abiotic
Pertaining to nonliving things.
algal bloom
An overabundance of algae in a body of water, resulting from an excess of nutrients. The many dead algae that fall to the bottom allow decomposing bacteria to flourish, using up so much oxygen that fish can suffocate.
aquifer
Porous underground rock in which groundwater is stored.
algal bloom
An overabundance of algae in a body of water, resulting from an excess of nutrients. The many dead algae that fall to the bottom allow decomposing bacteria to flourish, using up so much oxygen that fish can suffocate.
aquifer
Porous underground rock in which groundwater is stored.
atmosphere
The layer of gases that surrounds the Earth.
Bacteria
With Archaea and Eukarya, one of three domains of the living world, composed solely of single-celled, microscopic organisms that superficially resemble archaea but are genetically quite different.
biodegradable
Capable of being broken down by living organisms.
biogeochemical cycle
The movement of water and nutrients back and forth between biotic (living) and abiotic (nonliving) realms.
biomass
Material produced by living things, generally measured by dry weight.
biome
Large, terrestrial regions of the Earth that have similar climates and hence similar vegetative formations. Six biome types are recognized at a minimum: tundra, taiga, temperate deciduous forest, temperate grassland, desert, and tropical rain forest.
biosphere
The interactive collection of all the world’s ecosystems. Also thought of as that portion of the Earth that supports life.
biotic
Pertaining to living things.
carnivore
An animal that eats meat.
chloroflourocarbons (CFCs)
A class of human-made chlorine compounds that destroys the atmospheric ozone that protects life on land from damaging ultraviolet radiation.
climate
The average weather conditions, including temperature, precipitation, and wind, in a particular region.
climate
The average weather conditions, including temperature, precipitation, and wind, in a particular region.
coastal zone
The region lying between the high-tide point on shore and the point offshore where the continental shelf drops off.
consumer
Any organism that eats other organisms rather than producing its own food.
coral reef
Ocean structure, found in shallow, warm waters, that consists primarily of the piled-up remains of many generations of the animals called coral polyps. Such reefs provide habitat for a rich diversity of marine organisms.
decomposer
A type of detritivore that, in feeding on dead or cast-off organic material, breaks it down into its inorganic components. Most decomposers are fungi or bacteria.
desert
A biome in which rainfall is less than 25 centimeters or 10 inches per year and water evaporation rates are high relative to rainfall.
detritivore
An organism that feeds on the remains of dead organisms or the cast-off material from living organisms.
ecosystem
A community of living things and the physical environment with which they interact.
element
A substance that cannot be reduced to any simpler set of components through chemical processes. An element is defined by the number of protons in its nucleus.
energy-flow model of ecosystems
A conceptualization of ecosystems as units in which energy is first captured by given organisms and then transferred to other organisms.
estuary
An area where a river or stream flows into the ocean, bringing freshwater and saltwater habitat together. Estuaries are among the most productive ecosystems on Earth.
gross primary production (GPP)
The amount of material that a photosynthesizing organism produces through photosynthesis.
groundwater
Water contained within underground rock formations.
habitat
The type of surroundings in which individuals of a species are normally found.
herbivore
An animal that eats only plants.
intertidal zone
The region within the coastal zone of the ocean that extends from the ocean’s low-tide mark to its high-tide mark.
kilocalorie (kcal)
The amount of energy it takes to raise 1 kilogram of water 1°C. Food consumption is measured in kilocalories, often written as Calories.
net primary production (NPP)
The amount of material a plant (or other photosynthesizing organism) accumulates through photosynthesis. Net primary production is gross primary production minus energy lost to heat and the plant’s expenditures of energy on its own maintenance.
nitrogen fixation
The conversion of atmospheric nitrogen into a form that can be taken up by living things. Bacteria fix nitrogen, which is essential to life.
nutrient
A substance found in food that does at least one of three things: provides energy, provides a structural building block, or regulates a physical process. There are six classes of nutrients: water, minerals and vitamins; and carbohydrates, lipids, and protein.
omnivore
An animal that eats both plants and animals.
ozone
A gas in the Earth’s atmosphere consisting of three oxygen atoms bonded together that serves to protect living things from the sun’s ultraviolet radiation.
permafrost
The permanently frozen ground that begins about a meter below the surface in the tundra biome of the far north. Neither roots nor water can penetrate this layer.
photosynthesis
The process by which certain groups of organisms capture energy from sunlight and convert this solar energy into chemical energy that is initially stored in a carbohydrate.
phytoplankton
Small photosynthesizing organisms that drift in the upper layers of oceans or bodies of freshwater, often forming the base of aquatic food webs.
predation
One organism feeding on parts or all of a second organism.
primary consumer
Any organism that eats producers (organisms that make their own food).
producer
Any organism that manufactures its own food. Plants, algae, and certain bacteria are producers. By converting the sun’s energy into biomass, producers capture energy that is then passed along in food webs.
secondary consumer
Any organism that eats a primary consumer.
stratosphere
The layer of the Earth’s atmosphere situated above the troposphere, at about 20 to 35 kilometers (13 to 21 miles) above sea level. The ozone layer lies in this level.
taiga
The biome consisting of boreal (northern) forest, characterized by cold, dry conditions, a relatively short growing season, and large expanses of coniferous trees.
tertiary consumer
Any organism that eats secondary consumers.
trophic level
A position in an ecosystem’s food chain or web, with each level defined by a transfer of energy from one kind of organism to another. Plants and other photosynthesizers are producers of food and thus occupy the first trophic level. Organisms that consume producers are primary consumers and occupy the second trophic level, and so on.
tropical rain forest
A biome found in Earth’s equatorial regions characterized by warm year-round temperatures, abundant rainfall (averaging 200–450 cm per year), and great species diversity.
tropical savanna
A grassland biome characterized by seasonal drought, small seasonal changes in the generally warm temperatures, and stands of trees that punctuate the grassland.
troposphere
The lowest layer of the Earth’s atmosphere, extending from sea level to about 12 kilometers (7.4 miles) above sea level. This layer contains most of the gases in the atmosphere.
tundra
A biome of Earth’s far-northern latitudes characterized by very cold temperatures, very little rainfall (averaging 25 cm per year), and a short growing season.
wetland
Lands that are wet for at least part of the year. Wetlands are sites of great biological productivity, and they provide vital habitat for migrating birds.
zooplankton
Microscopic aquatic animals that occupy a trophic level above that of phytoplankton, or photosynthesizing aquatic microorganisms.
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Ecology Science |