BIOEE 1610 1st Edition Lecture 2 Outline of Last Lecture I. NewsII. ConditionsA) TemperatureB) SalinityOutline of Current Lecture I. EnergyII. PhotosynthesisA) Light reactionB) Dark reactionIII. Resources for photosynthesisA) Lighta. Phytoplanktonb. Land plantsc. C-4d. CAMB) Carbon dioxideIV. Animal resourcesCurrent LectureI. Energy*2nd law of thermodynamics: Increase in entropy over time, but only if you don’t add energy from the outside*Organisms are highly ordered systems… therefor they need energy to maintain it*Autotrophs: Organisms that create their own energy, usually through photosynthesis*Heterotrophs: Must consume other organisms to gain energyII. Photosynthesis*CO2 + H20 + light  organic matter + O2*Question: Photosynthesis always generates O2 and consumes CO2-Answer: FALSE!-There are other alternatives*Cyanobacteria: “blue-green algae”, photosynthetic bacteriaThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.*Photosynthesis in eukaryotes evolved from “engulfing” cyanobacteria*Chloroplast: organelles that undergo photosynthesisA) Light reaction*2H2O + 2NADP + 2ADP + 2P  2NADPH + 2ATP + O2*Uses light energy to split waterB) Dark reaction*CO2 + RuBP  2 x (C-3 sugar) [arrow represents Rubisco]*Rubisco makes up 25% of the total protein and nitrogen in leaves*On land, photosynthesis is greatest in the tropics*Photosynthesis in the oceans is greater at higher altitudesIII. RESOURCES for photosynthesisA) Light*Photosynthesis increases as light increases… to a point*Light penetrates farther in the open ocean than coastal watersa) Phytoplankton*Phytoplankton take up CO2 across the cell surface*When nutrients are low, small cells are favored (higher surface : volume ratio)*When nutrients are high, large cells are favored (more chlorophyll : volume)*A large part of phytoplankton are chlorophyll and Rubiscob) Land plants*Water far more scarce*Transpiration: evaporation of water from leaf interior when stomata are open*Fundamental tradeoff between obtaining CO2 and losing water… not a problem if water is abundant, but must make adaptations if water isscarce*In this case, they may undergo C-4 photosynthesis (evolved to deal with photorespiration, but also benefits plants in low water)c)C-4*C-4 plants reduce photorespiration by:1) using a different enzyme than Rubisco initially2) moving products to cell without a light cycle and use Rubisco there*C-4 plants evolved relatively recently*3% of plants are C-4, but 30% of photosynthesis on land is done by themAtmospheric CO2 concentration C-3 favoredC-4 favoredDaytime temperature*Why are most common C-4 plants grasses found in warm regions?-They are more competitive in warm areas because C-3 plants have to close their stomatad) CAM*Open stomata at night and store carbon in acid*Close stomata during the day to do photosynthesisB) Carbon dioxide*There is an overall increase in CO2 globally…. Does this make a difference for photosynthesis? -Quite often higher CO2 means higher photosynthesis, but not by more than 10% in agricultural situations, higher in forests-Why? IV. Animal resources*If an animal eats another animal, they’ll get more carbon than nitrogen*If an animal eats a plant, they’ll get more nitrogen than