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A view of the earth’s past


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Mesazoic and Cenezoic Eras

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A view of the earth’s past

  1. 1. A View of the Earth’s Past Geologic History
  2. 2. Geologic History Geologic history recorded in layers of rocks Theory of Evolution  Charles Darwin – 1859 – English naturalist (pre- biologists)  AKA “survival of the fittest”  States that organisms change over time and come from ancestral types of the same organisms  Geologic record of fossils supports this theory
  3. 3. Geologic History Theory of Evolution continued  Organisms must adapt to their environment or else they become extinct (cease to exist on the entire planet) Two types of environmental changes 1. Geologic  Dramatic decrease in the amount of water covering the surface 2. Climate  Decrease in atmospheric pressure
  4. 4. Precambrian Time Use “time” instead of “era” because it is so long 4.6 billion years to 570 million years ago 88% earth’s history Shields – large areas of exposed Precambrian rock  Severely deformed from crustal activity makes layer of rock hard to distinguish  Half deposits of valuable minerals found in these layers (Ni, Fe, Au, Cu)
  5. 5. Precambrian Time Fossils rare  Most precambrian life thought to have soft bodies – can’t be fossilized  Any hard bodies destroyed by crustal movements of subduction, volcanic activity and erosion  Stromatolites – precambrian fossils – reeflike depoits made from cyanobacteria  Imprints of marine worms, jellyfish have been found in late precambrian rocks in Austrailia
  6. 6. The Paleozoic Era 570 million to 245 million years ago Beginning of era – landmasses covered with water End of era – landmasses collided to form Pangea
  7. 7. Pangea
  8. 8. The Paleozoic Era Abundant fossil record  Huge increase in plant and animal life  So much that era is divided into 7 periods
  9. 9. The Paleozoic Era: Cambrian Period First period of era Advanced marine life showed up  Had hard parts but no backbones  Quickly replaced precambrian organisms  Lived in shallow seas that were abundant during this period  Invertebrates – animals with no backbones
  10. 10. The Paleozoic Era: Cambrian Period Most common: Trilobites  Lived on ocean floor
  11. 11. Trilobite
  12. 12. The Paleozoic Era: Cambrian Period Second most common: Brachiopods  15 different kinds still exist
  13. 13. Brachipods
  14. 14. The Paleozoic Era: Cambrian Period Other invertebrates: worms, jellyfish, snails and sponges No land plants or animals found
  15. 15. The Paleozoic Era: Ordovician Period Brachiopods increased Trilobites decreased Snails, clams and other mollusks became dominant life-forms Coral appeared Graptolites – tiny invertebrates – appeared  Useful index fossils
  16. 16. graptolites
  17. 17. The Paleozoic Era: Ordovician Period Ostracoderm - First vertebrate – fish covered with bony plates but no teeth or jaw Vertebrates – animals with backbones No plant or animal life on land
  18. 18. Ostracoderm
  19. 19. The Paleozoic Era: Silurian Period Marine life continued to thrive and evolve Echinoderms – relative of sea star – many during this period Eurypterids – scorpionlike sea creatures – abundant during this period  Some as long as 2.4 meters found in western New York
  20. 20. Echinoderms
  21. 21. eurypterid
  22. 22. The Paleozoic Era: Silurian Period First land animal such as, spiders and millipedes, show up at the end of this period
  23. 23. The Paleozoic Era: Devonian PeriodAGE OF FISHES – many kinds of bony fishes lungfish – primitive lungs, could breatheair rhipidistians – also able to breathe air and had strong fins that probably enabled them to crawl out of waterIchthyostega – first true amphibianLand plants began to develop
  24. 24. lungfish
  25. 25. The Paleozoic Era: Carboniferous Period Meaning “carbon bearing” In North America – divided into 2 sub-periods: Mississippian and Pennsylvanian Warm and humid climate Many coal deposits in these area came from this period
  26. 26. The Paleozoic Era: Carboniferous Period Crinoids – relatives of modern sea stars Giant cockroaches and dragonflies Toward end of Pennsylvanian period – first land vertebrates appeared  Early reptiles resembling large lizards
  27. 27. crinoids
  28. 28. The Paleozoic Era: Permian Period End of Paleozoic era – MASS EXTINCTION Pangea almost completely formed from collisions of tectonic plates  Mountains became so high that areas turned dessert from lack of rain – inland seas evaporated  Many marine invertebrates became extinct  Reptiles and amphibians managed to survive this extreme climate change
  29. 29. The Mesozoic Era Began 245 million years ago and ended 65 million years ago During this era, climate changes dramatically Pangea began to break up Shallow sea marshes covered most of the land Continental climates generally warm and humid
  30. 30. The Mesozoic Era Called the AGE OF REPTILES because favored the survival of reptiles  Lizards, turtles, crocodiles, snakes, etc.
  31. 31. record – National Geographic – 3 ’ 40”
  32. 32. The Mesozoic Era: Triassic Period AnimalsDinosaurs first appeared during this period“dinosaur” comes from the Greek wordmeaning “terrible lizard”Large variety of sizes  Most in Triassic period were 4-5 m long and moved fast
  33. 33. The Mesozoic Era: Triassic Period PlantsLush forests of cone-bearing trees  Plants that resemble todays palm trees
  34. 34. The Mesozoic Era: Triassic Period Ichthyosaurs – reptiles Ammonite appeared – marine invertebrate Earliest mammals appeared – small rodent-like forest creatures
  35. 35. ammonite
  36. 36. The Mesozoic Era: Jurassic Period Dinosaurs dominated this period Two major types 1. Sauischians – “lizard-hipped” – herbivores (largest called apatosaur) and carnivores 2. Ornithischians – “bird-hipped” – herbivores (stegosaurus)
  37. 37. The Mesozoic Era: Jurassic Period Pterosaur – flying reptiles – had skin over wings Archaeopteryx – first true feathered birds
  38. 38. Pterosaur
  39. 39. Archaeopteryx
  40. 40. The Mesozoic Era: Cretaceous Period Dinos continued to dominate Earth Tyrannosaurus rex - 6 m tall, huge jaws, razor teeth Ankylosaurs – dinos covered with bony armorlike plates - herbivores Ceratopsians – dinos with horns - herbivores Ornithopods – duck-billed dinos - herbivores
  41. 41.  Dinosaurs =ywQdc_N9_Jo
  42. 42. T-rex
  43. 43. The Mesozoic Era: Cretaceous Period Many plants showed up  Angiosperms – first flowering plants  Magnolias  Willows  Maples, oaks, and walnuts also showed up
  44. 44. Angiosperm flower
  45. 45. The Mesozoic Era: Cretaceous Period End of period – MASS EXTINCTION including all dinosaurs Theory 1: 2 mile wide meteor impacted Earth Theory 2: dramatic climate changes so severe no dinos could survive
  46. 46. end of the dinosaurs – Discovery – 3’ 30”
  47. 47. The Cenozoic Era 65 million years ago to present day In beginning, continents looked about same as today Alps and Himalayas formed in this era Extreme climate changes – like ice ages  Various species became extinct and appeared
  48. 48. The Cenozoic Era Called the AGE OF MAMMALS because mammals became dominant life-forms Era split into two periods: Tertiary and Quaternary  Tertiary is divided into 5 Epochs: Paleocene, Eocene, Oligocene, Miocene, and Pliocene  Quaternary is divided into 2 Epochs: Pliestocene and Holocene
  49. 49. Tertiary Period: Paleocene and Eocene Epochs Many mammals evolved – small rodents and few carnivores  Lemuroids – first primates  Hyracotherium – earliest ancestor of horses  Flying squirrels, whales, and bats appeared  Smaller reptiles increased even though dinos were completely extinct Climate dropped 40C worldwide
  50. 50. Lemuroids
  51. 51. Hyracotherium
  52. 52. Tertiary Period: Oligocene and Miocene EpochsOligocene epoch – climate continued to cool andget drierMediterranean Sea dried up – 2,000 m ofevaporites collected on sea floorGrass and cone-bearing plants thrived in thisclimateMany earlier mammals became extinct butsome larger mammals flourished
  53. 53. Tertiary Period: Oligocene and Miocene EpochsMiocene Epoch – called Golden Age ofMammalsClimate remained cool and dryDeer, rhinoceros, and pigs  Baluchitherium – rhinoceroslike animal – largest known land animal ever existed (2x as large as an elephant)  Saber-toothed cat
  54. 54. Baluchitherium
  55. 55. Tertiary Period: Pliocene Epoch Hunting animals – bear, dog and cats – fully evolved First modern horses Continental ice sheets began to spread Bering land bridge appears North and South America connect with a land bridge
  56. 56. Tertiary Period: Pleistocene and Holocene EpochsPleistocene EpochSeveral periods of glaciation occurred overEurasia and North America  Animals with fur handled cold  Other animals moved to warmer climates  Animals that didn’t adapt, like giant sloths and dire wolves, became extinct  Early ancestors of modern humans found  Hunting could have led to extinction of large mammals like mammoths
  57. 57. Tertiary Period: Pleistocene and Holocene EpochsHolocene Epoch11,000 years ago to presentIce sheets meltedCoastlines took shape they are nowHomo sapiens – modern humans – developedagriculture and began to make tools with bronzeand iron
  58. 58. Homo sapiens