SDSU Oceanography 100 Final Exam Questions and Correct Answers Verified

SDSU Oceanography 100 Final Exam Questions and Correct Answers Verified origin of earth - CORRECT ANSWER-• Supernova: death of a star (great explosion) • Supernova happened 4.6 bya, dust and gas flattens to a disk and spins faster due to gravity and solar nebula formed. • Solar Nebula: describes formation of Earth 4.5 bya • Nebula: gas cloud origin of oceans - CORRECT ANSWER-• volcanic explosion, H2O condensed and rained down for thousands of years to create oceans • icy comets hitting earth (responsible for 1/2 of earths ocean water) origin of life - CORRECT ANSWER-• 4.5 bya solar system formed • about 4 billion years ago bacteria (in rocks) • 2.5 bya photosynthetic organisms (algae) formed and put out O2 which lead to the development of plants which put out O2 leading to development of animals • 600 mya animals earths internal layers - CORRECT ANSWER-• lithosphere: - outermost layer of earth - first 100km of crust - strong, rigid, brittle - contains all the crust and outermost layer of the mantle • asthenosphere: - plastic, 600km - upper mantle - very hot - allows plates to move over it -ductile - directly below lithosphere • mesosphere: - lower mantle - outer core (liquid) + inner core (rigid)