- 行业: Government
- Number of terms: 30456
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NOAA Coral Reef Conservation Program, National Oceanic and Atmospheric Administration, U.S. Department of Commerce
Sound waves that have frequencies higher than what humans can hear, usually greater than 20,000 Hz. Some animals such as bats, a species of cave bird, and cetaceans use these high frequency ultrasonic sounds for communication and navigation.
Industry:Natural environment
The earliest part of a bivalve or brachiopod shell; in bivalves, it is the most dorsal section of the shell, while in brachyopods, it is the most posterior.
Industry:Natural environment
The population variance of a random variable is a non-negative number which gives an idea of how widely spread the values of the random variable are likely to be; the larger the variance, the more scattered the observations on average. It is a measure of the 'spread' of a distribution about its average value.
Industry:Natural environment
The tide at its fullest extent, when the water reaches its highest level.
Industry:Natural environment
The latitude at which reef growth just equals reef destruction by various physical forces.
Industry:Natural environment
A change that occurs in an organism to allow it to tolerate a new environment.
Industry:Natural environment
A flagellated cell that lines the interior of the central cavity (spongocoel) of a sponge. Choanocytes have a tubular collar with an extended flagellum that faces the spongocoel and creates currents that force water into the interstices of the sponge. Suspended food particles, such as plankton, are trapped by the choanocytes and passed to an amoebocyte that carries the food to other cells.
Industry:Natural environment
A marine sponge that chemically digests the limestone skeletons of corals and other calcareous organisms and structures during its search for food and living space. These "boring" activities can damage a coral reef; also called "excavating sponge".
Industry:Natural environment
A process for separating molecules by forcing them to migrate through a gel under the influence of an electric field.
Industry:Natural environment
A statement accepted without proof; a fundamental assumption.
Industry:Natural environment
