Rain containing acids and acid-forming compounds such as sulfur dioxide and oxides of nitrogen.
The movement of molecules from a region of low concentration to a region of high concentration through a semipermeable membrane at the expense of energy.
An inheritable structural or behavioral modification. A favorable adaptation gives a species an advantage in survival and reproduction. An unfavorable adaptation lessens a species' ability to survive and reproduce.
artificial system of classification
A method of classifying an object based on attributes other than its reason for existence, its ancestry, or its origin. Compare natural system of classification.
Natural processes that recycle nutrients in various chemical forms from the nonliving environment to living organisms and then back to the nonliving environment.
A biologically generated aspect of the environment, such as predation or metabolic waste products, that affects living organisms. Biological factors usually operate in association with purely physical factors such as light and temperature.
The movement of carbon from reservoirs (sediment, rock, ocean) through the atmosphere (as carbon dioxide), through food webs, and back to the reservoirs.
The synthesis of organic compounds from inorganic compounds using energy stored in inorganic substances such as sulfur, ammonia, and hydrogen. Energy is released when these substances are oxidized by certain organisms.
A pigment responsible for trapping sunlight and transferring its energy to electrons, thus initiating photosynthesis.
The evolution of similar characteristics in organisms of different ancestry; the body shape of a porpoise and a shark, for instance.
The movement—driven by heat—of molecules from a region of high concentration to a region of low concentration.
The lower part of the photic zone, where there is insufficient light for photosynthesis.
dissolved organic nitrogen (DON)
Nitrogen-containing organic molecules dissolved in seawater. Most DON is in the form of protein.
An organism incapable of generating and maintaining steady internal temperature from metabolic heat and therefore whose internal body temperature is approximately the same as that of the surrounding environment; a cold-blooded organism.
An organism capable of generating and regulating metabolic heat to maintain a steady internal temperature. Birds and mammals are the only animals capable of true endothermy. A warm-blooded organism.
The upper layer of the photic zone in which net photosynthetic gain occurs. Compare photic zone.
Change; the maintenance of life under constantly changing conditions by continuous adaptation of successive generations of a species to its environment.
An organism capable of tolerating extreme environmental conditions, especially temperature or pH level.
General term for organic molecules capable of providing energy to heterotrophs when combined with oxygen during biochemical respiration.
A group of organisms associated by a complex set of feeding relationships in which the flow of food energy can be followed from primary producers through consumers.
An organism that derives nourishment from other organisms because it is unable to synthesize its own food molecules.
Grouping of objects by degrees of complexity, grade, or class. A hierarchical system of nomenclature is based on distinctions within groups and between groups.
Referring to a solution having a higher concentration of dissolved substances than the solution that surrounds it.
Referring to a solution having a lower concentration of dissolved substances than the solution that surrounds it.
Referring to a solution having the same concentration of dissolved substances as the solution that surrounds it.
A physical or biological environmental factor whose absence or presence in an inappropriate amount limits the normal actions of an organism.
The band of coast alternately covered and uncovered by tidal action; the intertidal zone.
A complex structure of proteins and lipids that forms boundaries around and within the cell. It is usually semipermeable, allowing some kinds of molecules to pass through but not others.
A mechanism of evolution that results in the continuation of only those forms of life best adapted to survive and reproduce in their environment.
natural system of classification
A method of classifying an organism based on its ancestry or origin.
Bacteria capable of fixing gaseous nitrogen into nitrite, nitrate, or ammonium ions.
The cycle in which nitrogen moves from its largest reservoir (the atmosphere) through the ocean, ocean sediments, and food webs, and then back to the atmosphere.
Any needed substance that an organism obtains from its environment except oxygen, carbon dioxide, and water.
The diffusion of water from a region of high water concentration to a region of lower water concentration through a semipermeable membrane.
The thin film of lighted water at the top of the world ocean. The photic zone rarely extends deeper than 200 meters (660 feet). Compare euphotic zone.
The process by which autotrophs bind light energy into the chemical bonds of food with the aid of chlorophyll and other substances. The process uses carbon dioxide and water as raw materials and yields glucose and oxygen.
An aspect of the physical environment that affects living organisms, such as light, salinity, or temperature.
Initial consumer of primary producers. The consumers of autotrophs; the second level in food webs.
An organism capable of using energy from light or energy-rich chemicals in the environment to produce energy-rich organic compounds; an autotroph.
The synthesis of organic materials from inorganic substances by photosynthesis or chemosynthesis; expressed in grams of carbon bound into carbohydrate per unit area per unit time (gC/m2/yr).
second law of thermodynamics
Disorder (entropy) in a closed system must increase over time. If disorder decreases, it does so at the expense of energy. Because the universe as a whole may be considered a closed system, it follows that an increase in order in one part must result in a decrease in order in another.
The formation of new species. Charles Darwin suggested that this is accomplished through isolation and natural selection.
Any group of actually or potentially interbreeding organisms reproductively isolated from all other groups and capable of producing fertile offspring. (Note: The word species is both singular and plural.)
The ocean floor near shore. The inner sublittoral extends from the littoral (intertidal) zone to the depth at which wind waves have no influence; the outer sublittoral extends to the edge of the continental shelf.
The splash zone above the highest high tide; not technically part of the ocean bottom.
A physical constraint on the size of cells. As a cell's linear dimensions grow, its surface area does not increase at the same rate as its volume. As the surface-to-volume ratio decreases, each square unit of outer membrane must serve an increasing interior volume.
A model of feeding relationships among organisms. Primary producers form the base of the pyramid; consumers eating one another form the higher levels, with the top consumer at the apex.