ENVS 1000 Comprehensive Course Review Flashcards

Practice vocabulary flashcards covering foundational ecological, environmental science, population dynamics, fisheries management, and conservation forestry concepts based on course lecture materials.

Community

A group of populations of different species of organisms that live in the same place at the same time and interact with one another.

Species Equilibrium Model (Island Biogeography)

A theoretical model proposing that the number of species on an island reaches a dynamic balance determined by the opposing rates of species immigration and species extinction (or extirpation), both governed by island size and distance from the mainland.

SLOSS Dilemma

A foundational conservation debate regarding reserve design over whether it is more effective to protect biodiversity using a "Single Large Or Several Small" reserve system.

Commensalism

An ecological interaction between two species where one organism benefits while the other experiences no significant harm or benefit.

Intermediate Disturbance Hypothesis

An ecological hypothesis proposing that species richness and diversity are highest in ecosystems experiencing intermediate frequencies or intensities of environmental disturbance.

Trophic Cascade

A series of indirect ecological interactions triggered by changes in top predator abundance (such as sea otters) that ripple downward through food webs, altering the population density and biomass of lower trophic levels (such as sea urchins and kelp).

Indicator Species

A species whose presence, absence, or abundance acts as an early warning signal of ecological degradation or correlates directly with a specific aspect of environmental quality.

Primary Succession

A predictable series of ecological community changes that unfolds after a severe disturbance eliminates all preexisting vegetation, soil organisms, and organic matter from a site.

Secondary Succession

A sequence of community reorganization that occurs after an environmental disturbance dramatically alters or disrupts an existing community without destroying all local organisms or eliminating the soil substrate.

First Law of Thermodynamics

The principle of physics stating that energy cannot be created or destroyed, meaning the total amount of energy across the universe remains fixed.

Second Law of Thermodynamics

The physical principle asserting that when energy is transformed from one state to another, some useful energy is converted into a lower-quality, less usable form, driving systems toward disorder ($\text{entropy}$).

Net Primary Productivity (NPP)

The rate at which autotrophs convert solar energy into usable organic biomass (gross primary productivity, or $\text{GPP}$) minus the rate at which they consume that energy for their own cellular metabolic needs and aerobic respiration.

Ecological Efficiency

The percentage of usable chemical energy transferred from one trophic level up to the next consecutive rank in a food pyramid, typically averaging approximately $10\%$ (range $2\%$ to $40\%$).

Nitrogen Fixation

The biological or chemical process in which inert atmospheric nitrogen gas ($\text{N}_2$) is converted by specialized bacteria or lightning into ammonia ($\text{NH}_3$) or ammonium ions ($\text{NH}_4^+$) usable by primary producers.

Eutrophication

The process of aquatic ecosystem degradation triggered by nutrient over-enrichment (typically nitrogen or phosphorus), leading to rapid algal blooms, high decomposition, increased biochemical oxygen demand ($\text{BOD}$), and hypoxia.

Environmental Science

An applied, interdisciplinary academic field that examines how the Earth's natural systems function, how humans are influenced by those systems, and how human activities impact the environment and generate solutions to environmental problems.

Tragedy of the Commons

A socio-ecological dilemma described by Garrett Hardin in 1968 wherein individual resource users, acting independently and rationally according to self-interest, deplete or degrade an open-access, unregulated common resource.

IPAT Model

A conceptual equation that expresses human environmental impact ($I$) as the product of population size ($P$), affluence or per-capita consumption ($A$), and technological impact per unit of consumption ($T$): $I = P \times A \times T$.

Ecological Footprint

A metric measuring the environmental impact of an individual or population expressed as the total area of biologically productive land and water required to provide consumed resources and absorb generated waste.

Biocapacity

The capacity of a terrestrial or aquatic ecosystem to generate useful renewable biological materials and assimilate wastes generated by humans, including carbon dioxide ($\text{CO}_2$).

Commercial Extinction

The depletion of a wild population to a density so low that continued commercial harvesting of that species is no longer economically viable.

Total Allowable Catch (TAC)

A regional fishery management quota that establishes a maximum allowable limit on the total weight of a fish stock that can be harvested within an area before the fishery is officially closed.

Race to Fish

A phenomenon arising under competitive regional Total Allowable Catch regulations without individual allocations, where fishers invest heavily in gear and speed to catch as much fish as possible before the fleet-wide limit is reached.

Individual Transferable Quota (ITQ)

A fisheries management mechanism that divides the Total Allowable Catch into secure, transferable percentage shares allocated to individual fishers or vessels, allowing them to catch, buy, sell, or lease quota.

Maximum Sustainable Yield (MSY)

The largest catch or harvest that can be extracted from a biological population indefinitely without causing population decline, typically achieved at the population size where the annual growth rate is maximized.

Demographic Transition

A demographic model describing how human populations transition from high birth and death rates in pre-industrial conditions to low birth and death rates in developed societies, typically passing through a phase of rapid population growth.

Population Age Structure

The relative distribution of individuals within a population across biological sex and specific age brackets—specifically prereproductive ($0\text{--}14$), reproductive ($15\text{--}44$), and postreproductive ($\ge 45$) cohorts.

Exponential Growth

Population increase that occurs at a constant proportional rate over time, creating a $J$-shaped trajectory when environmental resources are unrestricted and limiting factors are absent.

Density-Dependent Limiting Factor

An environmental limiting factor whose regulatory influence on survival or reproductive success increases in intensity as the density of the population rises (e.g., resource competition, disease, predation).

K-selected Species

Species possessing low biotic potential that tend to stabilize near environmental carrying capacity ($K$), characterized by long gestation, few offspring, delayed maturity, and extensive parental care.

Emergent Property

A novel characteristic or behavior that arises from the synergistic interactions of components within a complex system that cannot be explained or predicted simply by examining individual parts in isolation.

Negative Feedback Loop

A regulatory feedback mechanism in which a change or output from a system acts as input that drives the system in the opposite direction, dampening fluctuations and maintaining dynamic equilibrium or homeostasis.

Grey Literature

Research materials, technical reports, working papers, patents, and government documents that are produced and distributed by organizations outside conventional academic peer-reviewed journal publishing channels.

Lentic System

A freshwater aquatic ecosystem composed of standing or still water, such as lakes, ponds, bogs, and reservoirs, characterized by distinct spatial zones including littoral, limnetic, profundal, and benthic zones.

Ramsar Convention

An international environmental treaty signed in 1971 in Ramsar, Iran, providing a global framework for national action and international cooperation regarding the conservation and sustainable management of internationally important wetlands.

Nonpoint Source Pollution

Pollution that originates from multiple unconfined, widespread landscape sources over a broad geographic area (such as agricultural fertilizers, urban runoff, and atmospheric deposition) rather than an identifiable, discrete discharge point.

CITES

The Convention on International Trade in Endangered Species of Wild Fauna and Flora; an international treaty that prohibits international trade in threatened species listed in Appendix I and regulates trade via permits for species listed in Appendix II.

Flagship Species

A charismatic, recognizable animal species used by conservation groups and wildlife agencies as an ambassador or symbol to rally public support, raise conservation funding, and protect broader ecosystems.

Umbrella Species

A species whose conservation demands such expansive territories and extensive habitat preservation that protecting it indirectly preserves many co-occurring species across the wider community.

Invasive Species

An introduced, non-native (exotic) organism that establishes, proliferates, and spreads rapidly in a new environment, often free of limiting predators or pathogens, causing substantial ecological or economic damage.

Forest Stratification

The multi-layered vertical organization of a forest community into specific vertical tiers—emergent trees, canopy, subcanopy, understorey, shrub layer, forest floor, and soil—which provides diverse structural niches that support high biodiversity.

Seed-Tree Cutting

A silvicultural timber harvesting practice in which nearly all mature trees in a stand are cut, leaving only a small number of evenly distributed, seed-bearing mature trees to naturally reseed and regenerate the harvested site.

Shelterwood Cutting

A forest harvesting method in which mature canopy trees are removed over several distinct, staged cuts across roughly $10\text{--}20$ years, retaining an overhead canopy to shelter regenerating seedlings and prevent soil erosion.