490
abiotic factor (āºbī ot’ik fakºtổr) Any nonliving part of an ecosystem, such as water, minerals, sunlight, air, or soil. (p. 27) abrasion (ổ brāºzhổn) The process that occurs when sand, stones, and pebbles move and scrape across Earth’s surface, acting like sandpaper to pit and polish the surface. (p. 359)
absorption (ab sụrpºshổn) The process of taking in radiant energy. (p. 220)
abyssal zone (ổ biºsổl zōnº) The part of the oceanic zone that is found at depths greater than 2,000 meters (6,562 feet), where there is no sunlight, it is very cold, and the water pressure is high. (p. 121) acidity (ổ sidºi tē) The amount of acid in a substance. (p. 33)
of the burning of coal and other fossil fuels; harms soils and water supplies and weathers statues and buildings. (p. 422) aerial roots (õrºē ổl rỹts) Roots that reach out above the ground for water and sunlight to nourish a plant. (p. 44)
air pressure (õr preºshổr) The force that air molecules exert on the objects beneath them; has a major effect on the weather. (p. 346)
alkalinity (alêkổ linºi tē) The amount of base in a substance. (p. 33)
alluvial deposit (ổ lỹºvē ổl di pozºit) A fan-shaped land deposit at the mouth of a stream. (p. 376)
amoeba (ổ mēºbổ) A protist, found in fresh water, salt water, and soil, that uses pseudopods to move and take in food.
(p. 61)
Pronunciation Key
The following symbols are used throughout the Macmillan/McGraw-Hill Science Glossaries.
a at e end o hot u up hw white ổ about  ape Ê me Ô old Û use ng song taken
ọ far i it ụr fork ỹ rule th thin pencil
õ care ẻ ice oi oil ự pull th this lemon
ụ law ợr pierce ou out ỷr turn zh measure circus ' = primary accent; shows which syllable takes the main stress, such as kil in kilogram (kil' e gram').
' = secondary accent; shows which syllables take lighter stresses, such as gram in kilogram.
amplitude (amºpli tỹdê) The distance from the midpoint to the crest or trough of a wave. (p. 176)
anticyclone (anêtīº sīklōn) An area of high pressure that usually brings fair weather. (p. 352)
arroyo (ổ roiºō) A small, water-carved channel with steep banks that is located in a dry area. (p. 374)
asthenosphere (as theºnổ sfợrê) The layer of semimolten mantle rock that lies directly below the lithosphere. (p. 287)
bank (bangk) The rising ground that borders a river or stream. (p. 371)
barrier island (barºē ổr īºlổnd) A sandbar that is more than 100 meters (328
feet) wide. (p. 385)
bathyal zone (baºthē ổl zōnê) The part of the oceanic zone that is between 200 meters (656 feet) and about 2,000 meters (6,562 feet) deep. (p. 121) beach drift (bēch drift) The pulling of sand particles sideways along a beach.
(p. 383)
beach erosion (bēch i rōºzhổn) The process by which waves pick up sand particles and move them along the shore. (p. 382)
benthos (benºthọs) Organisms that live on or near the ocean floor, such as seaweed, and tube worms. (p. 123)
biomass conversion (bīºō masê
kổn vỷrºzhổn) A method for changing plant and animal materials into high-quality fuels. (p. 189)
biome (bīºōm) A region with a particular climate that contains certain types of plants and ecosystems. (p. 102)
biotic factor (bī otºik fakºtổr) Any living thing that is part of an ecosystem. (p. 27) body wave (bodºē wāv) A seismic wave that travels through the interior of Earth; the two types are P waves and S waves. (p. 283)
breaker (brāºkổr) A wave that breaks into foam against the shore and washes back into the ocean at another angle. (p. 383) buoyancy (boiºổn sē) An upward force on an object or a substance that is in a liquid or a gas. (p. 202)
amplitude — buoyancy
492
California Current (kalºổ fụrºnyổ kỷrºổnt) An ocean current that carries cold water toward the equator along the western coast of the United States, keeping the climate of the northwest cool. (p. 247) calorie (kalºổ rấ) The amount of energy needed to raise the temperature of 1 gram of water by 1°C. (p. 167)
cambium (kamºbấ ổm) A layer of plant cells that sometimes separates the xylem and the phloem. (p. 45)
canopy (kanºổ pấ) The second-tallest layer of the rain forest; it shades the rain forest with a thick blanket of foliage.
(p. 104)
capillary action (kapºổ lerºấ akºshổn) A force that pulls water up into plants by water molecules’ sticking to one another and to other substances. (p. 48)
carbon cycle (kọrºbổn sīºkổl) The natural processes in which carbon is recycled between the atmosphere and living things. (p. 84)
carnivore (kọrºnổ vụrê) A secondary or tertiary consumer; an animal that eats other animals. (p. 72)
Central Valley (senºtrổl valºē) An area of low land bordered by the Sierra Nevada to the east and the Coast Ranges to the west. (p. 328)
chaparral (shapºổ ralê) A dry region with a thick growth of brush and small trees found in the foothills of California’s southern mountain ranges, in the Sierra Nevada, and along the California coast.
(p. 136)
chemical reaction (kemºi kổl rē akºshổ) A change in matter that produces new substances with properties different from those of the original substances. (p. 190) chemical weathering (kemºi kổl
wethºổr ing) The process that changes the composition of rock, forming new minerals that have properties different from those of the original rock. (p. 359)
chemosynthesis (kēºmō sinêthổ sổs) A chemical reaction that bacteria living near hydrothermal vents use to produce food. (p. 122)
chlorophyll (klụrºổ filê) A green substance in plants that absorbs energy from
sunlight. (p. 43)
chloroplast (klụrºổ plastê) A structure that contains chlorophyll and is found in the cells of leaves and stems of green plants. (p. 43)
cilia (silºē ổ) Small, hairlike projections extending from the outsides of some protists’ cells; used for movement and for capturing food. (p. 60)
ciliate (silºē ổt) Any protist that has small, hairlike projections, or cilia, extending from the outside of its cell. (p. 60)
cinder cone volcano (sinºdổr kōnº
vol kāºnō) A volcanic landform made up of small rock particles, or cinders, which pile up around the vent to form a small cone with steep sides. (p. 314)
climate (klīºmit) The average weather pattern of a region. (p. 102)
coal (kōl) A hard, black substance formed from plants that lived about 300 million years ago. Coal is a fossil fuel (p. 417) collection (kổ lekºshổn) A process in which water soaks into the ground and is stored as groundwater. (p. 83)
community (kổ mū’ni tē) All the populations living in an area. (p. 35) composite volcano (kổm pozºit
vol kāºnō) A landform made up of layers of lava flows alternating with layers of ash, cinders, and rocks; shaped like a symmetrical cone with steep sides that are concave, or curving inward.(p. 315)
composting (komºpōs ting) The process in which decomposers break down organic matter so it can be used as a natural fertilizer for gardening or farming. (p. 88) compound leaf (komºpound lēf) A leaf with two or more blades. (p. 46)
compound light microscope (komºpound līt mīºkrổ skōpê) A microscope that uses two or more lenses and a light source to magnify objects. (p. 57)
compression wave (kổm preshºổn wāv) A wave that moves back and forth in the same direction as the molecules of matter in the wave; sound waves are an example. (p. 180)
concrete (konºkrēt) A mixture of sand, gravel, and pebbles in a binding material such as mortar. (p. 452)
condensation (konêden sāºshổn) The process in which a gas changes into a liquid. (p. 83)
conduction (kổn dukêshổn) The movement of energy through direct contact. (p. 200) conductor (kổn dukºtổr) An object that absorbs heat and distributes it evenly; one example is metal. (p. 170)
conifer (konºổ fổr) An evergreen that produces seeds in special structures called cones. (p. 140)
conservation (konêsổr vāºshổn) Using natural resources wisely by limiting their use to times of need. (p. 438)
consumer (kổn sỹºmổr) An organism that gets energy by feeding directly on producers or by eating animals that feed on producers. (p. 69)
continental crust (konêtổ nenºtổl krust) Crust that makes up Earth’s land; made up mostly of a relatively lightweight rock called granite. (p. 286)
continental drift (konêtổ nenºtổl drift) The idea that a past supercontinent split apart into pieces, which drifted over time to their present locations. (p. 270)
cinder cone volcano — continental drift
494
convection (kổn vekºshổn) The transfer of energy by the flow of a liquid or a gas.
(p. 202)
convection current (kổn vekºshổn kỷrºổnt) The circulation of hot and cold fluids due to differences in temperature and resultant changes in density. (p. 243)
convective flow (kổn vekºtiv flō) The continuous circular pattern of fluids as they are heated and cooled. (p. 288)
convergent boundary (kổn vỷrºjổnt bounºdổ rấ) A boundary between plates that are moving toward each other, or colliding. (p. 291)
core (kôr) The central part of Earth that lies beneath the mantle and is made up of an outer, liquid part and an inner, solid part. (p. 285)
Coriolis effect (kụrêē ōºlổs i fektº) The shift in wind direction caused by Earth’s rotation. (p. 350)
cost-effectiveness (kôstº i fekºtiv nes) A measure determined by comparing the costs and the consequences of different ways of doing something. (p. 420)
crater (krāºtổr) A bowl-shaped depression. (p. 311)
crust (krust) The thin layer of solid rock that makes up the outermost part of Earth. (p. 284)
cuticle (kūºti kổl) A waxy coating secreted by cells of a plant’s epidermis to prevent water from leaving the plant. (p. 46)
cyanobacteria (sīºổ nōêbak tợrºē ổ) Prokaryotic producers that produced oxygen as a waste gas that made Earth inhabitable for other living things. (p. 58) cycle (sīºkổl) A series of events that happen in the same order, over and over again. (p. 83)
cyclone (sẻºklễn) A huge mass of spinning air that forms when an area of low
pressure is surrounded by high pressure on all sides. (p. 352)
dam (dam) A barrier constructed to control a flow of water or to raise a water level. (p. 423)
deciduous (di sijºỹ ổs) Belonging to the class of trees or forests that lose their leaves when winter comes. (p. 110)
decomposer (dēêkổm pōºzổr) An organism that breaks down dead organisms into simpler substances. (p. 69)
delta (delºtổ) The triangular-shaped
deposit of soil particles that forms where a stream enters a larger body of water.
(p. 376)
density (denºsi tē) The measure of how much material there is in a given amount of space. (p. 284)
deposition (depêổ zishºổn) The process by which eroded soil and rock are put down in new places, reshaping the landscape. (p. 360)
deuterium (dỹ tợrºē ổm) One of the two forms of hydrogen used in the process of nuclear fusion. (p. 435)
dew point (dü point) The temperature at which condensation occurs. (p. 348) diatom (dīºổ tomê) A very small,
photosynthetic protist that lives in either salt water or fresh water. (p. 59)
dinoflagellate (dīênō flaºjổ lổt) A protist that has characteristics of both plants and animals. (p. 59)
divergent boundary (di vỷrêjổnt bounºd ổ rē) A boundary between plates that are moving away from each other, or pulling apart. (p. 290)
dormant (dụrºmổnt) Less active or resting condition. (p. 29)
earthquake (ỷrthºkwākê) The shaking of the ground that occurs when tectonic plates shift and change positions. (p. 276) ecology (ē kolºổ jē) The study of organisms and how they interact in an ecosystem. (p. 34)
ecosystem (ēºkō sisêtổm) The living and nonliving things in an area that interact with one another. (p. 26)
eddy (edºē) A small, spinning air current that often develops when wind flows over buildings, mountains, or other obstructions. (p. 352)
efficiency (i fishºổn sē) The amount of usable energy given off by an energy conversion compared to the total amount of energy used in the conversion. (p. 421) electromagnetic spectrum
(i lekêtrō mag netºik spekºtrổm) The wide range of electromagnetic
radiation ordered by wavelength; consists of radio waves, microwaves, infrared rays, visible light, ultraviolet light, X rays, and gamma rays. (p. 218)
electromagnetic wave
(i lekêtrō mag netºik wāv) A wave that is made up of alternating electric and magnetic fields created by vibrating electric charges. (p. 182)
electron microscope (i lekºtron
mīºkrổ skōpê) A powerful microscope that uses a beam of electrons, rather than a light source, to magnify samples being observed. (p. 57)
emergent layer (i mỷrºjổnt lāºổr) The uppermost rain-forest layer, made up of very tall trees that emerge from the forest below into the sunlight above. (p. 104) emission (i mishºổn) The process of giving off absorbed electromagnetic waves.
(p. 221)
energy (enºổr jē) The ability to bring about changes or to do work. (p. 164)
energy conversion (enºổr jē kổn vỷrºzhổn) The process in which energy changes from one form into another. (p. 418)
deuterium — energy conversion
496
energy pyramid (enºổr jē pirºổ midê) A model that shows how energy moves through a food chain. (p. 76)
energy source (enºổr jē sụrs) The origin of the light, heat, or electrical energy people use. (p. 416)
ENSO/El Niủo/Southern Oscillation (el nēnºyō suthºổrn osêổ lāºshổn) The disruption of the ocean-atmosphere system in the Pacific Ocean and the impact that it has on weather around the globe. (p. 248)
epicenter (e’pi sen’tổr) The point on Earth’s surface directly above the focus of an earthquake; the place where the strongest shocks are felt and where the greatest damage usually occurs. (p. 301) epidermis (epºi dỷrêmis) The outermost layer of cells of a leaf or skin. (p. 46) erosion (i rōºzhổn) The wearing away of Earth’s surface by the breakdown of rocks and transportation of rock and soil.
(p. 360)
estuary (esºchỹ erêē) The part of a river where fresh water meets the sea and is affected by tides. (p. 126)
ethanol (ethºổ nụlê) A manufactured fuel that can be mixed with gasoline to run cars. (p. 189)
eukaryote (yỹºkerºē ōtê) An organism with a nucleus in each cell. (p. 58)
evaporation (i vapêổ rāºshổn) The process in which a liquid changes into a gas.
(p. 83)
evergreen (evºổr grēnê) A tree that usually keeps its leaves all year. (p. 140)
extinct (ek stingktº) Describes a volcano that has not erupted within recorded history. (p. 317)
fault (fôlt) A break, or crack, in the rocks of the lithosphere along which movements take place; usually located along the
boundaries between tectonic plates.
(p. 299)
fault zone (fôlt zōn) An area where there are many interconnected faults; usually located along the boundaries between tectonic plates. (p. 299)
feldspar (feldºspọrê) The name of a group of minerals that makes up almost 60% of Earth’s crust. (p. 386)
fibrous roots (fīºbrổs rỹts) Roots that branch out into a network of thin, hairy roots; can form thick mats. (p. 44)
fission (fishºen) The splitting of atoms into pieces. (p. 433)
flagella (flổ jelºổ) Long, hairlike structures that whip and lash to help flagellates swim. (p. 60)
flagellate (flajºổ lit) A protozoan that has flagella, or long, hairlike structures that whip and lash to help it swim. (p. 60) flood plain (flổd plān) The flat area of land on both sides of a river. (p. 371)
focus (fōºkổs) The point below the surface of the ground where an earthquake
begins. (p. 301)
food chain (füd chān) An arrangement that shows how energy flows from one organism to another in an ecosystem.
(p. 70)
food vacuole (fỹd vakºÛ ễlê) A structure inside certain cells where food is stored.
(p. 60)
food web (füd web) An arrangement that shows the food chains in an ecosystem and how they overlap; also shows the roles and relationships among all the species in an ecosystem. (p. 72)
forest floor (fôrºist flôr) The bottom level of the rain forest, which receives little or no sunlight. (p. 105)
fossil (fosºổl) The remains of an ancient plant or animal. (p. 188)
fossil fuel (fosºổl fūºổl) A fuel that comes from the remains of plants and animals and is formed beneath the surface of Earth over millions of years. (p. 188)
frequency (frēºkwổn sē) The number of vibrations a wave makes in a given period of time, usually 1 second. (p. 177)
friction (frikºshổn) The force that acts when two surfaces rub against each other.
(p. 193)
fumarole (fyỹºmổ rōlê) A hole in the ground through which gases and hot vapors pass;
located in a volcanic region. (p. 320)
fusion (fūºzhen) The process of merging nuclei with smaller masses to make a nucleus with a larger mass. (p. 434)
geologist (jē olºổ jist) A scientist who studies Earth’s origin, history, structure, composition, and processes. (p. 271) geothermal energy (jēêō thỷrºmổl enºổr jē) Heat energy produced inside Earth. (p. 417)
geyser (gī’zổr) A fountain of hot water and steam that shoots into the air. (p. 320) glacier (glā’shổr) A large mass of moving ice that forms over hundreds or thousands of years. (p. 364)
global winds (glōºbổl windz) Winds that blow from a specific direction and typically cover long distances. (p. 244)
greenhouse effect (grēnºhousê i fektº) Rise in temperature resulting from a buildup of gases such as carbon dioxide, nitric oxide, and methane, which trap heat that would otherwise escape from Earth’s atmosphere; this leads to global warming. (p. 84)
guard cell (gọrd sel) One of two cells surrounding each stomate of a leaf;
regulates when the stomates open and close. (p. 46)
focus — guard cell
498
Gulf Stream (gulf strēm) An ocean current that carries warm water from the southern tip of Florida north along the eastern coast of the United States.
(p. 246)
habitat (habºi tatê) The place in which a population lives. (p. 36)
heat flow (hēt flō) The transfer of energy from a warmer object to a cooler object. (p. 168)
herbivore (hỷrºbổ vụrê) A primary consumer, or an animal that eats producers. (p. 72)
hot spot (hot spot) A region of volcanic activity in the middle of a tectonic
plate. (p. 319)
hot spring (hot spring) A stream of hot, bubbling water that flows out of the ground continuously. (p. 320)
humidity (hū midºi tē) The amount of water vapor in the air. (p. 345)
humus (hūºmổs) The organic material in soil formed by the breakdown of plant and animal remains. (p. 32)
hurricane (hỷrºi kānê) A tropical cyclone that brings powerful winds and heavy rains and can cause great destruction. (p. 352)
hydroelectric power (hīêdrō i lek’trik pouºổr) The result of energy that is harnessed from the force of falling or running water; can be converted into electricity. (p. 435)
hydrothermal vent (hīêdrổ thổrºmổl vent) A jet of hot water rich in minerals that comes up through a crack in the ocean floor. (p. 122)
insulation (inºsổ lāêshổn) A material used to prevent heat from flowing into or out of a substance. (p. 170)
insulator (inêsổ lāºtổr) An object that absorbs heat but does not distribute it evenly; one example is wood. (p. 170) intensity (in tenºsi tē) The strength of an earthquake that can be felt at the surface. (p. 303)
intermittent (inêtổr mitºổnt) Type of volcano that erupts at fairly frequent intervals. (p. 317)
intertidal zone (inêtổr tīºdổl zōn) The shallowest part of the ocean, lying
between the high-tide line and the low-tide line. (p. 121)
jet stream (jet strēm) A current of fast- moving air in the upper atmosphere; one factor that determines weather in North America. (p. 249)
keystone species (kēºstōnê spēºshēz) A population that occupies a niche of such importance that many other organisms depend on it. (p. 139)
kinetic energy (ki netºik enºổr jē) The energy of any moving object. (p. 165)
lahar (lọºhọrê) A mudflow containing volcanic ash and rock. (p. 393)
land breeze (land brēz) A breeze that develops as wind blows from the land toward the water. (p. 351)
landslide (landºslīdê) The rapid, downslope movement of a mass of rock, soil, and debris. (p. 362)
lava (lọºvổ) Molten rock that flows out onto the surface of Earth. (p. 287)
levee (levºē) A wall or a large mound of earth built along a river to prevent it from flooding. (p. 397)
light wave (līt wāv) A wave within the visible part of the electromagnetic spectrum. (p. 182)
lithosphere (lithºổ sfợrê) The rigid outer part of Earth made up of rocks in the crust attached to the upper part of the mantle. (p. 286)
lithospheric plate (lithêổ sfợrºik plāt)
Plates of the lithosphere that move slowly within Earth. (p. 286)
local winds (lōºkổl winds) Winds that can blow from any direction and cover short distances. (p. 244)
Los Angeles Basin (lụs anºjổ lổs bāºsin) A depression lying between the Transverse and Peninsular ranges that is filled with rock material that has washed down from these mountains. (p. 328)
magma (magºmổ) Molten, or melted, rock deep below the surface of Earth;
reaches temperatures between 650°C and 1,200°C (between 1,202°F and 2,192°F). (p. 287)
magma chamber (magºmổ chāmºbổr) A reservoir from which volcanic materials erupt. (p. 311)
magnetite (magºni tītê) A black mineral with magnetic properties. (p. 386) magnitude (magºni tỹdê) The measure of the energy released during an earthquake. (p. 302)
jet stream — magnitude
500