ENS Test 2
Environmental Science Study Guide — Lectures 7–12
Lecture 7 — Population Biology
Population Characteristics
Population – Organisms of the same species living in one area that commonly breed with each other.
Population Biology – Study of populations and how they change.
Demographics – Statistics that describe a population.
Population Size – Total number of individuals in a population.
Population Density – Number of individuals in a certain area or volume.
Population Distribution – How individuals are spaced within an area.
Clumped Distribution – Individuals live close together, often because of resources or social behavior.
Uniform Distribution – Individuals are evenly spaced, usually because of competition.
Random Distribution – Individuals are scattered without a pattern; rare in nature.
Limited Dispersal – Organisms or offspring cannot travel far from their original location.
Population Sampling – Estimating population size without counting every individual.
Quadrat Sampling – Counting organisms in a small area to estimate the total population.
Mark-Recapture – Capturing, marking, releasing, and recapturing animals to estimate population size.
Population Growth – Occurs when births exceed deaths.
Exponential Growth – Rapid population growth when resources are unlimited.
Per Capita Growth Rate (r) – Population growth rate per individual.
Biotic Potential – Maximum possible population growth under ideal conditions.
Logistic Growth – Growth slows as population density increases and resources become limited.
Carrying Capacity (K) – Maximum population an environment can support indefinitely.
Limiting Factors – Conditions or resources that restrict population growth.
Density-Dependent Factors – Factors that become stronger as populations grow, such as competition and disease.
Density-Independent Factors – Events affecting populations regardless of size, such as hurricanes and floods.
Life History and Survival
Life History Traits – Characteristics such as reproduction rate, development, and lifespan.
Survivorship – Pattern of survival throughout an organism's life.
Cohort – Individuals born around the same time.
Survivorship Curve – Graph showing how survival changes with age.
Type I Survivorship – Most individuals survive until old age; common in large mammals.
Type II Survivorship – Individuals have a relatively constant chance of dying throughout life.
Type III Survivorship – Many individuals die young, but survivors may live much longer.
Opportunistic Life History (r-selected) – Producing many offspring with little parental investment.
Equilibrial Life History (K-selected) – Producing fewer offspring with greater parental investment.
r-selected Species – Species that reproduce quickly, especially in unpredictable environments.
K-selected Species – Species that reproduce slowly and often live near carrying capacity.
Important Formulas
Exponential Growth: Change in population = r × N
Logistic Growth: Change in population = r × N × (1 − N/K)
N = Population size
r = Per capita growth rate
K = Carrying capacity
Remember: Exponential growth creates a J-shaped curve, while logistic growth creates an S-shaped curve.
Lecture 8 — Human Populations
Human Population Growth
Human Population – Total number of people living in an area or worldwide.
Population Explosion – Rapid human population growth caused by declining death rates while birth rates remain high.
Thomas Malthus – Scientist who argued that human populations grow faster than food supplies.
Malthusian Theory – Human population growth could eventually exceed available food.
Linear Growth – Growth by a constant amount over time.
Human Carrying Capacity – Maximum number of people Earth can sustainably support.
Technological Innovation – New inventions or methods that can increase resources and potentially change carrying capacity.
Demography – Study of human populations.
Demographers – Scientists who study human population trends.
Immigration – Moving into a country or area.
Emigration – Moving out of a country or area.
Birth Rate – Number of births in a population over time.
Death Rate – Number of deaths in a population over time.
Crude Birth Rate (CBR) – Number of births per 1,000 people per year.
Crude Death Rate (CDR) – Number of deaths per 1,000 people per year.
Population Growth Rate – Percentage increase in population over time.
Doubling Time – Number of years needed for a population to double.
Rule of 70 – Formula used to estimate population doubling time.
Population Stabilization – When population size stops increasing significantly.
Fertility and Mortality
Total Fertility Rate (TFR) – Average number of children a woman is expected to have.
Replacement-Level Fertility – Fertility rate needed to replace the existing population.
Replacement Rate in Developed Nations – Approximately 2.1 children per woman.
Life Expectancy – Average number of years a newborn is expected to live.
Infant Mortality Rate – Deaths of children under age 1 per 1,000 live births.
Child Mortality Rate – Deaths of children under age 5 per 1,000 live births.
Infectious Disease – Disease caused by microbes that can spread between people.
HIV – Human immunodeficiency virus, which can lead to AIDS.
Age Structure – Proportion of people in different age groups.
Population Pyramid – Graph showing a population's age distribution.
Wide-Based Population Pyramid – Many young people; suggests rapid future growth.
Even Age Distribution – Similar proportions across age groups; suggests slow or stable growth.
Inverted Population Pyramid – More older people than younger people; suggests population decline.
Aging Population – Population with a growing proportion of older adults.
Demographic Transition
Demographic Transition Theory – Explains how population growth changes as countries industrialize.
Preindustrial Stage – High birth and death rates; slow population growth.
Early Industrial Stage – Death rates decline while birth rates remain high; rapid growth.
Mature Industrial Stage – Birth rates decrease and population begins stabilizing.
Postindustrial Stage – Low fertility and possible population decline.
Subsistence Economy – Economy focused on meeting basic survival needs.
Industrialization – Development of industries and manufacturing.
Affluence – Wealth and access to resources.
Environmental Impact
IPAT Equation – Estimates human environmental impact using population, affluence, and technology.
Population (P) – Number of people consuming resources and producing waste.
Affluence (A) – Level of consumption associated with wealth.
Technology (T) – Tools and processes that can increase or decrease environmental impact.
Destructive Technology – Technology that causes environmental damage or pollution.
Important Formulas
Global Population Growth Rate (%) = (CBR − CDR) ÷ 10
National Population Growth Rate (%) = [(CBR + immigration rate) − (CDR + emigration rate)] ÷ 10
Doubling Time = 70 ÷ annual growth rate (%)
IPAT = Impact = Population × Affluence × Technology
Example: If a population grows 2% per year, its doubling time is 70 ÷ 2 = 35 years.
Lecture 9 — Community Ecology
Competition and Resources
Community Ecology – Study of interactions between different populations.
Ecological Community – Different populations living and interacting in the same area.
Competition – Struggle between organisms for limited resources.
Limiting Resource – Resource in shortest supply relative to demand.
Liebig's Law of the Minimum – The scarcest needed resource limits population growth.
Competitive Exclusion Principle – Two species competing for the same limiting resource cannot coexist indefinitely.
Ecological Niche – A species' way of life and how it uses resources.
Resource Partitioning – Species dividing resources to reduce competition.
Resource Overlap – When species use the same resources.
Temporal Resource Partitioning – Species use resources at different times.
Spatial Resource Partitioning – Species use different physical areas.
Morphological Resource Partitioning – Differences in body shape or size allow species to use different resources.
Niche Specialization – Species becoming adapted to using particular resources.
Predation and Defense
Predation – One species uses another species as a resource.
Predator – Organism that consumes another organism.
Prey – Organism consumed by another organism.
True Predator – Organism that kills and consumes most of its prey.
Herbivore – Organism that eats plants.
Behavioral Defense – Avoiding predators through actions such as hiding or reduced movement.
Morphological Defense – Physical protection such as spines or camouflage.
Chemical Defense – Using toxins or unpleasant chemicals to discourage predators.
Camouflage – Blending into surroundings to avoid detection.
Mimicry – Resembling a more dangerous organism for protection.
Species Relationships
Symbiosis – Close relationship between two different species.
Parasitism – One organism benefits while harming another.
Parasite – Organism that lives on or inside a host and consumes its resources.
Host – Organism that provides resources to a parasite.
Parasitoid – Organism whose young develop inside a host and eventually kill it.
Mutualism – Relationship in which both species benefit.
Commensalism – Relationship where one species benefits and the other is unaffected.
Plant-Pollinator Mutualism – Plants receive pollination while pollinators receive resources.
Coral-Algae Mutualism – Relationship in which coral and algae benefit each other.
Community Structure
Keystone Species – Species whose removal has an unusually large effect on the community.
Trophic Cascade – Changes in one part of a food chain affect several other levels.
Predator-Mediated Competition – Predators influence competition among other species.
Ecological Engineer – Species that creates or maintains habitats for other organisms.
Beaver Ecosystem Engineering – Beavers create ponds and wetlands that support other species.
Ecological Succession – Gradual replacement of one group of species by another.
Primary Succession – Community development in an area without soil.
Secondary Succession – Community recovery after disturbance when soil remains.
Pioneer Species – Species that quickly colonize new or disturbed environments.
Disturbance – Event such as a fire or hurricane that changes a community.
Important examples to memorize:
Darwin's finches – Morphological resource partitioning through different beak sizes.
Wolves and coyotes – Temporal resource partitioning.
Desert plants with different root depths – Spatial resource partitioning.
Sea stars and mussels – Keystone species example.
Beavers and alligators – Ecological engineers.
New lava rock – Primary succession.
Forest after a fire – Secondary succession.
Lecture 10 — Geologic Processes
Earth's Layers
Core – Earth's innermost layer, mostly iron and nickel.
Inner Core – Solid central part of Earth's core.
Outer Core – Liquid portion of Earth's core.
Mantle – Layer beneath Earth's crust where slow material movement occurs.
Magma – Molten rock beneath Earth's surface.
Convection Cells – Circulating material driven by heat that helps move tectonic plates.
Asthenosphere – Semi-molten, slowly moving part of the upper mantle.
Crust – Earth's outermost rocky layer.
Lithosphere – Rigid outer layer of Earth divided into tectonic plates.
Geologic Cycles – Processes that continuously change Earth's materials.
Plate Tectonics
Tectonic Cycle – Movement and interaction of Earth's plates.
Alfred Wegener – Scientist who proposed that continents were once connected.
Pangaea – Ancient supercontinent containing Earth's joined landmasses.
Continental Drift – Idea that continents have moved over geologic time.
Plate Tectonics – Theory that Earth's lithosphere consists of moving plates.
Oceanic Plate – Dense, iron-rich plate beneath the ocean.
Continental Plate – Less dense plate beneath continents, rich in silica.
Seafloor Spreading – New oceanic crust forms as plates move apart.
Subduction – Denser plate sinks beneath another plate.
Divergent Boundary – Boundary where plates move apart.
Convergent Boundary – Boundary where plates move toward each other.
Transform Boundary – Boundary where plates slide sideways past each other.
Fault – Fracture in rock where movement occurs.
Fault Zone – Large region containing fractures where movement has occurred.
Earthquake – Sudden movement of rock along a fault.
Epicenter – Location associated with an earthquake's origin; identified on the surface above the focus.
Volcanic Eruption – Release of magma onto Earth's surface.
Rocks and Minerals
Rock Cycle – Continuous formation, breakdown, and transformation of rocks.
Rock – Solid material made of one or more minerals.
Mineral – Naturally formed solid substance with a crystalline structure.
Weathering – Breakdown of rocks into smaller pieces or altered materials.
Erosion – Movement of weathered material from one place to another.
Deposition – Settling and accumulation of transported material.
Igneous Rock – Rock formed when magma or lava cools and hardens.
Sedimentary Rock – Rock formed from compressed and cemented sediments.
Metamorphic Rock – Rock changed by high temperature and pressure.
Basaltic Rock – Dark igneous rock rich in iron, magnesium, and calcium.
Granitic Rock – Light-colored igneous rock containing minerals such as quartz and mica.
Intrusive Igneous Rock – Rock formed when magma cools underground.
Extrusive Igneous Rock – Rock formed when molten material cools at Earth's surface.
Sandstone – Sedimentary rock made from compressed and cemented sand.
Conglomerate Rock – Sedimentary rock containing gravel, cobbles, and sand.
Slate – Example of metamorphic rock.
Marble – Example of metamorphic rock.
Crystallization – Formation of solid crystals as molten material cools.
Soil Formation
Soil – Mixture of minerals, weathered rock, and organic material.
Soil Formation – Development of soil through weathering and organic matter accumulation.
Parent Material – Original rock or material from which soil develops.
Climate – Temperature and precipitation conditions that influence soil formation.
Topography – Shape and slope of land that influence soil erosion and accumulation.
Soil Organisms – Living things that mix soil and influence nutrient availability.
Soil Horizons – Different layers of soil.
O Horizon – Top layer made mostly of organic material.
A Horizon – Topsoil containing organic matter and minerals.
E Horizon – Layer where minerals are removed by leaching.
B Horizon – Subsoil containing minerals and little organic matter.
C Horizon – Partly weathered material similar to parent rock.
R Horizon – Solid, unweathered parent rock.
Leaching – Movement of dissolved minerals downward through soil.
Soil Texture – Proportions of sand, silt, and clay in soil.
Sand – Largest of the three main soil particle sizes.
Silt – Medium-sized soil particles.
Clay – Smallest soil particles.
Soil Porosity – Pore spaces in soil that affect water movement and storage.
Important: Remember the soil horizon order: O → A → E → B → C → R.
Lecture 11 — Water Resources
Water Distribution and Groundwater
Water Resources – Water available for organisms and human use.
Freshwater – Water containing very little dissolved salt.
Saltwater – Water with high salt content, mainly in oceans.
Surface Water – Freshwater found in rivers, streams, lakes, ponds, and wetlands.
Groundwater – Water stored underground in soil and rock.
Water Table – Upper boundary of fully saturated soil or rock.
Groundwater Recharge – Water moving from the surface into underground aquifers.
Recharge Area – Surface location where water enters an aquifer.
Aquifer – Underground rock or sediment that stores and transmits groundwater.
Unconfined Aquifer – Aquifer beneath porous soil that can recharge relatively quickly.
Confined Aquifer – Aquifer trapped between layers of impermeable material.
Impermeable Layer – Material that prevents or greatly slows water movement.
Artesian Well – Well where underground pressure pushes water upward.
Ogallala Aquifer – Major U.S. groundwater source used for agriculture, households, and industry.
Groundwater Withdrawal – Removing water from underground sources.
Overwithdrawal – Removing groundwater faster than it is replenished.
Cone of Depression – Lowered water table surrounding a pumping well.
Saltwater Intrusion – Saltwater entering freshwater aquifers, often because of excessive pumping.
Hydraulic Fracturing (Fracking) – Using water and chemicals under pressure to fracture rock and extract oil or gas.
Surface Water and Lakes
River – Flowing body of freshwater.
Floodplain – Land surrounding a river that may flood and often contains fertile soil.
Lake – Inland body of standing water.
Tectonic Lake – Lake formed by movement of Earth's crust.
Glacial Lake – Lake formed in depressions created by glaciers.
Primary Productivity – Rate at which producers create organic material.
Oligotrophic Lake – Lake with low nutrients and low productivity; often clear.
Mesotrophic Lake – Lake with moderate nutrients and productivity.
Eutrophic Lake – Lake with high nutrients and high productivity; often greener.
Nitrogen (N) – Nutrient that can influence aquatic productivity.
Phosphorus (P) – Nutrient that can influence aquatic productivity.
Lake Victoria – Lake with a large surface area but relatively shallow depth.
Caspian Sea – World's largest inland body of water by surface area.
Lake Baikal – World's deepest lake.
Great Lakes – Large North American lakes formed by glaciers.
Wetlands and Flooding
Wetland – Area where soil is saturated with water for long periods.
Wetland Flood Control – Wetlands absorb and store excess water.
Wetland Water Purification – Wetlands help remove pollutants and sediments from water.
Wetland Nursery Habitat – Wetlands provide shelter for young fish and shellfish.
Pantanal – Large wetland region in South America.
Florida Everglades – Major wetland ecosystem in Florida.
Drought – Extended period with insufficient water availability.
Dust Bowl – Historical example of drought and poor land use causing severe soil erosion.
Impermeable Surface – Pavement or buildings that prevent water from entering the ground.
Flooding – Water overflowing onto normally dry land.
Levee – Raised bank built alongside a river to prevent flooding.
Levee Failure – Collapse or erosion of a levee during high water.
Dike – Barrier built to prevent ocean water from flooding land.
Hurricane Katrina (2005) – Hurricane associated with major levee failures and flooding in New Orleans.
Human Water Management
Dam – Barrier built across a river to control water flow.
Reservoir – Water stored behind a dam.
Potable Water – Water safe for drinking.
Fish Ladder – Structure helping fish travel past dams.
Three Gorges Dam – Large dam on China's Yangtze River that displaced many people.
Aqueduct – Canal or pipe system that transports water between locations.
Catskill Aqueduct – Water transportation system supplying New York City.
Water Diversion – Redirecting water from its natural flow.
Aral Sea – Lake that shrank dramatically after rivers feeding it were diverted.
Desalination – Removing salt from seawater or salty water.
Distillation – Boiling water and condensing the steam to separate water from salt.
Reverse Osmosis – Forcing water through a membrane that blocks salt.
Semipermeable Membrane – Barrier that allows certain substances through while blocking others.
Brine – Highly concentrated saltwater left after desalination.
Water Rights – Legal or political claims over water use and ownership.
Water Conflict – Disagreement between groups or countries over water access.
Important Water Percentages
70% – Earth's surface covered by water.
97% – Earth's water that is saltwater.
3% – Earth's water that is freshwater.
30% – Approximate freshwater stored underground.
0.3% – Approximate freshwater in lakes, rivers, streams, and wetlands, according to the slide.
87% – Share of that surface-water category found in lakes.
11% – Share in wetlands.
2% – Share in rivers and streams.
Lecture 12 — Non-Renewable Energy
Energy Basics
Non-Renewable Energy – Energy from resources that cannot be replenished on a human timescale.
Fossil Fuels – Fuels formed from ancient biological material.
Nuclear Fuel – Radioactive material used to produce nuclear energy.
Joule (J) – Basic unit of energy.
Gigajoule (GJ) – One billion joules.
Exajoule (EJ) – One billion gigajoules.
Commercial Energy – Energy that is bought and sold.
Subsistence Energy – Energy collected by individuals for their own needs.
Energy Efficiency – How effectively energy is converted into useful work.
Embodied Energy – Energy required to produce, obtain, and use a resource or product.
Energy Return on Energy Investment (EROEI) – Ratio of energy gained to energy used to obtain it.
Primary Energy Source – Energy source found directly in nature, such as coal or natural gas.
Secondary Energy Source – Energy produced by converting primary energy.
Electricity – Secondary energy source produced by converting other forms of energy.
Energy Carrier – Form of energy that can transport usable energy from one place to another.
Turbine – Machine turned by moving steam, gas, or water.
Generator – Machine that converts mechanical motion into electricity.
Coal Power Plant – Facility that burns coal to produce steam and generate electricity.
Combined-Cycle Power Plant – Plant that uses gas combustion and waste heat to generate electricity more efficiently.
Coal and Petroleum
Coal – Fossil fuel formed from ancient plant remains.
Surface Mining – Removing resources from near Earth's surface.
Subsurface Mining – Extracting resources from underground.
Petroleum – Liquid fossil fuel formed from ancient organisms, especially phytoplankton.
Crude Oil – Unrefined petroleum taken from underground.
Phytoplankton – Microscopic photosynthetic organisms that contributed to petroleum formation.
Petroleum Refining – Separating crude oil into useful products using differences in boiling temperatures.
Gasoline – Refined petroleum fuel commonly used in vehicles.
Diesel – Refined petroleum fuel used in engines and transportation.
Kerosene – Petroleum product used in fuels and heating.
Asphalt – Heavy petroleum product used for roads.
Lubricating Oil – Petroleum product used to reduce friction in machinery.
Oil Spill – Accidental release of petroleum into the environment.
Exxon Valdez Spill (1989) – Major oil spill associated with an oil tanker.
Deepwater Horizon Spill (2010) – Major offshore oil spill in the Gulf of Mexico.
Gas Flare – Controlled burning of natural gas at an oil or gas site.
Natural Gas
Natural Gas – Fossil fuel made mostly of methane.
Methane (CH₄) – Main component of natural gas and a powerful greenhouse gas.
Ethane – Hydrocarbon found in natural gas.
Butane – Hydrocarbon found in natural gas.
Liquefied Petroleum Gas (LPG) – Petroleum gases stored as a liquid.
Greenhouse Gas – Gas that traps heat in Earth's atmosphere.
Natural Gas Combustion – Burning natural gas to produce heat or electricity.
Fracking Pollution – Potential contamination of water during hydraulic fracturing.
Nuclear Energy
Nuclear Energy – Energy released from changes in atomic nuclei.
Nuclear Fission – Splitting a large atomic nucleus to release energy and neutrons.
Chain Reaction – Repeated nuclear reactions triggered by released neutrons.
Neutron – Subatomic particle that can trigger nuclear fission.
Uranium-235 – Radioactive uranium isotope used in nuclear reactors.
Nuclear Reactor – System that controls nuclear reactions to produce heat.
Fuel Rod – Rod containing nuclear fuel pellets.
Control Rod – Rod that absorbs neutrons to slow or stop nuclear fission.
Nuclear Meltdown – Severe overheating that damages or melts nuclear reactor fuel.
Radioactive Waste – Hazardous material remaining after nuclear energy production.
Radioactive Contamination – Release or spread of radioactive material into the environment.
Three Mile Island (1979) – Pennsylvania nuclear accident involving a partial meltdown.
Chernobyl (1986) – Ukrainian nuclear disaster involving a reactor accident and widespread radioactive contamination.
Fukushima Daiichi (2011) – Japanese nuclear disaster triggered by an earthquake and tsunami.
Residual Heat – Heat remaining in a nuclear reactor after fission is stopped.
Cooling System – System that removes heat from a nuclear reactor to prevent overheating.
Lecture 13 — Renewable Energy
Renewable Energy Basics
Renewable Energy – Energy that can be replaced as quickly as it is used.
Nondepletable Energy – Energy sources that cannot be used up.
Examples of Nondepletable Energy – Solar, wind, geothermal, hydroelectric, and tidal energy.
Traditional Renewable Energy – Wood, manure, and animal oils used before fossil fuels.
Energy Conservation – Reducing energy use to protect resources and the environment.
Environmental Impact of Energy – Effects that energy production and use have on the environment.
Energy Taxes – Government taxes that encourage people to use less energy.
Tiered Rate System – Charging lower rates for low energy use and higher rates for high energy use.
Energy Rebates – Money returned to consumers for using less energy or improving efficiency.
Energy Tax Credits – Tax reductions given for energy-saving improvements.
Sustainable Buildings
Sustainable Design – Designing buildings to use energy and resources efficiently.
Passive Solar Design – Using sunlight to heat buildings naturally.
Thermal Inertia – Ability of materials to retain heat or cold.
High Thermal Inertia Materials – Stone and concrete, which retain temperatures well.
Green Roof – Roof covered with plants that help shade and cool a building.
Recycled Building Materials – Reused materials that reduce the need for new resources.
Recycled Denim Insulation – Using old denim as building insulation.
Biomass Energy
Biomass – Energy from organic materials such as wood, manure, and plant waste.
Biomass Examples – Wood, charcoal, manure, plant remains, municipal waste, ethanol, and biodiesel.
Biofuels – Fuels made from biological materials, including ethanol and biodiesel.
Modern Carbon – Carbon recently taken from the atmosphere by plants.
Fossil Carbon – Carbon stored underground for millions of years.
Carbon Neutral – Releasing no net additional carbon dioxide into the atmosphere.
Biomass Carbon Cycle – Plants absorb carbon dioxide that can be released again when burned.
Fossil Fuel Carbon Release – Burning fossil fuels adds ancient stored carbon to the atmosphere.
Solid Biomass – Solid organic materials burned for energy.
Wood Fuel – Burning wood for cooking or heating.
Unsustainable Wood Harvesting – Cutting trees faster than they can naturally regrow.
Soil Carbon Release – Stored carbon escaping from soil when it is disturbed.
Charcoal – Fuel made from wood that is lighter and burns with less smoke.
Charcoal Energy Content – About twice as much energy per unit weight as wood, according to the slides.
Dried Animal Manure – Animal waste burned for fuel where wood is scarce.
Particulate Matter – Small particles released into the air that can cause pollution.
Biomass Deforestation – Loss of forests from excessive harvesting of wood for fuel.
Ethanol
Ethanol – Alcohol fuel produced from plant sugars and starches.
Ethanol Production – Converting plant sugars and starches into alcohol and carbon dioxide.
Corn Ethanol – Ethanol made from corn, the main source used in the United States.
Sugarcane Ethanol – Ethanol produced from sugarcane, commonly used in Brazil.
Switchgrass – Plant that can be used to produce ethanol.
Crop Waste Ethanol – Ethanol made from leftover agricultural materials.
Gasohol (E10) – Gasoline containing 10% ethanol.
E85 Fuel – Fuel containing 85% ethanol and 15% gasoline.
Flex-Fuel Vehicle – Vehicle that can use gasoline or ethanol fuel blends such as E85.
Ethanol Oxygen Content – High oxygen content that can reduce some air pollutants.
Ethanol Energy Content – Lower energy per gallon than gasoline.
Ethanol Mileage Disadvantage – Ethanol blends can reduce fuel economy.
Food vs. Fuel Competition – Growing crops for fuel uses land that could produce food.
Ethanol Fossil Fuel Dependence – Growing and processing ethanol crops requires energy, sometimes from fossil fuels.
Biodiesel
Biodiesel – Diesel substitute made from vegetable oils or animal fats.
B20 Fuel – 20% biodiesel and 80% petroleum diesel.
Straight Vegetable Oil (SVO) – Vegetable oil used as fuel in modified diesel engines.
Waste Cooking Oil Fuel – Used restaurant oil converted or adapted for use as fuel.
Soybean Biodiesel – Biodiesel produced from soybean oil.
Algae Biodiesel – Biodiesel produced from oil-rich algae.
Algae Oil Production – According to the slides, algae can produce 15–300 times more oil per area than soybeans.
Hydroelectric Energy
Hydroelectricity – Electricity generated using the energy of moving water.
Kinetic Energy – Energy of motion.
Hydroelectric Turbine – Machine turned by flowing water to help generate electricity.
Run-of-the-River System – Hydroelectric system that directs river water through a channel without a large reservoir.
Run-of-the-River Advantage – Causes less upstream flooding and less disruption to seasonal water flow.
Run-of-the-River Disadvantage – Electricity production can be inconsistent.
Water Impoundment System – Hydroelectric system that stores water behind a large dam.
Hydroelectric Reservoir – Water stored behind a dam for electricity generation.
Hydroelectric Flood Control – Dams can help control downstream flooding.
Hydroelectric Recreation – Reservoirs can provide boating, fishing, and other activities.
Hydroelectric Relocation – People may be forced to move when land is flooded for reservoirs.
Aquatic Habitat Loss – Damage to habitats when free-flowing rivers become reservoirs.
Reservoir Methane – Methane released when flooded plants decay underwater.
Siltation – Sediment gradually accumulating in a reservoir.
Reservoir Lifespan – Reservoirs may fill with sediment over decades or centuries.
Hydroelectric Cultural Impact – Flooded land may contain important historical or archaeological sites.
Impoundment Water Diseases – Some human diseases become more common around stored water.
Tidal Energy
Tidal Energy – Energy generated from the movement of ocean tides.
Tidal Range – Difference between high and low tide.
Tidal Energy Limitation – Many areas do not have enough tidal movement for large-scale electricity production.
Tidal Energy Environmental Impact – Tidal systems can disrupt coastal and marine ecosystems.
Countries Using Tidal Energy – France, Korea, and Canada are examples from the slides.
Solar Energy
Solar Energy – Energy obtained from sunlight.
Passive Solar Heating – Heating buildings with sunlight without mechanical equipment.
South-Facing Windows – Windows positioned to collect winter sunlight for heating.
Solar Oven – Device that uses sunlight to cook food.
Solar Oven Benefit – Reduces the need for wood fuel and can help prevent deforestation.
Solar Pool Heating – Using sunlight to warm swimming pool water.
Active Solar Energy – Using technology to capture and use sunlight.
Solar Water Heating System – System that uses sunlight to heat water for homes or pools.
Photovoltaic (PV) System – Technology that converts sunlight directly into electricity.
Semiconductor – Material that can produce an electric current when exposed to sunlight.
Photovoltaic Efficiency – The slides report approximately 20–24% efficiency.
Grid-Connected Solar System – Solar system connected to the electrical grid.
Selling Solar Electricity – Sending extra solar electricity back to an electric utility.
Off-Grid Solar System – Solar system operating without connection to the electrical grid.
Solar Battery Storage – Storing solar electricity for later use.
Concentrating Solar Thermal Energy – Using mirrors or lenses to focus sunlight and produce heat.
Solar Thermal Electricity Generation – Using concentrated sunlight to create steam that turns a turbine.
Solar Energy Advantage – Produces electricity without direct air pollution or carbon dioxide emissions during operation.
Remote Solar Energy – Solar panels can provide electricity to homes far from electrical grids.
Solar Manufacturing Impact – Solar panel production requires energy, water, and potentially toxic metals.
Solar Installation Cost – Expense of manufacturing and installing solar technology.
Solar Energy Storage Limitation – Some solar systems need batteries when sunlight is unavailable.
Geothermal Energy
Geothermal Energy – Energy obtained from heat within Earth.
Radioactive Decay – Breakdown of radioactive elements that produces heat inside Earth.
Geothermal Heat Exchanger – System that circulates fluid underground to transfer heat.
Geothermal Electricity – Using Earth's heat to produce steam and generate electricity.
Geothermal Steam – Steam produced using underground heat.
Geothermal Groundwater Dependence – Some geothermal plants need groundwater to produce steam.
Geothermal Gas Pollution – Hazardous gases may escape with geothermal steam.
Iceland Geothermal Heating – The slides state that 87% of Icelandic homes use geothermal heating.
U.S. Geothermal Locations – California, Nevada, Hawaii, and Utah.
Ground-Source Heat Pump – System that transfers heat between buildings and the ground.
Underground Temperature Stability – Ground temperatures remain relatively constant at certain depths.
Ground-Source Summer Cooling – Underground pipes help remove heat from a building.
Ground-Source Winter Heating – Underground pipes help bring heat into a building.
Ground-Source Heat Pump Efficiency – The slides report 30–70% less energy use than conventional systems.
Wind Energy
Wind Energy – Energy generated from moving air.
Wind Formation – Unequal heating of Earth's surface by the Sun causes air movement.
Wind Turbine – Machine that converts wind energy into electricity.
Wind Farm – Group of wind turbines generating electricity.
Offshore Wind Energy – Electricity produced by turbines located in bodies of water.
Wind Energy Advantage – Produces electricity without direct air pollution or greenhouse gas emissions during operation.
Wind Land Sharing – Wind turbines can share land with activities such as cattle grazing.
Wind Energy Intermittency – Wind turbines only generate electricity when wind conditions allow.
Wind Battery Storage – Storing electricity produced by wind for later use.
Wind Turbine Noise – Sound produced by operating turbines.
Wind Wildlife Impact – Wind turbines can kill birds and bats.
Wind Turbine Visual Impact – Large turbines may affect how a landscape looks.
Wind Turbine Electricity Production – The slides give an example of a turbine generating 4.4 million kilowatt-hours per year.
Wind Turbine Capacity Example – The slide's example turbine produces enough electricity for about 400 homes.
Hydrogen Fuel Cells
Hydrogen Fuel Cell – Device that generates electricity by reacting hydrogen with oxygen.
Hydrogen (H₂) – Gas used as fuel in hydrogen fuel cells.
Oxygen (O₂) – Gas that reacts with hydrogen in a fuel cell.
Hydrogen Fuel Cell Reaction – Hydrogen and oxygen react to produce electricity, water, and heat.
Fuel Cell Membrane – Material that allows protons to move through while electrons travel separately.
Proton – Positively charged particle that moves through the fuel cell membrane.
Electron – Negatively charged particle whose movement creates electric current.
Hydrogen Energy Carrier – Hydrogen can store energy produced from other sources.
Hydrogen Energy Storage – Using extra electricity to produce hydrogen for later energy use.
Hydrogen Fuel Cell Vehicle – Vehicle powered by electricity from hydrogen fuel cells.
Electric Motor Efficiency – Electric motors are more efficient than combustion engines.
Hydrogen Fuel Cell Efficiency – The slides report approximately 80% efficiency in converting energy to electricity.
Hydrogen Fuel Cell Byproduct – Water.
Hydrogen Production Disadvantage – Energy is required to produce hydrogen, often from fossil fuels.
Hydrogen Safety Risk – Hydrogen is highly flammable and must be handled carefully.
Important Lecture 13 Numbers
Global Biomass Energy Use – The slides estimate biomass provides 10% of world energy consumption.
Sub-Saharan African Biomass Use – The slides report 86% of energy use comes from biomass.
U.S. Renewable Energy Use – The slides report 7% of total energy use.
Global Wood Fuel Use – Approximately 3 billion people use wood for cooking or heating, according to the slides.
U.S. Wood Heating Use – Approximately 20 million people use wood for heat at least sometimes, according to the slides.
Hydroelectric Global Electricity Share – The slides report approximately 20%.
Ground Temperature at 10 Feet – Approximately 50–60°F, according to the slides.
Hydrogen Fuel Cell Equation – 2H₂ + O₂ → energy + 2H₂O.
Lecture 14 — Environmental Health and Toxicology
Pathogens and Infectious Diseases
Environmental Health – Study of how environmental conditions affect human health.
Toxicology – Study of poisons and their effects on living organisms.
Pathogens – Organisms or infectious agents that cause disease.
Viruses – Infectious agents that reproduce inside living cells.
Bacteria – Single-celled microorganisms that can sometimes cause disease.
Protozoans – Single-celled organisms that can cause parasitic infections.
Parasitic Worms – Worms that live in or on a host and obtain resources from it.
Flukes – Parasitic flatworms that can infect humans and animals.
Infectious Disease – Disease caused by pathogens.
Influenza – Viral infection affecting the respiratory system.
Spanish Flu (1918) – Major influenza pandemic that killed millions of people.
COVID-19 – Infectious disease caused by SARS-CoV-2.
SARS-CoV-2 – Coronavirus responsible for COVID-19.
Pandemic – Disease outbreak that spreads across multiple countries or continents.
Epidemic – Rapid spread of a disease affecting many people in a population.
Intestinal Parasites
Giardia – Intestinal protozoan parasite spread through contaminated food or water.
Giardiasis – Intestinal illness caused by Giardia.
Fecal Contamination – Human or animal waste entering food or water.
Waterborne Disease – Disease transmitted through contaminated water.
Foodborne Disease – Disease transmitted through contaminated food.
Giardia Transmission – Infection from swallowing Giardia found in contaminated food or water.
Giardia Symptoms – Commonly causes diarrhea and intestinal problems.
Giardia Cyst – Protective form of Giardia that can survive outside a host.
Giardia Trophozoite – Active form of Giardia that lives in the intestines.
Intestinal Parasites – Organisms that live inside the intestines and obtain nutrients from a host.
Malaria
Malaria – Infectious disease caused by protozoan parasites transmitted by mosquitoes.
Malaria Transmission – Spread through bites from infected mosquitoes.
Malaria Parasite – Protozoan that infects humans and causes malaria.
Mosquito Vector – Mosquito that carries and transmits a pathogen.
Vector – Living organism that transmits disease between hosts.
Climate Change and Malaria – Warmer temperatures can allow mosquitoes to spread into new areas.
Malaria Cases – The slides estimate 300 million new cases annually.
Malaria Deaths – The slides estimate 1 million deaths annually.
Emerging Diseases
Emergent Disease – Disease that is newly recognized or has been absent for a long period.
Emergent Disease Increase – Emerging diseases have become more common since the 1940s.
Zoonosis – Disease transmitted between animals and humans.
Wildlife Trade and Disease – Trading wild animals can increase contact between humans and pathogens.
Biodiversity Loss and Disease – Changes in biodiversity can affect the spread of infectious diseases.
Climate Change and Disease – Changing temperatures can expand the range of disease-carrying organisms.
Population Growth and Disease – Growing populations can increase contact and disease transmission.
Poverty and Disease – Limited access to sanitation and healthcare can increase disease risks.
Anti-Vaccination and Disease – Reduced vaccination can allow preventable diseases to spread.
Measles – Infectious viral disease that can spread when vaccination rates are low.
Avian Influenza
Avian Influenza (H5N1) – Influenza virus commonly found in birds that can infect humans.
Bird Flu Transmission – Human infection can occur through direct contact with infected birds.
Enzootic Disease – Disease regularly maintained within an animal population.
Domestic Poultry – Farm birds such as chickens and turkeys.
H5N1 Human Transmission – The slides describe limited evidence of human-to-human transmission.
Avian Influenza Vaccines – Vaccines developed to help protect against certain bird flu viruses.
West Nile Virus
West Nile Virus – Virus transmitted by mosquitoes that can cause serious illness.
West Nile Transmission – Mosquitoes can transmit the virus from infected birds to humans or other animals.
Encephalitis – Inflammation of the brain.
West Nile Virus Origin – First identified in Africa in 1937.
West Nile Virus in the U.S. – First detected in the United States in 1999.
West Nile Virus in Horses – Can cause severe illness and death in infected horses.
West Nile Horse Vaccine – Vaccine available to protect horses against West Nile virus.
HIV/AIDS
HIV – Human immunodeficiency virus that attacks the immune system.
AIDS – Advanced stage of HIV infection involving severe immune system damage.
HIV/AIDS Global Impact – Major infectious disease responsible for millions of deaths.
HIV in Sub-Saharan Africa – Region heavily affected by HIV/AIDS.
HIV Treatment Access – Availability of modern medical treatment for people living with HIV.
HIV Global Prevalence – The slides report approximately 41 million people living with HIV in 2025.
HIV Annual Deaths – The slides estimate approximately 1 million deaths each year.
Ebola
Ebola – Serious viral disease that can cause severe illness and death.
Ebola Transmission – Spread through direct contact with infected blood or body fluids.
Ebola Animal Reservoirs – Animals that can carry the virus, including fruit bats.
Fruit Bats – Animals identified in the slides as important Ebola reservoirs.
Ebola Outbreak of 2014 – Major outbreak affecting several West African countries.
Ebola Discovery – Ebola was first identified in 1976.
Ebola Prevention – Avoiding direct contact with infected body fluids.
COVID-19 Health Effects
COVID-19 Risk Factors – Older age and preexisting health conditions increase the risk of severe illness.
COVID-19 Mortality Risk – Risk of death from COVID-19, which increases with age and certain health conditions.
Long COVID – Symptoms that continue or develop after a COVID-19 infection.
Long COVID Fatigue – Ongoing tiredness following COVID-19.
Long COVID Shortness of Breath – Breathing difficulties that can continue after infection.
COVID-19 Sex Differences – The slides report higher fatality rates among men in many locations.
Global Healthcare
Healthcare Inequality – Unequal access to medical treatment and healthcare resources.
Developing Nations and Disease – The slides describe a large disease burden in countries with fewer healthcare resources.
10/90 Gap – The slides state that 90% of diseases occur in developing nations, which receive only 10% of healthcare spending.
Doctors Without Borders – Humanitarian medical organization that provides healthcare in areas of need.
Healthcare Funding Gap – Difference between healthcare needs and available financial resources.
Access to Modern Medicine – Ability to receive effective medical treatments and healthcare services.
Gross Domestic Product (GDP) – Total value of final goods and services produced within a country.
Chemical Resistance
Chemical Resistance – Ability of organisms to survive chemicals previously used to control them.
Antibiotic Resistance – Ability of microorganisms to survive certain antibiotic treatments.
Insecticide Resistance – Ability of insects to survive chemicals used to kill them.
Malaria Drug Resistance – Malaria parasites becoming resistant to medicines.
Mosquito Insecticide Resistance – Mosquitoes becoming resistant to insecticides.
Natural Selection and Resistance – Resistant organisms survive and reproduce, spreading resistance traits.
Feedlots – Facilities where large numbers of livestock are kept and fed.
Antibiotic Use in Feedlots – Antibiotics given to livestock that can contribute to resistance.
Livestock Hormones – Hormones used in some animal production systems.
Antibiotic Waste – Antibiotic residues that may enter the environment through animal waste.
Animal Urine and Feces Pollution – Waste that can carry chemicals and pathogens into the environment.
Super-Virulent Pathogens – Pathogens capable of causing especially severe disease.
Toxicology Basics
Toxin – Poisonous substance that can harm living organisms.
Poison – Substance capable of causing injury, illness, or death.
Allergen – Substance that activates the immune system and may cause an allergic reaction.
Antigen – Substance that stimulates an immune response, including antibody production.
Antibody – Protein produced by the immune system to recognize specific antigens.
White Blood Cells – Immune cells that help protect the body against disease.
Toxic Substance – Material that can harm organisms through chemical effects.
Five Classifications of Toxic Substances
Neurotoxins – Substances that damage or interfere with the nervous system.
Heavy Metals – Metals such as lead and mercury that can cause toxic effects.
Lead Toxicity – Harmful effects of lead exposure, including nerve damage.
Mercury Toxicity – Harmful effects of mercury exposure, including nervous system damage.
Permanent Nerve Damage – Long-lasting injury to nerve cells caused by toxic exposure.
Anesthetics – Chemicals that interfere with nervous system function.
Ether – Chemical identified in the slides as an anesthetic.
Chloroform – Chemical identified in the slides as an anesthetic.
Mutagens – Chemicals or radiation that damage or change DNA.
DNA Mutation – Change in genetic material.
Reproductive Cell Mutation – Genetic change affecting sperm or egg cells.
Tumor – Abnormal mass of cells caused by uncontrolled growth.
Teratogens – Substances that cause abnormalities during embryonic development.
Embryonic Development – Early stage of growth and development before birth.
Fetal Alcohol Syndrome – Developmental condition caused by alcohol exposure before birth.
Craniofacial Abnormalities – Differences or defects affecting the skull and face.
Developmental Delay – Slower-than-expected physical or mental development.
Behavioral Problems – Difficulties involving behavior that can result from developmental damage.
Carcinogens – Substances that cause cancer.
Cancer – Disease involving uncontrolled cell growth and division.
Uncontrolled Cell Division – Cells multiplying without normal regulation.
Endocrine Disruptors – Chemicals that interfere with normal hormone function.
Hormones – Chemical messengers that regulate body functions.
DDT – Chemical pesticide identified in the slides as an endocrine disruptor.
PCB (Polychlorinated Biphenyls) – Industrial chemicals that can interfere with normal hormone function.
Environmental Estrogens – Environmental chemicals that mimic or interfere with estrogen activity.
Environmental Androgens – Environmental chemicals that mimic or interfere with androgen activity.
Reproductive Health Problems – Problems affecting reproductive development or function.
Measuring Toxicity
Toxicity – Degree to which a substance can harm living organisms.
Toxicity Testing – Testing substances to determine their harmful effects.
Animal Testing – Using animals to study the effects of potentially toxic substances.
Animal Testing Disadvantages – Can be expensive and time-consuming.
Computer Toxicity Simulations – Computer models used to predict toxic effects.
Artificial Intelligence in Toxicology – Using AI to help predict chemical toxicity.
Cell Cultures – Cells grown in a laboratory to study chemical effects.
LD50 (Lethal Dose 50%) – Dose of a substance that kills 50% of a test population.
Low LD50 – Indicates greater toxicity because a smaller dose causes death.
High LD50 – Indicates lower acute toxicity because a larger dose is required to cause death.
Important Lecture 14 Numbers
These figures are included for studying your professor's slides, not as verified current health statistics.
1918 Influenza Deaths – The slides report 30 million deaths in less than 12 months.
1918 Influenza U.S. Deaths – The slides report approximately 500,000 deaths.
COVID-19 First Three Years – The slides report more than 6.2 million deaths worldwide.
Emergent Disease Percentage – The slides estimate emerging diseases account for about 12% of human pathogens.
West Nile U.S. Cases in 2021 – The slides report 1,334 cases.
HIV in Sub-Saharan Africa – The slides state approximately two-thirds of HIV cases were in this region.
Long COVID Frequency – The slides estimate 10–20% of people experience Long COVID.
Cancer in the United States – The slides identify cancer as the second-leading cause of death.
Cancer Lifetime Risk – The slides report that 50% of men and 30% of women will develop cancer.
LD50 Percentage – 50% of the test population dies at the measured dose.
Important Energy Numbers and Formulas
EROEI = Energy obtained ÷ Energy invested
Coal EROEI example = 100 J ÷ 5 J = 20
Coal power plant efficiency = Approximately 35%
Combined-cycle plant efficiency = Approximately 60%
Natural gas composition = Approximately 80–95% methane
Uranium-235 – According to the slides, 1 gram contains approximately 3 million times more energy than 1 gram of coal.
EROEI examples from your slides:
Energy source | EROEI |
|---|---|
Biodiesel | 1.3 |
Corn ethanol | 1.6 |
Sugarcane ethanol | 5.0 |
Solar photovoltaic | 6.8 |
Natural gas | 10 |
Nuclear | 10 |
Oil | 12 |
Wind | 18 |
Coal | 20 |
Quick Review — Most Important Comparisons
These are especially useful for multiple-choice questions because the terms are easy to confuse.
Terms | Main difference |
|---|---|
Exponential vs. Logistic Growth | Unlimited growth vs. growth slowed by carrying capacity |
Density-Dependent vs. Independent | Affected by population density vs. unrelated to density |
r-selected vs. K-selected | Many offspring vs. few offspring |
Immigration vs. Emigration | Moving in vs. moving out |
Primary vs. Secondary Succession | No soil vs. soil remains |
Mutualism vs. Commensalism | Both benefit vs. one benefits, other unaffected |
Parasitism vs. Predation | Parasite lives on/in host vs. predator consumes prey |
Divergent vs. Convergent vs. Transform | Apart vs. together vs. sideways |
Igneous vs. Sedimentary vs. Metamorphic | Cooling magma vs. sediments vs. heat and pressure |
Confined vs. Unconfined Aquifer | Protected by impermeable layers vs. more exposed to surface recharge |
Oligotrophic vs. Eutrophic | Low nutrients vs. high nutrients |
Levee vs. Dike | Protects against river flooding vs. ocean flooding |
Distillation vs. Reverse Osmosis | Evaporation/condensation vs. filtration through membrane |
Fossil vs. Nuclear Energy | Ancient organic matter vs. radioactive material |
Fuel Rod vs. Control Rod | Contains nuclear fuel vs. controls reaction |