Page 96 - Reptiles & Dinosaurs (Britannica Illustrated Science Library)

92 GLOSSARY REPTILES AND DINOSAURS 93

Glossary

Adaptation Carbon-14 Class DNA Fossil Gondwana
Trait of an organism's structure, physiology, or Radioactive carbon isotope whose concentration Taxonomic group above order and below Deoxyribonucleic acid. Double-helix shaped Remains of various types of ancient life-forms, Ancient southern supercontinent that broke up
behavior that enables it to live in its can help determine the age of fossils. phylum. For example, the class Reptilia, within molecule that contains encoded genetic both plants and animals, in a rocky substrate. 180 million years ago to form Africa, South
environment. the phylum Chordata, contains orders such as information. They are found in the geological strata of the America, Australia, Antarctica, and India.
Carboniferous Squamata and suborders such as Sauria. Earth's surface.
Alkaline Duvernoy's Glands Gregarious
Geological period during the Paleozoic Era, Cloaca Fossilization
Substances that increase the number of which took place between 360 and 251 million System possessed by some snakes for injecting Animal whose typical behavior, as a species, is
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hydroxide ions (OH ) in a solution; having a pH years ago. Exit chamber of the digestive tract of venom. They are a pair of modified salivary Process by which a deceased organism becomes conducive to living in groups.
greater than 7; basic; opposite of acidic. reptiles and birds. In some species, it also glands, one on either side of the head. a fossil over thousands of years.
Carnivore functions as the site of the reproductive and Herbivore
Amino Acid excretory systems. Efferent Gastrolith
Animal that obtains its nutrients and energy by Animal that feeds on grass or other plants.
Organic molecule containing nitrogen in the eating flesh. Cold-blooded Nerve or blood vessel that flows from a central Stone found in the stomachs of certain
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form of ammonia (NH2 ) and a carboxyl point toward peripheral tissues or organs. herbivorous dinosaurs that helped them crush Inflammation
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group (COOH ) joined to the same carbon Carrion Eater Organism whose body temperature is mainly and digest food.
atom. They form the building blocks of controlled by an external heat source because it Egg Nonspecific defensive reaction of the body to
protein molecules. Animal that eats the flesh of a dead animal. has little capacity to generate its own heat Gene the invasion of a foreign substance or organism,
through its metabolism. Fertilized ovule that develops into a new frequently accompanied by the accumulation of
Amphibian Cellular Membrane individual. It usually also refers to the entire Unit of information in a chromosome; sequence pus and an increase in the temperature of the
Connective Tissue structure that covers and protects the of nucleotides in the DNA molecule that carries affected area.
Group of animals that today includes frogs, Flexible lipid envelope covering all living cells. It fertilized ovule. out a specific function.
toads, salamanders, and limbless caecilians. contains cytoplasm and regulates the Tissue that joins, supports, and protects the Jacobson's Organ
interchange of water and gases with the other three types of tissues: epithelial, muscular, Embryo Genetic Drift
Ancestor environment. and nervous. It contains a network composed of Organ on the upper part of the palate that takes
many fibers surrounding the cells. The first stage of development of a multicellular Change in the frequency of alleles, the result of in substances captured by a reptile's tongue and
Parent, grandparent, or more remote forebear Cerebellum animal or plant. random processes. analyzes them to determine various
that transmits certain genetic characteristics to Coprolite characteristics of the object they come from.
its descendants. A section of the brain in vertebrates located Estivation Genus Also called the vomeronasal organ.
above the brain stem and behind and below the Fossilized animal excrement.
Antidote cerebrum. It coordinates muscular activity and State of extreme lethargy or inactivity Taxonomic category that includes species. Lability
maintains balance. Cytoplasm caused by prolonged periods of drought or
Substance that neutralizes the action of a excessive heat. Gills Fragility of an organ; sensitivity to potentially
specific poison. Chelonia Fluid within the cell membrane. destructive agents.
Evolution Respiratory organs of aquatic animals. Often an
Antipoisonous Serum Collective term for land and sea turtles. Dental Battery Changes in the gene pool of a population caused extension of fine tissues from the outer surface Lamarck, Jean-Baptiste
of the body or, in vertebrates, from part of the
Specially prepared substance used to neutralize Chordate Set of teeth joined together to form a cutting by processes such as mutation, natural digestive tract. French naturalist (1744-1829). He was the first
toxins from the bite of a specific snake in and grinding surface. selection, and genetic drift. to propose a theory to explain the changes in
persons who show signs of poisoning. Animal that belongs to the phylum Chordata; Gland living beings.
any animal having a spinal cord, whether Dermis Family
Aorta throughout its development or only in certain Group of epithelial cells that produce Laurasia
stages. Animals that are not chordates are Internal layer of skin, located under the Taxonomic category lower than order and secretions, organized inside a covering
Main artery in blood circulation systems. It called invertebrates. epidermis. higher than genus. The family Viperidae, for membrane to form an organ whose function is Ancient northern supercontinent formed of North
sends blood to other tissues of the body. example, groups together the vipers. to synthesize and excrete molecules that the America, Europe, and Asia, excluding India.
organ itself does not use.
Chromosome Dewlap
Biped Fertilization Lipids
Structure that carries the genes and, in Fold of skin hanging below the chin and Gonads
Animal that stands upright, walks, or runs using eukaryotic cells, is composed of filaments of extending to the chest in some lizards and other The joining of a female sex cell with a male sex Group of water-insoluble substances, including
only the two hind limbs. chromatin that contract during mitosis and tetrapods. It can be unfolded in territorial cell to form a diploid zygote. Glands that produce reproductive sex cells. fats, oils, waxes, steroids, glycolipids,
meiosis. battles to intimidate or to display certain moods. phospholipids, and carotenes.