Ultimate Guide: AP Environmental Science

Ecosystem

A community of living organisms interacting with the non-living components of their environment.

Organism

A living thing that can function on its own.

Species

Organisms that resemble each other, are similar in genetic makeup, and can interbreed to produce fertile offspring.

Population

Organisms of the same species that interact and occupy a specific area.

Community

A population of different species within a specific area.

Ecological Niche

A particular area occupied by an organism and its role in the ecological community.

Symbiosis

Close and long-term biological interaction between two different organisms.

Amensalism

An interaction where one species suffers and the other is unaffected.

Commensalism

An interaction where one organism benefits and the other is unaffected.

Intraspecific competition

Competition among individuals of the same species.

Interspecific competition

Competition between individuals of different species.

Mutualism

An interaction where both species benefit.

Parasitism

An interaction where one species benefits at the expense of another.

Predation

The act of one organism hunting and killing another for food.

Law of Tolerance

The existence and distribution of species depend on their tolerance to physical and chemical factors.

Limiting Factor

Any abiotic factor that limits the growth of a population.

Resource Partitioning

The process by which competing species use the same resource but in different ways to minimize competition.

Biomes

Major regional or global biotic communities characterized by dominant forms of plant life and prevailing climates.

Deserts

Regions defined by low rainfall (less than 20 inches per year), not by temperature.

Forests

Regions that cover about one-third of Earth's land surface and account for a large percentage of Earth’s gross primary productivity.

Grasslands

Ecosystems characterized by lands dominated by grasses rather than large shrubs or trees.

Tundra

Cold regions with low temperatures, little precipitation, and low biotic diversity.

Succulents

Plants with fleshy leaves or stems that store water to survive arid conditions.

Photosynthesis

The process by which plants use sunlight to convert carbon dioxide and water into glucose and oxygen.

Trophic Level

The position an organism occupies in a food chain.

Energy Flow

The transfer of energy from one trophic level to another in an ecosystem.

Biomagnification

The increasing concentration of a substance in the tissues of organisms at successively higher trophic levels.

Endangered Species

Species at a very high risk of extinction in the wild.

Biodiversity

The variability among species, between species, and of ecosystems.

Sustainable Development

Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Aquifer

A geologic formation that contains water in quantities sufficient to support a well or spring.

Hydrologic Cycle

The continuous movement of water on, above, and below the surface of the Earth.

Thermal Pollution

The degradation of water quality by any process that changes ambient water temperature.

Urban Sprawl

The expansion of human populations away from central urban areas into low-density, car-dependent communities.

Pollution

The introduction of contaminants into the environment that cause adverse change.

Air Quality Index (AQI)

A measurement used to communicate how polluted the air currently is or how polluted it is forecast to become.

El Niño

A climate pattern characterized by the warming of ocean surface temperatures in the central and eastern tropical Pacific, leading to significant weather changes globally.

La Niña

A climate pattern that describes the cooling of ocean surface temperatures in the central and eastern tropical Pacific, often resulting in opposite weather patterns to El Niño.