Glossary 479toxicology The study of toxicants, chemicals with adverse effects on
health.
tropical rain forest A lush, species-rich forest biome that occurs
where the climate is warm and moist throughout the year.
tundra The treeless biome in the far north that consists of boggy
plains covered by lichens and mosses; it has harsh, cold winters
and extremely short summers.
ultraviolet (UV) radiation Radiation from the part of the
electromagnetic spectrum with wavelengths just shorter
than visible light; can be lethal to organisms at high levels of
exposure.
undernutrition A type of malnutrition in which an underconsumption
of calories or nutrients leaves the body weakened and
susceptible to disease.
urban heat island Local heat buildup in an area of high population.
urbanization A process whereby people move from rural areas to
densely populated cities.
utilitarian conservationist A person who values natural resources
because of their usefulness to humans but uses them sensibly
and carefully.
water pollution A physical, biological, or chemical change in
water that adversely affects the health of humans and other
organisms.
Western worldview A worldview based on human superiority over
nature, the unrestricted use of natural resources, and economic
growth to manage an expanding industrial base.
wilderness A protected area of land in which no human
development is permitted.
wind energy Electric energy obtained from surface air currents
caused by the solar warming of air.
zero population growth The state in which the population remains
the same size because the birth rate equals the death rate.sustainable forestry The use and management of forest ecosystems
in an environmentally balanced and enduring way.
sustainable soil use The wise use of soil resources, without a
reduction in the amount or fertility of soil, so it is productive for
future generations.
sustainable water use The wise use of water resources, without
harming the essential functioning of the hydrologic cycle or the
ecosystems on which present and future humans depend.
sustainable development Economic growth that meets the needs
of the present without compromising the ability of future
generations to meet their needs.
symbiosis An intimate relationship or association between members
of two or more species; includes mutualism, commensalism, and
parasitism.
systems perspective A perspective that considers not just immediate
or intended effects of activities, but all of the impacts of those
activities in other places or at other times.
temperate deciduous forest A forest biome that occurs in temperate
areas where annual precipitation ranges from about 75 cm to
126 cm (30 to 50 in).
temperate grassland A grassland with hot summers, cold winters,
and less rainfall than is found in the temperate deciduous forest
biome.
temperate rain forest A coniferous biome with cool weather, dense
fog, and high precipitation.
temperature inversion A layer of cold air temporarily trapped near
the ground by a warmer upper layer.
tertiary treatment Advanced wastewater treatment methods
that are sometimes employed after primary and secondary
treatments.
threatened species A species whose population has declined to the
point that it may be at risk of extinction.
total fertility rate (TFR) The average number of children born to each
woman.Berg_Gloss_475-479v2.indd 479 5/15/13 12:36 PM