evolutionism

Evolutionism is the view that the history of life is the result of gradual, natural processes that produce biological diversity. In modern biology, it refers to the theory of evolution—the idea that species change over time through heritable variation and mechanisms such as natural selection, mutation, genetic drift, and gene flow, with all life linked by common descent. The term has historically carried broader connotations, sometimes emphasizing a naturalistic and progressive view of development, and in some contexts has been used pejoratively by critics of evolutionary science.

History: early ideas of transmutation; Jean-Baptiste Lamarck proposed inheritance of acquired traits. Charles Darwin and Alfred Russel Wallace presented natural selection as the primary mechanism (Origin of Species, 1859). The Modern Synthesis (1930s–1940s) integrated population genetics with paleontology and systematics, defining evolution as changes in allele frequencies over time and the emergence of new species.

Evidence and scope: the fossil record, comparative anatomy, embryology, molecular biology, biogeography, and observable speciation support evolutionary change. Evolutionary biology covers microevolution within species and macroevolution across lineages, explaining adaptation and diversification.

Terminology today: while some scholars use "evolutionism" in historical or philosophical discussions, most scientists refer to "the theory of evolution" or "evolutionary biology."