Formation of the Earth Earth was formed approx

Formation of the Earth • Earth was formed approx. 4. 54 billion years ago out of the solar nebula. • Initially molten, the outer layer cooled to form a crust about 4. 3 B. Y. A. as water was brought to Earth by meteors. • By 3. 9 B. Y. A. Earth had cooled enough to form oceans.

Formation of the Earth • Out gassing and volcanic activity produced the primordial atmosphere consisting of water vapor, carbon dioxide, hydrogen, ammonia, methane, and other gasses. • The primordial ocean was most likely made up of water, with methane, ammonia, hydrogen, sulfur, and carbon dioxide. • No free oxygen in the atmosphere or oceans at this time.

First Life on Earth • Life – metabolism and reproduction, growth and response to stimuli (adaptation). • Proto-cells: cell-like spheroid formed from proteinoids (chained groups of amino acids). – Proto-cells containing RNA may have been the first cellular life forms on Earth. (3. 8 B. Y. A. )

The First Cells • Prokaryotic cells: Cells without a membranebound nucleus. (3. 5 - 2. 5 B. Y. A. ) – First autotrophs, blue-green algae. (supplied the first oxygen to the atmosphere) – Genetic material is in a circular loop called a plasmid

The First Cells • Eukaryotic cells: cells with a membrane-enclosed nucleus. – Developed approx. 2 billion years ago – Include all complex cells and make up all multi-cellular organisms. • Animals, plants, fungi, and protists are eukaryotes.

Precambrian • Proterozoic Eon – 2500 to 543 mya – Paleoproterozoic Era – 2500 to 1600 mya • Stable continents • 2400 – 2100: Huronian ice age – Mesoproterozoic Era – 1600 to 900 mya • • • Formation of supercontinent Rodinia Eukaryotic cells appear 1200 mya: spore/gamete formation (sexual reproduction) Photosynthetic organisms proliferate, oxygen above 10% Formation of the ozone layer 950 mya: start of Stuartian-Varangian ice age

Precambrian • Proterozoic Eon – 2500 to 543 mya – Neoproterozoic Era – 900 to 643 mya • Earth day is 18 hours long • Formation of a supercontinent Pangea – Cryogenian Period – 850 to 635 mya • 750 mya: End of last magnetic reversal • 650 mya: mass extinction of 70% of dominant sea plants.

Phanerozoic Eon 543 mya to present • Paleozoic Era – 543 to 251 mya – Vendian (Ediacaran) Period – 635 to 543 mya • 570 mya: end of Stuartian-Varangian ice age • Soft-bodied organisms developed, first jellyfish – Cambrian Period – 543 to 490 mya • Most of the major groups of animals first appear. • 530 mya: Animals with shells appeared.

Phanerozoic Eon • Paleozoic Era – 543 to 251 mya – Ordovician Period – 490 to 443 mya • Diverse marine invertebrates, first vertebrates appear, first green plants and fungi on land • 450 mya: start of Andean-Saharan ice age • 443 mya mass extinction of many marine invertebrates. – Silurian Period – 433 to 417 mya • End of Adean-Saharan ice age, stabilization of Earth’s climate • Coral reefs appeared, first fish with jaws, spiders, centipedes and plants appear on land.

Phanerozoic Eon 543 mya to present • Paleozoic Era – 543 to 251 mya – Devonian Period – 417 to 354 mya • • • Ferns and seed-bearing plants appeared, first amphibians Wingless insects and vertebrates appear on land Pannotia fragmented into Laurasia and Gondwana Atmospheric oxygen level about 16% 374 mya: mass extinction of 70% of marine species

Phanerozoic Eon 543 mya to present • Paleozoic Era – 543 to 251 mya – Carboniferous Period – 354 to 299 mya • Mississippian Epoch – 354 to 318 mya – Karoo ice age, large primitive trees, vertebrates appear on land, first winged insects • Pennsylvanian Epoch – 318 to 299 mya – First reptiles, atmospheric oxygen over 30%, giant arthropods, deposits of coal form in Europe and Asia.

Phanerozoic Eon 543 mya to present • Paleozoic Era – 543 to 251 mya – Permian Period – 299 to 251 mya • • • Formation of the supercontinent Pangaea, Earth is cold and dry Conifers appear 260 mya: end of Karoo ice age Oxygen levels drop from 30% to 12% 251 mya: Great Permian-Triassic mass extinction – 90% of ocean dwellers and 70% of land plants and animals.

Phanerozoic Eon 543 mya to present • Mesozoic Era – 251 to 65 mya – Triassic Period – 251 to 200 mya • Breakup of Pangea • First dinosaurs appear, first evidence of mammals • 201 mya: mass extinction 20% of marine animals

Phanerozoic Eon 543 mya to present • Mesozoic Era – 251 to 65 mya – Jurassic Period – 200 to 145 mya • • Earth is warm – no polar ice Age of the dinosaurs: giant herbivores and vicious carnivores. North America splits from Europe. 150 mya: First birds (archaeopteryx) appear

Phanerozoic Eon 543 mya to present • Mesozoic Era – 251 to 65 mya – Cretaceous Period – 145 to 65 mya • Africa and India split from Antarctica, South America splits from Africa • Flowering plants, crocodiles appear, modern mammals and birds developed. • 70 mya: T-Rex thrived • 65 mya: Meteor impact, Yucatan, Mexico – mass extinction of dinosaurs.

Phanerozoic Eon 543 mya to present • Cenozoic Era – 65 mya to today – Tertiary period – 65 to 1. 8 mya • Paleocene Epoch – 65 to 54. 8 mya – Appearance of placental animals – Formation of Rocky Mtns, major global warming Eocene Epoch – 54. 8 to 33. 7 mya India and Asia collide forming the Himalayas, Australia separates from Antarctica. Small modern mammals appear.

Phanerozoic Eon • Cenozoic Era – 65 mya to today – Tertiary period – 65 to 1. 8 mya • Oligocene Epoch – 33. 7 to 23. 8 mya – Start of Pleistocene ice age – Appearance of grasses, elephants, camels, early horses. • Miocene Epoch – 23. 8 to 5. 3 mya – The plants and animals of the Miocene were fairly modern. – Mammals and birds were well-established. Whales, seals, and kelp spread.

Phanerozoic Eon 543 mya to present • Cenozoic Era – 65 mya to today – Tertiary period – 65 to 1. 8 mya • Pliocene Epoch – 5. 3 to 1. 8 mya – Accumulation of ice at the poles – Spread of grasslands, rise of long-legged grazing animals – 2. 4 mya: Homo habilis appears, tool making humanoids

Phanerozoic Eon • Cenozoic Era – 65 mya to today – Quaternary Period – 1. 8 mya to today • Pleistocene Epoch – 1. 8 mya to 10, 000 yrs ago – Homo erectus moves out of Africa – Presence of large land mammals and birds – Global cooling and glaciation – Neanderthals – 500, 000 yrs ago – Homo sapiens – 200, 000 yrs ago

Phanerozoic Eon • Cenozoic Era – 65 mya to today – Quaternary Period – 1. 8 mya to today • Holocene Epoch – 11, 600 ya to today – Development of agriculture and domestication of animals. – 9, 000 ya: metal smelting – 5, 500 ya: wheel – 5, 000 ya: writing – 4, 500 ya: Pyramids – 2, 000 ya: Christian Era – 250 ya: industrialization – 50 ya: Space Travel