abiotic

The nonliving components of an ecosystem, such as rainfall and mineral composition of the soil. (Chapter 8)

acid deposition

Precipitation that contains sulfuric or nitric acid; dry particles may also fall and become acidified once they mix with water. (Chapter 20)

acid mine drainage

Water flowing past exposed rock in mines, leaching out sulfates. These sulfates react with the water and oxygen to form acids (low-pH solutions). (Chapter 18)

active solar technologies

Mechanical equipment for capturing, converting, and sometimes concentrating solar energy into a more usable form. (Chapter 23)

adaptation

A trait that helps an individual survive or reproduce. (Chapter 11); Efforts intended to help deal with a problem that exists, such as climate change. (Chapter 21)

adaptive management

A plan that allows room for altering strategies as new information becomes available or as the situation itself changes. (Chapter 2, 24)

additive effects

Exposure to two or more chemicals that has an effect equivalent to the sum of their individual effects. (Chapter 3)

age structure

The percentage of the population that is distributed into various age groups. (Chapter 4)

age structure diagram

A graphic that displays the relative sizes of various age groups, with males shown on one side of the graphic and females on the other. (Chapter 4)

agroecology

Scientific field that considers the area’s ecology and indigenous knowledge, and favors agricultural methods that protect the environment and meet the needs of local people. (Chapter 17)

air pollution

Any material added to the atmosphere (naturally or by humans) that harms living organisms, affects the climate, or impacts structures. (Chapter 21)

albedo

The ability of a surface to reflect away solar radiation. (Chapter 21)

annual crops

Crops that grow, produce seeds, and die in a year and must be replanted each season. (Chapter 17)

antagonistic effects

Exposure to two or more chemicals that has a lesser effect than the sum of their individual effects would predict. (Chapter 3)

anthropocentric worldview

A human-centered view that assigns intrinsic value only to humans. (Chapter 1)

anthropogenic

Caused by or related to human action. (Chapter 1, 21)

applied science

Research whose findings are used to help solve practical problems. (Chapter 1)

aquifer

An underground, permeable region of soil or rock that is saturated with water. (Chapter 14, 15)

artificial selection

A process in which humans decide which individuals breed and which do not in an attempt to produce a population with desired traits. (Chapter 11)

asthma

A chronic inflammatory respiratory disorder characterized by “attacks” during which the airways narrow, making it hard to breathe; can be fatal. (Chapter 20)

atmosphere

The blanket of gases that surrounds Earth and other planets. (Chapter 2)