Biology 2601A/B Lecture Notes - Lecture 4: Carbanion, Chloroplast, Triose
27 Oct 2014
School
Department
Course
Professor
Document Summary
Photosynthesis: most important biological process on earth. All of the oxygen on earth arose due to photosynthesis: we can see a global pattern of vegetation that affects atmospheric co2 concentrations on an annual scale. Large amounts of vegetation in the summer/fall draw down co2 through photosynthesis, thus altering the atmospheric concentration of co2. In the spring/winter, the vegetation is yet to become active. Thus, we have higher co2 concentrations (annual cycle-figure). Figure: co2 concentrations over time at the top of. Over time, we see rising levels of co2 (associated with climate change and increasing atmospheric temperatures): photosynthesis is extremely important for food security. Figure: decadal changes in rice yield for the three largest producing countries in the world. 1970s, there was a 15-40% yield increase compared to the previous 10 years (thanks to the green revolution). Those gains have now disappeared, and we worry that we will run out of food by 2050.
