3. 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.

4. 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.

5. 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.)

6. The First Cells Prokaryotic cells: Cells without a membrane- bound 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

7. 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.

8. 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

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

10. 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.

11. Phanerozoic Eon 543 mya to present Paleozoic Era – 543 to 251 mya –O–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. –S–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.

12. 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

13. 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.

14. Phanerozoic Eon 543 mya to present Paleozoic Era – 543 to 251 mya – Permian Period – 299 to 251 mya Formation of the supercontinent Pangea, 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.

15. 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

16. 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. 166 mya: split between marsupial and eutharian mammals. 150 mya: First birds (archaeopteryx) appear

17. 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.

18. Phanerozoic Eon 543 mya to present Cenozoic Era – 65 mya to today – Tertiary period – 65to 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.

19. Phanerozoic Eon 543 mya to present Cenozoic Era – 65 mya to today – Tertiary period – 65to 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.

20. Phanerozoic Eon 543 mya to present Cenozoic Era – 65 mya to today – Tertiary period – 65to 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

21. Phanerozoic Eon 543 mya to present 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

22. Phanerozoic Eon 543 mya to present Cenozoic Era – 65 mya to today – Quaternary Period – 1.8 mya to today Holocene Epoch – 11,600ya 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 – 2,230 ya: Archimedes advances mathematics – 2,000 ya: Christian Era – 250 ya: industrialization – 50 ya: Space Travel