Bio

• Geologic time scale


  System of dating the history of earth
• Geologic time scale

  • Based on chronological manner
  • Divided into eons, eras, periods, and epochs
• Phanerozoic eons


  Visible life, constructed through rocks unit that bear abundant fossils
• Precambrian eons


  Period between the birth of the planet and the appearance of life forms
• Epochs


  Shortest subdivision on earth's Geologic time scale which is characterized by charges in life forms
• Phanerozoic eon divisions


  • Paleozoic era
  • Mesozoic era
  • Cezenoic era
• Paleozoic era


  • Age of invertebrates, due to the presence of the fossils of animals without backbones
• Paleozoic era periods


  • Cambrian
  • Ordivician
  • Silurian
  • Devonian
  • Carboniferous
  • Permian
• Mesozoic era


  • Age of reptiles
• Mesozoic era periods


  • Triassic
  • Jurassic
  • Cretaceous
• Cezenoic era


  • Age of mammals, first human appeared
• Cezenoic era periods


  • Tertiary
  • Quarternary
• Theories on the origin of life on earth started during 16th century in Europe
• Chromosomes are thread-like structures made up of DNA and proteins found inside the nucleus.

  
• Stromatolite fossils


  Layered columns of sediments built up by the growth of cyanobacteria
• Stromatolite fossils


  • Earliest form of life on Earth in the form of fossilized microorganisms, precursors of photosynthetic organisms
  • Led to the buildup of oxygen in the atmosphere
• Multicellular Eukaryotes


  Organisms with differentiated cells forming several distinct functions
• Cambrian Explosion


  Most advanced form of animals such as vertebrates or animals with backbones
• Major subdivisions of the Precambrian Era

  • Hadean
  • Archean
  • Proterozoic
• During the Hadean, the Earth's surface was mostly in the form of liquid rock and boiling sulfur that built an ocean of hot materials
• The atmosphere was mostly filled with carbon dioxide, nitrogen and sulfur compounds
• Fossilized rock from this era is still found today
• In the Archean Eon, the continents mostly sank down and were submerged under vapor and formed a global ocean
• Carbon dioxide changed and formed limestone
• The atmosphere started to form and was mostly composed of nitrogen. Molten rock cooled down and formed the first continents
• The Earth's interior was still hot and active, with volcanic eruptions