Create an account
negative feedback loop
a process in which the output of one type acts as input that moves the system in the opposite direction
positive feedback loop
a process in which the output of one type acts as input that moves the system in the same direction; the input and output drive the system further toward one extreme or another
the collective system of rock at and just below the our planet's surface, including the crust and uppermost mantle
Earth's collective system of water - salt and fresh; liquid, ice, and vapor - in surface bodies, underground, and in the atmosphere
the sum total of all the planet's living organisms and the nonliving portions of the environment with which they interact
the process of nutrient enrichment, increased production of organic matter, and subsequent ecosystem degradation in a water body
law of conservation of matter
states that matter may be transformed from one type of substance into others, but that it cannot be created or destroyed
a fundamental type of matter; a chemical substance with a given set of properties, which cannot be broken down into substances with other properties
the property of a solution in which the concentration of hydrogen ions (H+) is greater than the concentration of hydroxide ions (OH-)
the property of a solution in which the concentration of hydroxide ions (OH-) is greater than the concentration of hydrogen ions (H+)
one of a chemically diverse group of macromolecules that are classified together because they do not dissolve in water; include fats, oils, waxes, and steroids
first law of thermodynamics
states that energy can change from one form to another but cannot be created or lost; the total energy in the universe remains constant and is said to be conserved
second law of thermodynamics
states that the nature of energy tends to change from a more ordered state to a less ordered state
an organism that can use the energy from sunlight to produce its own food; includes green plants, algae, and cyanobacteria; also called producers
the process by which a cell uses the chemical reactivity of oxygen to split glucose into its constituent parts, water and carbon dioxide, and thereby release chemical energy that can be used to form chemical bonds or to perform other tasks within the cell
an organism that consumes other organisms; includes most animals, as well as fungi and microbes that decompose organic matter; also called consumers
all organisms and nonliving entities that occur and interact in a particular area at the same time
net primary production
the energy or biomass of autotrophs that is available for consumption by heterotrophs
the study of how broad geographic areas affect the abundance, distribution, and interaction of organisms
a scientific discipline devoted to understanding the factors, forces, and processes that influence the loss, protection, and restoration of biological diversity within and among ecosystems
the comprehensive set of cyclical pathways by which a chemical substance moves through the environment
consists of the routes that carbon atoms take through the networks of environmental systems
consists of the routes that phosphorus atoms take through the networks of environmental systems
consists of the routes that nitrogen atoms take through the networks of environmental systems
the process by which inert nitrogen gas combines with hydrogen to form ammonium ions which are chemically and biologically active and can be taken up by plants
the flow of water - in liquid, gaseous, and solid forms - through our biotic and abiotic environment
the water from precipitation that flows into streams, rivers, lakes, and ponds, and (in many cases) eventually to the ocean
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together