Geography Reference
In-Depth Information
British naturalist Charles Darwin (1809-1882) made several contribu-
tions to biogeography. In fact, the key evidence that convinced him of evolu-
tion came from his study of geographic distribution (Mayr 1982). He was the
first author to postulate that the facts of geographic distribution might be ex-
plained by a combination of a theory of evolution with the study of dispersal
of plant and animal taxa (Bowler 1989). Darwin's interest in biogeography
can be categorized into three loosely defined stages: the notebooks and un-
bound notes of the late 1830s, his unpublished essays on species from the
1840s, and the manuscripts and books of the 1850s, including
On the Origin
of Species
(Camerini 1993). In his first sketch of the theory of natural se-
lection, drafted in 1842, and in his
Essay
(1844), Darwin speculated on the
changes in plant species ranges that were induced by climatic and altitudin-
al changes (Browne 1983). On the basis of Humboldt's account of mountain
zonation, Darwin envisaged climatic belts moving up or down the sides of
hills as climate changed or the land subsided or was elevated by geological
activity.
In
The Origin of Species
Darwin (1859) wrote two chapters on biogeo-
graphy. Contemporary creationists explained disjunct distributions as the
result of multiple centers of creation. To counter this idea, Darwin invoked a
theory of chance dispersal from single centers of origin. He wrote, “The sim-
plicity of the view that each species was first produced within a single region
captivates the mind. He who rejects it, rejects the
vera causa
of ordinary
generation with subsequent migration, and calls in the agency of a miracle”
(Darwin 1859:352). What is the essence of the Darwinian perspective? “The
view of each species having been produced in one area alone, and having
subsequently migrated from that area as far as its powers of migration and
subsistence under past and present conditions permitted, is the most prob-
able” (Darwin 1859:353).
Another British naturalist, Alfred Russel Wallace (1823-1913), is con-
sidered by several authors to be the father of evolutionary biogeography
(Brown and Lomolino 1998; George 1964; Riddle 2005). Interestingly, his
first four articles, published between 1855 and 1863, followed extensionist
ideas, whereas in the fifth, published in 1864, he showed a radical change to
permanentism (Bueno-Hernández and Llorente Bousquets 2003). His first
important paper,
On the Law Which Has Regulated the Introduction of New
Species
(Wallace 1855), constituted his first public announcement of his
evolutionary hypothesis (Camerini 1993). His main thesis was that “every
species has come into existence coincident both in space and time with a
