Ionizing radiation
enough energy to knock electrons from atoms forming ions, capable of causing cancer (ex gamma-X-rays-UV)
First Law of Thermodynamics
energy is neither created nor destroyed, but may be converted from one form to another
Second Law of Thermodynamics
when energy is changed from one form to another, some useful energy is always degraded into lower quality energy (usually heat)
Humus
organic, dark material remaining after decomposition by microorganisms
Leaching
removal of dissolved materials from soil by water moving downwards
Illuviation
deposit of leached material in lower soil layers (B)
Loam
perfect agricultural soil with equal portions of sand, silt, clay
Solutions to soil problems
conservation tillage, crop rotation, contour plowing, organic fertilizers
Parts of the hydrologic cycle
evaporation, transpiration, runoff, condensation, precipitation, infiltration
Aquifer
any water bearing layer in the ground
Salt water intrusion
near the coast, overpumping of groundwater causes saltwater to move into the aquifer
During an El Nino year
trade winds weaken & warm water sloshed back to SA
During a Non El Nino 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
Effects of El Nino
upwelling decreases disrupting food chains, N US has mild winters, SW US has increased rainfall, less Atlantic Hurricanes
Nitrogen fixing
because atmospheric N cannot be used directly by plants it must first be converted into ammonia by bacteria
Ammonification
decomposers covert organic waste into ammonia
Nitrification
ammonia is converted to nitrate ions (NO-3)
Denitrification
bacteria convert ammonia back into N
Largest reservoirs of C
carbonate rocks first, oceans second
Biotic/abiotic
living & nonliving components of an ecosystem
Producer/Autotroph
photosynthetic life
Major trophic levels
producers-primary consumer-secondary consumer-tertiary consumer
Phosphorus does not circulate as easily as N because
it does not exist as a gas, but is released by weathering of phosphate rocks
Ways to conserve water
(agriculture, drip/trickle irrigation)(industry, recycling)(home, use gray water, repair leaks, low flow fixtures)
Salinazation of soil
in arid regions, water evaporates leaving salts behind
Because soils contain very little phosphorus
it is a major limiting factor for plant growth
Excess phosphorus is added to aquatic ecosystems by
runoff of animal wastes, fertilizer discharge of sewage
Photosynthesis
plants convert atmospheric C (CO2) into complex carbohydrates (glucose C6H12O6)
Aerobic respiration
oxygen consuming producers, consumers & decomposers break down complex organic compounds & convert C back into CO2
Energy flow in food webs
only 10% of the usable energy is transferred
Why is only 10% transferred
usable energy lost as heat (2nd law), not all biomass is digested & absorbed, predators expend energy to catch prey
1st & 2nd most populated countries
China & India
Most important thing affecting population growth
low status of women
Ways to decrease birth rate
family planning, contraception, economic rewards & penalties
Percent water on earth by type
97.5% seawater, 2.5% freshwater
Age structure diagrams
(broad base, rapid growth)(narrow base, negative growth)(uniform shape, zero growth)
Postindustrial Stage
low birth & death rates
Industrial stage
decline in birth rate, population growth slows
Transitional stage
death rate lower, better health care, population grows fast
Preindustrial stage
birth & death rates high, population grows slowly, infant mortality high
World population
over 6 billion
Primary succession
development of communities in a lifeless area not previously inhabited by life (lava)
Secondary succession
life progresses where soil remains (clear cut forest)
Mutualism
symbiotic relationship where both partners benefit
Commensalism
symbiotic relationship where one partner benefits & the other is unaffected
Parasitism
relationship in which one partner obtains nutrients at the expense of the host
Biome
large distinct terrestrial region having similar climate, soil, plants & animals
Carrying capacity
the number of individuals that can be sustained in an area
R strategist
reproduce early, many small unprotected offspring
K strategist
reproduce late, few, cared for offspring
Natural selection
organisms that possess favorable adaptations pass them onto the next generation
Malthus
said human population cannot continue to increase;.consequences will be war, famine & disease
Doubling time
rule of 70 (70 divided by the percent growth rate)
Replacement level fertility
the number of children a couple must have to replace themselves (2.1 developed, 2.7 developing)
Natural radioactive decay
unstable radioisotopes decay releasing gamma rays, alpha & beta particles
Half-life
the time it takes for the mass of a radioisotope to decay. Each element has a specific half-life, could be from seconds to thousands of years. Know how to calculate: If you start with 100 Ci , 50Ci will be left in one half-life
Estimate of how long a radioactive isotope must be stored until it decays to a safe level
approximately 10 half-lives
Nuclear Fission
nuclei of isotopes split apart when struck by neutrons
Nuclear Fusion
2 isotopes of light elements (H) forced together at high temperatures till they fuse to form a heavier nucleus. Expensive, not cost effective yet as an answer to the nuclear waste problem
Ore
a rock that contains a large enough concentration of a mineral making it profitable to mine
Best solution to Energy shortage
conservation and increase efficiency
Ozone
(Formation: secondary pollutant, NO2+UV=NO+O O+O2=O3, with VOC's) (Effects: respiratory irritant, plant damage) (Reduction: reduce NO emissions & VOCs)
Eutrophication
rapid algal growth caused by an excess of N (nitrogen) & P (phosphorous)
Hypoxia
when aquatic plants die, the BOD rises as aerobic decomposers break down the plants, the DO drops & the water cannot support life
Sulfur oxides
(Source: coal burning) (Effects: acid deposition, respiratory irritation, damages plants) (Equation for acid formation: SO2 + O2 = SO3 + H2O = H2SO4) (Reduction: scrubbers, burn low sulfur fuel)
Nitrogen Oxides
(Source: auto exhaust) (Effects: acidification of lakes, respiratory irritation, leads to smog & ozone) ( Equation for acid formation: NO + O2 = NO2 + H2O = HNO3) (Reduction: catalytic converter)
Carbon Oxides
(Source: auto exhaust, incomplete combustion) (Effects: CO binds to hemoglobin reducing bloods ability to carry O, CO2 contributes to global warming) (Reduction: catalytic converter, emission testing, oxygenated fuel, mass transit)
Primary air pollutants
produced by humans & nature (CO, CO2, SO2, NO, hydrocarbons, particulates)
Secondary pollutants
formed by reaction of primary pollutants
BOD
biological oxygen demand, amount of dissolved oxygen needed by aerobic decomposers to break down organic materials
Effects of global warming
rising sea level (thermal expansion), extreme weather, droughts (famine), extinctions
Ozone depletion caused by
CFC's, methyl chloroform, carbon tetrachloride, halon, methyl bromide all of which attack stratospheric ozone
In natural ecosystems, 50-90% of pest species are kept under control by
predators, diseases, parasites
Major insecticide groups and examples
(chlorinated hydrocarbons, DDT) (organophosphates, malathion) (carbamates, aldicarb)
Incineration disadvantages
toxic emissions (polyvinyl chloride�>dioxin), scrubbers & electrostatic precipitators needed, ash disposal
Best way to alleviate the waste problem
reduce the amounts of waste at the source
Keystone species
species whose role in an ecosystem are more important than others
Love Canal, NY
chemicals from a company were buried underground, school & homes built over it, the chemicals leached out leading to birth defects & cancer Led to the Superfund act
Municipal solid waste is mostly
composed of paper
Most municipal waste is
sent to landfills
Sanitary landfill problems and solutions
(leachate, liner with collection system) (methane gas, collect gas and burn) (volume of garbage, compact & reduce)
Montreal Protocol
International meeting to phase out ozone depleting substances. Relatively successful
Kyoto Protocol (agreement)
International meeting to control global warming by setting greenhouse gas emission standards. Will be expensive.
Alternate energy sources
wind, solar, waves, biomass, geothermal, hydrogen fuel cells
Restricted Use lands
National Parks, National Wilderness Preservation System
Moderately restricted use land
National Wildlife Refuges
Multiple use US public land
National Forest & National Resource lands
Two most serious nuclear accidents
(Chernobyl, Ukraine-total meltdown) (Three Mile Island, PA - partial meltdown)
Major parts of a nuclear reactor
core, control rods, steam generator, turbine, containment building
Cons of petroleum
depleted soon, pollution during drilling, transport and refining, burning makes CO2
Pros of petroleum
cheap, easily transported, high quality energy
Acid deposition
caused by sulfuric and nitric acids resulting in lowered pH of surface waters
Greenhouse gases
(Examples: H2O, CO2, O3, methane (CH4), CFC's) (EFFECT: they trap outgoing infrared (heat) energy causing earth to warm
Pesticide cons
genetic resistance, ecosystem imbalance, pesticide treadmill, persistence, bioaccumulation, biological magnification
Pesticide pros
saves lives from insect transmitted disease, increases food supply, increases profits for farmers
LD50
the amount of a chemical that kills 50% of the animals in a test population
Mutagen, Teratogen, Carcinogen
causes hereditary changes, Fetus deformities, cancer
Surface mining
cheaper & can remove more mineral, less hazardous to workers
Point VS non point sources
(Point, from specific location such as pipe)(Non-point, from over an area such as runoff, good example: storm drains)
Electricity is generated by
using steam (from water boiled by fossils fuels or nuclear). falling water or wind to turn a generator, or photovoltaic cells
Petroleum forms from
microscopic aquatic organisms in sediments converted by heat & pressure into a mixture of hydrocarbons
Volcanoes and Earthquakes occur
at plate boundaries (divergent, spreading, mid-ocean ridges) (convergent, trenches) (transform, sliding, San Andreas)
Natural pest control
better agricultural practices, genetically resistant plants, natural enemies, biopesticides, sex attractants
Industrial smog
found in cities that burn large amounts of coal
Photochemical smog
formed by chemical reactions involving sunlight (NO, VOC, O)
Incineration advantages
volume of waste reduced by 90% & waste heat can be used
Indicator species
species that serve as early warnings that an ecosystem is being damaged
Effects of ozone depletion
increased UV, skin cancer, cataracts, decreased plant growth
Particulate matter (source, effect, reduction)
(burning fossil fuels & car exhaust) (reduces visibility & respiratory irritation) (filtering, electrostatic precipitators, alternative energy)