Unit 0 APES

1. Core Terminology & Concepts

Anthropogenic

Definition: Caused by humans.

• Examples (Good): Reforestation projects, pollution clean-up, renewable energy.

• Examples (Bad): Air pollution, deforestation, greenhouse gas emissions.

Science, Environment, Environmental Science/Studies

• Science: A systematic method to understand the natural world through observation, hypothesis, and experimentation.

• Environment: All external conditions, living and nonliving, influencing organisms.

• Environmental Science: An interdisciplinary field combining ecology, chemistry, geology, sociology, economics, etc., to study how natural systems work and how humans interact with them.

Rachel Carson

• Influential marine biologist and conservationist.

• Author of Silent Spring (1962), exposing the harm of pesticides like DDT and launching the modern environmental movement.

System, Ecosystem, Biotic & Abiotic

• System: A group of interacting parts working as a whole.

• Ecosystem: A biological community (biotic) plus its physical environment (abiotic) functioning as a unit.

• Biotic: Living components (e.g., plants, animals).

• Abiotic: Non-living components (e.g., sunlight, soil, water).

Environmental Scientist vs. Environmentalist

• Environmental Scientist: Studies how natural and human systems interact; conducts research, models ecosystems, monitors pollution, etc.

• Environmentalist: Advocates for environmental protection; can engage in activism, education, policy-making, or community organizing.

2. Fracking (Hydraulic Fracturing)

What it is: A method of extracting oil or natural gas from deep underground rock (typically shale) by injecting high-pressure fluids to create fractures.
Process: Drill deep well → inject mixture (water, sand, chemicals) → fractures → fossil fuels flow to well → brought to surface.
What’s harvested: Petroleum (oil) and natural gas.
Goods: Increased energy supply, economic growth, lower energy prices.
Bads: Water contamination, induced seismicity (earthquakes), methane leaks, habitat disruption, high water use.

3. Human Alterations to the Environment

Two major drivers:

1. Population growth

2. Technological development

Good outcomes:

• Increased agricultural productivity (feeding more people).

• Better infrastructure and energy access.

Bad outcomes:

• Habitat destruction, pollution, resource depletion, climate change.

Impacts on populations (plants/animals):

• Population decline

• Population increase

• Migration/distribution shifts

Which is more common lately? Many species are experiencing decline, largely due to habitat loss, climate change, invasive species.

4. Ecosystem Services & Environmental Indicators

Ecosystem Services

Definition: Benefits humans get from ecosystems.
Categories:

1. Provisioning (e.g., food, water, timber)

2. Regulating (e.g., climate control, flood regulation, pollination)

3. Supporting (e.g., nutrient cycling, soil formation)

4. Cultural (e.g., recreation, spiritual value)

Environmental Indicators

Definition: Measures that help assess the state of the environment (e.g., species counts, pollution levels).

• Examples: Indicator species (like amphibians for water quality), air quality indices, CO₂ concentrations.

5. Big Five Global-Scale Indicators

1. Biological Diversity

• Biodiversity: Variety of life across genetic, species, and ecosystem levels.

• Greatest near the equator (tropics).

• Levels:

  • Genetic diversity: Variability of genes within a population.

  • Species diversity: Variety of species in a community.

  • Ecosystem diversity: Variety of ecosystems in a region.

Why high diversity is good:

• Genetic: Greater resilience to disease, environmental change.

• Species: Ecosystem stability, more ecosystem services.

• Speciation: Formation of new species.

• Background extinction: Normal extinction rate between mass extinctions.

• Current issue: Elevated extinction rates above background levels—indicating biodiversity loss.

2. Food Production

• Depends on soil quality, water, and climate/technology.

• World population (2025): approximately 8 billion.

• Green Revolution: Mid‑20th-century agricultural innovations (like high-yield crops, fertilizers).

  • Good: Massive increase in food production.

  • Bad: Environmental degradation, inequality.

  • Father of the Green Revolution: Norman Borlaug.

• Climate change and resource constraints threaten future food production.

3. CO₂ Concentration & Global Temperature

• Greenhouse gases (GHGs): Gases trapping heat (e.g., CO₂, methane [CH₄], nitrous oxide [N₂O]).

• Trends: CO₂ levels increasing (over 400 ppm), rising global surface temps.

• Impacts: Sea-level rise, stronger storms, habitat shifts, coral bleaching.

4. Human Population

• Current world population: ~8 billion.

• Carrying capacity (K): Maximum population an environment can sustain long-term.

• If population exceeds K, resource shortages and degradation occur.

5. Resource Depletion

• Human population growth strains resources.

• Renewable resources: Replenish naturally (e.g., solar energy, forests [if managed], freshwater).

• Nonrenewable: Finite (e.g., fossil fuels, minerals).

• Who uses more: Wealthier, industrialized nations (like the U.S.) use more per capita resources (e.g., lumber, fossil fuels).

6. Sustainability & Ecological Footprint

Sustainability / Sustainable Living

• Definition: Meeting present needs without compromising future generations. Practically, developing in ways that maintain ecological balance.

• In your own words: Living so we don’t deplete resources or harm ecosystems for future people.

Ecological Footprint

• Definition: Measure of how much land/water area a person/population needs to produce resources and absorb waste.

• If everyone lived like the USA, we'd need ~ 5 Earths to sustain.

7. Scientific Method & Experimental Design

• Scientific Method: Observation → question → hypothesis → experiment → data → conclusion → communication.

• Hypothesis: Testable statement predicting relationship between variables (must reference both variables and be specific).

• Controlled Experiment: Manipulate independent variable, measure dependent variable, all else equal.

Key terms:

• Independent variable (IV): What you change.

• Dependent variable (DV): What you measure.

• Constants: Factors kept the same.

• Experimental group: Receives treatment.

• Control group: Baseline for comparison.

• Replication: Repeating experiments to ensure reliability.

• Sample size: Number of observations—larger is better for accuracy.

• Accuracy & precision: Allow you to reduce error and improve reliability.

Data display: Use appropriately labeled tables and graphs (with units, titles).
Controlled vs. natural experiments:

• Controlled: More precise, but possibly less realistic.

• Natural: More realistic, but less control over variables.

Environmental Justice

• Fair distribution of environmental benefits and burdens.

• Examples: Communities of color facing more pollution, unequal access to clean water.

8. Chemistry: Cycles of Matter

• System: Think of inputs/outputs—e.g., water in a watershed (input: rainfall; output: evaporation/runoff).

• Matter: Anything with mass and volume.

• Atoms: Protons (+, in nucleus), Neutrons (neutral, nucleus), Electrons (–, orbit).

• Elements: Pure substances defined by atomic number (number of protons).

• Molecule: Two or more atoms bonded.

• Compound: Molecule with different elements (e.g., H₂O).

From periodic table:

• Atomic number = protons.

• Mass number = protons + neutrons.

• Isotope = same element, different neutrons.

• Radioactive decay: Unstable isotope loses particles → transforms.

  • Half-life: Time for half the parent isotope to decay.

  • Parent → daughter. Used in carbon dating.

• Intramolecular bonds: Hold atoms together (covalent, ionic).

  • Covalent: Share electrons (e.g., H₂O).

  • Ionic: Transfer electrons (e.g., NaCl).

• Electron pairs: In covalent bonds.

• Polarity: Unequal sharing of electrons; one end slightly charged.

• Intermolecular bond (attraction): e.g., hydrogen bonding between molecules.

• Chemical reaction: Reactants → products. Balanced means atoms conserved. Helps track element cycles (like C, N, P) in ecosystems.

• Organic compound: Contains carbon (usually C–H bonds): e.g., glucose.

• Inorganic: Doesn’t (e.g., NaCl).

• Salt: Often an ionic compound; formed from acid-base reactions.

• Macromolecules: Carbs, lipids, proteins, nucleic acids.

  • Carbs: C, H, O; energy/growth (e.g., glucose, starch). Water soluble.

  • Proteins: Amino acids; functions include enzymes. Water soluble.

  • Lipids: Mostly C, H; fats/oils; insoluble in water.

  • Nucleic acids: DNA/RNA; store genetic information.

• Cell: Fundamental unit of life; cells form tissues, organs, systems.

9. Energy Flow & Thermodynamics

• Describe system inputs/outputs in energy terms—e.g., sun → plant (photosynthesis) → herbivore.

• Energy: Ability to do work or cause change.

• Key energy conversions: Photosynthesis & cellular respiration.

• Original energy source: The Sun.

• Photon: Particle of light.

• Electromagnetic spectrum: Shorter wavelengths (UV) carry more energy than longer (IR).

• Important spectrum for producers: Visible light (especially red, blue).

• Our concern: UV and infrared relating to warming and skin damage.

• Energy vs. Power:

  • Energy: Joules (J) or kilowatt-hour (kWh).

  • Power: Rate of energy use (Watts = J/s).

  • To get kWh: power (kW) × time (hours).

• Two energy “flavors”:

  • Kinetic (motion, e.g., heat).

  • Potential (stored, e.g., chemical). Temperature links to kinetic.

• 1st Law (Conservation): Energy not created or destroyed, only transformed.

• 2nd Law: With each transformation, energy becomes less usable (increased entropy).

• Energy efficiency: Output vs. input. Quality: How useful the energy is (electricity higher than heat).

• Determine efficiency: compare energy outputs and inputs.

• System types:

  • Closed (no mass exchange), Open (mass exchange).

  • Earth: Open for energy, technically closed for matter (almost no matter exchange).

• Equilibrium / Steady state: Inputs = outputs.

• Feedback:

  • Positive: Amplifies change (e.g., melting ice → less albedo → more warming).

  • Negative: Stabilizes (e.g., increased plant growth with CO₂, which absorbs some CO₂).

10. Water Chemistry & Life-Supporting Properties

• Water's atomic structure: Polar molecule (Oxygen partial negative, Hydrogens partial positive).

• Water’s intramolecular bonds: covalent. Intermolecular: hydrogen bonds.

5 Life-Supporting Properties:

1. Temperature moderation: Water’s high specific heat buffers temperature, aiding climate stability and helping organisms regulate heat.

2. Stickiness:

   • Cohesion: Water to water (surface tension).

   • Adhesion: Water to other surfaces (capillary action, e.g., plant xylem).

3. Universal solvent: “Like dissolves like”—polar water dissolves polar/hydrophilic substances; hydrophobic substances don’t dissolve. Important for transporting nutrients in organisms and ecosystems.

4. Acid/Base interactions:

   • pH scale: Logarithmic scale (pH 7 neutral; each unit change = 10×).

   • Acid: donates H⁺; base: accepts H⁺.

   • Buffers: resist pH change (e.g., bicarbonate in blood or lakes).

5. Ice floats: Solid water is less dense than liquid due to crystal structure. Ice insulates aquatic life in winter.

Math Review Basics

• Percent change: (New − Old) / Old × 100%

• Rates: Change in quantity over time (e.g., population/year).

• Dimensional analysis: Converting units by multiplication of conversion factors (e.g., grams to kilograms).