Review: ● There is a cycle going on. ● Sun is source of energy. ● Evolution is selfish. ● Species compete and die out, win/lose. ● But also speciation > creates new species.● why? ○ ex: the warbler birds, perhaps worms, types of food, climate.○ ex: humans have specialization within medicine > doctors > anesthesiologist○ complexity increasesThermodynamics● thermodynamics drives abiotic and biotic activities of ecosystem● change*FreeEnergy = change*Enthalpy - t*change*Entropy○ change is delta○ Enthalpy is heat change○ Entropy is amount of organization (ie. high entropy is highly organized)● Free Energy < 0○ = free energy change must be negative in order for work to be done.Energy Forms● Intensive vs. Extensive Parameters● Intensive - doesn’t depend on size● Extensive - depends on size of matterPressure Volume P*VTemperature Entropy T*EVoltage Change V*CChemical potential # of particles u*Mex: Humans say GDP is going up, but they aren’t taking into account the # of populations, therefore it’s not as high as they say it is.GDP/population > per capitaLaws & Application of Ecosystems **Important Info**● the elemental composition of life is constant● ex: plants and animals have same ratios of C112H224O112N16P○ carbon, nitrogen, hydrogen, phosphorus● Elemental cycles clearly indicate closed system of elemental recycling● Liebig’s Law - looking at one most limiting factor (light, temp, nutrients) will help determine the work to be done.● b/c ecosystems are so complex, it’s not easy to determine exactly● as you use energy, you lose some of it.Joseph Priestley (1733-1804)● first experiments in photosynthesis● realized air was composed of more than a void● use closed system > with bell jar, water, candle vs. rat vs. plant● discovered oxygen and carbon essentially.● then used ice > candle burnt and ice melted were same amount.● in good ecosystems, rates of respiration generally equal. or photosynthesis exceeds respiration● Q: so what determines productivity of a region?○ ex: Desert - low water○ Tundra - low water, low heat, low sunlight● Graph: divide earth’s regions based on precipitation and temperature● Graph: it takes more energy to keep a small animal alive (per unit per mass) than it doesa large animal● Video: How Wolves Change Rivers - by Sustainable Human○ Trophic Cascades■ ex: regenerating forests stabilized soil which focused
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