Biological Journal of the Linnean Society, 2018, https://doi.org/10.1093/biolinnean/bly003.
A preprint version is available (under the creative commons license 4.0) here.
A comparison of the evolutionary mechanisms of Patrick Matthew, Charles Darwin, and Alfred Wallace highlights their differences. In Matthew’s scheme, catastrophes initiate periods of radiation and speciation until a fully stocked environment gets into stasis. Catastrophes first needed to exterminate competing species before the survivors could radiate into free niches and diversify into new species. In Darwin's early theory conditions of life, such as prevail under domestication, first need to increase the variability of a species, before natural selection can transform it. In Darwin's mature theory competition replaced conditions as the main drive behind evolutionary change and sympatric speciation becomes possible. Wallace’s theory differed from both Matthew’s and Darwin’s. Interspecific competition was neither a brake halting transmutation (as in Matthew’s) nor intraspecific competition a sufficient drive for it. While each theory integrated natural selection with variability, competition and changed conditions in distinct ways, each allowed for species transmutation somehow. The result was similar (transmutation), but the mechanisms yielding that result (the integration of natural selection with variability, competition, change in conditions) differed significantly.