GeoTimeline - about 1 Bya multicellular eukaryotes still...

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Geological Eras – (Eras, Eons, Periods – were all named long ago, when we could only put fossils in relative order. Didn’t have radiometric and DNA techniques for dating) Precambrian 4.6 Bya 543 Mya Paleozoic 543 Mya 250 Mya (old, ancient life) Mesozoic 250 Mya 65 Mya (middle life Cenozoic 65 Mya now ( recent life Precambrian - very longest era - First one BILLION years of heat, volcanoes, crashing meteors and asteroids 4.6 - 3.6Bya - formation of Moon, atmosphere had no Oxygen, or Ozone protection, so intense solar radiation - a period of chemical evolution, simple molecules in ocean/atmosphere reacting to form energy- containing biomolecules - - Next 2 Billion years of most simple oeganisms. Prokaryotes – one celled bacteria - some of them acquired ability to collect sun’s energy, began photosynthesis process, with waste byproduct of Oxygen - about 1.6 Bya, first Eukaryotic single celled organisms (have nucleus and other organelles)
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Unformatted text preview: about 1 Bya multicellular eukaryotes, still not too exciting, – algae. Paleozoic – Cambrian explosion , then several eons-Sea critters with shells, many body plans and shapes-Vertebrates (backbones and internal skeletons)-First land plants. Geography, cold-Insects followed by seed plants-Reptiles mammal common ancestors-Note: ca 300 Mya, mild climate, vast swamps of huge plants growing, and laying down layers for 50 – 80 MILLION years. By end of this era, movement of continents submerged these forests, pressure turned them into coal/oil/natural gas deposits. Renewable?? Mesozoic – age of Reptiles Gave rise to dinosaurs. 220 mya 65 Mya Gave rise to mammals 200 Mya Gave rise to birds 150 Mya -land plants evolving – more about these later-Pangaea breaks into today’s continents.-Ends with 10 km diameter asteroid crashing into coast of Yucatan 65 Mya Cenozoic---...
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