– means “Hades-like” (after Greek mythology)
– 4600-3800 mya (4.6 billion years ago)
– Begins with formation of the Earth from dust and gas orbiting the Sun
– Earth is covered with oceans of liquid rock, boiling sulfur, impact craters everywhere, volcanic eruptions, neverending rain of rocks and asteroids from space (just like visions of Hades)
– No air: just carbon dioxide, water vapor, sulfur and nitrogen
– 4527 mya: possibly an asteroid as big as Mars hit the Earth and broke off a piece that became our moon.
– means “Ancient” or “Primitive”
– 3800-2500 mya
– 1 billion years after the formation of the Earth.
– everything cooled down, though some volcanic eruptions are still a lot more frequent than nowadays
– Most water vapor cooled and condensed to form global ocean, but it is called “poisonous seas” – they are not livable yet
– no continents yet, but little islands appear from volcanic activity; occasionally colliding and forming larger landmasses.
– first life: probably simple, non-nucleated, single-celled algae-like tiny organisms start the photosynthesis (Prokaryotes)
– means “Early Life”
– ~700 million years ago, 2 billion years after the formation of the earth
– 2500-570 mya (lasted 2 billion years)
– In the oceans the cyanobacteria and algae appear, releasing oxygen into the air and slowly forming our atmosphere
– two supercontinents are formed by collisions of many-many little islands
– Life: ~1.7 billion years ago, single-celled creatures appeared that had nucleus (eukaryote – animals, plants, mushrooms are all later examples of eukaryote, but at this point they were limited to different forms of algae).
– 30 million years before the end of the Proterozoic: multi-celled creatures appear. They have no shells, no teeth, so fossils are really hard to find.
– Earth is very cold, with huge bluish glacial ice sheets across the supercontinent, even around equator
– 570-245 mya
– In the beginning: an explosion of life in the water: multicellular organisms develop into trilobites, shellfish, corals followed by the first fish, sharks, other underwater creatures
– Plants and insects start appearing on the land; in the end: primitive conifers, ferns spread
– often called “The Age of Invertebrates”: animals with no backbone, like shellfish, insects, spiders are most common both on land and at sea
– In the end: mysterious largest underwater extinction wiped out 90percent of marine animal species.
– 380 mya: first vertebrate land animals appear! Some amphibians can already be found.
mountains are formed on the continents
– break up of world-continent Pannotia and in the end of the period a single continent Pangaea is formed
– 245-65 mya (Triassic 245-208 mya; Jurassic 208-146 mya; Cretaceous 146-65 ya)
– means “middle animals”
– Era of the Dinosaurs
– first birds and mammals appear
– first flowers start blooming
– the climate is so warm, that there are no ice caps even on the poles!
– continent Pangaea is breaking apart.
– 65 mya to present
– means “New Life”
– Pangaea is broken into modern day continents
– climate turned colder, with giant glaciers forming in the poles, covering some North America, Eurasia, Antarctica.
– called “The Age of the Mammals”, but could be called “Age of Flowering Plants” or the “Age of Insects” or the “Age of Teleost Fish” or even “The Age of Birds”.
– Mammals rule the Earth, the seas, and share the sky with dinos distant cousins: birds
– only 2 million years ago finally appeared humans. 10,000 years ago(blink of the eye in geologic time!) they spread across the lands of the Earth.