Botkin Environmental Science Earth as Living Planet 8th txtbk

G-20 Glossary
Wallace’s realms Six biotic provinces, or biogeographic
regions, divided on the basis of fundamental inherited
features of the animals found in those areas, suggested
by A. R. Wallace (1876). His realms are Nearctic (North
America), Neotropical (Central and South America), Palearctic
(Europe, northern Asia, and northern Africa), Ethiopian
(central and southern Africa), Oriental (the Indian
subcontinent and Malaysia), and Australian.
Wastewater renovation and conservation cycle The
practice of applying wastewater to the land. In some
systems, treated wastewater is applied to agricultural
crops, and as the water infiltrates through the soil layer,
it is naturally purified. Reuse of the water is by pumping it
out of the ground for municipal or agricultural uses.
Wastewater treatment The process of treating wastewater
(primarily sewage) in specially designed plants that
accept municipal wastewater. Generally divided into three
categories: primary treatment, secondary treatment, and
advanced wastewater treatment.
Water budget Inputs and outputs of water for a particular system
(a drainage basin, region, continent, or the entire Earth).
Water conservation Practices designed to reduce the amount
of water we use.
Water power An alternative energy source derived from flowing
water. One of the world’s oldest and most common energy
sources. Sources vary in size from microhydropower systems
to large reservoirs and dams.
Water reuse The use of wastewater following some sort of treatment.
Water reuse may be inadvertent, indirect, or direct.
Water table The surface that divides the zone of aeration
from the zone of saturation, the surface below which all
the pore space in rocks is saturated with water.
Watershed An area of land that forms the drainage of a stream
or river. If a drop of rain falls anywhere within a watershed,
it can flow out only through that same stream or river.
Weather What is happening in the atmosphere over a short
time period or what may be happening now in terms of
temperature, pressure, cloudiness, precipitation, and winds.
The average of weather over longer periods and regions
refers to the climate.
Weathering Changes that take place in rocks and minerals at
or near the surface of Earth in response to physical, chemical,
and biological changes; the physical, chemical, and
biological breakdown of rocks and minerals.
Wetlands A comprehensive term for landforms such as salt
marshes, swamps, bogs, prairie potholes, and vernal pools.
Their common feature is that they are wet at least part of
the year and as a result have a particular type of vegetation
and soil. Wetlands form important habitats for many
species of plants and animals, while serving a variety of
natural service functions for other ecosystems and people.
Wilderness An area unaffected now or in the past by human
activities and without a noticeable presence of human
beings.
Wildfire Self-sustaining rapid oxidation that releases light,
heat, carbon dioxide, and other gases as it moves across the
landscape. Also known as a fire in the natural environment
that may be initiated by natural processes such as lighting
strike or deliberately set by humans.
Wind power Alternative energy source that has been used by
people for centuries. More recently, thousands of windmills
have been installed to produce electric energy.
Work (physics) Force times the distance through which it
acts. When work is done we say energy is expended.
Zero population growth Results when the number of births
equals the number of deaths so that there is no net change
in the size of the population.
Zone of aeration The zone or layer above the water table in
which some water may be suspended or moving in a downward
migration toward the water table or laterally toward
a discharge point.
Zone of saturation Zone or layer below the water table in
which all the pore space of rock or soil is saturated.
Zooplankton Small aquatic invertebrates that live in the sunlit
waters of streams, lakes, and oceans and feed on algae and
other invertebrate animals.