Timeline of Earth's History

• Plate tectonics active during this period
• 125mya: emergence of angiosperms (flowers, global warming, rise in carbon dioxide levels
• 110mya: crocodiles emerge
• 90mya: global warming ends
• 65.5mya: MASS EXTINCTION: Large meteor impact in Mexico + excessive volcanic activity kill 80-90% of marine species and 85% of land - dinos extinct

• 'Age of dinosaurs'
• Warm earth w/ no polar ice, suited for dinos
• Mammals mostly confined and small, hunted by dinos
• giant herbivores and vicious carnivores are dominant
• 166mya: evolutionary split between primitive mammals and monotremes
• 150mya: first birds such as archaeopteryx
• 148mya: evolutionary split between marsupials and eutharians

-Pangea begins to break up
- Repopulation of earth by survivors of PT extinction
- Reptiles become dominant on land
- 240mya: sea-urchins appear
- 235mya: evolutionary split between dinosaurs and lizards
- First small dinosaurs emerge e.g. coelophysis
- 225mya: Adelobasileus proto-mammal emerged
- 205mya: first true mammals emerge
- 201mya: volcanism results in MASS EXTINCTION of 20% of all marine families

• 275mya: formation of Pangea supercontinent
• Conifers and cycads appear
• Cold, dry earth
• 260mya: end of Karoo ice age
• 251mya: MASS EXTINCTION: permian-triassic: Earth's temp. increases, intense volcanism in Siberia 90% of oceanic and 70% of terrestrial flora/fauna extinct

• ferns+seed-bearing plants emerge, first forests are formed
• 400mya: terrestrial animals emerge along with wingless insects
• Vertebrates with primitive legs emerge (e.g. Tiktaalik, a lobe-finned fish which was a transition between aquatic and terrestrial life)
• First amphibians emerge
  
• 374mya: MASS EXTINCTION: 70% of marine species over 20 million years - anoxia (depletion of oxygen) at depth in ocean, drop in temp.
• 270mya: First trees appear
  

• 420mya: end of Andean-Saharan ice age and eventual stabilization of climate
• terrestrial and marine plants reappear
• first fish with jaws (sharks)
• Insects (arachnids and centipedes)and plants appear on land

• marine invertebrates become common e.g. Trilobites
• photosynthetic green plants/fungi emerge on land for first time
• 443mya: MASS EXTINCTION of marine invertebrates: 2nd largest, due to Andean-Saharan ice age (450)and glaciation of Gondwana, 49% of genera of fauna dissappear
  

• 542mya: 'Cambrian explosion'; emergence and diversification of organisms
• Most major groups of multicellular organisms emerge during this period of abundance of multicellular life

• 580mya: soft-bodied organisms emerge inc. Jellyfish, Tribrachidium, and Dickinsonia
• 570mya: shelled invertebrates emerge at end of Stuartian-Varangian ice age

• 650mya: MASS EXTINCTION: 70% of marine flora dies because of global glaciation (cooling)

• 1000mya: Multicellular organisms emerge

• 1100mya: Supercontinent Rodinia forms

• Photosynthetic life proliferates
• 1500mya: Eukaryotic cells emerge (cells with nucleus)

• Complex single-celled life emerges (1800-1600mya)

• 2200mya: organisms with mitochondria (aerobic respirators) emerge
• 2100mya: Huronian Ice Age ends

• Stable continents appear
• 2500mya: free oxygen appears in atmosphere and oceans
• 2400mya: Oxygen Catastrophe - Anaerobic organisms die out due to increased oxidation, banded iron formations created -2400mya: Huronian Ice Age starts

• Episodes of major global cooling
• Hominids develop
• 370,000ya: Human ancestors diverge with neanderthals
• 160,000ya: Homo Sapiens emerge
• 12,900ya: Comet explodes over Canada, American Megafauna made extinct

• 14mya: Warmer global climate leads to drying of continental interiors and formation of grassland in place of forest
• 6mya: upright walking (bipedal) hominins emerge

• 50 mya: India collides with Asia, Himalayas formed
• 45 mya: Australia separates from Antarctica
• 45mya: modern mammals e.g. rhino, camel, horse appear
• 34mya: global cooling forms permanent polar ice caps

• 55.8mya: major global warming

• 300mya: first reptiles
• Giant anthropods (w/ exoskeletons like crustacean, arachnid, insect) populate the land

• Increased atmospheric oxygen
• First land vertebrates appear
• First winged insects
• Amniote eggs (eggs enclosed by a shell) appear

• 510mya: oceanic vertebrates emerge