bio

• Geologic time scale


  Calendar for events in Earth's history
• Stratigraphy


  Chronologically relating geological strata to time
• Principles of relative dating

  1. Oldest layer at bottom, youngest layer at top

  2. Heaviest settles first, lightest settles last

  3. Law of superposition
• Fault


  Slab of rock that cuts through another rock
• Magma intrusion


  Magma that intrudes into rock
• Rocks mixed up in sediment formation are always older than the sediment layer
• Divisions of the geologic time scale

  • Eons
  • Eras
  • Periods
  • Epochs
• 88% of geologic time is Precambrian, 12% is Phanerozoic
• Biodiversity


  Number and kinds of organisms in a habitat or ecosystem
• Speciation


  Emergence of new species due to divergence within a population
• Extinction


  Disappearance of species due to failure to adapt to environmental changes
• Geology


  Branch of science that studies the Earth and its processes
• Biogeography


  Branch of biology that studies how species spread across the planet
• Fossils


  Remains of extinct plants and animals embedded in sedimentary rocks
• Paleontology


  Science that studies fossils
• Radiometric dating


  Technique to estimate age of a specimen through radioactive isotope decay
• Hadean Eon


  • Chaotic surface, severe volcanism, meteorite bombardment, core and crust stabilization, moon formation
• Archean Eon


  • Methane-rich atmosphere, primitive ocean and atmosphere, first evidence of life (prokaryotes)
• Proterozoic Eon


  • Origin of eukaryotic life, Ediacara fauna, oxygenation of atmosphere, formation and breakup of supercontinents, glaciation
• Cambrian Period


  • Spectacular burst of new life, primitive animals like sponges and trilobites
• Ordovician Period


  • Plants colonized land, invertebrates and first fish evolved
• Silurian Period


  • Stabilization of Earth's climate, appearance of coral reefs and vascular plants
• Devonian Period


  • First seed plants, first tetrapods and terrestrial arthropods, evolution of fish lobe fins
• Carboniferous Period


  • Widespread forests, first amphibians that could reproduce on land
• Permian Period


  • Largest mass extinction, formation of supercontinent, extreme temperatures and dry climate
• Triassic Period


  • First dinosaurs, dominant invertebrates were mollusks, first turtles, separation of Pangea
• Jurassic Period


  • Golden age of dinosaurs, earliest birds evolved from reptile ancestors, first appearance of angiosperms
• Cretaceous Period


  • Warm climate, extinction of dinosaurs
• Tertiary Period


  • Warm and humid climate, mammals evolved to fill niches, primates including human ancestors evolved, flowering plants and insects abundant
• Quaternary Period


  • Cooling climate, ice ages, land bridges formed, some mammals adapted to cold, others went extinct
• Geologic time scale


  Calendar for events in Earth's history
• Stratigraphy


  Chronologically relating geological strata to time
• Principles of relative dating

  1. Oldest at bottom, youngest at top

  2. Fault/dike/magma intrusion is younger than surrounding rock

  3. Rocks mixed in sediments are older than sediment layer
• Divisions of geologic time scale

  • Eons
  • Eras
  • Periods
  • Epochs
• 88% of Earth's history is Precambrian, 12% is Phanerozoic
• Biodiversity


  Number and kinds of organisms in a habitat or ecosystem
• Speciation


  Emergence of new species due to divergence within a population
• Extinction


  Disappearance of species due to failure to adapt to environmental changes
• Geology


  • Branch of science that studies the Earth and its processes
• Biogeography


  • Branch of biology that studies how species spread across the planet