AP®︎ Environmental Science: Unit 2 Flashcards

The variety of life in a defined area, including genetic, species, and habitat diversity

Variation in genes, alleles, and inherited traits within a population or species; greater variation increases the likelihood that some individuals can tolerate environmental stress

Variation among species in a community, determined by both species richness and species evenness

The variety of habitats within a geographic area; more habitat types generally support species with a wider range of ecological requirements

The number of different species found in a defined area, regardless of each species’ abundance

How equally individuals are distributed among the species present in a community

A sharp population decline that leaves a limited sample of the original alleles, reducing genetic diversity even if abundance later recovers

Reduced genetic diversity and altered allele frequencies when a new population is established by a small, unrepresentative group from a larger population

An ecosystem’s ability to recover toward its prior structure and function after a disruption; greater species diversity generally increases this ability

A change that makes an area unable to provide organisms’ required conditions or resources, tending to eliminate specialists first, then generalists, and to reduce species needing large territories

The division of continuous habitat into smaller, isolated patches that restrict movement, reduce gene flow, and increase edge effects

A species that uses a narrow range of resources or environmental conditions and is therefore especially vulnerable to habitat loss

A species that can use a broad range of resources or conditions, allowing it to persist longer than specialists as habitat is lost

Benefits people obtain from ecosystems and the ecological processes occurring within them

Material products obtained from ecosystems, such as food, fresh water, timber, fibers, fuel, and medicines

Benefits produced when ecosystems control, moderate, or buffer environmental conditions

Nonmaterial ecosystem benefits involving recreation, education, identity, inspiration, aesthetics, or spiritual well-being

Fundamental ecological processes that maintain ecosystems and make the other service categories possible

Human-caused alteration of ecosystem components or processes that can weaken or eliminate services, potentially causing ecological and economic consequences

The stock of natural resources and ecosystems that provides a continuing flow of ecosystem goods and services

The study of organisms’ distribution, ecological relationships, and community structure on islands

The successful establishment of a population by a species arriving from elsewhere

A model in which island species richness tends to stabilize where the colonization and local-extinction rates are equal

The rate at which new species colonize an island; it is higher on nearby islands and declines as more source-pool species become established

The rate at which species disappear locally from an island; it is generally higher on small islands and rises as species richness and competition increase

The predicted number of island species at the intersection of the colonization and extinction curves

The pattern that larger areas generally support more species because they contain more habitats, resources, and larger populations with lower extinction risk

The tendency for islands nearer a source pool to receive more colonists and support more species than otherwise similar distant islands

A species native to and naturally found only in a particular geographic area

An introduced species that establishes, spreads, and causes ecological, economic, or other harm

The principle that two species competing for the same limiting resources cannot coexist indefinitely in the same niche

The factor-specific range of environmental conditions an individual organism or species can endure before injury or death results

The range of conditions in which survival, growth, and reproduction are most successful and abundance is generally highest

Reduced biological performance when conditions leave the optimal range but remain survivable

Conditions beyond a lower or upper tolerance limit where injury or death prevents organisms from persisting

An environmental resource or condition whose scarcity or unfavorable level restricts an organism’s survival, growth, reproduction, abundance, or distribution

An event or process that changes an ecosystem’s physical environment, resources, populations, species composition, or community structure without originating from human activity

A process that recurs in a generally regular and predictable pattern, though occurrences may vary in intensity

A process that occurs as distinct events or bursts separated by intervals, often with uncertain exact timing

A process without a predictable schedule or location at the scale considered, though it still has physical causes

The immense span of Earth’s history, divided into intervals based on major geological, climatic, and biological changes

A prolonged cold interval when continental ice sheets and glaciers expand and global sea level falls

A relatively warm interval between glacial periods when land ice retreats and global sea level rises

More water stored in land ice lowers global sea level; melting glaciers and land-based ice sheets raises it

A change in the geographic location of suitable environmental conditions that can force populations to move, adapt, or decline

The temporary, seasonal, or lasting movement of organisms to track resources or suitable environmental conditions

A heritable characteristic, produced by natural selection over generations, that improves survival and reproduction under particular environmental conditions

The process by which heritable traits that increase reproductive success under current conditions become more common in a population over generations

A genetically influenced characteristic that can be passed from parents to offspring

A change in DNA that creates new genetic variation and may be beneficial, harmful, or neutral

An environmental condition that causes individuals with some heritable traits to survive or reproduce more successfully than others

An individual's reproductive contribution to later generations, rather than simply its strength, health, or lifespan

A temporary physiological adjustment by an individual to environmental change, not an inherited population-level adaptation

Gradual change in an ecosystem’s species composition and community structure as organisms colonize new habitat or a community recovers after disturbance

Succession beginning on a newly exposed or formed surface with little or no developed soil, so soil must form before most plants establish

Succession following a disturbance where soil remains, so recovery generally proceeds faster than primary succession

The first species to colonize an unoccupied or severely disturbed habitat; they tolerate harsh conditions and often modify the habitat for later species

The development of soil as rock is weathered and mixed with water, air, decomposed organic matter, and organisms over time

Fast-growing, rapidly reproducing species that colonize disturbed habitats early and tolerate exposed or resource-poor conditions

Long-lived, slower-growing species that establish under more stable conditions and often compete effectively for light and other resources

A relatively stable late-successional community suited to local conditions, but not a permanent or inevitable endpoint

A species whose activities have a disproportionately large effect on community structure relative to its abundance or biomass

An organism whose presence, absence, abundance, condition, or chemical composition reveals an environmental condition or aspect of ecosystem quality

The total mass of living material in an area; it generally increases during succession and eventually slows or levels off

The rate at which producers store energy or biomass after producer respiration: NPP = GPP − R; it starts low, rises as producers establish, and may later stabilize or decline