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38 Cards in this Set
- Front
- Back
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autotrophs
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produce own food
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biophages
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consumers
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Saprophages
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detritovores
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solar constant
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sun rays come at constant rate
Solar Constant 2 cal/cm2/min |
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Fate of Incoming Radiation
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50% never makes it to earth
32% reflected back into space by dust, clouds (21) and earth 18% absorbed into atmosphere (15% by O3) |
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Photosynthetic Efficiency
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Energy Fixed by Plants/
Energy in Incident Sunlight |
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Why are plants inefficient?
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44% of sunlight in wrong wavelength
plant already saturated in light incomplete ground cover limited growing season turbidity and depth in water |
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Primary Productivity
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Gross PP: total rate of photosynthesis
Net PP: after respiration by autotrophs measured in g/m2/year or kcal/m2/year |
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Efficiency of PP
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in Forests, 50-75% of PP lost to respiration
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Exploitation Efficiency
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Ingestion/
Previous producer Inefficencies: NPP not all consumed NPP consumed but not all assimilated NPP assimilated but used for respiration |
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Assimilation Efficiency
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Assimilation/
Ingestion Efficiencies: Type of Food: plant or animal Maintenance: Ectotherm v. endotherm Nutrient Content: poor v. high |
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Trophic Cascade Hypothesis
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Top down control of primary production
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Trophic Level Efficiency
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Net production at level n
net production at level n-1 usually btw 5-20, estimated at 10% |
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Causes of deserts
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dry air dropping at 30 latitude
cool coastal deserts (often after upwelling) rain shadow effects |
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Water gain and loss in deserts
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Gain:
Oxidation water food drinking water Loss: evaporation from lung evaporation from skin water in feces water in urine |
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3 Plant Adaptations to drought:
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escape drought: annuals, seeds
Evade drought:2x shoots and roots Escape heat: aestivation, diapause (stop growing), migration, retreat |
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Leaf Adaptations to desert
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Leaf reduction in size - increased surface area, less evaporation
Leaf reduction - permanently lost or lose during dry season Succulent Leaves - thick wax, prevents evaporation Leaf color - light coloration Spines - gives shade and protects from predators |
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Roots in desert
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2:1 root ratio
rain roots - root buds rapidly after rain, dies when soil dries Long roots! |
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Amphibians in desert
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hold lots of water in bladder - 30-50% of body weight
absorb water through skin burrow nocturnal |
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Lizards in desert
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body heat comes from:
radiation, convection,conduction regulate temperature by behavior: move in/out of shade, bushes change color pant lay flat on rock to warm, stand up to cool may use burrows of other animals water storage in weird places - more water in blood or in tails |
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Mammals in desert
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many burrow
many nocturnal predators nocturnal too ectopic storage of fat (camel) large ears - effective heat loss mech. |
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Eland and Oryx
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breathe in coolish air, circulatory system right next to mouth, cools off blood, brings to brain. rest of body very hot.
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Antelope Ground Squirrel
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Color varies
burrows in winter tail used for shade |
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Insects in deserts
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different parts of insects hotter than others.
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Birds in deserts
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Nest building and reproduction tied to water.
cooling is done mostly through evaporative water loss (panting) some go long distances to build nests |
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concentration factor
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dietary intake
pollutant in organism/ pollutant in diet |
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accumulation factor
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pollutant in organism/
pollutant in water or air |
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Partition Coefficient
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Balance between the rate of uptake and the accumulation factor.
q/W = ki/ko q = amount in organism W = amount in medium |
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LD50
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Dose at which 50% of the population are killed within a specified period.
Sometimes shown as LC50 - lethal concentration |
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Effective Concentration (EC50)
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Point at which growth has been reduced by 50%
Fail to take into account: Synergistic or antagonistic interactions with other pollutants Chronic toxic effects Impact on the reproductive potential of a species Reduction of competitive ability of the species Done on one stage (often adult) - juveniles may be more sensitive |
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Other Pollution Measurements
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Population increase
bacteria, unicellular algae & small invertebrates Measures of metabolic state or activity: Respiration rate (CO2 produces or O2 uptake) Photosynthesis by plants RNA:DNA ratio Amounts of high-energy compounds (e.g. lipids, glycogen) 14C-aminoacid incorporation into proteins Others for microbes: nitrate production, enzyme activity, N fixation (acetylene reduction) |
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Monitor Species
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used to assess the scale and distribution of a pollution insult
Abundant Widely distributed Sedentary Body tissues reflect the level of pollutant availability Long-lived Size Easy to identify & collect Easy to age |
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Indicator Species
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susceptible to a pollutant
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Sentinel Species
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Type of Monitor species
When biological impact is not the main concern Ex.: lichens accumulate pollutants found in low concentrations lichens: map atmospheric fluoride Ascophyllum nodosum: used to monitor Cd, Cu, and Pb dissolved in water Littorina littoralis and L. littorea: monitoring Cd levels Mytilus edulis: global monitoring for toxic metals and hydrocarbons Advantages: range abundance sedentary nature longevity information we have on its response to pollutants |
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Indicator species examples:
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Lichens used as air pollution indicators in Paris in the 1800’s
Early 1900’s: indicator species used to detect sewage Either very sensitive to pollution or are typically found where the pollution occurs Marine worm Capitella capitata Theory: as pollution increases, total biomass falls, rises, and then falls. |
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Biochemical Measures of Stress in Organisms
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Mixed-function oxydases (MFOs) increase by high concentrations of drugs, pesticides and hydrocarbons.
induced by exposure to polychlorinated byphenyls (PCB’s) and polycyclic aromatic hydrocarbons (PAHs) found in industrial waste. ATP content of the soil directly reflects the size and activity of the microbial community |
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Scope for Growth
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Energy left for growth
(when under stress) SfG = A - M A = energy assimilated M = energy metabolized |
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Pollution summary
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The many responses of individuals and populations can be used as indicators of stress caused by pollution.
The effects of pollution need to be distinguished from the background variation. Effects of one pollutant can be dampened or strengthened by the addition of other pollutants. |
