ISB 202 1nd Edition Lecture 8Outline of Last Lecture I. EcosystemsOutline of Current Lecture II. Food Chains and Food WebsIII. Energy FlowIV. Material CyclesCurrent LectureFood Chains and Food Webs- Food Chain - linked feeding series - Food Web - Most consumers have multiple food sources.Energy Flow- 1st Law of Thermodynamicso Energy can neither be created or destroyed, it can only be converted from one form to another.- 2nd Law of Thermodynamicso No energy conversion is 100% efficient. In any conversion there is a net loss of energy.Material Cycles- Hydrologic Cycle - path of water through the environmento Solar energy continually evaporates water stored in the oceans and land and Transpiration from plants –Together Evapotranspiration This process distributes water vapor around the globe Condenses over land surfaces, supporting all terrestrial systems- Responsible for cellular metabolism, nutrient flow in ecosystems, and global distribution of heat and energyWhat ultimately drives the water cycle?1. GravityThese 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.2. Sun3. Evaporation4. Wind5. Plate TectonicsNitrogen Cycle- Nitrogen re-enters the environment:o Death of organismso Excrement and urinary wastes- Nitrogen re-enters atmosphere when denitrifying bacteria break down nitrates into N2 and nitrous oxide (N2O) gases.o Humans have profoundly altered the nitrogen cycle via use of synthetic fertilizers, nitrogen-fixing crops, and fossil fuels.Nitrogen Fertilizer-Pros and Cons- Proso Resulted in feeding 1/3 the world’s populationo Compounds used in manufacturing of pharmaceuticals- Conso Explosiveso Poison GasPhosphorous Cycle- Phosphorous is needed to make DNA, ATP (the energy currency of the cell) and other important biomolecules (Chap. 2).- Phosphorous compounds are leached from rocks and minerals and usually transported in aqueous form.o Taken in and incorporated by producers Passed on to consumers- Returned to environment by decomposition- Cycle takes a long time as deep ocean sediments are significant sinksCarbon Cycle- Begins with intake of CO2 during photosynthesis and ends with release of C through respiration. - 6H20+6CO2 + solar energy = C6H12O6+6O2o C6H12O6 + 6O2 = 6H2O +6CO2 + energy- Sometimes the carbon is not recycled for a long time. Coal and oil are the remains of organisms that lived millions of years ago. The carbon in these is released when we burn them. Some carbon is also locked in calcium carbonate (shells, limestone).Respiration Revisited- Aerobic Respirationo In the presence of oxygeno Produces CO2o Heat is a “waste” product- Anaerobic Respiration (Fermentation)o In the absence of oxygeno Produces other gases Methane (CH4)o Heat is a “waste” productCarbon Cycle The parts of the cycle that remove carbon dioxide from the atmosphere (vegetation) are called carbon sinks. The parts of the cycle that release carbon dioxide are called carbon sources. Burning of fuels generates huge quantities of carbon dioxide that cannot be taken up fast enough by the carbon sinks. This excess carbon dioxide contributes to global
View Full Document
Unlocking...