Environmental Science: Exam 2 Study Guide

Comprehensive vocabulary flashcards covering human demographics, agricultural practices, soil profiles, geologic hazards, mineral mining, hydrology, ocean ecosystems, water management, and fisheries biology.

Population Change Formula

The calculation of net population growth defined as $\text{Population change} = (\text{births} + \text{immigration}) - (\text{deaths} + \text{emigration})$.

IPAT Model

A framework calculating environmental impact ($I$) as the product of population size ($P$), affluence or consumption per person ($A$), and technology impact per unit of consumption ($T$), represented as $I = P \times A \times T$.

Thomas Malthus

An English cleric and scholar who warned that human population could grow faster than the food supply, leading to shortages if food production cannot keep pace.

Ecological Footprint

The amount of biologically productive land and water required to supply a person or population's resource use and absorb its generated wastes.

Biocapacity

The capacity of a given ecosystem to regenerate useful biological resources and absorb the wastes generated by humans.

Overshoot

The condition that occurs when human resource consumption and waste production exceed the ecosystem's biocapacity.

Ecological Sensitivity

The degree or strength to which an ecological system responds to a particular disturbance.

Functional Redundancy

The condition where multiple species perform similar ecological roles, helping maintain ecosystem functions without making species fully interchangeable.

Ecosystem Services

The ecological benefits provided to humans by natural systems, such as crop pollination, clean water provision, flood regulation, food production, and recreation.

Preindustrial Stage

The demographic stage characterized by high, fluctuating birth and death rates, resulting in slow overall population growth due to high mortality.

Transitional Stage

The demographic stage where death rates decline rapidly due to improved food supply and sanitation while birth rates stay high, causing rapid population growth.

Industrial Stage

The demographic stage where birth rates decline due to increased opportunities and urbanization while death rates remain low, leading to slowing population growth.

Postindustrial Stage

The demographic stage characterized by low birth and death rates, resulting in population stability, minimal growth, or decline, along with population aging.

Life Expectancy

The average number of years a person is expected to live under current mortality conditions, distinct from the maximum biological lifespan.

Maximum Lifespan

The upper biological limit of human life duration.

Arable Land

Land with suitable soil, climate, and topography that can be cultivated to grow agricultural crops.

Marginal Land

Land that possesses major physical or climatic limitations (such as steep slope, dry climate, or poor soil) and requires higher inputs to farm.

Green Revolution

An agricultural transformation that increased global food production through high-yield crop varieties combined with synthetic fertilizers, pesticides, irrigation, and mechanization.

Eutrophication

A process triggered by nutrient runoff (nitrogen and phosphorus) that stimulates excessive algal growth, followed by bacterial decomposition that depletes dissolved oxygen.

Golden Rice

A genetically engineered crop modified to produce beta-carotene, which the human body converts into vitamin A.

Bt Crops

Crops engineered to produce an insect-targeting protein derived from a bacterium, reducing the need for synthetic insecticidal sprays.

Herbicide-Tolerant Crops

Genetically engineered crops modified to survive applications of specific chemical herbicides, allowing targeted weed control.

Integrated Pest Management (IPM)

A management framework that uses pest monitoring, damage thresholds, multiple nonchemical controls (e.g., crop rotation, biological controls), and targeted chemical controls as a last resort.

Transgenic Organism

An organism that contains DNA sequences introduced from an entirely different species.

Gene Editing

A biotechnological method that modifies specific native DNA sequences within an organism without necessarily introducing foreign genes from another species.

Cover Crops

Non-harvested plants grown to protect bare soil from raindrop impact, reduce water and wind erosion, improve soil structure, suppress weeds, and retain nutrients.

Conservation Tillage (No-Till)

A farming practice that minimizes or avoids mechanical soil disturbance and leaves crop residue on the surface to retain moisture and prevent erosion.

CAFO (Concentrated Animal Feeding Operation)

An intensive livestock production facility where high densities of animals are confined, generating large volumes of concentrated manure that pose water and air quality risks.

Physical Weathering

The breakdown of rock into smaller fragments without altering its chemical composition, such as by freeze-thaw cycles.

Chemical Weathering

The decomposition or alteration of rock minerals through chemical reactions, such as the dissolution of minerals by acidic water.

Biological Weathering

The mechanical or chemical disintegration of rock caused by living organisms, such as tree roots widening fractures or lichens altering minerals.

Erosion

The physical transport and removal of weathered rock and soil particles by moving water, wind, ice, or gravity.

Humus

Relatively stable, fully decomposed dark organic matter found within the soil.

Leaching

The downward movement of dissolved plant nutrients and fine materials through the soil profile carried by percolating water.

O Horizon

The uppermost soil horizon, composed primarily of surface organic matter, fresh leaf litter, and decomposing plant residues.

A Horizon (Topsoil)

A critical, fertile soil layer consisting of mixed mineral matter and humus that hosts the majority of living organisms and plant roots.

E Horizon

The soil layer characterized as the zone of eluviation, where minerals, clay, and iron are leached out by descending water.

B Horizon (Subsoil)

The subsurface soil layer where clay, iron, aluminum, and nutrients leached from the upper horizons accumulate.

C Horizon

The soil layer composed of partially weathered parent material exhibiting minimal biological activity.

R Horizon

The unweathered, solid consolidated bedrock underlying the developed soil profile.

Divergent Plate Boundary

A tectonic boundary where plates move away from each other, producing new crust, rift valleys, mid-ocean ridges, volcanism, and earthquakes.

Convergent Plate Boundary

A tectonic boundary where plates move toward each other, resulting in subduction, volcanic island arcs, mountain building, strong earthquakes, and tsunamis.

Transform Plate Boundary

A tectonic boundary where plates slide horizontally past one another along faults without creating or destroying crust.

Mineral

A naturally occurring, inorganic crystalline solid possessing a characteristic chemical composition and orderly internal structure.

Lithosphere

The rigid, brittle outer layer of Earth comprising the crust and uppermost solid mantle, broken into tectonic plates.

Asthenosphere

The weaker, ductile upper mantle layer directly below the lithosphere that can slowly deform and flow over geologic time.

Subduction

The geological process where a denser oceanic tectonic plate sinks beneath an adjacent plate into the mantle.

Hotspot

A localized volcanic zone created by a rising plume of hot mantle material beneath a moving tectonic plate, often forming intraplate volcanic chains.

Overburden

The layer of overlying soil and rock that must be stripped away to expose a buried mineral or coal deposit.

Tailings

The fine mineral residues and waste slurry remaining after the target metals or valuable components have been extracted from crushed ore.

Reserves

The identified portion of a mineral or fuel resource that is both economically profitable and technically feasible to extract under current market conditions.

Acid Mine Drainage

Low-pH, acidic drainage formed when exposed sulfide minerals react with water and atmospheric oxygen, dissolving and mobilizing toxic heavy metals into waterways.

Surface Mining Control and Reclamation Act (SMCRA)

United States federal legislation establishing environmental standards and financial bonding requirements for coal mining operation reclamation.

Water Table

The upper boundary of the saturated zone in an unconfined aquifer, below which all connected pore spaces and fractures are filled with water.

Confined Aquifer

An aquifer trapped beneath an impermeable rock or clay layer, often under artesian pressure and isolated from direct vertical recharge.

Unconfined Aquifer

An aquifer with no overlying confining layer that receives direct recharge from water percolating downward from the land surface.

Riparian Vegetation

Plant communities bordering rivers and streams that stabilize shorelines, buffer water temperature through shade, filter nutrients, and prevent erosion.

Baseflow

Streamflow sustained between rainstorms by the steady discharge of groundwater through streambeds, banks, and springs.

Littoral Zone

The shallow edge along the perimeter of a lake or pond where sunlight penetrates to the sediments, allowing rooted aquatic plants to grow.

Limnetic Zone

The open, sunlit surface water zone of a lake located away from the shore, beyond the reach of rooted aquatic vegetation.

Profundal Zone

The deep, lightless open water layer of a lake situated below the limnetic zone where sunlight is insufficient to support net photosynthesis.

Oligotrophic Lake

A freshwater lake with low nutrient concentrations, low primary productivity, and clear, oxygen-rich waters.

Eutrophic Lake

A freshwater lake characterized by high concentrations of plant nutrients, elevated primary biological productivity, and oxygen depletion in deep zones.

Upwelling

An oceanographic process where cold, deep, nutrient-dense ocean water rises toward the sunlit surface, stimulating high marine primary productivity and fisheries.

El Niño

A climate phenomenon marked by weakened Pacific trade winds and unusually warm waters across the central and eastern tropical Pacific, which suppresses coastal upwelling.

Zooxanthellae

Symbiotic photosynthetic microalgae inhabiting coral polyps that supply the coral host with energy and organic nutrients.

Coral Bleaching

The stress-induced expulsion or loss of symbiotic zooxanthellae algae from coral tissues, typically caused by sustained elevated sea temperatures.

Consumptive Water Use

Water withdrawal that permanently removes water from a local watershed via evaporation, transpiration, or direct incorporation into crops or manufactured goods.

Point Source Pollution

Water pollution discharged from a single, distinct, and identifiable physical conveyance, such as a factory pipe or sewage outfall.

Nonpoint Source Pollution

Diffuse, unconfined water contamination arising from broad land areas, including agricultural runoff, urban street runoff, and construction sites.

Hypoxia

An aquatic state where dissolved oxygen concentrations drop below the threshold needed to sustain fish, crabs, and other aquatic fauna.

Primary Wastewater Treatment

The initial mechanical stage of sewage treatment that uses physical screening, sedimentation, and settling tanks to remove floating debris and heavy solids.

Secondary Wastewater Treatment

The biological treatment phase where aerobic microorganisms consume and break down dissolved biodegradable organic contaminants in wastewater.

Bycatch

The unintended capture, injury, or mortality of non-target marine species (e.g., sea turtles, marine mammals, seabirds, and non-commercial fish) during commercial fishing.

Fishing Down the Food Chain

The ecological shift where commercial fishing progressively targets smaller, lower-trophic-level organisms after overharvesting large predatory fish stocks.

Maximum Sustainable Yield (MSY)

The theoretical maximum long-term average harvest rate that can be extracted from a wild stock without compromising its ability to replenish itself.

Ecosystem-Based Management

A holistic fisheries and resource management approach that considers multi-species interactions, food webs, marine habitats, oceanographic changes, and human economics.

No-Take Marine Reserve

A fully protected marine area where all extractive activities, including commercial and recreational fishing, mining, and harvesting, are strictly prohibited.

Ocean Acidification

The ongoing chemical decline in ocean pH caused by seawater absorbing excess atmospheric carbon dioxide ($\text{CO}_2$), which depletes available carbonate ions needed for calcification.