-Love Canal: Niagara Falls:
1976-78 people are effected by an old toxic waste dump that they had built their community on top of.
1952, great smog on Dec. 4, killed thousands, helped trigger environmental movement. Result of burning more coal.
Accidental release of pesticides in India. 40 tons of Methyl isocyanate released which killed thousands outright. Transportation collapsed, people got trampled in the escape. Death due to pulmonary edema (a lung disorder) occured as well as due to accute cyanide poisoning. The factory was operating on untested technology.
Biggest commercial nuclear disaster ever. This happened due to unsafe procedures. Estimates of a total death toll range from 90,000 to 200,000. A radioactive cloud spread over much of Europe. 203 were hospitalized immediately, 30 people killed by the blast.
Mercury bioaccumulation, there was mercury in bay that got into fish which were consumed by people.
-Three Mile Island
Nuclear accident, a big nuclear scare in the US, a partial meltdown occurred.
Oil Spill from US tanker.
From burning coal, pollutants got trapped in a river valley near Pittsburgh, where 20 people were killed.
Oil Spill in Santa Barbara Channel. Leak due to high pressure.
Killed many seals and dolphins and birds.
- Kuwait Oil Fires
Gulf war 1991, retreating Iraqi soldiers set Kuwait oil fields on fire. Caused pollution in soil and air.
-Ozone is a compound that occurs naturally in the stratosphere and protects life on earth from UV radiation.
-Process between oxygen and ozone: (O2 + UV + 2O), (O + O2 + O3), (O3 + UV + O2 + O)
-CFCs (highly inert chemicals used as coolants, propellant, cleaners, and gas for foaming of Styrofoam.)
-Polar Stratospheric Clouds (PSCs) (form during the winter) provide surface for reactions that release chlorine.
-Process about how oxygen depletes:(CFCs + PSCs + Cl2 + UV + 2Cl), Cl + O3 + ClO + O2), (ClO + O + O2 + Cl) Chlorine is catalyst
-More UV radiation getting through causing increased skin and eye damage as well as mutations that cause cancer.
-Environmental Damage (global warming, destruction of ocean habitats, crop damage, etc.)
-Ozone hole forms in the stratosphere and is most prominent in the Artic and Antarctic in the spring
-Polar Vortex- forms when air is circulating around the poles and traps cold air and makes the ground and air colder.
-Depletion has increased in the past twenty years because of increased use of CFCs. CFCs were discovered to be harmful in 1974. It takes 20 years for CFC's to reach the stratosphere.
-Greenhouse Effect: greenhouse gases O3, H2O and CO2 & (water vapor) cause heat from the sun to become trapped in the earth's atmosphere and produce a warming effect. More specifically, UV rays are emitted from the sun and are absorbed by the earth, which in turn produces IR (infrared) rays. These get trapped in the atmosphere causing heating.
-Climate change goes in cycles: A cold period - roughly 100,000 years ago, now -10,000-year-old "warm" period.
-Scientists predict future climate change using mathematical models generated from supercomputers and general circulation models (GCMs), which are 3D representations of how energy, air mass, and moisture flow through the atmosphere because of their physical properties.
-Positive feedback loop exists with methane emissions in regard to permafrost and bogs. As permafrost melts and exposes methane-emitting bogs, the gas released by these areas continues the greenhouse effect and melts more permafrost. Similar patterns are seen with CO2 emissions.
-Vegetation depletion leads to increased global warming, because trees are unable to sequester CO2 from the atmosphere, which contributes to the greenhouse effect.
-Albedo: the earth's ability to reflect light. Reflected energy does not heat the earth's surface, and ice caps and other glacial regions have greatly increased albedo. Thus, the cooling effect of these areas is lost as they melt.
-The majority of greenhouse gases are emitted from, among other things, burning of fossil fuels and deforestation. Natural sources can include regular water evaporation, ozone, and CO2 due to respiration.
-Oceans moderate temperature by removing 29% of earth's CO2 and absorb a great deal of excess heat.
Effects on humans of global warming:
-Disease (respiratory illnesses and pathological diseases due to insects and other warm climate based carriers)
-Drought and flooding due to extreme weather patterns
-Rising sea levels due to ice melting leads to destruction of homes
-Higher irrigation demands and more pests for agriculture
-Non-human effects of global warming:
-Loss of habitat for animals
-Change in species location due to climate change
Sea temperature and level changes
-Extreme weather patterns
Thermohaline Regulation (Deep Water Circulation): Regulates temperature and salinity.
-Water cool and sinks or freezes (which makes the water saltier) and sinks.
-Water moves slowly at the bottom of the ocean.
-Winds blow surface water away causing cooler waters from lower depths to rise (upwelling).
El Nino and La Nina
-During El Nino, there are warmer temperatures, less upwelling, and weaker winds than during normal conditions.
-During La Nina, there are cooler temperatures, more strong upwelling, and stronger winds than during normal conditions.
-Estuaries: safe habitats for animals (breeding grounds) where rivers enter oceans - fresh and salt water mix
-Coral Reefs: Most diverse aquatic biome, 2nd most diverse biome overall, grow slowly and are disrupted easily, thrive in clear, warm, shallow waters, threats from erosion, runoff, boating, coral reef bleaching, flooding, etc
-Open Sea: Eupthotic, Bathyl, Abyssal (in order of least depth to most)
-Tragedy of the Commons (example: ocean fisheries and over fishing)
-Oil Spills (Exxon-Valdez oil spill). Varying methods of clean up available (such as adding coagulates to the water to cause the oil to stick together for easier pick up or hair mats).
-Thermal Pollution (coral bleaching caused by global warming)
-Ocean fishing is one of the top three food production industries
-Controlled by the Coriolis effect (thus causing them to move to the right of their intended path)
-Earth's first atmosphere (Primeval) is gone.
-Secondary atmosphere formed from outgassing volcanoes, comet impacts, and plant photosynthesis
-Layers of atmosphere (in order): troposphere, tropopause, stratosphere (including ozone layer), stratopause, mesosphere, mesopause, thermosphere
-Temperature change with altitude in different layers:
-Troposphere: Colder with altitude
-Stratosphere: Hotter with altitude why? Ozone layer - heats it up
-Mesosphere: Colder with altitude
-Thermosphere: Hotter with altitude
-Atmospheric composition: Nitrogen-78%, Oxygen-21%, Water 0-4%, and others
-Specific Humidity: mass of water vapor in air / mass of air
-Relative Humidity: mass of water vapor in air / mass of water in saturated air at that temperature * 100%
-Pressure areas: Low: Equator, 60° Latitudes; High: 30° Latitudes, Poles -Wind names: (Easterlies, Trade, Westerlies) named from the direction they come from
-Coriolis Effect: Because the Earth rotates, moving air (wind) is deflected to the right of intended path in the Northern Hemisphere
-Chemical weathering is where the chemical structure of the material (usually rock) changes.
-Mechanical weathering is where only the physical structure is changed.
-It is almost always surface or near surface.
-Erosion is when particles made from one of the two weathering's above move, either from air, water, or other devices.
-Mass Wasting is where the sediments are moved downward through gravity, eventually creating wetlands at the mouth of rivers, or other form of rocks and sand.
-Plants can also weather and erode rocks with their rocks, creating micro fractures that eventually split the rock.
-Rocks created deep within the Earth are hot and under great pressure; once it is released, they cool and expand, creating cracks.
-Wind, Ice, Water, Carbonic acid, gravity, and hydrolysis are some examples of different types of weathering and erosion.
-Horizontal sorting is the arrangement of largest (boulders, for example) to smallest (particulate) horizontally, as in a stream.
-Vertical sorting is caused by larger sediments settling faster, and smaller one settling slower.
-Weathering is the breakdown of rock chemically and physically.
-Chemical weathering (acid rain, chemical reactions O2, CO2 and H2O)
-Physical weathering can be aided by: plant roots, ice (frost wedging like what occurs in primary succession with lichens)
-Erosion is the movement of weathered sediments altering the surface of the land.
-Agents of erosion are wind and water
-Rock Cycle- weathering and erosion are important to creation of sedimentary rock
-Weathering- breaks down rocks into loose material, aka sediments.
-Erosion- moves the sediment to a location conducive to creation of sedimentary rocks
-Material cycling- long term loops of every cycle- Phosphorus, Nitrogen, Carbon, and Sulfur
-Phosphorus - major storage is in rocks (see #6 to show environmental impact)
-Nitrogen, Carbon and Sulfur cycles have important rock components as well.
-The hydrologic cycle is water, driving weathering and erosion processes.
-Soil Erosion- Human caused or natural
-Human caused- overcultivation and loss of plant cover i. As seen in Dust --Bowl, Grapes of Wrath/Okie style- overcultivated the Midwest plains- loss of fertile topsoil.
-Natural: rain or wind
Harmful Effects of Erosion
-Loss of fertility and water holding capacity- Nutrient rich and porous soil particles blow or wash away first (lightest and smallest)
-Sediment runoff pollutes water, clogs ditches, channels, lakes, and gills of fishies.
-Accelerated erosion can lead to runoff of phosphate/fertilized soil, leading to eutrophication.
-Types of water erosion
-Sheet- water peels off uniform sheets of soil
-Rill- tiny rivulets of H2O cut vermicelli-sized channels in soil
-Gully- rivulets join to create bigger channels, eventually creating ditches, or a Grand Canyon.
-Competitive Exclusion principle: if species do not outcompete other species or change their niche, they will die.
-Simpson's index: probability that two individual in a community come from the same phylum/order/species; if higher, less diverse.
-Simpson's index of diversity: probability that they belong to different categories; 1-10 Simpson's index; if higher, more diverse.
-Simpson's reciprocal index: number of equally common categories that will make the Simpson's index. If higher, community is more diverse.
-Jacquard's Index: comparison of biodiversity between two different ecosystems; if higher, more SIMILARITIES between ecosystems.
Theory of Island Biogeography
-Species richness (number of species on island) = immigration - extinction
-Smaller island = lower species richness=higher extinction, lower immigration
-Short distance from mainland = higher species=higher immigration, lower extinction
-Facilitation: making an ecosystem easier to be colonized
-Inhibition: the opposite
-Tolerance: no effect on colonization by new species
-Primary succession: starting an ecosystem from scratch; example: glacier, lava
-Secondary succession: starting from a disturbed ecosystem; example: colonization of a cultivated field or burned forest
-Biodiversity: variety and complexity of life on earth.
-Rivet popper hypothesis: each species is important in its own way; if we lose one, it's okay, but if we lose too many.
-Keystone hypothesis: many species are redundant; only a few are important enough to keep around permanently.
-Shapes: regular pyramid, diamond, column
-Types: developing country pyramid (regular pyramid), more developed -country (diamond, and column)
-What they represent: regular = population growth; diamond = past baby boom and decline in younger populations; column = stable population or 0 pop
-TFR stands for total fertility rate which refers to the amount children a women might have throughout her life. This is important because when the -TFR goes down, the population will most likely go down.
-Less developed countries (LDC) i.e. Sudan, Sub-Saharan Africa, some parts of India and More developed countries (MDC) i.e. Europe, and US.
-The transitional phase is when the death rate (concentration of deaths in children and newborns) has dropped but the birth rate has not yet dropped. -You see this in places like Kenya.
-Trend by youth not to get married and have families, and strain on social services because a large population is about to reach or has reached retirement age. This is also due to the education and empowered of women.
-This is happening in places like Japan.
-Population booms occur not because of birth rates increasing but because of death rates dropping. The same amounts of children are being born, but not as many of them are dying.
-Developing countries are held in place because of the lack of health care and education given to families, specifically women, so that they are trapped in a demographic transition (they are having the same amount of children and less are dieing).
-Replacement level fertility (RLF). 2.1 for a MDC and 2.5 for LDC. This is the amount of children a woman must have to keep the population stable.
-The US is unique because it has been below RLF for several years but has maintained a growing population due to the acceptance of immigrants into the United States.
-Any substance can be toxic, but toxicity depends on the dose.
-You can be exposed to a toxicant in three ways: ingestion, inhalation, dermal (skin) exposure.
-Fate is the ultimate resting location of a toxicant, and transport is the process by which it arrives there.
-Hydrophilic toxicants dissolve in water, and hydrophobic toxicants dissolve in fats and do not tend to dissolve in water.
-A cell responds to a toxicant by: altering permeability, destroying the toxicant, increasing repair, increasing production of toxicant's target, altering toxicant receptor.
-To relate to a cancer, a cell can control/alter: differentiation or development, apoptosis, its response to the environment.
-DNA can be damaged by: mutagens (anything that can alter DNA production), carcinogens (cancer causing mutagens), sunlight (UV damage), oxidation.
-Endocrine disruptors are chemicals that when absorbed into the body blocks, or mimics, hormones, thus changing the body's functions; they are found in household chemicals and chemicals used in agriculture.
-LD50 is dose that is lethal for 50% of population
-Risk = Exposure * Harm
-Two good options for disposing of solid wastes are landfills and incineration. Others that are not so good include dropping it in the ocean and exporting the waste.
-Options for disposal of hazardous waste: Deep well injection where hazardous waste is pumped below the water table underground, surface waste lagoons, hazardous waste landfills, above ground storage bunkers, and exporting to LDC's.
-Sanitary landfills: The compaction of waste into a lined pit. (Covered with earth and impermeable cover.)
-Hazardous Waste: Discarded solid of liquid material that: a) catches fire easily, b) is reactive and unstable (chance of explosion), c) Can corrode metal containers, and d) contains a great enough level of any chemical on a list of thirty nine chemicals that the EPA has determined are toxic.
-Reduce, Reuse, Recycle
-Methane is produced in landfills. Extremely flammable and potent greenhouse gas
-Detoxification and Phytoremediation: Biological treatment of hazardous waste.
-Incineration: Pros: Reduces volume, produces energy, and it does not create much water Pollution. Cons: Costs a lot, creates air pollution, and produces toxic byproducts.
-Economics play a large role in how waste is disposed. Weighing the cost to the possible detrimental effect on the environment, and comparing it's
effectiveness. This is why the best methods of disposal aren't always used.
-Leachate: Solution of stuff in a landfill that binds/mixes with water.
-Automobiles and Industries are the two biggest air polluters
-Photochemical Smog (Brown Air Smog): mixture of primary and secondary pollutants that form under the sunlight. Mostly ozone in the troposphere
-Industrial Smog (Grey Air Smog): made mostly from sulfur dioxide, sulfuric acid, which is mainly produced by burning coal and oil. China has the worst build up this pollution.
-When Nitrogen and Sulfur are released into the atmosphere as pollutants (NO and SO not as Nitrogen gas) they can form Sulfuric Acid and Nitric Acid; This falls back to the earth as acid rain.
-Point Source Pollution: direct, easily-traceable source of pollution into the atmosphere (factories)
-Non-Point Source Pollution: air pollution that can not be traced to a single spot (deforestation; agricultural runoff; stormwater runoff)
-Ozone, Nitrogen Dioxide:Secondary Pollutant
-Carbon Monoxide, Sulfur Dioxide: Primary Pollutant
Outdoor Air Pollution
-Carbon Monoxide: made from fossil fuels burning incompletely, like
automobiles, primary pollution
-effects: dizziness, asthma, brain cell damage
-chemically: CH4 + 3O2 --> 4H2O + 2CO
-concentration in an urban area: peak is at 6 am, noon, 6 p.m. because of people traveling to work and back
-Nitrogen Dioxide (NO2): fossil fuels burning in cars and industries, turns into acid deposition, secondary pollution
-effects: lung irritation, lung damage, asthma,
-concentration in an urban area: peak is after 7 am because it takes a few hours to be made since it is a secondary pollutant
-Sulfur Dioxide: burning fossil fuels, mainly coal and oil, turns into acid deposition, primary pollution
-effects: asthma, breathing problems
-chemically: S + O2 --> SO2, acid deposition 2SO2 + O2 --> 2SO3 SO3 +H2O --> H2SO4
-Suspended Particulate Matter- burning coal, diesel in automobiles
-effects: nose, throat irritation, lung damage
-Ozone: reacts with volatile organic compounds (VOC), and nitrogen oxides, which makes photochemical smog, Ozone is in the troposphere, secondary pollution
-effects: eye, throat, nose irritation, asthma,
-chemically: NO2 + UV Light --> NO + O O + O2 --> O3, * - not stable
Indoor Air Pollution
-Radon: decaying Uranium 222, which is in the ground, gets into house by cracks, hollow cement blocks, water supply
-effects: lung cancer
-asbestos: pipe insulation, building materials, like floor tiles
-effects: lung cancer, lung disease
-Carbon Monoxide: faulty furnaces, unvented gas stoves, wood stoves, kerosene heater
-effects: headaches, drowsiness, irregular heartbeats
-Nitrogen Oxides: unvented gas stoves, kerosene heater, wood stoves
-effects: irritated lungs, colds, headaches
-Temperature inversion: layer of warm air on top of layer of cold air, pollutants cannot rise above cold air causing pollution to build up. The worst place to be is with mountains on three sides, and wind blowing from the sea on the last side. This traps the pollution in the city.
Two factors that dilute the pollutants in the atmosphere
-wind speed: a higher wind speed pushes air pollution over a greater distance
-mixing height: warm air over cold air does not allow air pollution to escape because cold air is denser. In order for air pollution to be diluted, the warm air over cold air mass should be fairly high in the troposphere.
-Mix the water.
-Coagulate and Flocculate: sticks big particles together.
-Sand filtration: filter physically and mechanically.
-Sterilize with Chlorine and Ozone.
-Pump to costumers.
Waste Water Source
-Domestic waste water
-Primary: remove solids through screen filters
-Secondary: removes organics from water through an aeration tank. Also removes sludge.
-Tertiary: final cleanup. Removes excess nutrients through oxidation ponds and chlorine and UV.
-Point: easily able to distinguish where it is from. An example would be a drainage pipe.
-Non Point: not easily able to pick out a single source. An example is automobiles.
-Arsenic: a natural occurring mineral found in the ground, it causes headaches, nausea, and skin lesions. It can seep into the water and make the water useless.
-Polychlorinated biphenyls (PCBs): used in many industrial appliances including cooling liquids. It is a bioaccumulating pollutant. It can cause liver/kidney damage, birth defects, skin damage, hormonal changes, and tumors.
-Polychlorinated biphenyls (PCBs): used in many industrial appliances including cooling liquids. It is a bioaccumulating pollutant. It can cause liver/kidney damage, birth defects, skin damage, hormonal changes, and tumors.
-Nitrates and Phosphates: from fertilizer and factory/car production. It can cause algae blooms which take away the DO from the water and kills fish. This can reduce the recreation value of the lake.
-Sludge: a solid matter left over after wastewater treatment. It has toxic elements in it. Can kill people or be used in fertilizer which causes plants to accumulate the sludge.
-Methyl Tertiary-Butyl Ether (MTBE): an added component to gasoline that causes the oxygen content to go up. It can get into the air and water where it can irritate humans (smell/taste/headaches). It is possibly carcinogenic.
-BOD: Biochemical Oxygen Demand, the amount of dissolved oxygen needed by aerobic organisms to break down organic waste.
-COD: Chemical Oxygen Demand, the amount of dissolved oxygen needed by biological and non-biological to break down organic waste.
-DO: dissolved oxygen.
-Coal is the worst because of acid deposition, global warming and mercury emissions.
-Oil is the next worst because of possibility of spill; it also contributes to global warming.
-Natural Gas causes the least amount of pollution.
-Coal is extracted through deep or surface mining.
-Oil is welled and pumped, as is natural gas.
-Coal: Russia, China, India, U.S.A
-Oil: Persian Gulf
-Natural Gas: Kazakhstan, Persian Gulf, Russia
-Order of Abundance (most to least)- Coal, Oil, Natural Gas
-All three produce carbon dioxide, coal produces the most (per unit energy), then oil, then natural gas, which contributes to global warming.
-As of the year 2000, the United States used oil the most, then natural gas, and coal coming in a close third. China, on the other hand uses coal more than the other two fossil fuels.
-Because of extraction, habitat destruction is worst for coal, then oil and natural gas
-Pollution reduction: burn and use less fuels, catalytic converters on cars to reduce CO2 . Also industrial solutions include electrostatic precipitation, baghouse filter, cyclone separator, wet scrubber. These methods, however, are expensive and only divert the pollution problem by reducing air pollution, but not pollution as a whole.
-all form from decayed plant and animal matter
-nonrenewable: they do not renew themselves within 100 years
-Alternative Energy Resources include almost any energy sources other than fossil fuels
1. Hydroelectric Power: Flow of a river turns a turbine generating electricity
-Inexpensive Repairs and Replacement Costs
-Renewable Energy Source
-Requires flooding of large areas
-Potential displacement of people
-Build up of Sediment in water before the Dam
-Expensive to build
2. Solar Heating
-Passive Solar Heating - using strategies for regulating a buildings indoor air and water tempatures, a building is designed to take advantage of the suns energy to heat indoor air
-Active Solar Heating - using solar energy to convert the energy of the sun into forms of energy, primarily heat
- PV Cells - used to convert solar energy into electricity
-Takes up land area
-Requires a way to store energy when sun is obscured
3. Biomass:The burning of biomass (often garbage) for energy, the heat from the fire is used to boil water and the steam from the boiler is used to spin a turbine.
-Renewable Resource (if not used at a higher rate than can be replenished)
-A way to remove trash
-Creates massive amount of air pollution
4. Tidal Wave Energy - The movement of the tides and waves turns large turbines in the ocean that create electricity
-Little to no emission
-Can reduce visual appeal of a beach
-Construction is expensive
5. Ocean Thermal Energy Conversion (OTEC) - Plants channel difference in temperature (energy) into electricity
-No Pollution concerns
-Moderate Net Energy Yield
-Technology is still in the development stage
6. Wind Energy - wind spins turbine blades to produce electric current
-does not utilize a nonrenewable resource
-does not contribute to air pollution, (mitigating global warming),
-can be competitive economically,
-newer technology doesn't produce noise pollution
-taps a variable source of power
-takes land area, aesthetically ugly
7. Geothermal- harnessing the earth's heat to produce electricity or thermal energy
-Renewable source of energy,
-takes minimal land area,
-doesn't emit pollution
-Sites can be heat-depleted,
-not available in many areas,
-not competitive in other areas
-Controlled by the federal government through the Surface Mining Control and Reclamation Act of 1977. This law created two programs, one for regulating active coal mines and one for reclaiming abandoned mines for whom no party could be held legally responsible (such as when the mining company has gone bankrupt).
-Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or (coal) seam.
-Placer mining involves any type of mining where raw minerals are deposited in sand or gravel or on the surface and are picked up without having to drive, use dynamite or any other significant means. Ex. panning for gold in a stream bed.
-Open pit mines involve digging large open holes in the ground as opposed to a small shaft in hard rock mining. This method of mining is most often used with minerals like copper and molybdenum. Open pit mines are very large and devastate the surrounding landscape.
-Strip mining is a form of surface mining. The ore is close to the surface of the land but has one or more layers of rock and dirt on top of it. To mine the ore, these layers have to be taken off causing overburden. Coal in TN is mines by contour strip mining.
-Room and pillar mining: This is used in mining minerals such as Diamonds , silver, and sometimes coal. There are intersecting 'rooms' with pillars of coal or rock that hold up the roof. These pillars are mined last when the mine, or a part of it, is closing. They are careful when they do this because the roof caves in as they leave.
-Longwall mining: Usually a machine called a continuous miner slices layers of minerals from the walls and lets the rocks fall onto a conveyor belt to be taken out of the mine.
-There can be massive "cons" to the environment - the processing of the ore can require a chemical process - Gold mining for example cyanide heap leaching.
-Cons: Acid mine drainage; subsidence; habitat loss, erosion, spoil piles, slag piles, overburden refuse, loss of topsoil; dangerous to miners- black lung, carbon monoxide, radon.
-West Virginia coal mining accident 2010 - methane explosion and combustible coal dust - 28 killed.
-Soils are composed of four different components which include: minerals, water, gas, and humus. Also related to this, soil's controlling factors are parent material, environment, and age, some other soil properties include texture, pH, permeability, porosity, and nutrient levels (N, K)
-Parent Materials get into soils through weathering.
-Weathering- Any process where rock breaks down (changes chemically and physically)
-The textures of soil include Sand (largest), Silt (Silt), Clay (Small), and Loam (Mixture of all three).
-Porosity- Volume of pores/ spaces per volume of soil
-Permeability- Rate of Flow of materials through soil (infiltration- water permeating through soil)
-Erosion results in poor soils with low nutrients, which occurs through the dehydration of soil.
There are two different types of mining, surface and underground.
-Surface Mining- scoop ore off surface or earth
-Underground- Use of shafts to reach deeply buried ores.
There are three compositional layers of Earth, Crust, Mantle, and Core
-Crust: Thin, outer shell ranging from three km to 70 km thick.
-Mantle: Solid, quartz- rich layer that extends from crust to 2900 km.
-Core: Iron rich sphere from 2900 km to center of earth (6300 m in depth)
Layers of Soil:
-O: organic horizons, litter derived from dead plants and animals
-A: eluvial, mineral horizons which lie at or near the surface.
-B: illuvial, washed in, layer of accumulation
-C: unconsolidated material.
There are four eras in Earth History
-Precambrian: before complex life appeared
-Paleozoic: From the time complex life first appeared until a mass extinction allowed the dinosaurs to become dominant
-Mesozoic: From the time dinosaurs became dominant until the time dinosaurs went extinct
-Cenozoic: From the dominance of animals to the present day.
Plate tectonics- two types
-Subduction- When a denser oceanic plate meets a lighter continental plate
-Collision- mountain building occurs when two continental plates converge.