompting prey (mollusks, trilobites) to invent SHELLS for protection.

    • SIGHT is invented, and is most sophisticated in the compound eyes of trilobite arthropods, the lenses of which are transparent crystals of calcite: Earth begins to see. Sight will be invented afresh well more than a dozen times by different lineages of life.

    500-440 mya ORDOVICIAN

    • The APPALACHIAN MOUNTAINS begin to rise, as Laurentia (the continental core that will eventually become North America) collides with the supercontinent of Gondwanaland (which will eventually break apart into South America, Africa, Antarctica, and Australia).

    • Earliest tabulate and rugose "corals" begin building REEFS, along with older reef-builders such as sponges and calcareous algae. Graptolites (hemichordates) are abundant.

    • CLAMS begin to burrow, presumably to escape predators.

    • The first SEA URCHINS evolve.

    • 440 mya END OF ORDOVICIAN EXTINCTION. This is the first of six major mass extinctions that suddenly and globally appear in the fossil record (in this case, marine rocks). All forms of planktonic graptolites go extinct, never to re-evolve. Many families of trilobites and brachiopods (clamlike creatures distinct from mollusks) go extinct.

    440-410 mya SILURIAN

    • JAWED FISHES appear (before then, there were only jawless fishes, such as lampreys).

    • EURYPTERIDS (giant sea scorpions) are top carnivores, in their glory; they are the biggest arthropods of all time.

    • A freshwater green alga and aquatic fungus pool their talents (symbiosis), merging into the first LAND PLANTS. Life thus embarks on the adventure of weather and gravity. The continents grow green with low-lying ancestors of today's mosses and liverworts (nonvascular plants that go dormant in dry conditions).

    410-360 mya DEVONIAN

    360-290 mya CARBONIFEROUS

    • The peak of the "sea lily forests" in oceans; these CRINOIDS are echinoderms — like starfish on stems. This is also the heyday of the BRACHIOPODS, which look like clams but are not even mollusks. Both crinoids and brachiopods are filter feeders, filtering floating food out of flowing water.

    • Land plants discovered in the Devonian that by retaining the cells of previous generations and reinforcing these with lignin (WOOD), they can rise to new heights. But now TREES are abundant, having evolved independently in several different lineages (lycopods, horsetails, tree ferns), as plants compete for sunlight by overtopping their neighbors. Horsetails obtain their glory in the genus Calamites, which can grow to a height of 60 feet. Propagating clonally by rhizomes, clonal forests of Calamites may have been the biggest "individual" life form that ever evolved on Earth.

    • The kind of fungi that can decompose wood have not yet evolved, so massive coal fields result. The OXYGEN level in the atmosphere is much higher than today (owing to undecomposed coal?). This allows terrestrial arthropods to grow to the biggest sizes of all time, as a distinct system of "tracheid" vessels for air circulation (separate from the blood system) prohibits large size in all arthropods forevermore. Carboniferous dragonflies have wingspans like that of modern-day seagulls. Millipedes grow to perhaps six feet long.

    • Earth learns to fly, as insects evolve FLIGHT.

    • Earth learns to hear, as the ancestors of modern frogs (Temnospondyl amphibians, about 330 million years ago) evolved the first vertebrate ears capable of HEARING sound waves transmitted through the air, important for mating calls.

    • Reptiles appear with the first land-worthy eggs that can survive out of water; this is the AMNIOTIC EGG, whose shell and membrane allow for gas exchange without water loss (like the cuticle and stomate innovation of vascular plants). Reptiles also invent the PENIS — but not yet a distinct vagina, as reptiles (and, later, birds) retain a cloaca that combines the three functions of reproduction, metabolic waste excretion, and fecal elimination. Reptiles are thus freed to copulate outside of water.

    290-245 mya PERMIAN

    • PANGAEA forms, a single supercontinent.

    • The vast landmass, with central sections far removed from marine moisture, produces deserts in the interior reaches of Pangaea, depositing RED (highly oxidized) sediments that contain fossils. Many ferns gradually go extinct in the early Permian, as landscapes become more arid (ferns absolutely require a surface film of water for sexual reproduction.) Horsetails begin their decline — becoming in modern times a single genus of "living fossil": Equisetum, with just fifteen species worldwide.

    • The earliest ancestors of dinosaurs are all small, housecat-size "dinosauromorphs. In 2010 paleontologists discovered in 250 million year old rocks in Poland the footprints of such creatures (right). The fact that the 3 central digits are far more prominent than the outer digits, and that the ankle is hinged rather than rotary (lizards and crocodiles have the opposite features) secure this fossil find as of the pre-dinosaur lineage. Some of these creatures must have survived "The Great Dying" (next), otherwise there would have been no dinosaurs.
      		•

    • 245 mya END OF PERMIAN EXTINCTION. This marks the end of the Paleozoic Era. This third major mass extinction is the most devastating extinction Earth has ever endured, and it is sometimes called, "The Great Dying". It affected both marine and land life. More than 50% of animal families go extinct, meaning that 95% of species can be inferred to have gone extinct. Nearly 75% of all amphibian and reptile families go extinct on land. In the land plant realm, all of the tree forms of horsetails and club mosses vanish, never to re-evolve. In the sea, one half of all marine families (80% of all genera in the sea) die out. All blastoids (stalked echinoderms similar to crinoids), eurypterids, trilobites, stromatoporoids, and rugose and tabulate corals go entirely extinct, never to reappear. Dying out, as well, but not fully extinct are: 98% of all crinoid families, 78% of all articulate brachiopod families, 76% of bryozoan families, 71% of cephalopods, 50% of planktonic foraminfera. Recently discovered evidence indicates that the extinction may have been triggered by immense volcanic release (the basalt flows of the Siberian Traps; itself perhaps triggered by an asteroid impact in the ocean) and/or by an immense "methane burp".


    VII. Mesozoic Era (Age of Dinosaurs) begins.
    (Use small purple beads as spacers, with different hues of purple for each
    of the three geological periods.)

    245-210 mya TRIASSIC

    • Pangaea is still a supercontinent and thus an arid continental interior continues to deposit sediments as "TRIASSIC RED BEDS."

    • 225 mya is a MINI MASS EXTINCTION (not one of the 5 majors)

    • At the end of Triassic, PANGAEA BREAKUP begins, opening up an archaic east-west waterway called the Tethys Sea. First to split off is Laurasia to the north, which consists of the bedrock foundations of what will one day become North America (the Laurentian Shield) and Eurasia. To the south, across the Tethys Sea, is the supercontinent of Gondwanaland (South America, Africa, Antarctica, Australia, India). Eventually, as the continents draw apart, Earth will bring forth six times more biodiversity (which thrives on isolation) than when all land was together as Pangaea.

    • SHARK TEETH become abundant in the fossil record, because sharks evolve a dental strategy of replaceable teeth. Shark skeletons are still rarely preserved, however, as the skeletons are made of cartilage, not bone.
    • 210 mya END OF TRIASSIC EXTINCTION. This is the fourth major mass extinction. Because it is the third time Earth has been hit hard by extinctions in just 35 million years, biodiversity is severely stressed.

    210-145 mya JURASSIC

    • The ATLANTIC OCEAN is forming, as the supercontinent of Laurasia now starts to break apart. Gondwanaland is still intact and evolving a distinctive flora.

    • Proliferation of wind-dispersed POLLEN: Except for the plants that evolved in the early Paleozoic (mosses, ferns, horsetails), land plants now have long-distance sex without depending on water to disperse sperm. Pollen grains that land on receptive female parts grow sophisticated "pollen tubes" to deliver swimming sperm to the ovule.

    • GYMNOSPERMS — cycads, ginkgos, and ancient CONIFER TREES (such as redwoods, but not yet the pines) originate: all are seed plants that produce pollen. Great gymnosperm forests of the Mesozoic tower over the remnant lineages of lycopods and horsetails that lurk on the forest floor — lineages which had once been the forests of the Paleozoic.

    • DINOSAURS, which originated in the early Triassic, become the largest land animals of all time, in the form of the great herbivorous sauropods (e.g. Brachiosaurus, Seismosaurus, Diplodocus), which reach their zenith in size and diversity during the Jurassic.

    • LARGE MARINE REPTILES (the snake-necked Plesiosaurs, dolphinlike Ichthyosaurs, lizard-kin Mosasaurs, and crocodiliam-kin Metriorhynchids) arise, as do the flying PTEROSAURS.

    • The first BIRDS (Archaeopteryx) with feathers and teeth, originate.

    • The first FROGS evolve from amphibian ancestors.

    • MAMMALS are almost as ancient as dinosaurs. Although most were probably smaller than a squirrel and probably nocturnal, the fossil of 1 meter-long badger-like predatory mammal has been dated to 170 million years ago, and that of a beaver-like mammal about the size of a platypus is 164 million years old. The latter has evidence of hair and of sweat glands (that could have provided milk).

    145-65 mya CRETACEOUS

    • Early MAMMALS continue to diversify, but most still get no bigger than squirrel-size in the presence of the powerful dinosaurs. Modern lineages of mammal replace the cloaca of early mammals (such as the living duck-billed platypus) in females with three separate orifices, including a VAGINA. About 125 million years ago, the FIRST GLIDING MAMMAL evolves.

    • This is a time of glorious increase in the complexity of life on both land and at sea. Marine PREDATION AND PROTECTION escalates in an evolutionary arms race: the shells of mollusks grow thicker and some develop spininess, while clams live in deeper burrows. SCALLOPS invent a fast, clapping form of movement, like swimming castanets.

    • Earth is in a GREENHOUSE climate, with no polar ice.

    • MORE DINOSAURS: T. rex, Triceratops, duckbills, and raptors are on land; plesiosaurs and mosasaurs grow gigantic in the seas.

    • The biggest flying life form of all time, the pterosaur QUETZALCOATLUS, spreads its wings over 45 feet (15 meters)!

    • Earth bursts into SONG, with birds, insects, and crested dinosaurs making noises, largely as a means of sexual seduction.

    • Flowering plants become important parts of the flora, but remain as low, herbaceous plants or vines, until the very late Cretaceous (70 mya) when the tree form evolves in several different lineages (magnolia family, sycamores). Earth adorns herself magnificently and invites the sky creatures into a mutualistic symbiosis with plants. FLOWERS AND INSECTS CO-EVOLVE in an attractive dance of pollination (flower nectar) and a protective dance of chemical warfare (invention of alkaloids and aromatic oils, as in basil) to repel insect herbivores.

    • MADAGASCAR, which had been "drifting" away from Africa on a continental plate, becomes isolated when India breaks free from its eastern shore and continues the northeastern journey alone. Fortunately, Madagascar broke away after LEMURS evolved, but before monkeys evolved. Lemurs, once ranging widely from Africa to Asia and North America, would go extinct whenever and wherever monkeys show up; thus they would certainly be extinct today were it not for the island habitat of Madagascar.
    • AMMONITES (cephalopods related to the chambered nautilus and squid) flourish, with their intricately joined segments of coiling shell, just before they go extinct.

    • 65 mya END OF CRETACEOUS EXTINCTION marks the K/T (Cretaceous/Tertiary) boundary: the end of the Mesozoic Era. This is the fifth major mass extinction, affecting both land and sea creatures. It brought an end to all dinosaurs, pterosaurs, marine reptiles, ammonites, and many lineages of foraminifera. (Plants, which could wait out the holocaust as seed or spore, generally did not suffer a mass extinction at this time.) A buried crater 100 miles wide marks the spot where a mountain-size asteroid slammed into Earth at an estimated 50,000 miles per hour along Mexico's Yucatan Peninsula, releasing an amount of energy equivalent to 100 million megatons of TNT, which is 1,000 times more powerful than all humanity's currently existing nuclear weapons combined. The impact produced at least six tidal waves, some of which were more than 300 feet high, a magnitude 12 earthquake (which is a million times more powerful than a magnitude 6 earthquake), a deluge of sulfuric acid rain, and a huge cloud of dust that blocked the light from the Sun for months and contributed to the extinction of nearly every land animal whose adult form weighed more than 50 pounds. The impact also triggered a global firestorm that incinerated a quarter of the living biomass, releasing an enormous amount of carbon dioxide into the atmosphere that increased the average global temperature by 20F for a million years. The impact may also have released tremendous volcanic activity, especially the Deccan Traps basalt flows in India.


    Timeline 2 — 65,000,000 to 13,000 Years Ago

    Timeline 3 — 12,000 Years Ago to Present

     


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