LIFESCI 1 Lecture Notes - Lecture 10: Stoma, Heterotroph, Decomposer
Document Summary
Long-term records of co2 fluctuation: all through past 1000 years, co2 hasn"t changed much before industrial. Revolution: but 400,000 year record = co2 levels in air can change substantially over time, vostok = antarctic ice sheet shows that 20,000 years ago, co2 levels were only at. Atmospheric co2 oscillated from 180-285ppm for at least 400,000 years. Natural variations in carbon cycle can be large: temperature and co2 = direct relationship (also ice sheets growth/decay = direct) Greenhouse gases = allows incoming solar radiation to reach earth"s surface, but traps heat that is remitted from land and sea. 20,000 years ago, thick ice sheets expanded in northern and southern hemispheres. Now= interglacial interval = climate is relatively mild. Estimate that co2 levels for earlier intervals of earth"s history = measure chemical and paleontological features of ancient rocks that are thought to reflect co2 at time of formation.
