10Th Chem C

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C3 plants

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C3 plants a plant that fixes carbon exclusively through the Calvin cycle; named for the three-carbon compound that is initially formed

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C4 pathway

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C4 pathway a carbon-fixing process in which carbon dioxide is bound to a compound to form a four-carbon Cintermediate

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calcareous ooze

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calcareous ooze a type of ooze that is mostly calcium carbonate

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calcitonin

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calcitonin a hormone that stimulates removal of calcium from the blood

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caldera

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caldera a large, circular depression that forms when the magma chamber below a volcano partially empties and causes the ground above to sink

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calendar

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calendar a system used to measure and record the passage of time

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calorie

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the amount of energy needed to raise the temperature of 1 g of water 1°C; the Calorie used to indicate the energy content of food is a kilocalorie

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calorimeter

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calorimeter a device used to measure the heat absorbed or released in a chemical or physical change

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calorimetry

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calorimetry the measurement of heat-related constants, such as specific heat or latent heat

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Calvin cycle

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Calvin cycle a biochemical pathway of photosynthesis in which carbon dioxide is converted into glucose using ATP

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CAM

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CAM crassulacean acid metabolism, a biochemical pathway in certain plants in which carbon dioxide is incorporated into organic acids at night and released for fixation in the Calvin cycle during the day

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Canadian shield

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Canadian shield a plateau that extends over about a plant that fixes carbon exclusively through the Calvin cycle; named for the three-carbon compound that is initially formed 2 million square miles of Canada and the northeast of the United States

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cancer

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canCER a tumor in which the cells begin dividing at an uncontrolled rate and become invasive

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canine

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canine a sharp tooth located on either s a plant that fixes carbon exclusively through the Calvin cycle; named for the three-carbon compound that is initially formed ide of the jaw

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canopy

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canopy the layers of treetops that shade the forest floor

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capacitance

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capacitance the ability of a conductor to store energy in the form of electrically separated charges

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capillarity

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capillarity the attraction between molecules that results in the rise of a liquid in small tubes

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capillary

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capillary a tiny blood vessel that allows an exchange between blood and cells in tissue

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capillary action

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capillary action the attraction of the surface of a liquid to the surface of a solid, which causes the liquid to rise or fall

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capillary fringe

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capillary fringethe region of soil just above the water table that contains water under low atmospheric pressure

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cap rock

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cap rock the top layer of impermeable a plant that fixes carbon exclusively through the Calvin cycle; named for the three-carbon compound that is initially formed rock in an artesian formation

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capsid

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capsid the region of soil just above the water table that contains water under low atmospheric pressure

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capsule

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capsule in mosses, the part that contains spores; in bacteria, a protective layer of polysaccharides around the cell wall

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carageenan

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carageenan a substance that is found in the cell walls of red algae and that is used commercially as a smoothing agent in foods

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carapace

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carapace a shieldlike plate that covers the cephalothorax of some crustaceans

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carbohydrate

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carbohydrate any organic compound that is made of carbon, hydrogen, and oxygen and that provides nutrients to the cells of living things

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carbonation

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carbonation the conversion of a compound into a carbonate

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carbon cycle

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carbon cycle the movement of carbon from the nonliving environment into living things and back

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carbon fixation

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carbon fixation the synthesis of organic compounds from carbon dioxide, such as in photosynthesis

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carbonization

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carbonization the process in which a substance that contains carbon, such as plant materials, is reduced into a carbon film

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carboxylic acid

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carboxylic acid an organic acid that contains the carboxyl functional group

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carcinogen

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carcinogen a cancer-causing substance

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carcinoma

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carcinoma a malignant tumor that can grow anywhere in the body and can spread through the bloodstream

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cardiac muscle

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cardiac muscle the type of involuntary muscle found in the heart

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cardiac sphincter

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cardiac sphinctera circular muscle located between the esophagus and the stomach

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cardiac stomach

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cardiac stomach the enlarged foregut of some crustaceans, echinoderms, and other animals

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cardiovascular system

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cardiovascular system a collection of organs that transport blood throughout the body; the organs in this system include the heart, the arteries, and the veins

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carnivore

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carnivore an organism that eats animals

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carotenoid

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carotenoid a class of pigments that are present mostly in plants and that aid in photosynthesis

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carpel

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carpel the structure where the ovule is in flowering plants

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carrier

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carrier in biology, an individual who has one copy of a recessive autosomal allele that causes disease in the homozygous condition

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carrier

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carrier in physics, a wave that can be modulated to send a signal

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carrier protein

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carrier protein a protein that transports substances across a cell membrane

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carrying capacity

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carrying capacity the largest population that an environment can support at any given time

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cartilage

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cartilage a flexible and strong connective tissue

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cartography

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cartography the science of mapmaking

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cast

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cast a type of fossil that forms when sediments fill in the cavity left by a decomposed organism

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caste

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caste a group of insects in a colony that have a specific function

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catalysis

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catalysis the acceleration of a chemical reaction by a catalyst

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catalyst

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catalyst a substance that changes the rate of a chemical reaction without being consumed or changed significantly

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catastrophism

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catastrophism a principle that states that geologic change occurs suddenly

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catenation

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catenation the binding of an element to itself to form chains or rings

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cathode

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cathode the electrode on whose surface reduction takes place

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cathode-ray tube

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cathode-ray tube a tube that uses an electron beam to create a display on a phosphorescent screen

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cation

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cation an ion that has a positive charge

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caudal fin

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caudal fin in fish, a fin that extends from the tail

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cause-and-effect relationship

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cause-and-effect relationship a relationship between two variables in which a change in one variable leads to a change in the other

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cavern

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cavern a natural cavity that forms in rock as a result of the dissolution of minerals; also a large cave that commonly contains many smaller, connecting chambers

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cecum

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cecum a sac usually found at the beginning of the large intestine

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celestial equator

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celestial equator the great circle formed on the celestial sphere by extending the plane of the Earth's equator

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CelLIN BIO

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cell in biology, the smallest unit that can perform all life processes; cells are covered by a membrane and contain DNA and cytoplasm

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Cell IN ELECTRICTY

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cell in electricity, a device that produces an electric current by converting chemical or radiant energy into electrical energy

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cell cycle

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cell cycle the life cycle of a cell; in eukaryotes, it consists of a cell-growth period in which DNA is synthesized and a cell-division period in which mitosis takes place

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cell differentiation

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cell differentiation the process by which a cell becomes specialized for a specific structure or function

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cell division

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cell division the formation of two cells from one existing cell

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cell junction

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cell junction the connection between cells that holds them together as a unit

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cell-mediated immune response

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cell-mediated immune response an immune response that involves the presence and reaction of T cells

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cell membrane

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cell membrane a phospholipid layer that covers a cell’s surface and acts as a barrier between the inside of a cell and the cell’s environment

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cell plate

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cell platethe precursor of a new plant cell wall that forms during cell division and divides a cell into two

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cell theory

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cell theory the theory that states that all living things are made up of cells, that cells are the basic units of organisms, that each cell in a multicellular organism has a specific job, and that cells come only from existing cells

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cellular respiration

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cellular respiration the process by which cells produce energy from carbohydrates; atmospheric oxygen combines with glucose to form water and carbon dioxide

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cell wall

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cell wall a rigid structure that surrounds the cell membrane and provides support to the cell

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cementation

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cementation the process in which minerals precipitate into pore spaces between sediment grains and bind sediments together to form rock

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Cenozoic era

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Cenozoic era the current geologic era, which began 65.5 million years ago; also called the Age of Mammals

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center of mass

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center of mass the point in a body that moves as if the entire mass were concentrated there and as if all of the forces were applied there

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central nervous system

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central nervous system the brain and the spinal cord; its main function is to control the flow of information in the body

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central vacuole

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central vacuole a large cavity or sac that is found in plant cells or protozoans and that contains air or partially digested food

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centric diatom

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centric diatom a radially symmetrical member of the phylum Bacillariophyta

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centriole

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centriole an organelle that is active during mitosis

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centripetal acceleration

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centripetal acceleration the acceleration directed toward the center of a circular path

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centromere

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centromere the region of the chromosome that holds the two sister chromatids together during mitosis

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centrosome

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centrosome an organelle that contains the centrioles and is the center of dynamic activity in mitosis

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cephalization

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cephalization the concentration of nerve tissue and sensory organs at the anterior end of an organism

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cephalopod

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cephalopod a marine mollusk that has tentacles extending from the head; an octopus, squid, cuttle-fish, or nautilus

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cytotoxic T cell

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cephalothorax in arachnids and some crustaceans, the body part made up of the head and the thorax

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cereal

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cereal any grass that produces grains that can be used for food, such as rice, wheat, corn, oats, or barley

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cerebellum

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cerebellum a posterior portion of the brain that coordinates muscle movement and controls subconscious activities and some balance functions

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cerebral cortex

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cerebral cortex the gray, outer portion of the cerebrum that controls the higher mental functions, general movement, organ function, perception, and behavioral reactions

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cerebral ganglion

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cerebral ganglion one of a pair of nerve-cell clusters that serve as a primitive brain at the anterior end of some invertebrates, such as annelids

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cerebral hemisphere

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cerebral hemisphere either of the two lobes of the cerebrum

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cerebrospinal fluid

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cerebrospinal fluid a fluid that provides a cushion that protects the brain and spinal cord

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cerebrum

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cerebrum the upper part of the brain that receives sensation and controls movement

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cervix

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cervix the inferior portion of the uterus

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Chagas' disease

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Chagas' disease a disease that is caused by trypanosomes and is characterized by a swollen face on only one side, fever, and swollen spleen and liver

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chain reaction

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chain reaction a reaction in which a change in a single molecule makes many molecules change until a stable compound forms

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change of state

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change of state the change of a substance from one physical state to another

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channel

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channel the path that a stream follows

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chaparral

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chaparral a type of vegetation that includes broad-leafed evergreen shrubs and that is located in areas with hot, dry summers and mild, wet winters

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character displacement

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character displacement the difference in character in populations of two species located in different geographical areas relative to populations of the same two species living in the same geographical area, as a result of competition for food and other re

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Charles's law

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Charles's law the law that states that for a fixed amount of gas at a constant pressure, the volume of the gas increases as the temperature of the gas increases and the volume of the gas decreases as the temperature of the gas decreases

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chelicera

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chelicera in arachnids, either of a pair of appendages used to attack prey

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cheliped

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cheliped in arthropods, one of the pair of appendages that have claws

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chemical

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chemical any substance that has a defined composition

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chemical bond

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chemical bond the attractive force that holds atoms or ions together

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chemical bonding

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chemical bonding the combining of atoms to form molecules or ionic compounds

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chemical change

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chemical change a change that occurs when one or more substances change into entirely new substances with different properties

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chemical energy

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chemical energy the energy released when a chemical compound reacts to produce new compounds

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chemical equation

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chemical equation a representation of a chemical reaction that uses symbols to show the relationship between the reactants and the products

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chemical equilibrium

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chemical equilibrium a state of balance in which the rate of a forward reaction equals the rate of the reverse reaction and the concentrations of products and reactants remain unchanged

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chemical equilibrium expression

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chemical equilibrium expression the equation for the equilibrium constant, Keq

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chemical formula

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chemical formula a combination of chemical symbols and numbers to represent a substance

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chemical kinetics

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chemical kinetics the area of chemistry that is the study of reaction rates and reaction mechanisms

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chemical property

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chemical property a property of matter that describes a substance's ability to participate in chemical reactions

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chemical reaction

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chemical reaction the process by which one or more substances change to produce one or more different substances

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chemical sedimentary rock

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chemical sedimentary rock sedimentary rock that forms when minerals precipitate from a solution or settle from a suspension

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chemical structure

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chemical structure the arrangement of the atoms in a molecule

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chemical weathering

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chemical weathering the process by which rocks break down as a result of chemical reactions

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chemiosmosis

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chemiosmosis In chloroplasts and mitochondria, a process in which the movement of protons down their concentration gradient across a membrane is coupled to the synthesis of ATP

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chemistry

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chemistry the scientific study of the composition, structure, and properties of matter and the changes that

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chemoautotroph

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chemoautotroph an organism that synthesizes organic compounds by using inorganic compounds instead of light

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chemosynthesis

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chemosynthesis the production of carbohydrates through the use of energy from inorganic molecules instead of light

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chemotropism

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chemotropism the tendency of an organism or a part of an organism to grow toward or away from a chemical stimulus

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chinook

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chinook a wind that flows down the eastern slope of the Rocky Mountains

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chitin

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chitin a carbohydrate that forms part of the exoskeleton of arthropods and other organisms, such as insects,

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chlorofluorocarbons

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chlorofluorocarbons hydrocarbons in which some or all of the hydrogen atoms are replaced by chlorine and fluorine; used in coolants for refrigerators and air conditioners and in cleaning solvents; their use is restricted because they destroy ozone molecul

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chlorophyll

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chlorophyll a green pigment that is present in most plant cells, that gives plants their characteristic green color, and that reacts with sunlight, carbon dioxide, and water to form carbohydrates

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chloroplast

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chloroplast an organelle found in plant and algae cells where photosynthesis occurs

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choanocyte

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choanocyte any of the flagellate cells that line the cavities of a sponge

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chordate

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chordate an animal that at some stage in its life cycle has a dorsal nerve, a notochord, and pharyngeal pouches; examples include mammals, birds, reptiles, amphibians, fish, and some marine lower forms

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chorion

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chorion the outer membrane that surrounds an embryo

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chorionic villi

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chorionic villi fingerlike projections of the chorion that extend into the uterine lining (singular, chorionic villus)

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chorionic villi sampling

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chorionic villi sampling a procedure in which the chorionic villi to are analyzed to diagnose fetal genotypes

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chromatic aberration

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chromatic aberration a defect in a lens that makes the lens focus different colors of light at various points, producing a spectrum

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chromatid

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chromatid one of the two strands of a chromosome that become visible during meiosis or mitosis

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chromatina

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chromatina portion of the cell nucleus made up of DNA and proteins; it is the carrier of the genes in inheritance

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chromatophore

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chromatophore in photosynthetic bacteria, an organelle that contains chlorophyll and other pigments

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chromosome

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chromosome in a eukaryotic cell, one of the structures in the nucleus that are made up of DNA and protein; in a prokaryotic cell, the main ring of DNA

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chromosome map

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chromosome map a diagram of gene positions on a chromosome

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chromosphere

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chromosphere the thin layer of the sun that is just above the photosphere and that glows a reddish color during eclipses

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chronic bronchitis

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chronic bronchitis a continued inflammation of the bronchi

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chrysalis

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chrysalis the hard-shelled pupa of certain insects, such as butterflies

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chyme

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chyme the mixture formed in the stomach from digested food particles and gastric fluid

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cilium

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cilium a hairlike structure arranged in tightly packed rows that projects from the surface of some cells

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cinder cone

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cinder cone a steep-sloped deposit of solid fragments ejected from a volcano

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circadian rhythm

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circadian rhythm a biological daily cycle

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circuit

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circuit a complete path of an electric current

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circuit board

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circuit board a sheet of insulating material that carries circuit elements and that is inserted in an electronic device

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circuit breaker

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circuit breaker a switch that opens a circuit automatically when the current exceeds a certain value

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circulatory system

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circulatory system the heart and vessels that move blood through the body

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circumpolar

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circumpolar describes any star that is always visible from a certain latitude

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cirque

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cirque a deep and steep bowl-like depression produced by glacier erosion

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cirrhosis

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cirrhosis a disease in which normal liver tissues are replaced by fibrous tissue

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cirri

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cirri In insects, hairlike tufts located on an appendage (singular, cirrus)

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cirrus cloud

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cirrus cloud a feathery cloud that is composed of ice crystals and that has the highest altitude of any cloud in the sky

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citric acid

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citric acid a six-carbon compound formed in the Krebs cycle

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cladistics

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cladistics a phylogenetic classification system that uses shared derived characters and ancestry as the sole criterion for grouping taxa

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cladogram

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cladogram a diagram that is based on patterns of shared, derived traits and that shows the evolutionary relationships between groups of organisms

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clasper

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clasper in male fish, a structure that transfers sperm into the female's body

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class

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class a taxonomic category containing orders with common characteristics

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classification

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classification the division of organisms into groups, or classes, based on specific characteristics

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clastic sedimentary rock

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clastic sedimentary rock sedimentary rock that forms when fragments of preexisting rocks are compacted or cemented together

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clear cutting

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clear cutting a method of harvesting timber in which all of the trees are removed from a land area, providing full sunlight to allow new seeds to develop

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cleavage

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cleavage in biological development, a series of cell divisions that occur immediately after an egg is fertilized

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cleavage

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cleavage in geology, the tendency of a mineral to split along specific planes of weakness to form smooth, flat surface

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cleavage furrow

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cleavage furrow the area of the zygote that pinches in and eventually separates the dividing cell

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climate

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climate the average weather conditions in an area over a long period of time

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climatologist

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climatologista scientist who gathers data to study and compare past and present climates and to predict future climate change

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climax community

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climax community a final, stable community in equilibrium with the environment

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clitellum

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clitellum in many leeches and earthworms, a thick depression of the body wall that protects the eggs

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cloaca

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cloaca in all vertebrates except mammals and reptiles, a chamber in the intestine that receives materials from the digestive, reproductive, and excretory systems

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clone

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clone an organism that is produced by asexual reproduction and that is genetically identical to its parent; to make a genetic duplicate

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cloning vector

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cloning vector an agent, usually a plasmid, that is used to receive and transfer foreign DNA in gene cloning and in recombinant-DNA experiments

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closed circulatory system

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closed circulatory system a circulatory system in which the heart circulates blood through a network of vessels that form a closed loop; the blood does not leave the blood vessels, and materials diffuse across the walls of the vessels

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closed system

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closed system a system that cannot exchange matter or energy with its surroundings

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cloud

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cloud a collection of small water droplets or ice crystals suspended in the air, which forms when the air is cooled and condensation occurs

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cloud seeding

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cloud seeding the process of introducing freezing nuclei or condensation nuclei into a cloud in order to cause rain to fall

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cluster

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cluster a group of stars or galaxies bound by gravity

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cnidocyte

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cnidocyte a stinging cell of a cnidarian

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coacervate

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coacervate a mass of colloidal substances held together by electrostatic attraction

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coal

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coal a combustible sedimentary rock formed by the compaction of partially decomposed plant material

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coalescence

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coalescence the formation of a larger droplet by the combination of smaller droplets

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coccus

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coccus a sphere-shaped bacterium

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cochlea

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cochlea a coiled tube that is found in the inner ear and that is essential to hearing

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Coconino Sandstone

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Coconino Sandstone the rock layer of the Grand Canyon that was deposited during the Permian period

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cocoon

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cocoon a protective case produced by some insects at their pupal stage

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code

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code a set of rules used to interpret data that convey information

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codominance

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codominance a condition in which both alleles for a gene are fully expressed

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codon

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codon in DNA, a three-nucleotide sequence that encodes an amino acid or signifies a start signal or a stop signal

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coefficient

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coefficient a small whole number that appears as a factor in front of a formula in a chemical equation

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coefficient of friction

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coefficient of friction the ratio of the force of friction between two objects immediately before sliding to the normal force

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coelom

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coelom a body cavity that contains the internal organs

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coelomate

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coelomate an animal that has a body cavity in which the internal organs are located

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coenocytic

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coenocytic describes filaments that do not have cell walls

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coevolution

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coevolution the evolution of two or more species that is due to mutual influence, often in a way that makes the relationship more mutually beneficial

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coherence

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coherence The correlation between the phases of two or more waves

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cohesion

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cohesion the force that holds molecules of a single material together

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cold front

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cold front the front edge of a moving mass of cold air that pushes beneath a warmer air mass like a wedge

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collar cell

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collar cell any of the flagellate cells that line the cavities of a sponge; also called a choanocyte

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collenchyma

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collenchyma a group of elongated, thick-walled plant cells that support the growth of leaves and stems

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colligative property

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colligative property a property that is determined by the number of particles present in a system but that is independent of the properties of the particles themselves

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collision theory

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collision theory the theory that states that the number of new compounds formed in a chemical reaction is equal to the number of molecules that collide, multiplied by a factor that corrects for low-energy collisions

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colloblast

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colloblast a cell that is found on the tentacles of a ctenophore and that secretes a sticky substance

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colloid

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colloid a mixture consisting of tiny particles that are intermediate in size between those in solutions and those in suspensions and that are suspended in a liquid, solid, or gas

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colon

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colon a section of the large intestine

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colonial organism

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colonial organism a collection of genetically identical cells that are permanently associated but in which little or no integration of cell activitiesOCCURS

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color blindness

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color blindness the inability to distinguish one color from another

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columella

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columella the axis of the cochlea

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coma

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coma a bright shell of gas and dust that surrounds the nucleus of a comet

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combined gas law

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combined gas law the relationship between the pressure, volume, and temperature of a fixed amount of gas

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combustion

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Combustion the burning of a substance

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combustion reaction

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combustion reaction the oxidation reaction of an organic compound, in which heat is released

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comet

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comet a small body of ice, rock, and cosmic dust that follows an elliptical orbit around the sun and that gives off gas and dust in the form of a tail as it passes close to the sun

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commensalism

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commensalism a relationship between two organisms in which one organism benefits and the other is unaffected

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common-ion effect

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common-ion effect the phenomenon in which the addition of an ion common to two solutes brings about precipitation or reduces ionization

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communication

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communication a transfer of a signal or message from one animal to another that results in some type of response

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community

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community a group of various species that live in the same habitat and interact with each other

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compact bone

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compact bone the layer of bone that is just beneath the periosteum and that gives that bone its strength and rigidity

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compaction

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compaction the process in which the volume and porosity of a sediment is decreased by the weight of overlying sediments as a result of burial beneath other sediments

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companion cell

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companion cell a cell that gives rise to sieve tubes in angiosperms

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competition

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competitionthe relationship between two species (or individuals) in which both species (or individuals) attempt to use the same limited resource such that both are negatively affected by the relationship

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competitive exclusion

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competitive exclusion the exclusion of one species by another due to competition

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complementary

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complementarya characteristic of nucleic acids in which the sequence of bases on one strand is paired to the sequence of bases on the other

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complementary base pair

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complementary base pair the nucleotide bases in one strand of DNA or RNA that are paired with those of another strand; adenine pairs with thymine or uracil, and guanine pairs with cytosine

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complement system

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complement system a system of proteins that circulate in the bloodstream and that combine with antibodies to protect against antigens

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complete dominance

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complete dominancea relationship in which one allele is completely dominant over another

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complete metamorphosis

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complete metamorphosis the transformation from larva to adult in insects

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components of a vector

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components of a vector the projections of a vector along the axes of a coordinate system

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composite volcano

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composite volcano a volcano made of alternating layers of lava and pyroclastic material; also called stratovolcano

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composition

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composition the chemical makeup of a rock; describes either the minerals or other materials in the rock

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compost

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compost a mixture of decomposing organic matter, such as manure and rotting plants, that is used as fertilizer and soil conditioner

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compound

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compound a substance made up of atoms of two or more different elements joined by chemical bonds

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compound eye

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compound eye an eye composed of many light detectors separated by pigment cells

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compound leaf

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compound leaf a type of leaf in which the blade is divided into leaflets

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compound light microscope

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compound light microscope an instrument that magnifies small objects so that they can be seen easily by using two or more lenses, one lens to magnify the object and the other lens to magnify the first lens's image

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compound machine

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compound machine a machine made of more than one simple machine

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compression

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compression in physics, a point of highest density in a longitudinal wave; corresponds to maximum amplitude

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compression

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compression in geology, a reduction in the volume of a substance due to pressure changes

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Compton shift

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Compton shift an increase in the wavelength of a photon emitted relative to the photon absorbed when scattered by individual electrons or nucleons

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computer

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computer an electronic device that can accept data and instructions, follow the instructions, and output the results

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concave lens

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concave lens a lens that is thinner in the middle than at the edges

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concave mirror

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concave mirror a mirror that is curved inward like the inside of a spoon

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concave spherical mirror

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concave spherical mirror a mirror whose reflecting surface is an inward-curved segment of a sphere

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concentration

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concentration the amount of a particular substance in a given quantity of a mixture, solution, or ore

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concentration gradient

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concentration gradient a difference in the concentration of a substance across a distance

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conceptual model

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conceptual model a verbal or graphical explanation for how a system works or is organized

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concretion

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concretion a piece of mineral matter that forms in the pores of a rock and that hasa different composition from that of the main rock body

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condensation

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condensation the change of state from a gas to a liquid

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condensation nucleus

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condensation nucleus a solid particle in the atmosphere that provides the surface on which water vapor condenses

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condensation polymer

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condensation polymer a polymer formed by condensation reactions

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condensation reaction

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condensation reaction a chemical reaction in which two or more molecules combine to produce water or another simple molecule

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conditioning

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conditioning the process of learning by association

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cone

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cone in plants, a seed-bearing structure

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cone

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cone in animals, a photoreceptor within the retina that can distinguish colors and is very sensitive to bright light

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cone of depression

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cone of depression a lowered area of a water table produced when water withdraws from a well

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conformer

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conformer an organism whose physiological reactions follow environmental changes

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conglomerate

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conglomerate a sedimentary rock composed of rounded gravel or pebbles cemented together by minerals

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conic projection

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conic projection a map projection that is made by transferring the surface features of the globe onto a cone

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conidiophore

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conidiophore a type of hypha that bears asexual spores called conidia

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conidium

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conidium an asexual spore produced in certain fungi

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conjugate acid

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conjugate acid an acid that forms when a base gains a proton

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conjugate base

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conjugate base a base that forms when an acid loses a proton

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conjugation

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conjugation in prokaryotes, algae, and fungi, a type of sexual reproduction in which two cells join temporarily to recombine nuclear material

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conjugation bridge

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conjugation bridge in certain algae and fungi, a passageway for the transfer of genetic information from one organism to another

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connective tissue

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connective tissue a tissue that has a lot of intracellular substance and that connects and supports other tissues

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conservation

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conservation the preservation and wise use of natural resources

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conservation biology

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conservation biology a branch of biology that is the study of the management of natural resources and the preservation of biodiversity

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constellation

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constellation one of 88 regions into which the sky has been divided in order to describe the locations of celestial objects; a group of stars organized in a recognizable pattern

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constrictor

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constrictor a snake that kills its prey by crushing and suffocating it

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constructive interference

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constructive interference a superposition of two or more waves that produces a greater intensity than the sum of the intensities of the individual waves

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consumer

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consumer an organism that eats other organisms or organic matter instead of producing its own nutrients or obtaining nutrients from inorganic sources

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consumption crisis

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consumption crisis a situation in which natural resources are being used up, wasted, or polluted faster than they can be renewed, replaced, or cleaned up

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contact metamorphism

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contact metamorphism a change in the texture, structure, or chemical composition of a rock due to contact with magma

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continental glacier

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continental glaciera massive sheet of ice that may cover millions of square kilometers, that may be thousands of meters thick, and that is not confined by surrounding topography

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continental crust

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continental crust the rocks underlying the continents

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continental drift

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continental drift the hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

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continental margin

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continental margin the shallow sea floor that is located between the shoreline and the deep-ocean bottom

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continental polar

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continental polar a cold air mass that forms over land and that has low humidity

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continental rise

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continental rise the gently sloping section of the continental margin located between the continental slope and the abyssal plain

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continental shelf

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continental shelf the gently sloping section of the continental margin located between the shoreline and the continental slope

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continental slope

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continental slope the steeply inclined section of the continental margin located between the continental rise and the continental shelf

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continental tropical

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continental tropicaa warm air mass that forms over land and that has low humidity

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continuous spectrum

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continuous spectrum the uninterrupted broad band of all colors (wavelengths) emitted by incandescent solids

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contour feather

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contour feather one of the most external feathers that cover a bird and that help determine its shape

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contour interval

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contour intervalthe difference in elevation between one contour line and the next

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contour line

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contour line a line that connects points of equal elevation on a map

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contractile vacuole

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contractile vacuole in protozoans, an organelle that accumulates water and then releases it periodically to maintain osmotic pressure

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control group

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control group in an experiment, a group that serves as a standard of comparison with another group to which the control group is identical except for one factor

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controlled experiment

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controlled experiment an experiment that tests only one factor at a time by using a comparison of a control group with an experimental group

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control rod

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control rod a neutron-absorbing rod that helps control a nuclear reaction by limiting the number of free neutrons

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conus arteriosus

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conus arteriosus in fish, the frontmost chamber of the heart

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convection

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convection the movement of matter due to differences in density that are caused by temperature variations; can result in the transfer of energy as heat

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convection cell

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convection cell a pattern of circulation in which warmer materials rise in one location while cooler materials sink in another location

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convection current

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convection current the vertical movement of air currents due to temperature variations

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convective cooling

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convective coolingthe process in which the temperature of a mass of air decreases as the air rises and expands

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convective zone

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convective zone the region of the sun’s interior that is between the radiative zone and the photosphere and in which energy is carried upward by convection

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convergent boundary

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convergent boundary the boundary between tectonic plates that are colliding

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convergent evolution

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convergent evolution the process by which unrelated species become more similar as they adapt to the same kind of environment

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conversion factor

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conversion factor a ratio that is derived from the equality of two different units and that can be used to convert from one unit to the other

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convex lens

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convex lens a lens that is thicker in the middle than at the edges

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convex mirror

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convex spherical mirror a mirror whose reflecting surface is an outward-curved segment of a sphere

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convex spherical mirror

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copolymer a polymer made from two different monomers

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copolymer

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coprolite ancient feces, or dung, that have become fossilized

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coprolite

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coral reef a limestone ridge found in tropical climates and composed of coral fragments that are deposited around organic remains

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coral reef

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core The central part of the Earth below the mantle; also the center of the sun

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core

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core sample a cylindrical piece of sediment, rock, soil, snow, or ice that is collected by drilling

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core sample

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Coriolis effect the curving of the path of a moving object from an otherwise straight path due to the Earth's rotation

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Coriolis effect

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cork the outer layer of bark of any woody plant

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cork

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cork cambium a layer of tissue under the cork layer where cork cells are produced

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cork cambium

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cornea a transparent membrane that forms the front portion of the eyeball

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cornea

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coronathe outermost layer of the sun's atmosphere

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corona

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coronal mass ejectiona part of coronal gas that is thrown into space from the sun

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coronal mass ejection

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coronary artery one of the two arteries that supply blood directly to the heart

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coronary artery

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coronary circulation the flow of blood in the arteries that supply the heart

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coronary circulation

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corpus callosum

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corpus callosum

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the broad band of white matter that connects the cerebral hemispheres of the brain

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corpus luteum

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corpus luteum the structure that forms from the ruptured follicle in the ovary after ovulation; it releases hormones

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correlation

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correlation the linear dependence between two variables

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corrosion

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corrosionthe gradual destruction of a metal or alloy as a result of chemical processes such as oxidation or the action of a chemical agent

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cortex

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cortex in plants, the primary tissue located in the epidermis; in animals, the outermost portion of an organ

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cortisol

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cortisol a hormone that regulates certain phases of carbohydrate, protein, and water metabolism, affects muscle tone, increases gastric secretion, and alters tissue response to injury

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cosmic background radiation

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cosmic background radiation radiation uniformly detected from every direction in space; considered a remnant of the big bang

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cosmology

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cosmology the study of the origin, properties, processes, and evolution of the universe

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cotyledon

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cotyledon the embryonic leaf of a seed

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countercurrent flow

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countercurrent flow in fish gills, an arrangement whereby water flows away from the head and blood flows toward the head

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covalent bond

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covalent bond a bond formed when atoms share one or more pairs of electrons

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covalent compound

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covalent compound a chemical compound that is formed by the sharing of electrons

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coxal gland

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coxal gland in some arthropods, a gland that has ducts that open at the base of the leg

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cranial cavity

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cranial cavity the area in which the brain rests

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cranial nerve

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cranial nerve one of the nerves that enter or emerge from the brain

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cranium

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cranium the skeleton of the head, especially the portion of the skull where thebrain is enclosed

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crater

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crater a bowl-shaped depression that forms on the surface of an object when a falling body strikes the object’s surface or when an explosion occurs; a similar depression around the central vent of a volcano or geyser

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craton

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craton a large area of the continental crust that has not experienced active deformation for a long time

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creep

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creep the slow downhill movement of weathered rock material

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crest

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crest the highest point of a wave

Front 335

cretinism

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cretinism a form of mental retardation caused by hypothyroidism

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crevasse

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crevasse in a glacier, a large crack or fissure that results from ice movement

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crista

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crista one of the many foldings of the inner membrane of mitochondria

Front 338

critical angle

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critical angle the angle of incidence at which acoustic waves are totally reflected

Front 339

critical mass

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critical mass the minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction

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critical point

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critical point the temperature and pressure at which the gas and liquid states of a substance become identical and form one phase

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critical pressure

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critical pressure the lowest pressure at which a substance can exist as a liquid at the critical temperature

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critical temperature

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critical temperature the temperature above which a substance cannot exist in the liquid state

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critical thinking

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critical thinking the ability and willingness to assess claims critically and to make judgments on the basis of objective and supported reasons

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crop

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crop a sac or pouch used by birds and some insects to store food

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crop milk

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crop milk a nutritious milklike fluid secreted by the crop of pigeons and doves to feed their young

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crossing-over

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crossing-over the exchange of genetic material between homologous chromosomes during meiosis; can result in genetic recombination

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cross-pollination

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cross-pollination a reproductive process in which pollen from one plant is transferred to the stigma of another plant

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crude oil

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crude oil unrefined petroleum

Front 349

crustacean

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crustacean an arthropod that has mandibles, antennae, and other appendages; examples include lobsters, shrimp, barnacles, crabs, and water fleas

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crustose

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crustose a type of lichen that has a crustlike body

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crystal

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crystal a solid whose atoms, ions, or molecules are arranged in a regular, repeating pattern

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crystal lattice

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crystal lattice the regular pattern in which a crystal is arranged

Front 353

crystalline solid

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crystalline solid a solid that consists of crystals

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crystal structure

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crystal structure the arrangement of atoms, ions, or molecules in a regular way to form a crystal

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cud

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cud partly digested food that is regurgitated, rechewed, and reswallowed for further digestion by mammals that have a rumen

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cultivar

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cultivar a cultivated species or organism that does not have a known wild ancestor; a variety produced by selective breeding, also called cultigen

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cumulus cloud

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cumulus cloud a low-level, billowy cloud that commonly has a top that resembles cotton balls and a dark bottom

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current

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current in geology, a horizontal movement of water in a well-defined pattern, such as a river or stream; the movement of air in a certain direction

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cuticle

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cuticle a waxy or fatty and watertight layer on the external wall of epidermal cells

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cuttings

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cuttings a root, stem, or leaf that is cut from a living plant and that can produce a new plant

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cyanobacterium

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cyanobacterium a bacterium that can carry out photosynthesis, such as a blue-green alga

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cyclic process

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cyclic process a thermodynamic process in which one form of energy is partly converted into another and the remainder is released as heat

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cycloalkane

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cycloalkane a saturated carbon chain that forms a loop or a ring

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cyclone

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cyclone an area in the atmosphere that has lower pressure than the surrounding areas and has winds that spiral toward the center

Front 365

cylindrical projection

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cylindrical projectiona map projection that is made by moving the surface features of the globe onto a cylinder

Front 366

cyst

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cyst a cavity or cell that contains embryos or bacteria in a resting stage

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cystic fibrosis

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cystic fibrosis a fatal genetic disorder in which excessive amounts of mucus are secreted, blocking intestinal and bronchial ducts and causing difficulty in breathing

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cytokinesis

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cytokinesis the division of the cytoplasma of a cell; cytokinesis follows the division of the cell's nucleus by mitosis or meiosis

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cytokinin

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cytokinin a plant hormone that affects cell division, plant metabolism, and the synthesis of RNA and proteins

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cytolysis

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cytolysis the bursting of a cell

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cytoplasm

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cytoplasm the region of the cell within the membrane that includes the fluid, the cytoskeleton, and all of the organelles except the nucleus

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cytoplasmic streaming

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cytoplasmic streaming the flow of cytoplasm in larger cells to facilitate the dispersion of cellular components

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cytosine

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cytosine one of the four bases found in DNA and RNA; cytosine pairs with guanine

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cytoskeleton

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cytoskeleton the cytoplasmic network of protein filaments that plays an essential role in cell movement, shape, and division

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cytosol

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cytosol the soluble portion of the cytoplasm, which includes molecules and small particles, such as ribosomes, but not the organelles covered with membranes

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cephalothorax

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cytotoxic T cell a type of T cell that recognizes and destroys cells infected by virus