Evolution of the atmosphere 0.0 / 5 ? ChemistryEvolution of the atmosphereGCSEEdexcel Created by: Hannah16.12Created on: 02-10-15 16:16 Phase 1-Volcanoes gave out gases The earth's surface was orginally molten Its was so hot that any atmosphere boiled away When things eventually cooled down a thin crust formed However volcanoes continued to erupt The volcanoes gave out lots of gases The main ones are; carbon dioxide and water vapour However there was also small amounts of other gases too According to this theory, the early atmosphere was mainly Carbon dioxide There was barely any oxygen It was like the atmosphere of Mars and Venus today The oceans were formed when the water vapour condensed 1 of 3 Phase 2- green plants evolved and produced oxygen A lot of the carbon dioxide dissolved into the ocean Later, when the marine organisms evolved, they absorbed some of the carbon dioxide When they died they were buried under layers of sediment and carbon dioxide They became locked up in carbonate rocks Green plants evolved over most of the earth They were happy The green plants removed the carbon dioxide and replaced it with oxygen They did using photosynthesis This caused the oxgen levels to gradually increase 2 of 3 Phase 3- ozone layer allows evolution of complex a The increase of oxgen killed some of the early organisms that couldnt take it However it allowed other, more complex organisms, to evolve and grow healthily The oxygen created the ozone layer The ozone layer blocks harmful rays from the sun It also allows more complex organisms to evolve There isnt much carbon dioxide left now 3 of 3
Comments
No comments have yet been made