Glossary - Environmental Science - page 327

industrial waste Waste created during industrial processes such as agriculture, mining, consumer goods pro-
duction, and the extraction and refining of petroleum products.
infiltration The process by which water on the Earth's surface enters the soil.
inner core The solid part of the Earth's core that is mainly made up of nickel and iron.
innocent until proven guilty When addressing a substance's toxicity, the approach that assumes a product to
be harmless until proven otherwise.
integrated pest management (IPM) A form of pest control that uses knowledge about the pest's life cycle and
environmental interactions in conjunction with other control methods such as biological control, crop rotation,
and chemicals when necessary. The goal of IPM is to reduce pest impact while also reducing pesticide use.
intercropping The planting of alternating crops throughout a field (as opposed to monoculture).
International Union for Conservation of Nature (IUCN) An international organization dedicated to the con-
servation of natural resources. The goal of IUCN is to help find solutions to the most important environmental
issues. The organization publishes an influential "Red List" showing the world's most endangered species.
interspecific competition The process by which two different species compete.
intraspecific competition The process by which members of the same species compete.
IPAT model A model proposing that environmental impact (I) is the product of population (P), affluence (A),
and technology (T), represented by the formula I = P · A · T . Sometimes S is added to represent the sensitivity
of an ecosystem.
irrigation The practice of supplying water for agricultural purposes.
kinetic energy The energy possessed by a moving object; a form of mechanical energy.
K-selected species Species that have relatively few offspring and devote a large amount of time, energy, and
resources toward nurturing and raising their young.
La Niña The cooling phase of ENSO in the eastern Pacific Ocean, accompanied by lower air surface pressure
in the western Pacific Ocean.
land pollution See soil pollution .
latitude A measurement of distance from the equator, measured in angular degrees by lines that are parallel to
each other. The equator is 0°, the North Pole is 90° N, and the South Pole is 90° S.
latitudinal gradient The increase in biodiversity closer to the equator.
laws of thermodynamics The transport of heat and work in the thermodynamic processes. The first law of
thermodynamics states that energy is neither created nor destroyed but can change forms. The second law of
thermodynamics states that in any conversion of heat energy into useful work some of the initial energy is lost.
LD 50 The dose of a substance that is lethal for 50 percent of the test population.
leaching The process by which water, filtering down through the soil, dissolves and transports materials, in-
cluding naturally occurring minerals and nutrients and man-made toxic substances.