Environmental Science, Physical Systems, and Geology Flashcards

Principles of Environmental Science and Sustainability

• Environmental science is the study of how the natural world works, how the environment affects humans, and how humans affect the environment.

• The environment encompasses all living and nonliving things around us, including climate, soil, water, atmospheric systems, and human-built structures.

• Humans are not separate from nature; human society depends entirely on functioning natural systems.

Categorization of Natural Resources

• Natural resources are the substances and energy sources taken from the environment that organisms need to survive.

• Renewable natural resources are perpetually replenished or renewed over short time periods:

  • Inexhaustible renewable resources: Permanently available and constantly renewed, including solar energy, wind energy, wave energy, and geothermal energy.

  • Exhaustible renewable resources: Renew over months, years, or decades, but can be depleted if harvested faster than they naturally replenish. Examples include fresh water, forest products, biodiversity, and agricultural soils.

• Nonrenewable natural resources: Formed over millions of years and exist in finite amounts. Once depleted, they cannot be replenished on a human timescale. Examples include crude oil, natural gas, coal, and mineral ores.

Ecosystem Services

• Ecosystem services arise from normal ecosystem function and sustain human life and economies.

• Key ecosystem services include:

  • Purification of air and water.

  • Cycling of essential nutrients ($\text{N}$, $\text{P}$, $\text{C}$).

  • Regulation of water flow and hydrologic cycles.

  • Prevention and mitigation of flooding.

  • Reduction of soil erosion.

  • Provision of game, wildlife habitat, timber, recreation, and aesthetic value.

Human Population Growth and Historical Transitions

• The human population has experienced two primary historical shifts that exponentially accelerated growth and environmental impact:

  • Agricultural Revolution ($\sim 10,000\,\text{years before present}$): Transition from a hunter-gatherer lifestyle to an agricultural lifestyle. Domestication of plants and animals led to permanent village settlements and increased population growth rates.

  • Industrial Revolution (beginning in the mid-1700s): Shift from rural agrarian life to an urban society powered by fossil fuels (coal, oil, natural gas).

  • Introduced mass production, factory systems, and industrialized agriculture.

  • Provided advances in medicine, public health, and sanitation.

  • Triggered exponential human population growth, reaching over 7.8 billion people today.

Ecological Footprint and Global Overshoot

• An ecological footprint measures the cumulative area of biologically productive land and water required to provide the resources a person or population consumes and to dispose of or assimilate the waste generated.

• Calculated by Mathis Wackernagel and the Global Footprint Network, the global ecological footprint consists of six major resource categories:

  • Carbon footprint ($59.9\%$): Forest land required to absorb $\text{CO}_2$ emissions from burning fossil fuels.

  • Cropland ($19.4\%$): Land required to grow crops for food, animal feed, and fiber.

  • Forest ($10.0\%$): Forested land needed for timber, pulp, and wood products.

  • Pasture ($5.1\%$): Grazing land needed for livestock and animal products.

  • Fishing grounds ($3.3\%$): Marine and aquatic area required to support seafood harvesting.

  • Built-up land ($2.3\%$): Land occupied by infrastructure, housing, transportation, and commerce.

• Overshoot occurs when human resource consumption surpasses the Earth's biocapacity (capacity to sustainably replenish resources and absorb waste).

  • The global human population is consuming renewable resources $64\%$ faster than they can be replenished (operating at an overshoot equivalent to roughly $1.64$ Earths).

  • Living unsustainably depletes Earth's natural capital—akin to drawing down the principal balance of a bank account rather than living strictly off the interest generated.

• Per-capita ecological footprints vary widely based on national affluence and industrialization:

  • United States: $8.1\,\text{ha}$ per person.

  • Canada: $7.7\,\text{ha}$ per person.

  • Israel: $4.9\,\text{ha}$ per person.

  • France: $4.4\,\text{ha}$ per person.

  • China: $3.6\,\text{ha}$ per person.

  • Brazil: $2.8\,\text{ha}$ per person.

  • World Average: $2.7\,\text{ha}$ per person.

  • Mexico: $2.6\,\text{ha}$ per person.

  • Indonesia: $1.7\,\text{ha}$ per person.

  • Sustainable Target Level: $1.6\,\text{ha}$ per person.

  • India: $1.2\,\text{ha}$ per person.

  • Rwanda: $0.8\,\text{ha}$ per person.

  • Afghanistan: $0.7\,\text{ha}$ per person.

  • Haiti: $0.7\,\text{ha}$ per person.

Interdisciplinary Nature of Environmental Science

• Environmental science relies on techniques and insights from multiple academic fields across both natural and social sciences:

  • Natural Sciences (examine physical and biological systems): Ecology, Biology, Chemistry, Atmospheric Science, Oceanography, Geology, Geography.

  • Social Sciences (examine human interactions, culture, and institutions): Archaeology, Anthropology, History, Political Science, Engineering, Economics, Ethics.

• Distinctions among disciplines and movements:

  • Environmental Science: Primary focus on natural science components, physical systems, and empirical testing.

  • Environmental Studies: Primary focus on social science aspects, political policies, economics, and human behavior.

  • Environmentalism: A social and political movement dedicated to protecting the natural world from human-induced degradation; it is distinct from empirical scientific research.

The Scientific Method, Research Process, and Source Evaluation

• Descriptive science: Research involving basic observation, collection, and description of organisms, materials, or natural systems without direct manipulation.

• Hypothesis-driven science: Structured research designed to test targeted explanations for specific phenomena using the scientific method.

Scientific Method Steps and Variables

1. Observation: Identifying an unexplained phenomenon in the natural world.

2. Questions: Formulating specific questions based on observations (e.g., "What causes excessive algal growth on a local pond surface?").

3. Hypothesis: Constructing a testable, educated explanation to answer the question (e.g., "Agricultural fertilizer runoff causes increased algal growth in ponds").

4. Predictions: Formulating specific, verifiable statements derived from the hypothesis that can be directly measured (e.g., "If agricultural fertilizer is added to a pond, the total quantity of algae will increase").

5. Experimentation: Designing and running tests to isolate variables and evaluate predictions.

   • Variables: Parameters or conditions that can fluctuate:

     • Independent Variable: The factor manipulated directly by the scientist (e.g., quantity of fertilizer added).

     • Dependent Variable: The factor that changes in response to adjustments in the independent variable (e.g., total mass or surface area coverage of algae).

   • Experimental Controls:

     • Controlled Experiment: Running two identical groups simultaneously while manipulating only a single variable.

     • Control Group: Unmanipulated comparison group left in its natural state (e.g., pond receiving no fertilizer runoff).

     • Treatment Group: Experimental group subjected to the independent variable manipulation (e.g., pond receiving measured fertilizer runoff).

6. Data Collection and Quantitative Analysis:

   • Quantitative Data: Numeric measurements that reduce bias and allow objective comparison (e.g., dry mass of algae per volume unit of water, percentage of surface area covered).

Experimental Types and Graphical Data Representations

• Manipulative Experiments: The researcher actively controls and alters the independent variable directly under laboratory or controlled field settings.

• Natural Experiments: Conducted when variables cannot be physically controlled or ethically manipulated (e.g., planetary climate change). Researchers measure naturally occurring variation and calculate statistical correlations between variables.

• Graphical analysis transforms raw data into visually accessible patterns:

  • Line Graphs: Display long-term trends and continuous quantitative changes over time.

  • Pie Charts: Portray relative proportions or percentages of a discrete whole (e.g., species composition of pond algae: Species #1 $32\%$, Species #2 $23\%$, Species #3 $18\%$, Species #4 $16\%$, Species #5 $11\%$).

• Bar Charts: Compare discrete mean measurements across treatment and control groups (e.g., mean percentage of pond area covered by algae in fertilized treatment ponds vs. unfertilized control ponds).

• Scatter Plots: Display correlations and mathematical relationships between two continuous variables across multiple individual sampling points (e.g., percentage of pond covered by algae plotted against fertilizer application rate in $\text{kg\,ha}^{-1}$).

• Hypothesis Outcomes:

  • Hypotheses are either rejected (disproven) or supported by data.

  • A hypothesis is never considered permanently proven. Alternative explanations may exist and must undergo further testing.

Scientific Process Beyond Individual Research

• The broader scientific process operates beyond individual researchers through community scrutiny:

  1. Scientific Paper: Research findings, quantitative data, and logical interpretations are formatted into a formal manuscript.

  2. Peer Review: The manuscript is submitted to a peer-reviewed scientific journal. Unbiased expert scientists in the same field evaluate the experimental design, statistical validity, clarity, and logical rigor.

  3. Publication/Revision: The paper is accepted, returned for revision based on comments, or rejected.

  4. Replication: Independent scientific groups attempt to reproduce the experimental findings.

  5. Theory Formation: If a hypothesis survives extensive peer review, repeated testing, and validation across diverse conditions, it may be integrated into a scientific theory.

  • Scientific Theory: A comprehensive, widely accepted explanation of fundamental natural mechanisms that unifies numerous individual hypotheses.

  1. Paradigm Shifts: A dominant, universally accepted scientific framework is termed a paradigm. A paradigm shift occurs when accumulating evidence invalidates established assumptions, causing a fundamental transformation in scientific understanding (e.g., shifting from a geocentric to a heliocentric astronomical model).

Critical Evaluation of Information Sources

• Assessing information quality requires applying analytical criteria (such as the CRAAP test criteria):

  • Author Credentials and Affiliations: Examine professional qualifications, academic degrees, funding sources (university, private enterprise, government body, non-profit), and web domains (.com, .org, .edu, .gov).

  • Presenter Motivation: Identify whether the objective is objective education versus commercial promotion, persuasion, or political lobbying. Inspect for hidden financial or institutional conflicts of interest.

  • Evidence and Verification: Ensure assertions are grounded in empirical evidence, cite primary peer-reviewed literature, present unbiased language, declare methodology, maintain currency, and remain verifiable across external independent databases.

Campus Sustainability Initiatives

• Sustainability: Managing Earth's natural systems and resource usage in a manner that preserves their functional integrity and availability for future generations.

• Campus Sustainability Initiatives:

  • Waste Reduction: Reusing materials, recycling, composting food scraps, conducting trash audits, hosting recycling competitions, and pursuing zero-waste targets (e.g., e-waste recycling programs at Wayne State University).

  • Green Buildings: Constructing facilities using environmentally sound materials engineered to minimize energy use, maximize daylighting, optimize water efficiency, and achieve LEED (Leadership in Energy and Environmental Design) certification (e.g., Oberlin College).

  • Water Conservation: Retrofitting structures with low-flow faucets, dual-flush toilets, waterless urinals, and efficient showerheads; installing rainwater harvesting systems, rain gardens, and greywater treatment facilities (e.g., Loyola University Chicago).

  • Energy Efficiency: Installing high-efficiency lighting (LEDs), occupancy motion sensors, real-time energy dashboards, lowering winter thermostat setpoints, and running student energy conservation campaigns (e.g., Xavier University of Louisiana).

  • Renewable Energy: Transitioning heating plants and electrical power to solar panel arrays, biomass combustion, and wind turbines; allocating student activity fees toward purchasing green tags or carbon offsets (e.g., Catholic University of America; Mount Wachusett Community College).

  • Food and Dining: Establishing campus agricultural plots and urban gardens to supply dining halls with local organic food; implementing trayless dining (eliminating trays reduces food waste by an average of $25\%$ by curbing excess food selection); composting organic dining waste (e.g., Yale University).

  • Transportation Options: Commuting accounts for approximately $50\%$ of an average educational institution's greenhouse gas emissions. Schools mitigate transportation emissions through shuttle systems, alternative-fuel fleet vehicles, carpooling incentives, and bicycle-share infrastructure (e.g., UBIKE program at the University of Virginia).

  • Native Landscaping and Restoration: Removing invasive plant species, restoring native flora, establishing green roofs, building greenhouses, and designing botanical arboretums to enhance ecosystem function and provide educational field sites (e.g., University of Arizona).

  • Carbon-Neutrality: Setting operational goals to emit zero net greenhouse gas emissions. Hundreds of university leaders have signed the Presidents' Climate Leadership Commitments.

  • Fossil Fuel Divestment: Higher education institutions hold over $\$400\text{ billion}$ in collective investment endowments. Student movements actively pressure boards of trustees and fund managers to divest (sell off) holdings in fossil fuel extraction corporations (e.g., Tufts University "Divest Now" movement).

Matter, Atomic Structure, and Chemical Principles

Central Case Study: Fukushima Daiichi Nuclear Tragedy

• On March 11, 2011, a magnitude $9.0$ earthquake struck off the coast of Tohoku, Japan, generating a massive tsunami.

• The tsunami overtopped the $5.7\,\text{m}$ protective seawall guarding the Fukushima Daiichi nuclear power facility.

• Seawater flooded the basement diesel generator rooms, knocking out emergency power supplies to the cooling pumps for Reactors 1, 2, and 3 (Reactors 4, 5, and 6 were offline for maintenance).

• Deprived of active liquid coolant, residual decay heat boiled off reactor water, exposing the nuclear fuel rods.

• Reactor fuel overheated, causing nuclear meltdowns in Units 1, 2, and 3.

• Chemical interactions between superheated zircaloy fuel cladding and steam generated high volumes of volatile hydrogen gas ($\text{H}_2$).

• Hydrogen gas accumulated inside the reactor containment structures and exploded, blowing off outer structural roofs, damaging adjacent infrastructure, and releasing severe radioisotope contamination into the atmosphere and Pacific Ocean.

• Emergency response units flooded the damaged reactor cores directly with raw seawater to prevent further catastrophic meltdowns.

Conservation of Matter and Atomic Composition

• Matter: Any material that occupies physical space and possesses mass. Chemistry is the study of matter and its interactions.

• Law of Conservation of Matter: Matter can be transformed from one form to another, but it cannot be created or destroyed.

  • Environmental Implications: Pollutants, heavy metals, and radioactive nuclear waste do not disappear when discarded; they persist and cycle endlessly through biological and physical systems.

• Element: A fundamental chemical substance with specific properties that cannot be broken down into simpler substances with other properties.

Subatomic Structure

• Atom: The smallest unit of an element that retains all chemical properties of that element.

• Subatomic Particles:

  • Protons: Positively charged particles ($+1$) located within the dense atomic nucleus. The number of protons defines the element's atomic number.

  • Neutrons: Uncharged particles ($0$ charge) located within the atomic nucleus. Protons plus neutrons define the mass number of an atom.

  • Electrons: Negatively charged particles ($-1$ charge) orbiting the nucleus in complex electron shells.

Isotopes, Radioisotopes, and Half-Lives

• Isotopes: Atoms of the same element containing an identical number of protons but varying numbers of neutrons, resulting in different atomic mass numbers (e.g., Hydrogen $\text{H}$ with 0 neutrons vs. Deuterium ${}^2\text{H}$ with 1 neutron).

• Ions: Atom or molecule that has gained or lost electrons, acquiring a net positive or negative electrical charge (e.g., losing an electron converts neutral Hydrogen $\text{H}$ into a hydrogen ion $\text{H}^+$; losing two electrons converts Calcium to $\text{Ca}^{2+}$).

• Radioisotopes: Unstable isotopes that spontaneously decay, emitting subatomic particles and high-energy ionizing radiation until converting into stable daughter isotopes.

  • Radiation Damage: Radioisotopes incorporated into living organisms through inhalation or ingestion emit ionizing radiation that strips electrons from biological molecules, breaking DNA strands and altering tissue structure.

  • Half-Life: The specific time required for exactly half of the radioactive atoms in a sample to decay.

  • Iodine-131 (${}^{131}\text{I}$): Half-life of approximately $8\,\text{days}$.

  • Cesium-137 (${}^{137}\text{Cs}$): Half-life of approximately $30\,\text{years}$.

Element Distribution Across Earth Systems

• Elemental composition by mass across major Earth reservoirs:

Earth's Crust

• Oxygen ($\text{O}$): $49.5\%$

• Silicon ($\text{Si}$): $25.7\%$

• Aluminum ($\text{Al}$): $7.4\%$

• Iron ($\text{Fe}$): $4.7\%$

• Calcium ($\text{Ca}$): $3.6\%$

• Sodium ($\text{Na}$): $2.8\%$

• Potassium ($\text{K}$): $2.6\%$

• Magnesium ($\text{Mg}$): $2.1\%$

• Other Elements: $1.6\%$

Oceans

• Oxygen ($\text{O}$): $88.3\%$

• Hydrogen ($\text{H}$): $11.0\%$

• Chlorine ($\text{Cl}$): $1.9\%$

• Sodium ($\text{Na}$): $1.1\%$

• Magnesium ($\text{Mg}$): $0.1\%$

• Sulfur ($\text{S}$): $0.1\%$

• Calcium ($\text{Ca}$): $<0.1\%$

• Potassium ($\text{K}$): $<0.1\%$

• Bromine ($\text{Br}$): $<0.1\%$

Atmosphere (Air)

• Nitrogen ($\text{N}$): $78.1\%$

• Oxygen ($\text{O}$): $21.0\%$

• Argon ($\text{Ar}$): $0.9\%$

• Other Gases: $<0.1\%$

Living Organisms

• Oxygen ($\text{O}$): $65.0\%$

• Carbon ($\text{C}$): $18.5\%$

• Hydrogen ($\text{H}$): $9.5\%$

• Nitrogen ($\text{N}$): $3.3\%$

• Calcium ($\text{Ca}$): $1.5\%$

• Phosphorus ($\text{P}$): $1.0\%$

• Potassium ($\text{K}$): $0.4\%$

• Sulfur ($\text{S}$): $0.3\%$

• Other Elements: $0.5\%$

Chemical Bonding and Compounds

• Molecule: Chemical combination of two or more atoms bound together (e.g., $\text{O}_2$).

• Compound: A molecule composed of atoms belonging to two or more distinct elements (e.g., $\text{H}_2\text{O}$, $\text{CO}_2$).

• Chemical Bond Types:

  • Covalent Bonds: Formed when atoms share pairs of electrons to achieve stable shell configurations.

  • Polar Covalent Bonds and Hydrogen Bonds: In water ($\text{H}_2\text{O}$), oxygen attracts shared electrons more strongly than hydrogen, creating partial negative ($\delta^-$) and positive ($\delta^+$) charges. The weak electrostatic attraction between opposite partial charges of adjacent water molecules creates hydrogen bonds.

• Ionic Bonds: Formed when electron transfer occurs completely due to severe differences in electronegativity, generating oppositely charged ions that bind via electrostatic attraction (e.g., $\text{NaCl}$).

  • Solutions: Uniform, evenly distributed mixtures of chemical compounds or elements that do not react chemically with one another.

Organic Chemistry and Macromolecules

• Organic Compounds: Carbon-based compounds held together by covalent bonds, often forming complex rings or chain backbones.

• Hydrocarbons: Organic compounds consisting exclusively of hydrogen and carbon atoms. Found extensively in fossil fuels and crude oil derivatives like plastics.

  • Methane ($\text{CH}_4$): Single carbon attached to four hydrogen atoms.

  • Ethane ($\text{C}_2\text{H}_6$): Two-carbon alkane chain.

  • Naphthalene ($\text{C}_{10}\text{H}_8$): Dual aromatic carbon ring structure.

• Macromolecules: Large biological polymers crucial to living systems:

  • Proteins: Polymers built from amino acid monomers. Function as structural components (skin, hair, muscle tissue), signaling molecules, immune defenses, and enzymatic catalysts that accelerate metabolic reactions.

  • Nucleic Acids: Polymers composed of nucleotide monomers (each containing a sugar ring, phosphate group, and nitrogenous base). Encode genetic blueprints:

  • Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA).

  • Specific coding segments on DNA strands form genes.

• Carbohydrates: Simple and complex sugars ($\text{C}_n\text{H}_{2n}\text{O}_n$):

  • Glucose ($\text{C}_6\text{H}_{12}\text{O}_6$): Primary cellular fuel source.

  • Cellulose: Complex structural carbohydrate building plant cell walls, stems, and bark.

  • Chitin: Structural polysaccharide forming arthropod exoskeletons.

• Lipids: Diverse hydrophobic organic compounds that do not dissolve in water:

  • Fats and Oils: Energy storage compounds.

  • Waxes: Protective waterproof structural barriers.

  • Steroids: Hormonal messenger molecules.

The Logarithmic pH Scale and Solution Acidity

• In aqueous solution, a fraction of water molecules dissociate into hydrogen ions ($\text{H}^+$) and hydroxide ions ($\text{OH}^-$):

$\text{H}_2\text{O} \rightleftharpoons \text{H}^+ + \text{OH}^-$

• The pH Scale: A inverse logarithmic scale quantifying the concentration of hydrogen ions ($\text{pH} = -\log[\text{H}^+]$).

  • Neutral Solution: $\text{pH} = 7.0$; equal concentrations of $\text{H}^+$ and $\text{OH}^-$ ions (e.g., pure water).

  • Acidic Solutions: $\text{pH} < 7.0$; elevated $\text{H}^+$ concentration.

  • Basic (Alkaline) Solutions: $\text{pH} > 7.0$; elevated $\text{OH}^-$ concentration.

  • Logarithmic Step Scaling: Every single unit change on the pH scale represents a 10-fold change in hydrogen ion concentration.

• Representative pH Values:

  • Car Battery Acid: $\text{pH} \approx 0.0$

  • Stomach Acid: $\text{pH} \approx 1.0$

  • Lemon Juice: $\text{pH} \approx 2.0$

  • Acid Rain: $\text{pH} \approx 4.0$

  • Normal Rainwater: $\text{pH} \approx 5.6$

  • Pure Water: $\text{pH} = 7.0$

  • Seawater: $\text{pH} \approx 8.0$

  • Soft Soap: $\text{pH} \approx 10.0$

  • Household Ammonia: $\text{pH} \approx 11.5$

  • Sodium Hydroxide ($\text{NaOH}$ / Lye): $\text{pH} = 14.0$

Energy Fundamentals and Metabolic Thermodynamics

Forms of Energy and Thermodynamic Laws

• Energy: The capacity to perform work or change the position, physical state, or temperature of matter.

• Primary Energy Classifications:

  • Potential Energy: Energy stored by virtue of position, spatial configuration, or chemical composition (e.g., river water held behind a hydroelectric dam; high-energy chemical bonds in glucose).

  • Kinetic Energy: The energy of physical movement or thermal kinetic motion (e.g., river water rushing through a dam; thermal motion of molecules).

• Laws of Thermodynamics:

  • First Law of Thermodynamics: Energy can change from one form to another, but it cannot be created or destroyed (Law of Conservation of Energy).

  • Second Law of Thermodynamics: The physical state of energy will transform from a more-ordered, concentrated state to a less-ordered, highly dispersed state during any energy transformation. Entropy (molecular disorder) increases continuously. Conversion efficiency is always lower than $100\%$.

  • Example: A log of wood possesses concentrated, structural potential energy in chemical bonds. Combustion transforms this energy into dispersed kinetic energy (heat and visible light), releasing low-energy gas molecules ($\text{CO}_2$, $\text{H}_2\text{O}$) and disordered ash.

The Electromagnetic Spectrum

• Solar radiation released by the sun spans the electromagnetic spectrum across varying wavelengths (measured in meters):

  • Radio Waves: Wavelengths $\sim 1\,\text{m}$ (Low energy, non-ionizing).

  • Microwaves: Wavelengths $\sim 10^{-2}\,\text{m}$.

  • Infrared Radiation: Wavelengths $\sim 10^{-4}\,\text{m}$.

  • Visible Light Spectrum: Wavelengths $\sim 10^{-6}\,\text{m}$ (detected by human eyes and utilized by plants).

  • Ultraviolet Radiation (UV): Wavelengths $\sim 10^{-8}\,\text{m}$.

  • X-Rays: Wavelengths $\sim 10^{-10}\,\text{m}$.

  • Gamma Rays: Wavelengths $\sim 10^{-12}-10^{-14}\,\text{m}$ (High energy, ionizing radiation).

Metabolic Pathways: Photosynthesis, Respiration, and Chemosynthesis

• Autotrophs: Primary producers (plants, algae, cyanobacteria) that synthesize complex organic food molecules directly from solar radiation or inorganic chemical bonds.

• Heterotrophs: Organisms (animals, fungi, microbes) that satisfy nutritional energy needs by consuming other organisms.

Photosynthesis

• Occurs inside cellular organelles called chloroplasts.

• Chlorophyll absorbs red and blue light wavelengths to energize electron transport chains.

• Two-stage metabolic mechanism:

  1. Light Reactions: Solar energy splits water molecules ($\text{H}_2\text{O}$), releasing oxygen gas ($\text{O}_2$), hydrogen ions ($\text{H}^+$), and generating energy-carrying molecules (ATP and NADPH).

  2. Calvin Cycle: ATP and NADPH drive reactions that fix atmospheric carbon dioxide ($\text{CO}_2$) into high-energy sugars (glucose).

• Balanced Photosynthesis Chemical Equation:

$6\text{CO}_2 + 6\text{H}_2\text{O} + \text{solar energy} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2$

Cellular Respiration

• Process by which autotrophs and heterotrophs break down organic molecules to release chemical energy (ATP) for cellular work.

• Balanced Cellular Respiration Chemical Equation:

$\text{C}_6\text{H}_{12}\text{O}_6 + 6\text{O}_2 \rightarrow 6\text{CO}_2 + 6\text{H}_2\text{O} + \text{chemical energy (ATP) + heat}$

• Energy efficiency: Captures approximately two-thirds ($\sim 66\%$ ) of stored chemical bond energy, dissipating the rest as thermal waste heat.

Chemosynthesis

• Operates in lightless environments, such as deep-sea hydrothermal vents, powered by geothermal heat.

• Specialized archaebacteria fix inorganic carbon using chemical energy stored in hydrogen sulfide ($\text{H}_2\text{S}$).

• Balanced Chemosynthesis Chemical Equation:

$6\text{CO}_2 + 6\text{H}_2\text{O} + 3\text{H}_2\text{S} \rightarrow \text{C}_6\text{H}_{12}\text{O}_6 + 3\text{H}_2\text{SO}_4$

Earth's Geological Systems, Plate Tectonics, and the Rock Cycle

• Geology: The study of Earth's physical structure, underlying material composition, history, and dynamic physical processes.

Concentric Earth Layers

• Inner Core: Solid sphere composed of metallic iron and nickel at the center of the planet ($\sim 5150-6370\,\text{km}$ depth).

• Outer Core: Layer of fluid, molten iron and nickel surrounding the inner core ($\sim 2900-5150\,\text{km}$ depth).

• Mantle: Thick layer of dense, elastic, semi-solid rock surrounding the core ($\sim 100-2900\,\text{km}$ depth).

• Asthenosphere: Region of the upper mantle consisting of soft, highly ductile rock ($\sim 100-250\,\text{km}$ depth).

• Lithosphere: Rigid, brittle outer shell comprising the uppermost mantle and the overlying crust ($\sim 0-100\,\text{km}$ depth).

• Crust: Thin, brittle, low-density outer rock envelope covering Earth's surface:

  • Continental Crust: Thicker, less dense granitic rock.

  • Oceanic Crust: Thinner, denser basaltic rock.

Plate Tectonics and Boundary Interactions

• Thermal convection currents driven by geothermal radioactive decay circulate material within the mantle.

• These deep convection loops slowly move overlying lithospheric plates across Earth's surface at speeds of $2-15\,\text{cm\,yr}^{-1}$.

• Three Principal Tectonic Plate Boundaries:

  1. Divergent Plate Boundaries: Plates pull apart as convective upwelling forces magma upward. Magma cools at the surface, forming new oceanic crust (e.g., Mid-Atlantic Ridge).

  2. Transform Plate Boundaries: Plates grind and slide past one another horizontally along strike-slip faults. Friction generates seismic stress leading to severe earthquakes (e.g., San Andreas Fault along the Pacific and North American plate boundaries).

  3. Convergent Plate Boundaries: Plates collide, forming two primary geological configurations:

  • Subduction Zones: Denser oceanic crust plunges downward beneath lighter continental (or younger oceanic) crust into the asthenosphere, forming deep ocean trenches and volcanic mountain arcs (e.g., Pacific Northwest Coast, Andes Mountains).

  • Continental Collision: Two low-density continental plates collide, buckle, compress, and uplift, forming non-volcanic mountain ranges (e.g., the Himalayas).

The Rock Cycle

• Rock: Any solid aggregation of minerals or mineraloid matter.

• Mineral: A naturally occurring inorganic solid element or compound with a crystalline structure, specific chemical formula, and distinct physical properties.

• The Rock Cycle: The process by which rocks and minerals undergo heating, melting, cooling, weathering, erosion, deposition, compaction, and physical modification over geological time.

Primary Rock Types

• Igneous Rock: Forms directly from the cooling and crystallization of molten rock (magma or lava).

  • Intrusive Igneous Rock: Magma cools slowly beneath Earth's surface, allowing large mineral crystals to grow, creating coarse-grained rock (e.g., Granite).

  • Extrusive Igneous Rock: Lava erupts onto Earth's surface and cools rapidly, forming fine-grained or glassy rock (e.g., Basalt in Japan).

• Sedimentary Rock: Formed as wind, water, or ice weather existing rock into small particulate sediment. Layers accumulate, compact under pressure, and cement together through mineral precipitation (lithification) (e.g., Sandstone in Arizona; Limestone).

• Metamorphic Rock: Formed when existing rocks are subjected to intense heat and pressure within Earth's crust, altering their crystalline lattice, physical texture, and chemical properties without complete melting (e.g., Granite metamorphoses into Gneiss in Utah; Limestone metamorphoses into Marble).

Geological Deep Time and the Anthropocene

• Earth's history spans approximately $4.5\text{ billion years}$, subdivided by geologists into eras, periods, and epochs based on rock strata layers:

  • Quaternary Period: Began $1.8\text{ million years ago}$.

  • Holocene Epoch: The post-glacial epoch spanning the last $11,700\,\text{years}$.

  • The Anthropocene Epoch: A proposed new geological epoch designated to reflect the period during which human activities began exerting dominant, transformative impacts on global climate, atmospheric composition, soil erosion rates, and biological mass extinctions.

Geologic Hazards and Disaster Risk Management

• The Circum-Pacific Belt ("Ring of Fire"): An arc surrounding the Pacific Ocean basin where subduction zones and tectonic plate margins generate $90\%$ ($9\text{ out of }10$) of Earth's earthquakes and contain the vast majority of active volcanoes.

Earthquakes

• Earthquakes: A sudden release of built-up strain energy along plate boundaries, transform faults, or interior fault lines, sending destructive seismic shockwaves through the crust.

• Seismic Building Engineering: Modern structural engineering designs employ flexible foundations, counterweights, and sway joints to withstand seismic shaking. Poor nations lacking capital and building code enforcement suffer severe structural failures (e.g., the 2010 Haiti earthquake destroyed poorly built concrete structures, killing roughly 236,000 people).

• Building codes in high-risk zones mandate structural earthquake protections.

Historical Earthquake Events

• 1556 Shaanxi Province, China: Magnitude $\sim 8$; 830,000 fatalities.

• 1755 Lisbon, Portugal: Magnitude $8.7$; 70,000 fatalities (includes tsunami deaths).

• 1906 San Francisco, California: Magnitude $7.8$; 3,000 fatalities.

• 1923 Kwanto, Japan: Magnitude $7.9$; 143,000 fatalities.

• 1964 Anchorage, Alaska: Magnitude $9.2$; 128 fatalities.

• 1976 Tangshan, China: Magnitude $7.5$; 255,000+ fatalities.

• 1985 Michoacan, Mexico: Magnitude $8.0$; 9,500 fatalities.

• 1989 Loma Prieta, California: Magnitude $6.9$; 63 fatalities.

• 1994 Northridge, California: Magnitude $6.7$; 60 fatalities.

• 1995 Kobe, Japan: Magnitude $6.9$; 5,502 fatalities (includes tsunami deaths).

• 2004 Northern Sumatra: Magnitude $9.1$; 228,000 fatalities (includes tsunami deaths).

• 2005 Kashmir, Pakistan: Magnitude $7.6$; 86,000 fatalities.

• 2008 Sichuan Province, China: Magnitude $7.9$; 50,000+ fatalities.

• 2010 Port-au-Prince, Haiti: Magnitude $7.0$; 236,000 fatalities.

• 2010 Maule, Chile: Magnitude $8.8$; 500 fatalities.

• 2011 Northern Japan (Tohoku): Magnitude $9.0$; 18,000 fatalities (includes tsunami deaths).

• 2015 Kathmandu, Nepal: Magnitude $7.8$; 8,900 fatalities.

Volcanic Activity and Hotspots

• Volcanoes: Geological structures where molten rock, ash, cinder, and pressurized gases erupt through fissures in Earth's crust (commonly situated at subduction zones, ocean rifts, or mantle hotspots).

  • Japan contains over 100 active volcanoes ($\sim 10\%$ of the global active total).

• Hotspots: Stationary plumes of ultra-hot mantle material rising to erupt through moving lithospheric plates. Plates slide across stationary hotspots over geological deep time, creating linear chains of volcanic islands (e.g., the Hawaiian Islands chain formed over 60 million years as the Pacific Plate moved northwest over the hotspot).

• Volcanic Eruption Styles:

  • Effusive Eruptions: Continuous, fluid lava flows (e.g., Mount Kilauea erupting continuously since 1983).

  • Explosive Eruptions: Highly pressurized ash, cinder, and violent pyroclastic flows (e.g., Mount Saint Helens eruption in 1980; Mount Vesuvius eruption in A.D. 79 burying Pompeii).

• Climate Impacts: Eruptions eject huge sulfur dioxide gas clouds into the stratosphere, forming sulfate aerosols that reflect incoming sunlight. The 1815 eruption of Mount Tambora dropped global surface temperatures by $0.4-0.7^\circ\text{C}$.

Mass Wasting and Landslides

• Landslides: Occur when huge volumes of rock, regolith, or soil collapse and slide downhill under gravity.

• Mass Wasting: The downhill movement of soil and rock driven directly by gravity, commonly triggered on steep unstable slopes by rain saturation, seismic shaking, or human deforestation.

Tsunamis

• Tsunamis: Giant ocean waves triggered by massive water displacement from subduction earthquakes, submarine landslides, or coastal volcanic collapses (e.g., 2004 Indian Ocean tsunami killing 228,000 people; 2011 Tohoku tsunami in Japan).

• Mitigation Strategies: Installing deep-ocean tsunami buoy warning sensors, building sea walls, and restoring coastal ecosystems like mangrove forests to absorb wave energy.

Human Alteration of Hazard Severity

• Human decisions exacerbate natural hazards:

  • Constructing human settlements on river floodplains or vulnerable coastlines.

  • Damming or diking river channels, altering natural hydrologic sediment flows.

  • Clearcutting forests on steep slopes, destabilizing soils and triggering mass wasting landslides.

  • Driving human-induced climate change, altering weather patterns, sea level, and drought-deluge cycles.

Review Questions and Self-Assessment Answers

• Question: Which of the following are not included in the term "environment"?

  • Choice A: Living organisms, such as animals and plants

  • Choice B: Nonliving structures, such as rivers or soil

  • Choice C: Human structures and urban centers

  • Choice D: None of the above

  • Correct Answer: D. None of the above (all items are included in the environment).

• Question: How are fresh water and soil classified?

  • Choice A: Inexhaustible renewable natural resources

  • Choice B: Exhaustible renewable natural resources

  • Choice C: Nonrenewable natural resources

  • Choice D: These are not natural resources

  • Correct Answer: B. Exhaustible renewable natural resources.

• Question: Which of the following is true regarding the ecological footprint concept calculated by Wackernagel and the Global Footprint Network?

  • Choice A: Our ecological footprint decreased following the industrial revolution.

  • Choice B: Nonrenewable resources like fossil fuels are not part of the footprint calculation.

  • Choice C: The average ecological footprint is so high that we are experiencing an overshoot of Earth's capacity.

  • Choice D: The ecological footprint is higher in populations that are less affluent.

  • Correct Answer: C. The average ecological footprint is so high that we are experiencing an overshoot of Earth's capacity.

• Question: A series of aquariums is set up, each with an identical level of nutrients, types of organisms, and light exposure. The water in each is kept at a different temperature. The algae dry mass is measured after 2 weeks. What is the independent variable in this experiment?

  • Choice A: The temperature of the water

  • Choice B: The dry mass of the algae

  • Choice C: The time period (2 weeks)

  • Choice D: The nutrients and organisms in the water

  • Correct Answer: A. The temperature of the water.

• Question: The scientists in this study hypothesized that algae would grow fastest in warmer waters. Which is not a possible outcome following data collection in this experiment?

  • Choice A: The hypothesis is proven correct.

  • Choice B: The hypothesis is supported.

  • Choice C: The hypothesis is rejected.

  • Choice D: The hypothesis is modified.

  • Correct Answer: A. The hypothesis is proven correct (hypotheses are supported or rejected, never proven).

• Question: Which of these would be part of a movement that promoted sustainability?

  • Choice A: Increasing the alteration of natural ecosystems

  • Choice B: Increasing the ecological footprint of poorer countries, such as India

  • Choice C: Decreasing resource consumption in wealthy populations

  • Choice D: Utilizing resources as rapidly as possible while they are still available

  • Correct Answer: C. Decreasing resource consumption in wealthy populations.

• Question: What term would not apply to water, $\text{H}_2\text{O}$?

  • Choice A: Molecule

  • Choice B: Compound

  • Choice C: Element

  • Choice D: Inorganic

  • Correct Answer: C. Element.

• Question: What part of the atom is negatively charged, is found outside the nucleus, and is attracted by other atoms during chemical bonding?

  • Choice A: Protons

  • Choice B: Neutrons

  • Choice C: Electrons

  • Choice D: Atomic number

  • Correct Answer: C. Electrons.

• Question: Iodine-131 is a radioisotope with a half-life of about 8 days. What happens after 8 days?

  • Choice A: Its atomic mass decreases by half.

  • Choice B: Half of its atoms decay to a stable isotope.

  • Choice C: It stops releasing ionizing radiation.

  • Choice D: Half of its electrons are lost to other atoms.

  • Correct Answer: B. Half of its atoms decay to a stable isotope.

• Question: According to the pH scale, which of these solutions would be classified as the strongest acid?

  • Choice A: Lye, pH 13

  • Choice B: Pure water, pH 7

  • Choice C: Tomato juice, pH 5

  • Choice D: Vinegar, pH 3

  • Correct Answer: D. Vinegar, pH 3.

• Question: Which of these would be classified as kinetic energy?

  • Choice A: The energy in the bonds of a hydrogen sulfide molecule

  • Choice B: The energy present in an apple

  • Choice C: The energy in a fully charged battery

  • Choice D: The energy of wind flowing past a windmill

  • Correct Answer: D. The energy of wind flowing past a windmill.

• Question: An inventor claims to have the ability to transform potential energy to kinetic energy without any decrease in the energy's quality. What law does this violate?

  • Choice A: The first law of thermodynamics

  • Choice B: The second law of thermodynamics

  • Choice C: The law of conservation of matter

  • Choice D: None of the above; 100% efficiency can be achieved

  • Correct Answer: B. The second law of thermodynamics.

• Question: According to the photosynthesis reaction, autotrophs use _____ as a source of energy and _____ as a source of mass.

  • Choice A: glucose; oxygen

  • Choice B: sunlight; carbon dioxide and water

  • Choice C: geothermal heat; hydrogen sulfide

  • Choice D: radioisotopes; magma

  • Correct Answer: B. sunlight; carbon dioxide and water.

• Question: What layer of the Earth includes continental and oceanic crust?

  • Choice A: The outer core

  • Choice B: The lower mantle

  • Choice C: The asthenosphere

  • Choice D: The lithosphere

  • Correct Answer: D. The lithosphere.

• Question: The San Andreas fault is located in Southern California, between the Pacific Plate and the North American plate. As the landmasses move horizontally against each other, they cause earthquakes. What type of plate boundary is this?

  • Choice A: Divergent

  • Choice B: Transform

  • Choice C: A subduction zone of a convergent boundary

  • Choice D: A continental collision at a convergent boundary

  • Correct Answer: B. Transform.

• Question: Marble is formed when limestone is subjected to heat and pressure over a long period of time. What type of rock is marble?

  • Choice A: Metamorphic

  • Choice B: Extrusive igneous

  • Choice C: Intrusive igneous

  • Choice D: Sedimentary

  • Correct Answer: A. Metamorphic.

• Question: Cities along the "Ring of Fire" are more at risk from which types of natural hazards?

  • Choice A: Earthquakes

  • Choice B: Volcanic eruptions

  • Choice C: Tsunamis

  • Choice D: All of the above

  • Correct Answer: D. All of the above.

• Question: Which natural hazard is the direct result of mass wasting?

  • Choice A: Earthquakes

  • Choice B: Landslides

  • Choice C: Volcanic eruptions

  • Choice D: Tsunamis

  • Correct Answer: B. Landslides (and C. Volcanic eruptions, as classified in presentation reviews).