Environmental Science Key Terms: Ecology, Biodiversity, and Conservation

Natural Resources ⇢

Materials and energy sources from the environment that humans rely on; include renewable and nonrenewable types.

Ecological Footprint ⇢

The amount of land and water required to provide resources and absorb waste for an individual or population.

Ecosystem Services ⇢

Benefits provided by nature such as pollination, water purification, climate regulation, and nutrient cycling.

Scientific Method ⇢

Process of testing hypotheses through controlled experiments and observation.

Hypothesis ⇢

A testable explanation for an observation.

Evolution ⇢

Genetic change in populations over generations.

Natural Selection ⇢

Individuals with advantageous traits reproduce more successfully, driving evolutionary change.

Speciation ⇢

Formation of new species, often through geographic isolation.

Mass Extinction ⇢

Global events where large percentages of species go extinct rapidly; human activity is causing the 6th.

Carrying Capacity ⇢

Maximum population size an environment can sustain over time.

Exponential Growth ⇢

Population growth at a constant percentage; produces a J-curve.

Logistic Growth ⇢

Growth that slows as it reaches carrying capacity; produces an S-curve.

Invasive Species ⇢

Non-native species that spread rapidly and harm ecosystems.

Species Interactions ⇢

Includes competition, predation, parasitism, mutualism.

Trophic Levels ⇢

Feeding positions in food webs; only about 10% of energy transfers to the next level.

Ecological Succession ⇢

Predictable changes following disturbance; primary occurs without soil, secondary occurs with soil.

Biomes ⇢

Large ecological regions defined by climate (temperature and precipitation).

Demographic Transition ⇢

Model of population change from high birth/death rates to low birth/death rates through industrialization.

Population Growth Factors ⇢

Influenced by birth, death, immigration, and emigration.

One-Child Policy (China) ⇢

Policy to reduce growth; caused long-term aging and gender imbalance.

Family Planning ⇢

Deciding number and spacing of children; reduces fertility rates.

Industrial Agriculture ⇢

High-input farming using machinery, fertilizers, pesticides; boosts yield but harms soil, water, and pollinators.

Soil Degradation ⇢

Decline in soil quality from erosion, nutrient loss, and overgrazing.

Erosion ⇢

Removal of soil by wind or water; worsened by over-plowing and deforestation.

Desertification ⇢

Loss of >10% productivity in drylands due to erosion, overgrazing, and climate pressures.

Dust Bowl ⇢

Severe 1930s soil erosion from drought and plowing native grasses.

Pollination ⇢

Essential ecosystem service mainly performed by bees; required for most fruit and vegetable crops.

Bee Decline ⇢

Caused by pesticides, habitat loss, parasites, and disease.

Fertilizers ⇢

Substances that supply nutrients; inorganic types may cause water pollution through runoff.

Green Revolution ⇢

Dramatic yield increases through technology and high-yield crops; caused environmental impacts.

Feedlots (CAFOs) ⇢

Concentrated animal feeding operations producing large waste volumes and pollution.

Genetic Engineering ⇢

Direct manipulation of DNA for traits such as pest resistance.

Organic Agriculture ⇢

Avoids synthetic fertilizers, pesticides, and GMOs; emphasizes ecological balance.

Biodiversity ⇢

Variety of life at genetic, species, and ecosystem levels.

Benefits of Biodiversity ⇢

Provides food, medicine, stability, resilience, and economic value.

Causes of Biodiversity Loss ⇢

Habitat destruction, pollution, invasive species, climate change, overharvesting.

Endangered Species Act ⇢

U.S. law protecting threatened and endangered species and their habitats.

Conservation Biology ⇢

Scientific field aimed at protecting biodiversity and preventing extinction.

Bioaccumulation ⇢

Toxin buildup in individual organisms over time.

Biomagnification ⇢

Increasing toxin concentrations at higher trophic levels.

Environmental Health ⇢

Study of how environmental factors affect human health.

Toxicology ⇢

Study of harmful chemicals and their effects.

Synthetic Chemicals ⇢

Human-made chemicals that can harm health or ecosystems.

Silent Spring ⇢

Rachel Carson's book revealing pesticide dangers; sparked the environmental movement.

Exposure Types ⇢

Acute exposure is high dose/short term; chronic exposure is low dose/long term.

Synergistic Effects ⇢

When combined chemicals cause more harm than individually.

Deforestation ⇢

Clearing forests faster than they regrow; results in biodiversity loss and climate impacts.

Primary vs. Secondary Forests ⇢

Primary forests are uncut natural forests; secondary forests regrow after disturbance.

Forest Ecosystem Services ⇢

Include carbon storage, water purification, soil stabilization, and wildlife habitat.

Maximum Sustained Yield ⇢

Harvesting at the point where population growth is fastest—typically half carrying capacity.

Ecosystem-Based Management ⇢

Managing resources to reduce ecosystem impact and maintain long-term ecological health.

Timber Harvest Methods ⇢

Clear-cutting, seed-tree, shelterwood, and selection systems.

Wildfire Management ⇢

Recognizes fire as a natural process; controlled burns reduce fuel buildup.

Island Biogeography Theory ⇢

Species richness depends on island size and distance from mainland.

Policy ⇢

Formal government plan or rule designed to address problems.

Tragedy of the Commons ⇢

Shared resources are overused when individuals act in self-interest.

External Costs ⇢

Costs of environmental harm not paid by the polluter.

Three Branches of Government ⇢

Legislative makes laws, executive enforces laws, judicial interprets laws.

Public Trust Doctrine ⇢

Principle that governments must protect natural resources for public use.

Environmental Policy Approaches ⇢

Litigation, command-and-control regulation, and economic incentives.

Subsidy ⇢

Government financial support intended to encourage specific activities.

Emissions Trading ⇢

Market system where pollution permits can be bought and sold under a capped total amount.