Ecology, Biosphere, and Population Dynamics Vocabulary Flashcards

Vocabulary flashcards generated from lecture notes on ecology, population growth, species interactions, community structure, and global ecosystem dynamics.

Longitude Lines (Meridians)

Lines that circle the Earth north to south and intersect at the poles, dividing the Earth into Eastern and Western Hemispheres relative to the prime meridian ($0^\circ$ longitude) in Greenwich, England.

Latitude Lines

Flat, parallel lines that circle the Earth east to west, measuring position north or south of the equator ($0^\circ$ latitude).

Beam Spreading

The reduction in solar radiation density occurring when incoming solar rays strike the Earth at an oblique angle, spreading energy across a larger surface area.

Nutrient Upwelling

An oceanographic process where winds push warm surface water away from coastlines, creating a vacuum that pulls colder, nutrient-rich bottom water up to nourish shallow waters.

Rain Shadow

An arid region formed on the leeward side of a tall mountain range because moisture-laden air cools, condenses, and drops precipitation on the windward side as it rises.

Photic Zone

The illuminated upper layer of an aquatic body into which sunlight penetrates, supporting aquatic vegetation and photosynthesis.

Aphotic Zone

The deep layer of a lake or ocean that receives insufficient sunlight for photosynthesis, lacking plant life.

Neritic Zone

The shallow open-water marine region situated above continental shelves, characterized by high nutrient levels, light availability, and high productivity.

Oceanic Zone

The region of open ocean lying beyond the continental shelves, characterized by low nutrient levels.

Population Density

The number of individuals of a species per unit area of habitat, which systematically decreases as average animal body size increases.

Per Capita Growth Rate ($r$)

The difference between per capita birth rate ($b$) and per capita death rate ($d$), expressed in the population growth formula as $r = b - d$.

Carrying Capacity ($K$)

The maximum population size ($N$) of a species that a given environment can support indefinitely based on available resources.

Dispersion Patterns

The spatial distributions of individuals within a population across their habitat, categorized as uniform, random, or clumped.

Intraspecific Competition

Competition for limited resources occurring between individuals of the exact same species, leading to density-dependent population regulation.

Density-Independent Events

Abiotic events (such as wildfires, severe storms, or floods) that limit population size regardless of local population density.

Aposematic Coloration

Bright, high-contrast warning coloration used by toxic or venomous animals to deter potential predators.

Batesian Mimicry

A defensive phenomenon where a harmless or non-toxic species (the mimic) evolves to resemble a toxic or dangerous species (the model).

Müllerian Mimicry

A mutual defensive phenomenon where two or more unpalatable or toxic species evolve similar warning signals to reinforce predator avoidance.

Exploitative Competition

An indirect form of interspecific competition where one species depletes a shared limited resource, leaving less available for competitors without direct physical interaction.

Interference Competition

A direct form of competition where organisms physically fight, display aggression, or release inhibitory chemicals to prevent competitors from accessing resources.

Competitive Exclusion Principle

The ecological rule stating that two species competing for identical limited resources or occupying the exact same ecological niche cannot stably coexist.

Fundamental Niche

The full range of environmental conditions and locations where a species could live and reproduce in the absence of predators and competitors.

Realized Niche

The actual set of conditions and locations where a species survives and reproduces in the presence of competitors and predators.

Character Displacement

The evolutionary divergence of physical traits (such as finch beak sizes) in sympatric populations of competing species to promote resource partitioning.

Species Richness

The total number of distinct biological species present within a community.

Species Evenness

The relative abundance and proportional representation of each species within a biological community.

Shannon-Wiener Diversity Index ($H'$)

A quantitative index measuring community species diversity based on richness and relative abundance, calculated as $H' = -\sum (p_i \ln p_i)$.

Trophic Cascade

An indirect interaction where the addition or removal of a top predator alters the abundance or behavior of prey, triggering reciprocal changes across lower trophic levels.

Keystone Predator

A dominant predator (such as Pisaster ochraceus) that exerts top-down control over dominant prey populations, preventing monocultures and maintaining community diversity.

Primary Succession

Ecological succession occurring on barren, newly exposed substrate devoid of pre-existing soil (such as cooled lava or retreat areas of glaciers).

Secondary Succession

Ecological succession taking place after a disturbance disrupts an existing community but leaves soil, organic matter, and seeds intact.

$r$-selected Species

Species adapted to pioneer successional stages, characterized by small size, fast growth, early reproduction, high reproductive rates, and minimal parental investment.

$K$-selected Species

Species adapted to competitive climax communities, characterized by larger size, slow growth, delayed reproduction, lower reproductive output, and high parental investment.

Latitudinal Diversity Gradient

The ecological trend wherein biological species richness increases systematically from high-latitude polar regions toward the equator.

Net Primary Productivity (NPP)

The amount of solar energy converted into chemical biomass remaining for plant growth and reproduction after accounting for cellular respiration ($\text{NPP} = \text{GPP} - \text{respiration}$).

10% Rule

The ecological principle stating that approximately $10\%$ of chemical energy available at one trophic level is converted into biomass at the next trophic level.

Standing Stock Biomass

The total weight or mass of living organisms present within a designated area or volume at a specific point in time.

Bottom-Up Control

Ecosystem regulation where the abundance of organisms across higher trophic levels is determined primarily by the abundance and productivity of primary producers.

Top-Down Control

Ecosystem regulation where higher-level consumers and predators dictate the structure and abundance of organisms at lower trophic levels.

Biological Amplification

The progressive concentration and buildup of persistent, fat-soluble chemicals (such as DDT) in organisms at higher trophic levels in a food chain.

Eutrophication

The over-enrichment of aquatic ecosystems with excess nitrogen and nitrates from human fertilizers, triggering excessive algal blooms and oxygen depletion.