AP Environmental Science Review

abiotic

abiotic

Pertaining to factors or things that are separate and independent from living things; nonliving.

acid

Any compound that releases hydrogen ions when dissolved in water. Also, a water solution that contains a surplus of hydrogen ions.

A layer

a soil horizon; the layer below the O layer is called the A layer. The A layer is formed of weathered rock, with some organic material; often referred to as topsoil.

alkaline

a basic substance; chemically, a substance that absorbs hydrogen ions or releases hydroxyl ions; in reference to natural water, a measure of the base content of the water.

aquifer

an underground layer of porous rock, sand, or other material that allows the movement of water between layers of nonporous rock or clay. Aquifers are frequently tapped for wells.

arable

land that's fit to be cultivated.

asthenosphere

the part of the mantle that lies just below the lithosphere.

atmosphere

the gaseous mass or envelope surrounding a celestial body, especially the one surrounding the Earth, which is retained by the celestial body's gravitational field.

barrier island

a long, relatively narrow island running parallel to the mainland-built up by the action of waves and currents and serving to protect the coast from erosion by surf and tidal surges.

biological weathering

any weathering that's caused by the activities of living organisms.

biotic

living or derived from living things.

B layer

a soil horizon; B receives the minerals and organic materials that are leached out of the A horizon.

chemical weathering

the result of chemical interaction with the bedrock that is typical of the action of both water and atmospheric gases.

C layer

a soil horizon, horizon C is made up of larger pieces of rock that have not undergone much weathering.

clay

the finest soil, made up of particles that are less than 0.002 mm in diameter.

convection

the vertical movement of a mass of matter due to heating and cooling; this can happen in both the atmosphere and Earth's mantle.

convection currents

air currents caused by the vertical movement of air due to atmospheric heating and cooling.

convergent boundary

a plate boundary where two plates are moving toward each other.

coral reef

an erosion-resistant marine ridge or mound consisting chiefly of compacted coral together with algal material and biochemically deposited magnesium and calcium carbonates.

Coriolis effect

The observed effect of the Coriolis force, especially the deflection of an object moving above the Earth, rightward in the Northern Hemisphere, and leftward in the Southern Hemisphere.

crop rotation

the practice of alternating the crops grown on a piece of land - for example, corn one year, legumes for two years, and then back to corn.

delta

a usually triangular alluvial deposit at the mouth of a river.

divergent boundary

a plate boundary at which plates are moving away from each other. This causes an upwelling of magma from the mantle to cool and form new crust.

drip irrigation

a method of supplying irrigation water through tubes that literally drip water onto the soil at the base of each plant.

earthquake

the result of vibrations (often due to plate movements) deep in the Earth that release energy. They often occur as two plates slide past one another at a transform boundary.

El Nino

a climate variation that takes place in the tropical Pacific about every three to seven years, for a duration of about one year.

erosion

the process of soil particles being carried away by wind or water. Erosion moves the smaller particles first and hence degrades the soil to a coarser, sandier, stonier texture.

estuary

the part of the wide lower course of a river where its current is met by the tides.

fault

the place where two plates abut each other.

greenhouse effect

the phenomenon whereby the Earth's atmosphere traps solar radiation, caused by the presence in the atmosphere of gases such as carbon dioxide, water vapor, and methane that allow incoming sunlight to pass through, but absorb heat radiated back from the Earth's surface.

Hadley cell

a system of vertical and horizontal air circulation predominating in tropical and subtropical regions and creating major weather patterns.

Headwaters

the water from which a river rises; a source.

Horizon

a layer of soil.

humus

the dark, crumbly, nutrient-rich material that results from the decomposition of organic material.

hurricane (typhoon, cyclone)

a severe tropical cyclone originating in the equatorial regions of the Atlantic Ocean or Caribbean Sea or eastern regions of the Pacific Ocean, traveling north, northwest, or northeast from its point of origin, and usually involving heavy rains.

inner core

the molten core of the Earth.

jet stream

a high-speed, meandering wind current, generally moving from a westerly direction at speeds often exceeding 400 km (250 miles) per hour at altitudes of 15 to 25 km (10 to 15 miles).

land degradation

when soil becomes water-logged and then dries out, and salt forms a layer on its surface.

La Nina

a cooling of the ocean surface off the western coast of South America, occurring periodically every 4 to 12 years and affecting Pacific and other weather patterns.

lithosphere

the outer part of the Earth, consisting of the crust and upper mantle, approximately 100 km (62 miles) thick.

loam

soil composed of a mixture of sand, clay, silt, and organic matter.

mantle

the layer of the Earth between the crust and the core.

monoculture

the cultivation of a single crop on a farm or in a region or country; a single, homogeneous culture without diversity or dissension.

O layer

the uppermost horizon of soil. It is primarily made up of organic material, including waste from organisms, the bodies of decomposing organisms, and live organisms.

physical (mechanical) weathering

any process that breaks rock down into smaller pieces without changing the chemistry of the rock; typically wind and water.

plate boundaries

the edges of tectonic plates.

rain shadow

the low-rainfall region that exists on the leeward (downwind) side of a mountain range. This rain shadow is the result of the mountain range's causing precipitation on the windward side.

red tide

a bloom of dinoflagellates that causes reddish discoloration of coastal ocean waters. Certain dinoflagellates of the genus Gonyamfox produce toxins that kill fish and contaminate shellfish.

R horizon

The bedrock, which lies below all of the other layers of soil.

salinization

the process in which soil becomes saltier and saltier until, finally, the salt prevents the growth of plants. Salinization is caused by irrigation because salts brought in with the water remain in the soil as water evaporates.

sand

the coarsest soil, with particles 0.05,2.0 mm in diameter.

silt

soil with particles 0.002,0.05 mm in diameter.

Southern Oscillation

the atmospheric pressure conditions corresponding to the periodic warming of El Nino and cooling of La Nina.

subduction zone

in tectonic plates, the site at which an oceanic plate is sliding under a continental plate.

thermocline

a layer in a large body of water, such as a lake, that sharply separates regions differing in temperature, so that the temperature gradient across the layer is abrupt.

thermosphere

the outermost shell of the atmosphere, between the mesosphere and outer space, where temperatures increase steadily with altitude.

topsoil

the A layer of soil is often referred to as topsoil and is most important for plant growth.

trade winds

the more or less constant winds blowing in horizontal directions over the Earth's surface, as part of Hadley cells.

transform boundary

also known as transform faults, boundaries at which plates are moving past each other, sideways.

tropical storm

a cyclonic storm having winds ranging from approximately 48 to 121 km (30 to 75 miles) per hour.

upwelling

a process in which cold, often nutrient-rich, waters from the ocean depths rise to the surface.

volcanoes

an opening in the Earth's crust through which molten lava, ash, and gases are ejected.

watershed

the region draining into river system or other body of water.

water-scarce

countries that have a renewable annual water supply of less than 1,000 m3 per person.

water-stressed

countries that have a renewable annual water supply of about 1,000,2,000 m3 per person.

weather

the day-to-day variations in temperature, air pressure, wind, humidity, and precipitation mediated by the atmosphere in a given region.

weathering

the gradual breakdown of rock into smaller and smaller particles, caused by natural chemical, physical, and biological factors.

wetlands

a lowland area, such as a marsh or swamp, that is saturated with moisture, especially when regarded as the natural habitat of wildlife.

assimilation

the process in which plants absorb ammonium (NH3), ammonia ions (NH4+), and nitrate ions (NO3) through their roots.

autotroph

an organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. autotrophs use energy from the sun or from the oxidation of inorganic substances to make organic molecules from inorganic ones.

bioaccumulation

the accumulation of a substance, such as a toxic chemical, in various tissues of a living organism.

biomagnification

the process by which the concentration of toxic substances increases in each successive link in the food chain.

biosphere

the part of the Earth and its atmosphere in which living organisms exist or that is capable of supporting life.

carnivore

an animal that only consumes other animals.

chemotroph (chemoautotroph)

an organism such as a bacterium or protozoan, that obtains its nourishment through the oxidation of inorganic chemical compounds, as opposed to photosynthesis.

climax community

a stable, mature community in a successive series that has reached equilibrium after having evolved through stages and adapted to its environment.

combustion

the process of burning.

community

formed from populations of different species occupying the same geographic area.

competitive exclusion

the process that occurs when two different species in a region compete and the better adapted species wins.

consumer

an organism that must obtain food energy from secondary sources, for example, by eating plant or animal matter.

decomposer

bacteria or fungi that absorb nutrients from nonliving organic matter like plant material, the wastes of living organisms, and corpses. They convert these materials into inorganic forms.

denitrification

the process by which specialized bacteria (mostly anaerobic bacteria) convert ammonia to NOy NO2, and N2 and release it back to the atmosphere.

detritivore

organisms that derive energy from consuming nonliving organic matter.

ecological succession

transition in species composition of a biological community, often following ecological disturbance of the community; the establishment of a biological community in any area virtually barren of life.

energy pyramid

the structure obtained if we organize the amount of energy contained in producers and consumers in an ecosystem by kilocalories per square meter, from largest to smallest.

evaporation

to convert or change into a vapor.

evolution

change in the genetic composition of a population during successive generations as a result of natural selection acting on the genetic variation among individuals and resulting in the development of new species.

extinction

being extinct or the process of becoming extinct.

food chain

a succession of organisms in an ecological community that constitutes a continuation of food energy from one organism to another as each consumes a lower member and, in turn, is preyed upon by a higher member.

food web

a complex of interrelated food chains in an ecological community.

Gross Primary Productivity

the amount of sugar that the plants produce in photosynthesis and subtracting from it the amount of energy the plants need for growth maintenance, repair, and reproduction.

habitat

the area or environment where an organism or ecological community normally lives or occurs.

habitat fragmentation

when the size of an organism's natural habitat is reduced, or when development occurs that isolates a habitat.

heterotroph

an organism that cannot synthesize its own food and is dependent on complex organic substances for nutrition.

indigenous species

species that originate and live, or occur naturally, in an area or environment.

invasive species

an introduced, normative species.

keystone species

a species whose very presence contributes to an ecosystem's diversity and whose extinction would consequently lead to the extinction of other forms of life.

law of conservation of matter

states that matter can neither be created nor destroyed.

mutualism

a symbiotic relationship in which both species benefit.

natural selection

the process by which, according to Darwin's theory of evolution, only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics in increasing numbers to succeeding generations, while those less adapted tend to be eliminated.