Charles Robert Darwin (February 12, 1809 – April 19, 1882) is one of the most celebrated and eminent scientists of the past few centuries, with his broadest and most notable influence arising from his theory of evolution by means of natural selection. Darwin’s remarkable investigations and insights obtained during his voyage on the HMS Beagle (1831–1836) led him to theorize about concepts of evolutionary biology and to develop revolutionary ideas related to adaptation and speciation. Although previous scientific thinkers had laid down some of the foundations for Darwin’s work, and others later expanded upon and more fully developed the scientific bases for his conclusions, Darwin set forth and formulated the controversial but coherent ideas about organic evolution that have impacted the world at large. His groundbreaking On the Origin of Species was originally published in 1859. Later, in 1871, Darwin argued in The Descent of Man and Selection in Relation to Sex that humans had evolved just as other organisms had, creating a storm of controversy that continues today. See also: Adaptation (biology); Animal evolution; Organic evolution; Plant evolution; Speciation
Darwin distinguished himself as a naturalist and theorist. However, his importance is preeminent in a wide variety of sciences and extends into other areas such as philosophy, theology, and sociology. See also: Anthropology; Genetics; Paleontology; Zoology
Darwin’s core insights regarding natural selection have proven inspirational and profound. In the process of natural selection, organisms often tend to produce more progeny than the environment will allow to subsist. In the struggle for existence that ensues, progeny with favorable variations in their traits will survive and leave more offspring than others do; the favorable variations accumulate through subsequent generations, and descendants with a set of adaptations to their environment eventually diverge from their less adapted ancestors. Working from this basic foundation of evolution through natural selection, modern scientists and investigators have been able to formulate more specific principles and ideas relating to many topics. See also: Biodiversity; Macroevolution; Phylogeny; Species concept
For example, Darwin’s observations of the adaptive radiations of finches on the Galápagos helped to provide some of the insights necessary for his formulation of the principles of evolution and natural selection. Oceanic islands proved to be exceptional locations for studying the processes of evolution and natural selection because they can act as evolutionary laboratories: islands are isolated locales with often unique island biogeography. They are completely surrounded by large expanses of water, which isolates their land-dwelling life forms from populations on other continents. Islands are also geologically younger than continents are, so any evolutionary changes in an oceanic island’s biota must have arisen under conditions that are very restricted spatially and temporally, which offers advantages for the study of speciation and phylogenetic branching. See also: Island biogeography; Oceanic islands: evolutionary laboratories