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Darwinism. Darwinism is a theory of biological evolution developed by the English naturalist Charles Darwin (1809–1882) and others, stating that all species of organisms arise and develop through the natural selection of small, inherited variations that increase the individual's ability to compete, survive, and reproduce.
The modern synthesis [a] was the early 20th-century synthesis of Charles Darwin 's theory of evolution and Gregor Mendel 's ideas on heredity into a joint mathematical framework. Julian Huxley coined the term in his 1942 book, Evolution: The Modern Synthesis. The synthesis combined the ideas of natural selection, Mendelian genetics, and ...
Theory of Change. A theory of change ( ToC) is an explicit theory of how and why it is thought that a social policy or program activities lead to outcomes and impacts. [1] ToCs are used in the design of programs and program evaluation, across a range of policy areas. Theories of change can be developed at any stage of a program, depending on ...
Phyletic gradualism is a model of evolution which theorizes that most speciation is slow, uniform and gradual. [1] When evolution occurs in this mode, it is usually by the steady transformation of a whole species into a new one (through a process called anagenesis ). In this view no clear line of demarcation exists between an ancestral species ...
Stabilizing selection. 1: directional selection: a single extreme phenotype favoured. 2, stabilizing selection: intermediate favoured over extremes. 3: disruptive selection: extremes favoured over intermediate. Stabilizing selection (not to be confused with negative or purifying selection [1] [2]) is a type of natural selection in which the ...
e. Evolutionary thought, the recognition that species change over time and the perceived understanding of how such processes work, has roots in antiquity—in the ideas of the ancient Greeks, Romans, Chinese, Church Fathers as well as in medieval Islamic science. With the beginnings of modern biological taxonomy in the late 17th century, two ...
The Transmutation of species and transformism are 18th and early 19th-century ideas about the change of one species into another that preceded Charles Darwin 's theory of evolution through natural selection. [1] The French Transformisme was a term used by Jean Baptiste Lamarck in 1809 for his theory, and other 18th and 19th century proponents ...
Various commentators view the teleological phrases used in modern evolutionary biology as a type of shorthand for describing any function which offers an evolutionary advantage through natural selection. For example, the zoologist S. H. P. Madrell wrote that "the proper but cumbersome way of describing change by evolutionary adaptation [may be ...