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44 Cards in this Set
- Front
- Back
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Ecosystems:
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Take into account the biological community and its interactions with the abiotic world.
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Nutrients:
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Are extracellular components that supply:
- energy (sunlight, chemical energy) - bioelements (C, N, P - build the cell itself) - electrons (for biochemical reactions) - terminal eletron acceptors to a cell (oxygen) |
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Biogeochemical cycling:
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Recycling component. Energy is in the bonds of organic matter.
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Primary Production (Autotrophy):
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Using energy from sunlight/chemical energy to fix CO2 into organic matter.
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Primary Production:
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Primary process for the input of energy to the food web, and part of the carbon biogeochemical cycle.
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Oxygenic Photosynthesis:
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12H20 + 6CO2 + ENERGY -> C6H12O6 + 6H20 + 602.
Oxygen as a waste product. |
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Aerobic Respiration:
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C6H12O6 + 6O2 -> 6CO2 + 6H20 + ENERGY
CO2 as a waste product. |
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Standing crop (biomass):
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Grams of carbon.
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Gross Primary Production/Productivity (GPP):
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Amount of new carbon fixed per unit time.
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Net Primary Production/Productivity (NPP):
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GPP - Carbon lost due to respiration per unit time.
RESPIRATION CONSUMERS ~ 1/2 OF GPP. |
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Carbon fixation is also known as:
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Photosynthesis.
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Primary place where photosynthesis occurs:
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The ocean (Synecoccocus + Prochbrococcus). The rate is slower than on land, but a greater surface area.
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Efficiency of plants in converting light to primary production is due to:
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- Latitude
- Cloudiness, dust and water in the atmosphere - Leaf area and arrangement - Concentration of CO2. |
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Harvest Method (How primary production is measured) :
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Measure the biomass between two points in time, then converted into units of energy using a bomb calorimeter.
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Carbon Dioxide Consumption/Oxygen Evolution (How primary production is measured) :
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Cover plants with a transparent chamber and measure gas concentrations.
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Isotope Analyses (How primary production is measured) :
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Cover plants with a transparent chamber, introduce C14, harvest the plants, and measure the amount incorporated into the biomass (it will glow!)
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Light Use Efficiency:
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NPP (GPP - amount of carbon lost due to respiration)/ absorbed photosynthetically active radiation.
- PAR = amount of energy available to have been used. |
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Sample water from Depths (measuring primary productivity in aquatic systems):
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Take two bottles, one light (photosynthesis + respiration), and one dark (respiration only) and suspend at various depths.
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Isotope Analyses (measuring primary productivity in aquatic systems):
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Put HCO3- and measure incorporation into the biomass.
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Oxygen Consumption (measuring primary productivity in aquatic systems):
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Measure oxygen consumption over a time period.
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What factors limit productivity in aquatic systems?
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Light intensity and temperature
- water attenuates intensity and wavelengths of light - rate of photosynthesis decreases with depth - temperature decreases with depth, confounding the lights effects |
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What mineral nutrient limits primary productivity in open ocean waters?
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Iron! N + P are still important, iron is just ran out of first, so it is the limiting resource.
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What mineral nutrient limits primary productivity near the shores?
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Nitrogen! Limiting Resource.
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Liebig's Law of the Minimum:
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At some point, different nutrients will limit productivity if others are in excess.
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What mineral nutrient limits primary productivity in freshwaters?
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Phosphorus! Far more nitrogen available, so it will not run out first.
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Eutrophic:
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Possessing high nutrient levels.
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Oligotrophic:
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Possessing low nutrient levels.
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Eutrophication:
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Process of increasing nutrient levels (usually by human activity.)
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Ratio of Nitrogen:Phosphorus influences:
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Competition and community composition.
EXAMPLE: Blue-green algae - photosynthesis under intense light, likes warmer waters, and protection against UV. |
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What factors limit productivity in terrestrial systems?
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Temperature, moisture, and light.
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Tropical jungles:
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Are light limited.
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Australia/Africa:
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Are water limited.
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Northern Regions:
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Are temperature limited.
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Evapotransporation (solar radiation, temperature, and rainfall) :
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Used to predict above ground biomass (potential primary productivity)
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What nutrients limit productivity in terrestrial systems?
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Nitrogen and Phosphorus - need these to build cells (phospholipids, nucleic acids, and proteins)
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Synergistic Effect
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Enhance productivity with BOTH nutrients, greater than the single thing alone. EXAMPLE: nitrogen + phosphorus
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Secondary Production (Heterotrophy):
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Only uses a fraction of the energy derived from the lower trophic levels.
- Energy not used is lost as heat. |
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Secondary Production can be measured by:
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Growth and reproduction.
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What are the problems with estimating secondary production:
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1) Individuals do not fit into discrete trophic levels.
2) Detritus can be derived/eaten by many different trophic levels. |
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How to estimate secondary production for a species:
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1) Construct from a life table
- measure growth of individuals (death - decreases biomass, birth - increases biomass) |
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What limits secondary production?
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Primary production because only a fraction of energy is passed on from trophic level to trophic level.
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Trophic Efficiency:
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Net Production of Trophic Level(i+1)/
Net Production of Trophic Level(i) |
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Eltonian pyramid/Pyramid of Biomass/Pyramid of Numbers:
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Organisms at the base of the food web are more abundant than those at higher trophic levels.
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Biomagnification:
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- When pollutant is taken in by an organism, it is stored in their fat
- The next trophic level will then feed on the organism with the pollutant, resulting in that organism now accumulating the pollutant. |
