Precambrian Eon
4.6 - 541 M 4.059
Proterozoic Eon
2.5 - 541 M 2.047
Neoproterozoic Era 1B - 541 659
Ediacaran Period
635 - 541 94
| 600 It is thought that earliest multicellular life on Earth was a sponge-like creature. |
? Sponges are among simplest of animals, with partially differentiated tissues but without muscles, nerves, or internal organs.
Sponges ( Porifera) are phylogenetically oldest animal phylum extant today.
In some ways they are closer to being cell colonies than multicellular organisms. |
| 580 movement of all animals may have started with cnidarians. Almost all cnidarians possess nerves & muscles and, because they are simplest animals to possess it, their direct ancestors were very likely first animals to use nerves & muscles together. Cnidarians are also first animals with an actual body of definite form & shape. They have radial symmetry. |
579 Gaskiers glaciation is a period of widespread glacial deposits (e.g. diamictites) that lasted under 340 thousand years, between 579.63 ± 0.15 and 579.88 ± 0.44 |
| 555 diverse Ediacaran community was discovered in 1995 in Sonora, Mexico |
| 550 - 330 Proto-Tethys or Theic Ocean |
| 550 Flatworm
earliest animals to have a brain, & simplest animals alive to have bilateral symmetry. They are also simplest animals with organs that form from three germ layers. |
| 580 - 0 Platytrochozoa Basal Clade |
| 550 - 180 370 Gondwana (South America, Africa, peninsular India, Australia, & Antarctica) to south. |
| 549 - 530 Baykonurian glaciation |
| 542 Treptichnus pedum 1st preserved burrow of an animal |
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Phanerozoic Eon 541 - Present
Paleozoic Era 541 - 252 289
Cambrian Period
541 - 485.4 55.6
541 - 521 20 Terreneuvian System
541 - 529 12 Fortunian Age
| 541 Cambrian explosion or Cambrian radiation |
| 541 Large negative peak δ 13Ccarb excursio |
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Phanerozoic Eon 541 - Present
Paleozoic Era (Ancient Life)
541 - 252 289
Cambrian Period
541 - 485.4 55.6
Terreneuvian Epoch 541 - 521 20
Fortunian Stage 541 - 529 12
| 540 Laurentian Mountain range is one of the oldest mountain ranges in the world. It contains rocks deposited before the Cambrian Period 540 |
540 Acorn worms are considered more highly specialised & advanced than other similarly shaped worm-like creatures. They have a circulatory system with a heart that also functions as a kidney. Acorn worms have gill-like structure it uses for breathing, a structure similar to that of primitive fish. Acorn worms are thus sometimes said to be a link between vertebrates & invertebrates.
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| 536 - 0 Lophotrochozoa superphylum |
| 535 - P Agnatha, first vertebrates appear: ostracoderms, jawless fish related to present-day lampreys & hagfishes. Haikouichthys & Myllokunmingia are examples of these jawless fish, or Agnatha. (See also prehistoric fish). They were jawless & their internal skeletons were cartilaginous. They lacked paired (pectoral & pelvic) fins of more advanced fish. They were Precursors to bony fish. |
| 530 - 0 Lancelet fish. Resembles Pikaia |
530 Pikaia earliest known ancestor of chordates. It is first known animal with a notochord.Pikaia is believed to be ancestor of all chordates & vertebrates.
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Stage 2 (Tommotian) 529 - 521 8
| Other earliest known chordate-like fossils is from a conodonts a "eel-shaped animal of 4-20 cm long" with a pair of huge eyes at head end were & a complex basket of teeth. |
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Series 2 Epoch 521 - 09 12
Stage 3 521 - 514 7
| 520 Vertebrates—primitive fish with bony armor plates. |
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Stage 4 514 - 509 5
| 511 - 0 Crustaceans (shellfish) |
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Miaolingian Epoch 509 - 497 12
| Wuliulan Stage 509 - 504.5 4.5 |
| Drumian Stage 504.5 - 500.5 4 |
| Guzhangian Stage 500.5 - 497 3.5 |
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Furongian Epoch 497 - 485.4 10.6
| Paibian Stage 497 - 494 3
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Stage 10 489.5 - 485.4 12.5
| 490 - 0 brachiopods phylum |
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Ordovician Period
485.4 - 443.8 41.6
Early 485.4 - 470 15.4
Tremadocian stage 485.4 - 477.7 7.7
| 480 Appalachian mountain range. Europe & North America straddle equator. |
480 Placodermi were prehistoric fish. Placoderms were first of jawed fishes, their jaws evolving from first of their gill arches .Their head & thorax were covered by articulated armoured plates & rest of body was scaled or naked.
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Phanerozoic Eon 541 - Present
Paleozoic Era (Ancient Life)
541 - 252 289
Ordovician Period
485.4 - 443.8 41.6
Late Ordovician Subperiod
485.4 - 470 15.4
Sandbian stage 485.4 - 453 5.4
| 470 - 425 Cameroceras genus of extinct, giant orthoconic cephalopod |
| 466 - 465 1 Flat Landing Brook Formation volcanos Telagouche Group |
| 455 - 430 25 last Ordovician–Silurian extinction events |
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Katian stage 453 - 445.2 7.8
| Scafells, Lake District, England; VEI8; Ordovician (488.3–443.7 volcanos |
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Hirnantian stage 445.2- 443.8 11.4
| 444 Ice age begins mass extinctions of marine life |
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Silurian Period
443.8 - 419.2 24.6
Llandovery epoch443.8 - 433.4 10.4
| Rhuddanian Age 443.8 - 440.8 3 |
Telychian Age 438.5 - 433.4 5.1
| 433.4 Ireviken event was the first of three relatively minor extinction events (the Ireviken, Mulde, and Lau events) lasted around 200,000 years comprises eight extinction "datum points"—the first four being regularly spaced, every 30,797 years, and linked to the Milankovic obliquity cycle.[3] The fifth and sixth probably reflect maxima in the precessional cycles, with periods of around 16.5 and 19 ka.[3] The final two data are much further spaced, so harder to link with Milankovic changes |
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Ludlow epoch
427.4 - 423 4.4
| Gorstian Age 427.4 - 425.6 1.8
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Ludfordian Age 425.6 - 423 2.6
| 425 - 0 psilophytes 1st land plants leafless, vascular plants |
| 425 - 200 225 Laurasia (North America, Greenland, Eurasia, & Scandinavia) to north of equator, & |
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Silurian Regional Stages
North American Silurian Regional Stages
436 - 416 20
Cayugan Regional Stage
421.3 - 416 5.3 |
Lockportian Regional Stage
426.2 - 422.9 3.3 |
Tonawandan Regional Stage
428.2 - 426.2 2 |
Ontarian Regional Stage
436 - 428.2 9.8 |
Alexandrian Regional Stage
428.2 - 419.2 9 |
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Estonian Silurian regional stages
443 - 417 26
Ohessaare Regional stage
Late Silurian – early Přídolí ? |
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Phanerozoic Eon 541 - Present
Paleozoic Era (Ancient Life)
541 - 252 289
Devonian Period 419.2 - 358.9 60.3
Early Devonian Subperiod
419.2 - 393.3 25.9
Lochkovian Stage
419.2 - 410.8 8.4
| Collisions between Laurasia & Gondwana form major mountain ranges. Coal-forming sediments are laid down in vast swamps. |
Global climatic changes occur, changing from warm & wet to cooler & drier. result is a long interval of glaciation in southern hemisphere.
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| Great swamp forests covered land. |
| Shallow flooding of continental areas deposits sediments; |
| later withdrawal of ocean water leaves oxidized "red beds" & extensive salt deposits. |
| As seas recede, they leave a thick layer of limestone. |
| Later in period, seas recover North America, depositing quartz, sandstones, & more limestone. |
| Metazoan invertebrates are still dominant form of life on Earth. |
| benthic (bottom-dwelling) |
| planktonic (floating, swimming) organisms. |
| Benthic (bottom-dwelling) marine |
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Pragian Stage
410.8 - 407.6 3.2
409 - 66 343 Ammonites evolve from nautiloids & become one of dominant invertebrate forms.
As ozone layer forms, first air-breathing arthropods—spiders & mites—evolve on land. Amphibians evolve & venture onto land.
Plant life, including lowland forests of giant psilophyta plants, develop & spread over planet. |
| 409 - 0 Coelacanth "living fossil" related lobe-finned fish without these shallow-water adaptations. These fishes used their fins as paddles in shallow-water habitats choked with plants & detritus. universal tetrapod characteristics of front limbs that bend backward at elbow & hind limbs that bend forward at knee can plausibly be traced to early tetrapods living in shallow water. |
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Emsian Stage
407.6 - 393.3 14.3
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Middle Devonian Subperiod
393.3 - 382.7 10.6
Eifelian Stage
393.3 - 387.7 5.6
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Givetian Stage
387.7 - 382.7 5
| 385 Widespread shrubs & trees |
| 385 - 0 Elpistostegali or Panderichthyida order of prehistoric lobe-finned fishes |
| 385 - 380? Elpistostege extinct genus of tetrapod-like vertebrate Escuminac Formation in Quebec, Canada. |
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Late Devonian Subperiod
382.7 - 358.9 23.8
Frasnian Stage
382.7 - 372.2 10.5
| 380 Panderichthys is a 90-130 cm long fish from Late Devonian period. It have a large tetrapod-like head. Panderichthys exhibits features transitional between lobe-finned fishes & early tetrapods. Lungfishes retain some characteristics of early Tetrapodas. One example is Australian Lungfish. |
| 375 Elginerpeton stem-tetrapod |
| 375 Tiktaalik is a genus of sarcopterygian (lobe-finned) fishes from late Devonian with many tetrapod-like features. |
| 372.2 Kellwasser extinction event "Late Devonian extinction" first event to be detected based on marine invertebrate record. Volcanos |
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Famennian Stage
372.2 - 358.9 13.3
| 372.2 - 359.2 3 Ventastega |
| 365 Sarcopterygii (fresh water lobe-finned fish) >< tetrapods in shallow & swampy freshwater habitats. |
| 365 Acanthostega four-limbed vertebrate |
| 365 Tulerpeton four-limbed vertebrate |
| 365 - 60 5 Ichthyostega four-limbed vertebrates |
| 365 - 360 5 Acanthostega Ichthyostega amphibian, among first animals to have recognizable limbs. It is a candidate for being one of first vertebrates to be capable of coming onto land. It lacked wrists, & was generally poorly adapted to come onto land. limbs could not support animal's weight. Acanthostega had both lungs & gills, also indicating it was a link between lobe-finned fish & terrestrial vertebrates. hybrid between a fish & an amphibian. legs to paw their way through mud. |
| armored fish become extinct. |
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Phanerozoic Eon 541 - Present
Paleozoic Era (Ancient Life)
541 - 252 289
Carboniferous Period 358.9 - 298.9 60
Mississippian Subperiod
358.9 - 323.2
Tournais Age
358.9 - 346.7 12.2
| 358 Hangenberg extinction event marked by an anoxic black shale layer and an overlying sandstone deposit.[18] Unlike the Kellwasser event, the Hangenberg event affected both marine and terrestrial habitats.[
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| Reptiles adapt to life in sea, in air, & on land. |
| Mammals are small, shrew-like animals. |
350 - 0 Dentaliida one of the two orders of scaphopod mollusks, commonly known as elephant's tusk shells
Dentaliidae is a family of relatively large tusk shells, scaphopod mollusks in the order Dentaliida.
Antalis is a genus of tusk shells, marine scaphopod mollusks.
| Sandstone forms in shallow seas over continents. |
| Shale forms in shallow seas over continents. |
| Limestone forms in shallow seas over continents. |
| Conglomerate forms in shallow seas over continents. |
| Gondwana in south incorporates South America, Africa, Antarctica, & Western Australia as well as peninsular India & parts of Arabia. |
| Marine metazoans with mineralized skeletons |
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Visean Age
346.7- 330.9 15.8
| 345.3 - 318.1 Pholidogaster ('scaly stomach') is an extinct genus of tetrapod |
| 340 - 0 tusk shells or tooth shells scaphopods class youngest Mollusc |
335 - 175 160 Pangaea supercontinent extends across all climatic zones & nearly from one pole to other.
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| 331 - 23 8 Proterogyrinus |
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Pennsylvanian Subperiod
323.2 - 298.9
Bashkirian Stage 323.2 - 315.2 8
| 323.2 - 0 Octopuss 300 species |
| 323.2 Pohlsepia mazonensis is the earliest described octopod |
Pangea begins to breakup as North America separates from Eurasia & Africa. Atlantic Ocean begins to form. Tectonic plate subduction along western North America causes Earth's crust to fold & mountains form in western part of continent.
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| First birds appeared (e.g. Archaeopteryx). |
323 Amniota, reptiles who can reproduce on land & lay eggs on dry land. They did not need to return to water for reproduction. This adaptation gave them capability to colonize uplands for first time.
Reptiles have advanced nervous system, compared to amphibians. They have twelve pairs of cranial nerves. |
| 510 - 320 graptolites Extinct |
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Moscovian Stage 315.2 - 307 8.2
| 312 Reptiles >< Reptiliomorph tetrapods |
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Kasimovian Stage 307 - 303.7 3.3
| 305 - 299 6 Meganeura Liaoning Province, China |
305 Carboniferous rainforest collapse Late Carboniferous, tropical rainforests lay over the equator of Euramerica. A major, abrupt change in vegetation occurred when the climate aridified. The forest fragmented and the lycopsids which dominated these wetlands thinned out, being replaced by opportunistic ferns. There was also a great loss of amphibian diversity and simultaneously the drier climate spurred the diversification of reptiles.[1]
Invertebrates
| High oxygen levels had made the enormous arthropods of the time possible. Due to the decreasing oxygen, these sizes could no longer be accommodated, and thus between this and the loss of habitat, the giant arthropods were wiped out in this event, most notably the giant dragonflies (Meganeura) and millipedes (Arthropleura). |
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Vertebrates
| Labyrinthodont amphibians were particularly devastated, while the amniotes (the first members of the sauropsid and synapsid groups) fared better, being physiologically better adapted to the drier conditions. |
many amphibian families failed to occupy new ecological niches and became extinct.[6]
Synapsids and sauropsids acquired new niches faster than amphibians, and new feeding strategies, including herbivory and carnivory, previously only having been insectivores and piscivores. |
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| 305 - 303 2 Earth returning to normal tempetature |
| 305 - 300 5 Vegetation recovery period |
| 305 - 295 10 Biodiversity recovering with dinosaurs as dominant species |
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| Gzhelian Stage 303.7 - 298.9 4.8
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