warning coloration Coloration that allows organisms
to escape from predators by advertising something harmful or distasteful.
waste stream The steady flow of varied wastes,
from domestic garbage and yard wastes to industrial, commercial,
and construction refuse.
water column The vertical column of seawater that
extends from the surface to the bottom.
water cycle The recycling and reutilization of
water on Earth, including atmospheric, surface, and underground
phases and biological and nonbiological components.
water droplet coalescence A mechanism of condensation
that occurs in clouds too warm for ice crystal formation.
water mass A body of water that can be identified
by its temperature and salinity.
water potential The relative ability of water molecules
to do work by interacting with each other.
water stress A shortage of water in plants resulting
in decreased ability to function properly, because water affects
all biochemical controls and is the medium for all chemical reactions.
water table The top layer of the zone of saturation;
undulates according to the surface topography and subsurface structure.
water vascular system A network of water-filled
canals in echinoderms used in locomotion and food-gathering.
water-soluble vitamin A vitamin that is not
readily stored in the body, with excess eliminated in the urine;
includes B vitamins and vitamin C.
water-vascular system. System of fluid-filled
closed tubes and ducts peculiar to echinoderms; used to move tentacles
and tube feet that serve variously for clinging, food handling,
locomotion, and respiration.
waterlogging Water saturation of soil that fills
all air spaces and causes plant roots to die from lack of oxygen;
a result of overirrigation.
wave crest The highest part of a wave.
wave reinforcement The process by which two waves
collide and add together to create a higher wave.
wave shock The intensity of the impact of a wave.
wave trough The lowest part of a wave.
wave The undulation that forms as a disturbance
moves along the surface of the water. Waves can be described by
their height (the vertical distance between crest and trough),
wavelength (the horizontal distance between adjacent crests),
and period (the time the wave takes to move past a given point).
wax A lipid material with considerable oxygen inserted
in the molecule; high melting point and relatively impermeable
to water.
weather Description of the physical conditions
of the atmosphere (moisture, temperature, pressure, and wind).
weathering Changes in rocks brought about by exposure
to air, water, changing temperatures, and reactive chemical agents.
weed A plant not valued for its use or beauty and
not intentionally planted; a category of hay fever plants that
includes nongrass and nontree species.
weir Filtration apparatus in flame-cell protonephridia
of flatworms.
westerlies The winds that blow from west to east
at middle latitudes.
wetlands Ecosystems of several types in which rooted
vegetation is surrounded by standing water during part of the
year. See also swamp, marsh, bog, fen.
whirling disease Disease of fishes, caused by the
protozoan Myxobolus cerebralis.
white blood cell (leukocyte) A type of blood cell
involved with body defenses.
whorled arrangement Three or more leaves per node.
whorled Three or more leaves attached at a node.
Wilderness ActLegislation of 1964 recognizing
that leaving land in its natural state may be the highest and
best use of some areas.
wilderness An area of undeveloped land affected
primarily by the forces of nature; an area where humans are visitors
who do not remain.
wildlife refuges Areas set aside to shelter, feed,
and protect wildlife; due to political and economic pressures,
refuges often allow hunting, trapping, mineral exploitation, and
other activities that threaten wildlife.
wildlife Plants, animals, and microbes that live
independently of humans; plants, animals, and microbes that are
not domesticated.
wind farms Large numbers of windmills concentrated
in a single area; usually owned by a utility or large-scale
energy producer.
windbreak Rows of trees or shrubs planted to block
wind flow, reduce soil erosion, and protect sensitive crops from
high winds.
windward The side toward which the wind is blowing.
winnowing The process that separates the grain
from the fragments of chaff.
winter sleep A period of inactivity in which a mammal's
body temperature remains near normal and the mammal is easily
aroused.
Winterbottom's sign Swollen lymph nodes at the
base of the skull, symptomatic of African sleeping sickness.
Wisconsin General Test Apparatus (WGTA) An apparatus
designed originally at the University of Wisconsin Primate Center
for use with various species of primates in a series of learning
problems. Modifications of this apparatus have been used for a
variety of animal species.
Wise Use Movement A coalition of ranchers, loggers,
miners, industrialists, hunters, off-road vehicle users,
land developers, and others who call for unrestricted access to
natural resources and public lands.
withdrawal A description of the total amount of
water taken from a lake, river, or aquifer.
wood pulp A watery suspension of pulverized wood
used in the production of paper, cardboard, fiberboard, rayon,
cellophane, and other products.
wood Secondary xylem.
woodland A forest where tree crowns cover less
than 20 percent of the ground; also called open canopy.
work The application of force through a distance;
requires energy input.
world conservation strategy A system of maintaining essential ecological processes, preserving genetic diversity, and ensuring that utilization of species and ecosystems is sustainable.
World Ocean The interconnected world seas and oceans.