L2: History of Earth BIOLOGY

• GEOLOGIC TIME SCALE

  • It is the chronological arrangement of events throughout the earth's history through radiometric dating.

  • A time line of prehistoric events.
• HADEAN- Formation of Earth and moon, core accretion, formation of magnetic field.
• Hades means Hellish
• ARCHEAN- ​Formation of atmosphere, continent began to form (Vaalbara) and ocean, rise of photosynthetic prokaryotes (atmosphere oxygenated for the first time)
• Archean Eras: Eoarchean Paleoarchean Mesoarchean Neoarchean
• Archean means Archaios (ancient)
• Proterozoic- Rapid oxygen build up (formation of ozone), oxygen crisis, rise of eukaryotic and multicellular organism
• Proterozoic Eras- Paleoproterozoic Mesoproterozoic Neoproterozoic
• Proterozoic means Proteros(earlier) Zoon (animal)
• Phanerozoic- Life diversification, experienced series of mass extinctions, most recent eon.
• Phanerozoic Eras - Paleozoic Mesozolc Cenozolc
• Phanerozoic means Phaneros (Visible)
• Paleozoic Era : 544-250 Million
• Mesozoic: 250-65 Million
• Cenozoic Era: 65 Million to Present
• Algae means plants
• Chytrid means fungi
• Protozoa means animals
• PALEOZOIC ERA - Age of "ancient life" (Popular name: Age of Invertebrates) Palaios - old; Zoon → animal
• Cambrian Period: Rapid diversifications of invertebrates - "Cambrian Explosion"

  Algae blooms - "Age of Algae"
• Ordovician Period: Appearance of first vertebrates (fish)

  First Mass Extinction event, 85% of marine life died
• Silurian Period: Land invasion of algae, appearance of insects crawlers in land.
• Devonian Period: Age of Fish and appearance of amphibians

  Second Mass Extinction event, 80% of marine life died
• Carboniferous Period: Coal formation, rise of reptiles, seed plants, flying insects appears.
• Permian Period: Pangea forms

  Third Mass extinction (The Great Dying), 96% of organisms died
• 245 Million Years Ago Pangaea existed when some of the earliest dinosaurs were roaming the Earth. It was surrounded by a sea called Panthalassa, meaning "all sea"
• 180 Million Years Ago Gradually Pangaea broke into two big pieces. The northem piece is called Laurasia. The southern piece is called Gondwana
• 65 Million Years Ago By the time the dinosaurs became extinct, Laurasia and Gondwana had split into smaller pieces.
• Common Organisms that lived during Paleozoic Era are Stromatolites, Trilobites and Brachiopods. Also, Variety of bony (armored) and predatory fishes.
• MESOZOIC ERA - Age of "Middle life" (Popular name: Age of Reptile) Mesos - middle; Zoon → animal
• Triassic Period: First land dinosaur and mammals appears (small in size)

  Fish like reptiles appears, Gymnosperms appear

  Fourth mass extinction, 76% of species died (Pangea breaks apart)
• Jurassic Period: Bird like reptiles appears

  Golden Age of Dinosaurs (large reptiles dominates both air, land and water regions)
• Cretaceous Period: ​Angiosperms evolved, first primates appear

  Fifth mass extinction (K-T Mass extinction), 76% of species died
• Common organisms that lived during Mesozoic Era

  PROCONSUL - Artcestor to Hominids
• Monkey- ​fiat palms and soles arched vertebral column limbs equal in length narrow rib cage shoulder blades parallel Immobile shoulder joint
• K-T Extinction: K-Abbreviation for Cretaceous Period, derived from the German name Kreidezeit; T- Abbreviation for the Tertiary Period.

  : K-T boundary sedimentary band all over the world has iridium ranging from 20- 160 times normal amount.; Iridium is rare in Earth's crust, but abundant in asteroids/comets

  : Chixiclub crater - impact site, located at Mexico
• CENOZOIC ERA - Age of "Recent life" (Popular name: Age of Mammals) Kainos-new; Zoon → animal
• Tertiary Period:

  Paleogene- Reign of Mammals

  Epoch: Paleocene (Palaios- old) Eocene ( Eos- dawn) ​Oligocene (Oligo- few)

  Large diversification of mammalian species.
• Tertiary Period:

  Neogene- Appearance of Man

  Epoch: ​Miocene (Meios- less) Pliocene (Pleios- more)

  Hominids develop
• Tertiary Period has two Periods Paleogene and Neogene