Periodic movements of animals in response to seasonal changes or reproductive instinct. Hormonal changes are the trigger in at least some animals. Most migrations are made for reasons of climatic change, feeding, or breeding.
A huge subclass of mostly marine CRUSTACEA, containing over 14,000 species. The 10 orders comprise both planktonic and benthic organisms, and include both free-living and parasitic forms. Planktonic copepods form the principle link between PHYTOPLANKTON and the higher trophic levels of the marine food chains.
Minute free-floating animal organisms which live in practically all natural waters.
A body of water covering approximately one-fifth of the total ocean area of the earth, extending amidst Africa in the west, Australia in the east, Asia in the north, and Antarctica in the south. Including the Red Sea and the Persian Gulf, it constitutes the third largest ocean after the ATLANTIC OCEAN and the PACIFIC OCEAN. (New Encyclopaedia Britannica Micropaedia, 15th ed, 1990, p289)
A kingdom in the domain ARCHAEA comprised of thermoacidophilic, sulfur-dependent organisms. The two orders are SULFOLOBALES and THERMOPROTEALES.
Instinctual behavior pattern in which food is obtained by killing and consuming other species.
An order of BIRDS including over 300 species that primarily inhabit coastal waters, beaches, and marshes. They are comprised of shorebirds, gulls, and terns.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Warm-blooded VERTEBRATES possessing FEATHERS and belonging to the class Aves.
Large natural streams of FRESH WATER formed by converging tributaries and which empty into a body of water (lake or ocean).
Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The pattern of any process, or the interrelationship of phenomena, which affects growth or change within a population.
The protection, preservation, restoration, and rational use of all resources in the total environment.
Number of individuals in a population relative to space.
An animal or plant species in danger of extinction. Causes can include human activity, changing climate, or change in predator/prey ratios.
A functional system which includes the organisms of a natural community together with their environment. (McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
Accidents on streets, roads, and highways involving drivers, passengers, pedestrians, or vehicles. Traffic accidents refer to AUTOMOBILES (passenger cars, buses, and trucks), BICYCLING, and MOTORCYCLES but not OFF-ROAD MOTOR VEHICLES; RAILROADS nor snowmobiles.
Celestial bodies orbiting around the sun or other stars.
Habitat of hot water naturally heated by underlying geologic processes. Surface hot springs have been used for BALNEOLOGY. Underwater hot springs are called HYDROTHERMAL VENTS.
Discussions, descriptions or catalogs of public displays or items representative of a given subject.
Using ice skates, roller skates, or skateboards in racing or other competition or for recreation.
The solid substance formed by the FREEZING of water.
A colloidal, hydrated aluminum silicate that swells 12 times its dry size when added to water.
Any of the numerous types of clay which contain varying proportions of Al2O3 and SiO2. They are made synthetically by heating aluminum fluoride at 1000-2000 degrees C with silica and water vapor. (From Hawley's Condensed Chemical Dictionary, 11th ed)
A thick mass of ICE formed over large regions of land; RIVERS; LAKES; ponds; or SEAWATER.
A region, north-central Asia, largely in Russia. It extends from the Ural Mountains to the Pacific Ocean and from the Arctic Ocean to central Kazakhstan and the borders of China and Mongolia.
The unconsolidated mineral or organic matter on the surface of the earth that serves as a natural medium for the growth of land plants.