AP Environmental Science: Ecosystem Services, Biodiversity, and Ecological Dynamics

Vocabulary flashcards covering ecosystem services, biodiversity levels, island biogeography, ecological tolerance, biomes, aquatic zones, natural disruptions, ecological succession, and invasive species.

Ecosystem

A community of living organisms (plants, animals, microbes) interacting with each other and with the nonliving environment (water, air, soil, climate).

Ecosystem services

The concrete benefits that human populations obtain for free from healthy ecosystems.

Provisioning services

Tangible goods harvested or used directly from ecosystems, such as food, fresh water, timber, medicinal resources, and fiber.

Regulating services

Natural processes that moderate environmental conditions, such as water purification, flood control, climate regulation through carbon storage, and natural pest control.

Supporting services

Underlying natural processes that make other ecosystem services possible, including nutrient cycling, soil formation, and primary production.

Cultural services

Nonmaterial benefits people obtain from ecosystems, including recreation, aesthetic value, and spiritual or educational enrichment.

Genetic diversity

The variation in DNA within a species, encompassing the range of all expressed and recessive traits that comprise its gene pool.

Population bottleneck

A large reduction in the size of a single population caused by a catastrophic environmental event, which diminishes the remaining gene pool.

Minimum viable population size (MVP)

The smallest possible population size at which a species can persist without facing extinction from random events or natural disasters.

Species richness

The total number of different species represented in a community or region.

Species evenness

A measure of how evenly individual organisms are distributed among the different species present in an area.

Ecosystem diversity

The variety and range of distinct habitats or ecosystems found within a specific geographic area.

Generalist species

Organisms that live in many types of environments and can survive on a wide variety of diets.

Specialist species

Organisms that require unique resources, often have limited diets, and may depend on a specific habitat.

Keystone species

A species that has an impact on ecosystem structure that is disproportionately large relative to its abundance.

Indicator species

An organism whose presence, absence, or abundance reflects a specific environmental condition and indicates ecosystem health.

Theory of island biogeography

A model proposing that the number of species on an island is determined by a balance between immigration and extinction, driven primarily by island size and distance from the mainland.

Habitat fragmentation

The process by which continuous habitat is broken into smaller, isolated pieces by human development, logging, roads, and other disturbances.

Edge effects

Changes in abiotic and biotic conditions, such as increased light, wind, temperature fluctuation, and predator access, occurring near the boundaries of fragmented habitats.

Law of Tolerance

The principle stating that the existence, abundance, and distribution of a species depend on its tolerance limits to physical and chemical factors in the environment.

Biome

A large ecological region characterized by its climate and typical plant and animal communities adapted to it.

Permafrost

A permanently frozen subsurface layer of soil common in the tundra that limits plant root growth and slows organic decomposition.

Ecotone

A transitional boundary zone where two distinct biomes or ecological communities blend together, often supporting high biodiversity.

Photic zone

The upper layer of an aquatic ecosystem that receives sufficient sunlight for photosynthesis to occur.

Aphotic zone

The deeper aquatic layer that receives too little sunlight for photosynthesis to take place.

Estuary

A highly productive aquatic mixing zone where freshwater from rivers meets seawater, characterized by brackish and variable conditions.

Intertidal zone

A coastal marine zone that is exposed to air at low tide and submerged under water at high tide.

Eutrophication

An aquatic phenomenon where excess nutrients trigger algal blooms, whose eventual death and decomposition severely consume dissolved oxygen.

Episodic processes

Earth-system events or disruptions that occur occasionally and at irregular intervals, such as El Niño and La Niña.

Periodic processes

Earth-system events that occur at regularly repeated intervals, such as ocean tides.

Random processes

Earth-system events that lack any regular pattern or predictability, such as meteorite impacts.

Ecological succession

The gradual and orderly process of ecosystem development brought about by directional, cumulative changes in community composition over time.

Facilitation

A successional mechanism where an established species modifies the environment in a way that makes it more suitable for another species to colonize.

Inhibition

A successional mechanism where an established species alters the environment in a way that makes it unsuitable for other species to establish.

Pioneer species

Early-successional organisms, typically niche generalists and r-strategists, that first colonize barren or disturbed habitats.

Primary succession

Ecological succession that begins in a barren, lifeless habitat where no soil is present initially, such as on cooled volcanic rock.

Secondary succession

Ecological succession that takes place after a disturbance clears existing organisms but leaves the soil intact.

Resistance

A measure of how much an ecosystem's structure or function changes when subjected to an environmental disturbance.

Resilience

The rate or speed at which an ecosystem recovers and returns to its prior state after a disturbance.

Invasive species

A non-native organism that spreads rapidly beyond its point of introduction and causes ecological, economic, or human health harm.

Enemy release

The ecological mechanism where an introduced species thrives because the predators, parasites, and pathogens from its native range are absent.

Biological control

A management strategy that introduces a natural predator, parasite, or pathogen to control an invasive or pest population.