ENSC 1: Environmental Science, Ethics, Energy, and Biogeochemical Cycles

Vocabulary practice flashcards covering introductory environmental science topics including sustainability, environmental ethics, economic externalities, thermodynamics, ecology, and biogeochemical cycles.

Anthropocene

The current epoch of Earth's history, named using the prefix anthro- ("human"), recognized because of the significant global impacts of human activities on Earth's systems.

System

A collection of interacting components that produce emergent patterns of behavior over time.

Renewable Natural Resources

Resources that can be naturally replenished or maintained on human timescales, such as direct solar energy, wind, clean air, fresh water, fertile soil, and biological diversity.

Ecological Footprint

A metric estimating the amount of productive land and water area required to perpetually provide the resources consumed and absorb the wastes generated by an individual or population.

Sustainability

Meeting current human needs without compromising the ability of the environment to support future generations.

Tragedy of the Commons

An environmental dilemma formulated by Garrett Hardin ($1968$) describing how individual users, acting independently in their self-interest by overusing shared pastureland or open-access resources, ultimately deplete and spoil that shared resource for everyone.

Sustainability Tripod (Three Es)

A sustainable development framework that balances Environmentally sound decisions, Economically viable decisions, and socially Equitable decisions.

Environmental Justice (EJ)

A field and social movement addressing the inequity wherein poor and marginalized communities bear disproportionate harms from resource extraction and land uses while receiving fewer environmental amenities like clean air.

Hypothesis

An educated explanation formulated as a testable statement that makes predictions capable of being supported or disproved through experimentation and observation.

Controlled Experiment

An experimental test where an independent variable is manipulated to observe its effect on a dependent variable, while keeping a control unaltered to serve as a baseline comparison.

Scientific Theory

An integrated explanation of numerous hypotheses that is supported by a large body of empirical observations and experiments and validated through peer review.

Misinformation vs. Disinformation

Misinformation is false or incorrect information spread unintentionally or intentionally, whereas disinformation is false information deliberately generated and distributed to deceive or cause harm.

Deontological Ethics

An ethical framework asserting that actions are intrinsically right or wrong based on established moral duties, obligations, or rights, regardless of their consequences.

Biocentric Perspective

An ethical viewpoint holding that all living organisms—such as trees, birds, and fungi—possess intrinsic value and have a right to exist regardless of their utility to humans.

Utilitarian Perspective

An ethical approach holding that environmental decisions are justified if the beneficial consequences outweigh the negative outcomes, aiming to maximize the greatest good.

Anthropocentric Perspective

A human-centered ethical viewpoint that values the environment solely in terms of its direct and indirect benefits or harms to human beings.

Ecocentrism

An environmental philosophy, pioneered by Aldo Leopold, stating that moral consideration extends to both living (biotic) and nonliving (abiotic) parts of an ecological community.

Economics

The study of how individuals, businesses, and governments allocate scarce resources to fulfill their needs and wants, encompassing the production, distribution, and consumption of goods and services.

Jevons Paradox

An economic phenomenon identified by William Jevons where increases in efficiency in the use of a resource lower its cost, paradoxically driving an increase in overall consumption of that resource.

Externalities

Hidden costs or benefits associated with economic activities that are not reflected or accounted for in the market price of a good or service.

Marginal Cost of Pollution

The additional societal and environmental damage caused by producing one additional unit of pollution discharge.

Marginal Cost of Abatement

The financial cost required to clean up, mitigate, or reduce one additional unit of pollution.

Ecosystem Services

Essential positive externalities and ecological processes provided by healthy ecosystems—such as soil retention, climate regulation, carbon storage, water filtration, and pollination—that benefit human society.

Public Goods

Goods or services provided by governments through general taxation that cannot be produced profitably by free markets because nonpaying users cannot easily be excluded from receiving their benefits.

General Revision Act of 1891

A landmark US legislative act granting the president executive authority to establish protected public forest reserves from public lands.

The Midnight Forests

A total of $16\text{ million acres}$ of national forest land designated by President Theodore Roosevelt in $1907$ immediately before signing the Agriculture Appropriations Act, which sought to strip executive authority over forest reserves.

Antiquities Act of 1906

A federal law enabling the US president to designate public lands containing landmarks, prehistoric structures, and objects of historic or scientific significance as National Monuments.

Soil Conservation Service

A federal agency created in $1935$ by President Franklin D. Roosevelt in response to severe soil erosion and dust storms across the Great Plains during the American Dust Bowl.

Environmental Protection Agency (EPA)

A federal agency established in $1970$ responsible for establishing and enforcing minimum national regulatory standards for water quality, air quality, toxins, and waste management.

Isotopes

Atoms of the same element containing the same number of protons but varying numbers of neutrons, resulting in differences in atomic mass while preserving identical chemical behavior.

Law of Conservation of Mass

A fundamental physical law dictating that matter cannot be created or destroyed in chemical reactions; atoms are simply rearranged, keeping total mass constant.

Hydrogen Bond

A weak intermolecular attraction formed between an electronegative atom (like oxygen in water) and a slightly positive hydrogen atom in another polar molecule.

pH Scale

A numerical scale from $0$ to $14$ denoting the acidity or basicity of a solution; values below $7$ represent acidic conditions (higher $H^+$ concentration), and values above $7$ indicate basic conditions.

Redox Reaction

A chemical reaction involving electron transfer between reactants, combining oxidation (the loss of electrons) and reduction (the gain of electrons).

Photosynthesis

The biological process in which autotrophs capture solar radiant energy to transform carbon dioxide and water into oxygen and high-energy carbohydrates according to $6\text{ CO}_2 + 12\text{ H}_2\text{O} + \text{radiant energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{ H}_2\text{O} + 6\text{ O}_2$.

Cellular Respiration

The metabolic process in plants and animals where chemical energy stored in carbohydrates is released within cells to carry out biological work.

First Law of Thermodynamics

The physical law stating that energy cannot be created or destroyed, but can only be transformed from one form to another.

Second Law of Thermodynamics

The physical law stating that energy transformations naturally proceed toward higher entropy (disorder), resulting in some energy dissipating into the environment as low-quality heat.

Entropy

A thermodynamic measure of the disorder or randomness in a physical system, which naturally increases over time unless sustained by an input of energy.

Trophic Level

An organism's position in a food web or energy pyramid, where roughly $10\%$ of energy transfers to each successive feeding level while approximately $90\%$ is lost as metabolic heat.

Emergent Properties

New characteristics or complex behaviors that arise from the interaction of a system's individual components that are not present in any individual component alone.

Stock and Flow

A foundational modeling framework where a stock (pool) is a measured reservoir of material or energy, and flows (fluxes) represent the rates of inflow or outflow altering that stock over time.

Reinforcing Feedback (Positive Feedback)

A system loop that amplifies and magnifies an initial disturbance, driving a stock further in its current direction of change.

Balancing Feedback (Negative Feedback)

A regulatory feedback mechanism that suppresses or counteracts directional change in a stock, stabilizing the system toward an equilibrium.

Biogeochemical Cycle

The natural movement and cyclical transfer of chemical elements and compounds among Earth's four spheres: atmosphere, lithosphere, hydrosphere, and biosphere.

Transpiration

The evaporation of water into the atmosphere from the leaves and stems of terrestrial plants, accounting for up to $97\%$ of the water drawn through plant root systems.

Apatite

A sedimentary or igneous phosphate rock mineral extracted by mining from the lithosphere and used primarily to manufacture agricultural fertilizers.

Eutrophication

A process where aquatic ecosystems become overly enriched with nutrients (phosphorus or nitrogen), causing excessive algal blooms, reduced sunlight penetration, and rapid oxygen depletion as decomposing microbes consume dead organic matter.

Nitrogen Fixation

The initial biochemical conversion of inert atmospheric gas ($N_2$) into biologically usable soluble nitrogen compounds like ammonium ($NH_4^+$), executed by specialized root-dwelling bacteria, lightning, or industrial systems.

Nitrification

The biological process wherein specialized soil microorganisms oxidize ammonia ($NH_3$) or ammonium ($NH_4^+$) into nitrite ($NO_2^-$) and subsequently into nitrate ($NO_3^-$).

Ammonification

The breakdown of organic nitrogen compounds in biological waste products and dead organic material by decomposing bacteria and fungi, releasing ammonia ($NH_3$) or ammonium ($NH_4^+$).

Denitrification

The biochemical pathway carried out by anaerobic bacteria in soils and aquatic sediments that reduces nitrate ($NO_3^-$) back into inert atmospheric nitrogen gas ($N_2$).

Haber-Bosch Process

An industrial chemical synthesis method that combines atmospheric nitrogen gas ($N_2$) with hydrogen under high pressure and temperature to manufacture synthetic nitrogen fertilizers, doubling global nitrogen fixation rates.

Hypoxic Dead Zone

A low-oxygen area in marine or freshwater environments (such as the northern Gulf of Mexico) caused by agricultural nutrient runoff and decomposition where mobile organisms flee and sessile organisms suffocate.

Methanogens

Anaerobic microorganisms that thrive in oxygen-free environments like wetlands and ruminant digestive tracts, producing and releasing methane ($CH_4$) during the breakdown of organic material.

Calcination

An industrial manufacturing process for cement in which limestone (calcium carbonate, $CaCO_3$) is thermally decomposed into calcium oxide ($CaO$), releasing significant volumes of carbon dioxide ($CO_2$) into the atmosphere.

Ocean Acidification

The progressive lowering of seawater pH caused by the ocean absorbing excess anthropogenic atmospheric $CO_2$, forming carbonic acid ($H_2CO_3$) and reducing carbonate ions required by marine organisms to form calcium carbonate ($CaCO_3$) shells.