Chapter 1 - Earth Syst.ppt - University of Ari..PPT

* * * * * * * * * * * * * * * * * * * * Sun The Sun drives Earth’s external engine. Solar energy is responsible for our climate and weather. Earth’s internal engine is powered by trapped heat… Sun The Sun drives Earth’s external engine. Solar energy is responsible for our climate and weather. Earth’s internal engine is powered by trapped heat… …and radioactivity in its interior. Sun The Sun drives Earth’s external engine. Solar energy is responsible for our climate and weather. Earth’s internal engine is powered by trapped heat… …and radioactivity in its interior. Heat radiating from Earth balances solar input and heat from interior. Sun The Sun drives Earth’s external engine. Solar energy is responsible for our climate and weather. Earth’s internal engine is powered by trapped heat… …and radioactivity in its interior. Heat radiating from Earth balances solar input and heat from interior. Meteors move mass from the cosmos to Earth. 6. Overview of Geologic Time 6. Overview of Geologic Time 4.6 billion years ago – formation of solar system 3.5 billion years ago – formation of geodynamo; first known fossils (bacteria) 2.7 billion years ago – oxygen begins to build up in atmosphere 2.5 billion years ago – large continents in crust 2.0 to 1.0 billion years ago – more complex life like algae evolved 6. Overview of Geologic Time 6. Overview of Geologic Time 600 million years ago – first animals 542 million years ago – evolutionary “big bang” 443 million years ago – first mass extinction of life 420 million years ago – first land mammals 359, 251, and 200 million years ago – mass extinctions of life 125 million years ago – first flowering plants 6. Overview of Geologic Time 65 million years ago – last mass extinction (death of the dinosaurs and many other species) 5 million years ago – appearance of first hominids 200,000 years ago – appearance of Homo sapiens 6. Overview of Geologic Time Asthenosphere Climate Climate system Convection Core