A Darwinian View of Life

He was the grandson of Erasmus Darwin on his father's side, and of Josiah Wedgwood on his mother's side. Both families were largely Unitarian, though the Wedgwoods were adopting Anglicanism. Robert Darwin, himself quietly a freethinker, made a nod toward convention by having baby Charles baptised in the Anglican Church. Nonetheless, Charles and his siblings attended the Unitarian chapel with their mother, and in 1817, Charles joined the day school, run by its preacher. In July of that year, when Charles was eight years old, his mother died. From September 1818, he attended the nearby Anglican Shrewsbury School as a boarder. During his lifetime, Darwin journeyed on The Beagle. The Beagle survey took five years, two-thirds of which Darwin spent on land. He carefully noted a rich variety of geological features, fossils and living organisms, and methodically collected an enormous number of specimens, many of them new to science. At intervals during the voyage he sent specimens to Cambridge together with letters about his findings, and these established his reputation as a naturalist. His extensive detailed notes showed his gift for theorizing and formed the basis for his later work. The journal he originally wrote for his family, published as The Voyage of the Beagle, summarizes his findings and provides social, political and anthropological insights into the wide range of people he met, both native and colonial.

After becoming eminent among scientists for his field work and inquiries into geology, he proposed and provided scientific evidence that all species of life have evolved over time from one or a few common ancestors through natural selection. Natural selection is the process by which favorable traits that are heritable become more common in successive generations of a population of reproducing organisms, and unfavorable traits that are heritable become less common. Natural selection acts on the phenotype, or the observable characteristics of an organism, such that individuals with favorable phenotypes are more likely to survive and reproduce than those with less favorable phenotypes. Phenotype is determined by an organism's genetic make-up (genotype) and the environment in which the organism lives. Often, natural selection acts on specific traits of an individual, and the terms phenotype and genotype are used narrowly to indicate these specific traits. If these phenotypes have a genetic basis, then the genotype associated with the favorable phenotype will increase in frequency in the next generation. Over time, this process can result in adaptations that specialize organisms for particular ecological niches and may eventually result in the emergence of new species.