79 terms

AP Enviro Sci Review

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Photosynthesis
plants convert CO2 (atmospheric carbon) into complex carbohydrates (glucose C6H12O6).
Respiration (Aerobic)
oxygen consuming producers, consumers & decomposers break down complex organic compounds & convert organic carbon back into CO2.
Energy Flow through Food Webs
Only about 10% of usable energy is transferred from one trophic level to the next. Reason: usable energy lost as heat (2nd law of Thermodynamics), not all biomass is digested & absorbed, predators expend energy to catch prey.
Biotic
the living components of an ecosystem
Abiotic
the nonliving components of an ecosystem.
Nitrogen Fixation
atmospheric nitrogen (N2), which cannot be used directly by plants, is first converted into ammonia by bacteria.
Nitrification
ammonia is converted to nitrate ions (NO3-)
Assimilation
inorganic nitrogen (nitrate) is converted into organic molecules such as DNA/amino acids & proteins.
Ammonification
decomposers covert organic waste into ammonia
Denitrification
bacteria convert ammonia into atmospheric nitrogen (N2).
Phosphorus
does not exist at the Earth's surface as a gas; released into ecosystems through the weathering of phosphate rocks, it is a major limiting factor for plant growth. The phosphorus cycle is relatively slow, without an atmospheric step.
Producer/Autotroph
organisms that make their own food. Photosynthetic life (plants).
Trophic Levels in Food Chains
producers >>primary consumer >> secondary >> consumer >> tertiary consumer
Mutualism/Symbiosis
symbiotic relationship where both organisms benefit
Commensalism
symbiotic relationship where one organism benefits & the other is unaffected
Parasitism
relationship in which one organism (the parasite) obtains nutrients at the expense of the host
Carrying Capacity
the number of individuals that can be sustained in an area
r-strategist
reproductive strategy in which organisms reproduce early, bear many small, unprotected offspring (ex. insects, mice)
K-strategist
reproductive strategy in which organisms reproduce late, bear few, cared for offspring (ex. humans, elephants)
Primary succession
development of communities in a lifeless area not recently inhabited by life (ex. lava flow, retreating glacier)
Secondary succession
life progresses where soil remains (ex. clear-cut/burned forest, old farm, vacant lot).
Natural Selection
organisms that possess favorable adaptations pass them onto the next generation
Humus
organic, dark material remaining after decomposition by microorganisms
Loam
perfect agricultural soil with equal portions of sand, silt, and clay
Leaching
the removal of dissolved material from soil by water as it moves downward (percolates) through soil.
Soil Conservation
Methods include conservation tillage, crop rotation, contour plowing, terracing, windbreaks, no-till
Soil Salinization
in arid regions, water evaporates leaving salts behind. (ex. fertile crescent, southwestern US)
Waterlogging
water completely saturates soil starves plant roots of oxygen, rots roots
Watershed
all of the land that drains into a body of water
Aquifer
underground layers of porous rock allow water to move slowly.
ENSO
El Nino Southern Oscillation, trade winds weaken & warm surface water moves toward South America. Diminished fisheries off South America, drought in western Pacific, increased precipitation in southwestern North America, fewer Atlantic hurricanes.
Saltwater Intrusion
near the coast, overpumping of groundwater causes saltwater to move into the aquifer
La Nina
A "normal" year, easterly trade winds and ocean currents pool warm water in the western Pacific, allowing upwelling of nutrient rich water off the West coast of South America.
Doubling Time (rule of 70)
doubling time is equal to 70 divided by the percent rate of growth. (ex. a population growing at 5% annually doubles in 70 ÷ 5 = 14 years)
Replacement Level Fertility
the number of children a couple must have to replace themselves (averages 2.1 in more developed nations, 2.7 in less developed nations)
World Population
7.3 Billion
US Population
330 Million
Demographic Transition Model: Preindustrial stage
birth & death rates high, population grows slowly, infant mortality high.
Demographic Transition Model: Transitional stage
death rate (infant mortality) lower, birth rates remain high, better health care, population grows fast.
Demographic Transition Model:: Industrial stage
decline in birth rate, population growth slows.
Demographic Transition Model: Postindustrial stage
low birth & death rates.
Rapid Population Growth Age Structure
Slow Growth Population Age Structure
Negative Growth Population Age Structure
Most Populous Nation
China
2nd Most Populous Nation
India
3rd Most Populous Nation
USA
Seawater on Earth
97.5%
Freshwater on Earth
2.5%
Aquaculture
farming aquatic species, commonly salmon, shrimp, tilapia, oysters.
Point Source Pollution
source from specific location such as pipe or smokestack
Non-Point Source Pollution
source spread over an area such as agricultural/feedlot runoff, urban runoff, traffic.
Eutrophication
rapid algal growth (algal bloom) caused by an excess of nitrogen & phosphorus (phosphorus usually limits), blocks sunlight, causing the death/decomposition of aquatic plants, decreasing dissolved oxygen (DO), suffocating fish
Hypoxia
water with very low dissolved oxygen levels, the end result of eutrophication, for example
Primary Sewage Treatment
first step of sewage (wastewater) treatment; eliminates most particulate material from raw sewage using grates, screens, and gravity (settling).
Secondary Sewage Treatment
second step of sewage treatment; bacteria break down organic waste, aeration accelerates the process
Tertiary Sewage Treatment
final step of sewage treatment; ponds/wetlands used to remove nutrients nitrogen & phosphorus.
BOD
Biological Oxygen Demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials.
Turbidity
a measure of the cloudiness of water, caused by suspended solids (sediment).
Water Hardness
the result of dissolved calcium ions (Ca2+) and magnesium (Mg2+).
CAFE standards
Corporate Average Fuel Economy standards enacted into law in 1975, established fuel efficiency standards for passenger cars and light trucks.
Primary Air Pollutants
produced by humans & nature (CO, CO2, SO2, NO, hydrocarbons, particulates)
Secondary Air Pollutants
formed via the atmospheric reaction of primary air pollutants.
Particulate Matter (PM2.5 & PM10):
sources include burning fossil fuels and car exhaust. Effects include reduced visibility, respiratory irritation. Methods of reduction include filtering, electrostatic precipitators, and using alternative sources of energy.
Photochemical Smog
formed by chemical reactions involving sunlight (NOx, hydrocarbons, O2).
Ozone:
Secondary pollutant, NO2 + UV -->NO + O; O + O2-->O3, with VOCs. Causes respiratory irritation and plant damage. Reduced by reducing NO emissions and VOCs.
Nitrogen Oxides: (NOx)
Major source is auto exhaust. Primary and secondary effects include acidification of lakes, respiratory irritation, leads to smog and ozone. Reduced using catalytic converters.
Equation for acid formation: NO + O2-->NO2 + H2O-->HNO3 (nitric acid)
Acid Deposition
caused by sulfuric and nitric acids formed from NOx and SOx resulting in lowered pH of surface waters
Sulfur Oxides
(SOx) Primary source is coal burning. Primary and secondary effects include acid deposition, respiratory irritation, plant damage. Reduction methods include: scrubbers, burn low sulfur fuel. Equation for acid formation: SO2 + O2 -->SO3 + H2O -->H2SO4 (sulfuric acid)
Carbon Dioxide
(CO2) Sources include the combustion of fossil fuels. Effects: greenhouse gas-contributes to global warming. Reduction accomplished by increased fuel efficiency (gas mileage), mass transit (reduction).
Carbon Monoxide
(CO) Sources include incomplete combustion of fossil fuels. Effects: binds to hemoglobin reducing bloods ability to carry O2. Reduction accomplished by catalytic converters, oxygenated fuel, mass transit (reduction).
Greenhouse Effect
Most significant (not anthropogenic) - H2O. Also (and largely anthropogenic) - CO2, methane (CH4), and CFCs. Trap outgoing infrared energy (heat) causing earth to warm.
Effects of Global Warming
rising sea level (due primarily to thermal expansion, not melting ice), extreme weather, droughts (famine), and extinctions
Ozone Depletion
caused by CFCs, methyl chloroform, carbon tetrachloride, halon, methyl bromide all of which attack stratospheric ozone. Negative effects of ozone depletion include increased UV, skin cancer, cataracts, and decreased plant growth
Municipal Solid Waste
: is mostly paper and mostly put into landfills
Sanitary Landfill
problems include leachate, which is solved using a liner with a collection system; methane gas, which may be collected and burned; and the volume of garbage, which may be compacted and/or reduced
Waste Incineration
Advantages-volume of waste reduced by 90% and waste heat can be used. Disadvantages-toxic emissions (polyvinyl chloride, dioxin), scrubbers and electrostatic precipitators needed, ash disposal
Brownfield
an abandoned industrial site
Remediation
return a contaminated area to its original state

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