Important points of evolution chapter

EVOLUTION

20 bya - Universe Age
4.5 bya - Earth was formed
4 bya - Life appeared on earth [ which is actually 500 million after Earth was formed ]
3 bya - First Non-cellular Life forms
2 bya - Cellular Life forms
200 mya - fish-like reptiles [ e.g. Ichthyosaurs ]
65 mya - dinosaurs dissappeared
15 mya - Dryopithecus & Ramapithecus
2 mya - Australopithecus
1.5 mya - Homo-erectus
100k - 40k yrs back - Neanderthals
75k - 10k yrs back - Homo-Sapiens
18k yrs back - Cromagnon
10k yrs back - Modern Man

Evolution of Organisms

Geological time scale of earth is divided into 6 era

  1. Azoic - Era of no life.
  2. Archaeozoic - Era of invisible life.
  3. Proterozoic - Invertebrates and microbe originate. (Q 2012)
  4. Palaeozoic - Vertebrates appear.
  5. Mesozoic - Age of reptiles.
  6. Coenozoic - Age of mammals and birds. (Q 1993)
    Archaeozoic and proterozoic are together called precambrian.
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