In The Origin of Species (1859) Darwin challenged many of the most deeply-held beliefs of the Western world. Arguing for a material, not divine, origin of species, he showed that new species are achieved by "natural selection." The Origin communicates the enthusiasm of original thinking in an open, descriptive style, and Darwin's emphasis on the value of diversity speaks more strongly now than ever. As well as a stimulating introduction and detailed notes, this edition offers a register of the many (...) writers referred to by Darwin in the text. (shrink)

Classifications of animals and plants have long been represented by hierarchical lists of taxa, but occasional authors have drawn diagrammatic versions of their classifications in an attempt to better depict the "natural relationships" of their organisms. Ornithologists in 19th-century Britain produced and pioneered many types of classificatory diagrams, and these fall into three groups: (a) the quinarian systems of Vigors and Swainson (1820s and 1830s); (b) the "maps" of Strickland and Wallace (1840s and 1850s); and (c) the evolutionary diagrams of (...) the post-Darwin authors (1860 on). The quinarians distinguished between affinity and analogy and used both in their classifications, whereas Strickland rejected the quinarians' belief in numerical regularity and their use of analogy. Wallace's "maps" are easily given an evolutionary interpretation, and his approach was taken up and modified by later evolutionary anatomists. Sharpe returned to Strickland's methods and merely appended a superficial evolutionary interpretation. Contrary to common belief systematics has a rich conceptual history, and many of the conceptual developments in 19th-century systematics were made by ornithologists. (shrink)

By the 1840s and 1850s biogeographical theory had polarized into two opposing views — both of which had their origins in the sixteenth or seventeenth centuries. At issue in this polarization was the question of God's involvement with His creation. At one end of the spectrum were Sclater, Agassiz, Kirby, and others who saw a neatly designed world in which geographical distributions were planned and executed by the hand of God at creation. For most of these naturalists, organisms were created (...) en masse within the regions they now occupy. Disjunct distributions were proof to them that God had indeed created species in situ as many individuals. These naturalists hoped to reveal God's biogeographical plan by discovering His regions of creation. They had hoped to demonstrate a neatly devised set of regions of creation which might be applicable to all creatures, but in attempting to do so, they arrived at conflicting sets of delineations — thus helping to undermine their conceptions of nature in which design (both idealist and utilitarian) played an important part.93At the other end of the biogeographical spectrum were the theoretical ideas of Prichard and Lyell, who viewed a more remote God — one who allowed His creation to be shaped and modified by secondary laws. Lyell in particular wished to leave considerations of design aside, hoping to demonstrate that the shape of the present creation is due to natural laws. Prichard and Lyell saw God's role in the creation of species (and distributions) as being extremely limited. In fact, the regions of creation seen today are in actuality only natural artifacts produced by migrations and barriers. They saw distributions being in constant flux, as was the rest of nature.Those supporting the views of Prichard and Lyell spent a great deal of effort in attempting to remove a major obstacle in their paths — disjunct distributions. If disjunct distributions were indeed the products of separate creative acts, as Sclater and others claimed, then the arguments of Prichard and Lyell would be negated. For if the creation of a species was shown to be the product of multiple creations, then what was the need of migrations and dispersal mechanisms? Also at stake, of course, was the concept of species based upon generation. Darwin was well aware that if the supernatural implications of disjunct distributions could not be refuted, then his evolutionary system — founded upon a species concept based on descent — would be in peril.94A further barrier to the acceptance of the Prichard/Lyell view was the fact that those sympathetic to a nonsupernatural explanation of disjunct distributions could not agree upon a natural explanation for those anomalies, and an internal debate between naturalists within this group raged for decades.95By 1859 a biogeographical stalemate had occurred. Sclater and others, supporting their static view of nature, continued to look for regions of creation, pointing to disjunct distributions in support of their arguments, while those favorable to the views of Prichard and Lyell continued to search for natural explanations for such biogeographical anomalies.The key needed to resolve the biogeographical debate was a credible theory for species origins. By 1858 there were essentially three options for British naturalists: supernatural creation, Lamarckian transmutation, or natural creation. A few British naturalists grasped at these straws, but most workers preferred the option of remaining silent until a more viable explanation for the origin and distribution of species could be advanced.96 And not until the publication of Darwin's theory did that explanation become available. (shrink)