Darwin formerly Palmerston Seaport (pop., 2001 prelim.: 69,698), capital of Northern Territory, Australia. Located on Port Darwin, a deep inlet of Clarence Strait in the Timor Sea, it has one of Australia’s best harbours. The harbour was named in 1839 for Charles Darwin. The port, settled in 1869, was known as Palmerston until 1911. Located in a largely undeveloped region, Darwin is a supply and shipping centre for northern
Australia. A military base in World War II, it was bombed by the Japa¬ nese in 1942, then extensively rebuilt. A cyclone in 1974 damaged or destroyed nearly all of the city; rebuilt a second time, it is now one of Australia’s most modem cities.
Darwin, Charles (Robert) (b. Feb. 12, 1809, Shrewsbury, Shrop¬ shire, Eng.—d. April 19, 1882, Downe, Kent) British naturalist. The grandson of Erasmus Darwin and Josiah Wedgwood, he studied medicine at the University of Edinburgh and biology at Cambridge. He was rec¬ ommended as a naturalist on HMS Beagle, which was bound on a long scientific survey expedition to South America and the South Seas (1831- 36). His zoological and geological discoveries on the voyage resulted in numerous important publications and formed the basis of his theories of evolution. Seeing competition between individuals of a single species, he recognized that within a local population the individual bird, for example, with the sharper beak might have a better chance to survive and repro¬ duce and that if such traits were passed on to new generations, they would be predominant in future populations. He saw this natural selection as the mechanism by which advantageous variations were passed on to later generations and less advantageous traits gradually disappeared. He worked on his theory for more than 20 years before publishing it in his famous On the Origin of Species by Means of Natural Selection (1859). The book was immediately in great demand, and Darwin’s intensely con¬ troversial theory was accepted quickly in most scientific circles; most opposition came from religious leaders. Though Darwin’s ideas were modified by later developments in genetics and molecular biology, his work remains central to modern evolutionary theory. His many other important works included Variation in Animals and Plants Under Domes¬ tication (1868) and The Descent of Man... (1871). He was buried in Westminster Abbey. See also Darwinism.
Darwin, Erasmus (b. Dec. 12, 1731, Elston Hall, Nottinghamshire, Eng.—d. April 18, 1802, Derby, Der¬ byshire) British physician, grandfa¬ ther of Charles Darwin and Francis Galton. A freethinker and radical,
Darwin often wrote his opinions and scientific treatises in verse. In Zoonomia; or, The Laws of Organic Life (1794-96), he advanced a theory of evolution similar to that of La¬ marck, suggesting that species modi¬ fied themselves by adapting to their environment in an intentional way.
His conclusions, drawn from simple observation, were rejected by the more sophisticated 19th-century sci¬ entists, including his grandson Charles.
Darwinism Theory of the evolu¬ tionary mechanism proposed by Charles Darwin as an explanation of organic change. It denotes Darwin’s specific view of how evolution works. Darwin developed the con¬ cept that evolution is brought about by the interplay of three principles: variation (present in all forms of life), heredity (the force that transmits similar organic form from one generation to another), and the struggle for existence (which determines the variations that will be advantageous in a given environment, thus altering the species through selective reproduc¬ tion). Present knowledge of the genetic basis of inheritance has contrib¬ uted to scientists’ understanding of the mechanisms behind Darwin’s ideas, in a theory known as neo-Darwinism.
Darwin's finch or Galapagos finch Any of 14 species (in three genera) of songbirds (family Fringillidae) whose adaptations to several ecological niches in the Galapagos Islands and Cocos Island gave Charles Darwin evidence for his thesis that “species are not immutable.” All the species are 4-8 in. (10-20 cm) long and brownish or black, but they dif¬ fer greatly in the configuration of the bill, which is suited to each species’ particular feeding habit.
Dassault \da-'so\, Marcel orig. Marcel Bloch (b. Jan. 22, 1892, Paris, France—d. April 18, 1986, Paris) French aircraft designer and industrialist. He designed aircraft during World War I, and in 1930 he
Erasmus Darwin, detail of an oil paint¬ ing by Joseph Wright, 1770; in the National Portrait Gallery, London
COURTESY OF THE NATIONAL PORTRAIT GALLERY, LONDON
© 2006 Encyclopaedia Britannica, Inc.
514 I data compression ► Daudet
started his own company to build military and civilian airplanes. Sent to Buchenwald as a Jew during World War II, he later changed his last name (to that of his brother’s byname in the Resistance) and resumed his busi¬ ness. His company produced Europe’s first supersonic plane, the Mystere, and in 1956 began production of the Mirage warplane, which would be acquired by countries worldwide.
data compression Process of reducing the amount of data needed for storage or transmission of a given piece of information (text, graphics, video, sound, etc.), typically by use of encoding techniques. Data com¬ pression is characterized as either lossy or lossless depending on whether some data is discarded or not, respectively. Lossless compression scans the data for repetitive sequences or regions and replaces them with a single “token.” For example, every occurrence of the word the or region with the colour red might be converted to $. ZIP and GIF are the most com¬ mon lossless formats for text and graphics, respectively. Lossy compres¬ sion is frequently used for photographs, video, and sound files where the loss of some detail is generally unnoticeable. JPEG and MPEG (see MP3) are the most common lossy formats.
data encryption Process of disguising information as “ciphertext,” or data that will be unintelligible to an unauthorized person. Decryption is the process of converting ciphertext back into its original format, some¬ times called plaintext (see cryptography). Computers encrypt data by applying an algorithm to a block of data. A personal key known only to the message’s transmitter and intended receiver is used to control the encryption. Well-designed keys are almost impregnable. A key 16 char¬ acters long selected at random from 256 ASCII characters could take far longer than the 15-billion-year age of the universe to decode, assuming the perpetrator attempted 100 million different key combinations per sec¬ ond. Symmetric encryption requires the same key for both encryption and decryption. Asymmetric encryption, or public-key cryptography, requires a pair of keys, one for encryption and one for decryption.
data mining Type of database analysis that attempts to discover use¬ ful patterns or relationships in a group of data. The analysis uses advanced statistical methods, such as cluster analysis, and sometimes employs arti¬ ficial intelugence or neural network techniques. A major goal of data min¬ ing is to discover previously unknown relationships among the data, especially when the data come from different databases. Businesses can use these new relationships to develop new advertising campaigns or make predictions about how well a product will sell. Governments also use these techniques to discern illegal or embargoed activities by indi¬ viduals, associations, and other governments.
data processing Manipulation of data by a computer. It includes the conversion of raw data to machine-readable form, flow of data through the CPU and memory to output devices, and formatting or transformation of output. Any use of computers to perform defined operations on data can be included under data processing. In the commercial world, data processing refers to the processing of data required to run organizations and businesses.