BIOL 215 Midterm: BIOL 215 Notes for Midterm.doc

• School: McGill University
• Department: Biology
• Course: BIOL 215
• Professor: Catherine Potvin

Document Summary

2. 5-2. 0 bya change from anoxygenic to oxygenic environment. This reaction yielded lots of energy, which created a dense core forming elements to iron while burning. Once the core is composed largely of iron the protostars stop burning. It had consumed most of the fuel (h and he) once fuel is exhausted the protostar explodes to form a supernova releasing all of the elements into space as hot gases. Planets around the sun form from gradual accumulation of solid matter called planetisismals". Earth was initially molten and composed of largely fe, mg, si and o. Crust forms 4. 2-4. 1 bya as earth cools elements and frozen gases) Meteors and comets bombard earth 4. 5-3. 8 bya supplying lighter. Earth forms fossils crust forms comets & meteors oldest. Generated by volcanic out-gassing (80%) and impact bodies (20%) Co2 (100-1000 x greater than present) n2, h20. No free o2 in atmosphere initially important since 02 would have prevented the build-up of organic molecules.