Geologic time scale

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Geologic time scale

  1. 1. Geologic Time Scale<br />Relevant to Primate & Hominin Evolution<br />
  2. 2. Animal life diversifies starting in the Phanerozoic<br />Paleozoic Era<br />Mesozoic Era<br />Carboniferous<br />Triassic<br />Jurassic & Cretaceous<br />Ordovician<br />Silurian<br />Devonian<br />Permian<br />Cambrian<br />570 mya<br />500<br />430<br />395<br />345<br />280<br />225<br />190<br />Marine invertebrates<br />First<br />vertebrates<br />Arthropods<br />Expansion of reptiles,<br />decline of amphibians<br />Age of Fishes, <br />1st amphibians & insects<br />Age of amphibians, <br />1st reptiles, 1st great<br /> insect radiation<br />
  3. 3. Cenozoic Era<br />Cretacous<br />Period<br />Triassic Period<br />Jurassic Period<br />225<br />190<br />136<br />65<br />Age of dinosaurs<br />1st birds<br />Mammals, <br />birds, insects<br />flourish<br />1st Mammals (Monotremes) & <br /> dinosaurs<br />1st flowering trees (angiosperms)<br />!st Marsupials, Placental mammals<br />Dinosaurs vanish @ 65mya <br />Mesozoic Era<br />
  4. 4. Primates finally start to enter the scene, 65 mya<br />Cenozoic Era: 65 my - present: 3 Periods: 7 Epochs<br />Pliocene<br />Pleistocene<br />Eocene<br />Oligocene<br />Paleocene Epoch<br />Miocene<br />1.8 mya<br />Holoocene<br />10 kya<br />5<br />23<br />65<br />54<br />34<br />Oldest primates(?)<br /> Plesiadapiforms<br />First Primates Evolve<br />Prosimians thrive<br />1st Anthropoids<br />Evolve<br />Monkeys &<br />1st primates<br />in South America<br />Hominins<br />Humans<br />1st<br />Hominoids<br />
  5. 5. Mammalian Evolution: A summary<br />Paleozoic: Devonian: First mammal-like reptiles (Therapsids)<br />Mesozoic: Triassic: First mammals (Monotremes)<br />Mesozoic: Cretaceous: First Marsupials & Placental mammals, <br />Cenozoic<br />Paleocene: Plesiadapiforms & 1st true primates<br />Eocene: Prosimians thrive + first Anthropoids<br />Oligocene: Anthropoids spread + first Hominoids<br />Miocene & Pliocene: First Hominids (7-1.7 mya)<br />Pleistocene: First Hominines (1.7-0.1 mya)<br />200,000-100,000 ya: First Humans<br />Holocene: 10,000 ya: History<br />
  6. 6. Over last 200 my, the earth rearranged itself<br />
  7. 7. Continental drift is important part of human history because it changed global climates <br />Temperatures have declined steeply from Eocene to present<br />Huge fluctuations in last 5 my<br />25C = 77 F<br />10C = 50 F<br />
  8. 8. The Mesozoic<br />Triasic (225 mya)<br />Pangea was a single continent<br />Dinosaurs & small mammals evolve<br />Pangea HUGE land mass = cold winters, hot moist summers (Wisconsin)<br />200 mya Pangea starts breaking up --> Laurasia & Gondawana<br />Oceans are barriers to gene flow = new species form<br />World gets warmer when continent splits<br />Dinosaurs and mammals evolve in this warmer world<br />Rise of angiosperms = fruits bearing trees = new foods<br />
  9. 9. The Cenozoic: Paleogene Period<br />Mammalian adaptive radiation to fill angiosperm niches<br />Paleocene wet & warm<br />Eocene wetter & warmer<br />Tropical forests<br />SA isolated from NA & Europe = new species<br />Primates (prosimians) highly successful & diverse<br />First anthropoids appear<br />Oligocene getting colder & drier, more seasonal variation<br />Mostly modern continent positions<br />SA still separate<br />Cold water currents cooling earth but Africa & SA tropical forests<br />Monkeys prosper, first hominoids appear<br />
  10. 10. The Cenozoic: Neogene Period & Quaternary<br />Neogene Period<br />Miocene warm & moist at beginning, got colder & drier<br />Forests retreating = open woodland habitat<br />Himalayas form = block warm & create cold air currents<br />Rift valley forms = rain shadow & dry savannah in Africa<br />First hominins evolved (late Miocene)<br />Pliocene begins frequent temperature fluctuations<br />Hominins diversify<br />Quaternary Period<br />Pleistocene: extreme temperature fluctuations<br />Modern humans evolve<br />

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