1 / 20

Earth’s History

Earth’s History. 4 Eras of Geologic Time. 4 Eras of Geologic Time. Precambrian Paleozoic Mesozoic Cenozoic. Precambrian Events. The earth’s crust formed The atmosphere formed The ocean’s formed First life forms developed. The earth’s crust.

hiero
Download Presentation

Earth’s History

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Earth’s History 4 Eras of Geologic Time

  2. 4 Eras of Geologic Time • Precambrian • Paleozoic • Mesozoic • Cenozoic

  3. Precambrian Events • The earth’s crust formed • The atmosphere formed • The ocean’s formed • First life forms developed

  4. The earth’s crust • The earth was very hot from its formation (The nebular theory) • It cooled from the outside • As it cooled, the earth’s crust formed and cracked to form plates

  5. An atmosphere developed • Volcanic activity was very common as the crust formed and cracked • CO2 and Nitrogen • H20 vapor • Methane, ammonia, and sulfur dioxides

  6. Earth’s atmosphere Earth has an atmosphere for 3 reasons • Volcanic history • Mass of the planet • Amount of radiation from the sun

  7. The oceans formed • As the earth continued to cool, the water vapor in the atmosphere condensed and fell as rain. • This water formed the oceans, rivers, lakes, streams, and underground water ways.

  8. What were the conditions on the early earth? • Intense volcanic activity • Warm, shallow seas • Turbulent atmosphere • Lots of lightning • Lots of storms

  9. How did life form on this planet? • Life originated on this planet • Life was seeded here by • A comet carrying carbon compounds • An asteroid carrying single-celled life forms

  10. What did the first organisms on earth look like? • The oldest fossils of life on this planet are • Bacteria • Blue Green algae

  11. Bacteria • Single-celled life forms • No true nucleus or organelles (prokaryotes) • Very hardy and resistant to extreme conditions • Many species do not need oxygen

  12. Blue Green Algae • Single celled organisms • Prokaryotes • Able to photosynthesize—use CO2 and H2O to produce glucose (food) and O2 • Put tons of oxygen into atmosphere

  13. Oxygen in the atmosphere • Toxic to many forms of bacteria • Changed our atmospheric makeup by adding ozone to the earth’s atmospheric makeup • O2 is converted to O3 (ozone) by lightning

  14. What happens to early life forms? • In order to survive they must adapt to using oxygen • Single-celled organisms that have well-defined nuclei develop (eukaryotes) • Multicellular algal forms develop (first plants)

  15. Paleozoic—Age of Fishes • “Paleo”—means early and –”zoic” means animals • Life “exploded” on the planet • Many marine life forms developed • Plants and animals move onto land • Small wetlands plants and simple insects • Amphibians developed • Atlantic ocean begins to develop and continents begin to move apart

  16. Mesozoic—Age of Reptiles • “Meso” means middle “-zoic” means animals • All continents joined together at the beginning of this era, but begins to break apart • Animals—dinosaurs evolve and become extinct • Plants—ferns the predominant plant form—flowering plants evolve

  17. Cenozoic—Age of Mammals • “Ceno” means recent “-zoic” means animals • Mammals evolve and flourish • Humans and human civilizations develop

More Related