Columbia Encyclopedia

Search results

341 results found

species

(Encyclopedia)species, in biology, a category of classification, the original and still the basic unit in the demarcation of plant and animal types. The species marks the boundary between populations of organisms r...

Shockley, William Bradford

(Encyclopedia)Shockley, William Bradford, 1910–89, American physicist, b. London. He graduated from the California Institute of Technology (B.S., 1932) and the Massachusetts Institute of Technology (Ph.D., 1936)....

Russell, Henry Norris

(Encyclopedia)Russell, Henry Norris, 1877–1957, American astronomer, b. Oyster Bay, N.Y., grad. Princeton, 1897. In 1902 he went to Cambridge, England, to study. He returned to Princeton in 1905, was professor of...

Ramapithecus

(Encyclopedia)Ramapithecus räməpəthēˈkəs, –pĭthˈə– [key], former name for an extinct group of primates that lived from about 12 to 14 million years ago, for a time regarded as a possible ancestor of Au...

histone

(Encyclopedia)histone hĭsˈtōn [key], any of a class of protein molecules found in the chromosomes of eukaryotic cells. They complex with the DNA (see nucleic acid) and pack the DNA into tight masses of chromatin...

geochemistry

(Encyclopedia)geochemistry, study of the chemical changes on the earth. More specifically, it is the study of the absolute and relative abundances of chemical elements in the minerals, soils, ores, rocks, water, an...

object-oriented programming

(Encyclopedia)object-oriented programming, a modular approach to computer program (software) design. Each module, or object, combines data and procedures (sequences of instructions) that act on the data; in traditi...

Nicolson, Sir Harold

(Encyclopedia)Nicolson, Sir Harold, 1886–1968, English biographer, historian, and diplomat, b. Tehran, Iran. Educated at Oxford, he entered the foreign office in 1909, and, until his resignation 20 years later, h...

miracle

(Encyclopedia)miracle, preternatural occurrence that is viewed as the expression of a divine will. Its awe and wonder lie in the fact that the cause is hidden. The idea of the miracle occurs especially with the evo...

selection

(Encyclopedia)selection. In Darwinism, the mechanism of natural selection is considered of major importance in the process of evolution. Popular formulations sometimes envisage a struggle for existence in which dir...