Adaptation - Any genetically controlled structural, physiological, or behavioral characteristic that helps an organism survive and reproduce under a given set of environmental conditions

Background extinction - The ongoing extinction of individual species due to environmental or ecological factors such as climate change, disease, loss of habitat, or competitive disadvantage in relation to other species 

Biodiversity hotspot - An area that supports an especially great diversity of species, particularly species that are endemic to the area

Biomagnification - Increasing concentration of toxic substances as they move up through different trophic levels in a food chain 

Buffer zone - A portion of a nature reserve surrounding a core natural area where controls on land use are less stringent than in the core natural area, yet land uses are at least partially compatible with many species’ resource requirements 

Climax community - Fairly stable, self-sustaining community in an advanced stage of ecological succession 

Colonization - When an organism or group of organisms starts a population in a habitat where the species was not already present 

Deforestation - Temporary or permanent removal of large expenses of forest for agriculture or settlements 

Ecological restoration - To reverse degradation and reestablish some aspects of an ecosystem that previously existed 

Ecological tolerance - Range of conditions (such as temp, salinity, pH, or sunlight) that an organism or species can endure before injury or death results

Ecosystem diversity - The earth’s variety of deserts, grasslands, forests, mountains, oceans, lakes, rivers, and wetlands 

Ecotourism - Tourism to exotic or threatened ecosystems to observe wildlife or help preserve nature 

Edge effect - Change in population or community structures that occur at the boundary of two or more habitats 

Endemic species - Species that are native to and found only within a limited area 

Foundation species - Species that plays a major role in shaping a community by creating and enhancing a habitat that benefits other species 

Founder effect - Reduction in genomic variability that occurs when a small group of individuals becomes separated from a larger population 

Generalist species - A species with a broad ecological niche that can tolerate a wide range of conditions and can use a variety of resources 

Genetic diversity - Variation of genes that exist within a species population 

Genetic drift - A change in the genetic composition of a population over time as a result of random mating 

Global extinction - The ubiquitous disappearance of a species 

Habitat corridors - A link of wildlife habitat, generally native vegetation, which joins two or more larger areas of similar wildlife habitat 

• Critical for the maintenance of ecological processes, including allowing for the movement of animals and the continuation of viable populations 

Habitat fragmentation - Occurs when a large, continuous area of habitat is reduced in area and divided into smaller, more scattered and isolated patches or “habitat islands”

Habitat island - Any island surrounded by a different one 

Indicator species - Species whose presence or absence serves as an early warning sign of environmental change or degradation of a natural community 

Intrinsic/existence value - Value of an organism, species, ecosystem, or the earth’s biodiversity based on its existence, regardless of whether it has any usefulness to us 

Keystone species - A species whose impact on its community or ecosystem are much larger and more influential than would be expected from mere abundance (ex. Tropical figs, fungi)

Local extinction - The disappearance of a species from part of its natural range 

Mass extinction - Catastrophic, widespread, often global event in which major groups of species are wiped out over a short time compared with normal (background) extinctions 

MPAs (marine protected areas) - Any area of the marine environment that has been reserved by Federal, State, territorial, tribal, or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein 

Multiple-use land - A US classification used to designate lands that may be used for recreation, grazing, timber, harvesting, and mineral extraction 

National Forest - Area of federally-owned land where logging and grazing are permitted under more heavily-managed conditions 

National Park - One form of reserve that are managed for scientific, educational, and recreational use, and sometimes for their beauty or unique land-forms 

National Wildlife Refuge (NWR) - Federal public lands managed for the primary purpose of protecting wildlife 

Old-growth forests - An uncut or regenerated forest that has not been seriously disturbed by human activities or natural disasters for several hundred years or more 

Overgrazing - When too many animals graze for too long, damaging the grasses and their roots, and exceeding the capacity of a rangeland area 

Pioneer species - First species to populate an area during primary succession 

Poaching - illegal hunting, capturing, or killing of wildlife, usually for commercial purposes 

• Involves the exploitation of protected species and can have severe ecological consequences 

Population bottleneck - A sharp reduction in the size of a population due to environmental events (such as famines, earthquakes, floods, fires, disease, and droughts); or human activities (such as genocide, speciocide, widespread violence, or intentional culling)

Precautionary principle - When an activity raises threats of harm to the environment or human health, precautionary measures should be taken even if some cause and effect relationships are not fully established  

Primary succession - The process by which pioneer species colonize an area otherwise uninhabitable for plant life and generate nitrogen for other plant communities 

• When a new patch of land is created or exposed for the first time 

• Organisms must start from scratch 

Range of tolerance - The limits to the abiotic conditions that a species can tolerate 

Reproductive isolation - Separation of species or populations so that they cannot interbreed and produce fertile offspring 

Secondary succession - Type of ecological succession in which plants and animals recolonize a habitat after a major disturbance 

Specialist species - Species with a narrow ecological niche 

• Ex. live in only one type of habitat; tolerate only a narrow range of climatic and other environmental conditions; or only use one type or a few types of food 

Speciation - Process by which new species form because of divergent natural selection in response to changes in environmental conditions 

Species diversity - The number and variety of species in the world or in a particular region 

Species evenness - The relative abundance of different species within a community--measures how evenly individuals are distributed among the various species present 

Species richness - The number of different species in a community 

Transpiration - The process where plants absorb water through the roots and then give off water vapor through pores in their leaves

CITES - Convention on International Trade on Endangered Species - Multilateral treaty that ensures that international trade in specimens of wild animals and plants does not threaten the survival of the species in the wild and accords varying degrees of protection for more than 37k species 

Environmental Protection Agency (EPA) - Charged with conducting and evaluating research, monitoring environmental quality, setting standards, enforcing those standards, assisting the states in meeting standards and goals, and educating the public

U.S. Endangered Species Act (ESA) - Aims to protect those species from extinction by restricting the national and international commercial trade in apes, it also regulates the treatment of “endangered” apes in the U.S. by making it illegal to “take” (meaning harass, harm, wound, or kill) captive apes

U.S. Fish and Wildlife Service (USFWS) - Dedicated to the management of fish, wildlife, and natural habitats

U.S. Forest Service - A federal agency under the U.S. Department of Agriculture that manages 193 million acres of land

U.S. National Park Service - Manages all US national parks