A - B - C - D - E - F - G - H - I - J - K - L - M - N - O - P - Q - R - S - T - U - V - W - X - Y - Z

(Terms in italics are defined elsewhere in the glossary)

deduction A process of reasoning by which more specific consequences are inferred by rigorous argument from more general propositions ( cf. induction ) . (Chapter 12)

deductive nomological (D-N) explanation A formal method of explanation based on the testing of hypotheses derived from general laws. (Chapter 12)

deep-sea cores Cores drilled from the sea bed that provide the most coherent record of climate changes on a worldwide scale. The cores contain shells of microscopic marine organisms (foraminifera) laid down on the ocean floor through the continuous process of sedimentation. Variations in the ratio of two oxygen isotopes in the calcium carbonate of these shells give a sensitive indicator of sea temperature at the time the organisms were alive. (Chapter 4)

demography The study of the processes which contribute to population structure and their temporal and spatial dynamics. (Chapter 11)

dendrochronology The study of tree-ring patterns; annual variations in climatic conditions which produce differential growth can be used both as a measure of environmental change, and as the basis for a chronology. (Chapter 4)

diachronic Referring to phenomena as they change over time; i.e. employing a chronological perspective ( cf. synchronic ) . (Chapter 12)

diatom analysis A method of environmental reconstruction based on plant microfossils. Diatoms are unicellular algae, whose silica cell walls survive after the algae die, and they accumulate in large numbers at the bottom of rivers and lakes. Their assemblages directly reflect the floristic composition of the water's extinct communities, as well as the water's salinity, alkalinity, and nutrient status. (Chapter 6)

diffusionist approach The theory popularized by V.G. Childe that all the attributes of civilization from architecture to metalworking had diffused from the Near East to Europe. (Chapter 1)

DNA (Deoxyribonucleic acid) The material which carries the hereditary instructions (the "blueprint") which determine the formation of all living organisms. Genes , the organizers of inheritance, are composed of DNA. (Chapter 11)

dowsing The supposed location of subsurface features by employing a twig, copper rod, pendulum, or other instrument; discontinuous movements in these instruments are believed by some to record the existence of buried features. (Chapter 3)