biodiversity
the number of different species in an area
gene
a structure in an organism's cells that carries its hereditary information
extinction
the disappearance of all members of a species from Earth
endangered species
a species in danger of becoming extinct in the near future
threatened species
a species that could become endangered in the near future
habitat destruction
the loss of a natural habitat
habitat fragmentation
the breaking of a habitat into smaller, isolated pieces
exotic species
species that are carried to a new location by people
captive breeding
the mating of animals in zoos or wildlife preserves
poaching
illegal killing or removal of wildlife from their habitats
nitrogen fixation
the process of changing free nitrogen gas into a usable form
evaporation
the process by which molecules of a liquid absorb energy and change to a gas
condensation
the process by which a gas changes to a liquid
precipitation
rain, snow, sleet, or hail
classification
the process of grouping things based on their similarities
binomial nomenclature
the system for naming organisms in which each organism is given a unique, two-part scientific name indicating its genus and species
taxonomy
the scientific study of how living things are classified
genus
a classification grouping that consists of a number of similar, closely related species
photosynthesis
the process by which plants and some other organisms capture the energy in sunlight and use it to make food
pigment
a colored chemical compound that absorbs light
stomata
small openings on the underside of a leaf through which oxygen and carbon dioxide can move
autotroph
an organism that makes its own food
heterotroph
an organism that cannot make its own food
chlorophyll
a green pigment found in the chloroplasts of plants, algae, and some bacteria
fermentation
the process by which cells break down molecules to release energy without using oxygen
cellular respiration
the process by which cells break down simple food molecules to release the energy they contain
surface runoff
Precipitation, snow melt, or irrigation water in excess of what can infiltrate the soil surface and be stored in small surface depressions
discharge
the flow of water from groundwater or aquifers into a body of water, such as a river, lake or ocean
infiltration
The penetration of water through the ground surface into sub-surface soil
percolation
The movement of water downward and radially through subsurface soil layers, usually continuing downward to ground water. Can also involve upward movement of water.
transpiration
The process by which water vapor is lost to the atmosphere from living plants.
interception
the process of direct absorption of precipitation by any above-ground part of a plant
aquifer
An underground bed or layer of earth, gravel, or porous stone that contains water.
groundwater
The supply of fresh water under the Earth's surface that forms a natural reservoir.
sublimation
The process of conversion from the solid state directly to the gaseous state, without passing through the liquid state.
water table
Top of an unconfined aquifer, below which the pore spaces are saturated with water.
reservoir
Any natural or artificial holding area used to store, regulate, or control water.
watershed
The land area that drains into a stream; the watershed for a major river may encompass a number of smaller watersheds that ultimately combine at a common point
wetlands
An area that is saturated by surface or ground water with vegetation adapted for life under those soil conditions, as swamps, bogs, fens, marshes, and estuaries.
glacier
a slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains or near the poles.
collection
when precipitation that falls from the clouds collects in the oceans, rivers, lakes, streams.