Evolution__3rd_Edition

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Darwin developed evolutionary
views ...
CHAPTER 1 / The Rise of Evolutionary Biology 9
became generally thought of as Britain’s leading anatomist. By the first half of the nineteenth
century, most biologists and geologists had come to accept Cuvier’s view that
each species had a separate origin, and then remained constant in form until it went
extinct.
1.3.2 Charles Darwin
Figure 1.3
Charles Robert Darwin (1809–82), in 1840.
Meanwhile, Charles Darwin (Figure 1.3) was forming his own ideas. Darwin, after
graduating from Cambridge, had traveled the world as a naturalist on board the Beagle
(1832–37). He then lived briefly in London before settling permanently in the country.
His father was a successful doctor, and his father-in-law controlled the Wedgwood
china business; Charles Darwin was a gentleman of independent means. The crucial
period of his life, for our purposes, was the year or so after the Beagle voyage (1837–38).
As he worked over his collection of birds from the Galápagos Islands, he realized that he
should have recorded which island each specimen came from, because they varied from
island to island. He had initially supposed that the Galápagos finches were all one
species, but it now became clear that each island had its own distinct species. How easy
to imagine that they had evolved from a common ancestral finch! He was similarly
struck by the way the ostrich-like birds called rheas differed between one region and
another in South America. These observations of geographic variation probably first
led Darwin to accept that species can change.
The next important step was to invent a theory to explain why species change. The
notebooks Darwin kept at the time still survive. They reveal how he struggled with
several ideas, including Lamarckism, but rejected them all because they failed to explain