THE VOYAGE OF THE BEAGLE.
Darwin learned from Henslow about the possibility of joining a round-the-world
expedition on the ship H.M.S. Beagle with Robert FitzRoy as the captain. The
ship was a rather small affair, equipped with three masts. The personnel quarters
were below deck, and below that was the cargo space. Darwin’s first meeting
with FitzRoy was rather negative because the captain pursued a pseudo science
called phrenology, which allowed him to study the cranial features of people
and from that to deduce their characters. One look at Darwin was enough for
the captain to say that based on the shape of his nose he was not suited for
the hardships of a sea voyage. Nonetheless, after a period of deliberation he
did accept Darwin as the unpaid naturalist of the expedition.
On Dec. 27, 1831, they sailed from Plymouth, England. The voyage, took five
years to complete. Darwin kept careful notes about his observations of animals
and plants he encountered through his many excursions. He also obtained a large
collection of geological and biological specimens. The irony of the situation
was that the captain’s first impression about Darwin was correct, because
Darwin became seasick the moment the ship was in motion, and remained seasick
all through the voyage. Nothing would help but laying in a hammock and subsisting
on raisins and rum. He was all right on dry land and spent as much time ashore
as possible. He organized expeditions into the rain forest of Brazil, visited
numerous places off the shorelines of Argentina and Chile. He studied the natives
of Tierra del Fuego, and was tremendously impressed by the rather peculiar features
and habits of the animals and plants on the islands of the Galapagos.
Darwin had brought along for the journey several of his own books, among them
the first volume of Charles Lyell's Principles of Geology. Lyell proposed the
idea that the face of the Earth had changed gradually over long periods of time
through the effects of volcanic eruptions, earthquakes, erosion, and sedimentation.
He also stated that such changes had been going on in the past, and they can
be observed today. This idea of the constantly ongoing and gradual geological
transformation of the face of the Earth was new and was rather different from
the understanding of the time. During the journey, Darwin became convinced by
his own observations that Lyell was right. The following is the chronology of
the voyage, listing only the most important findings and impressions, which
had a bearing on the discovery of evolution by means of natural selection, published
in The Origin much later in 1859.
27 December, 1831 Departure from Devonport, England.
28 February, 1832 Bahia, Brazil: tropical rain forest.
6 September, 1832 Bahia Blanca: fossils of ground sloth.
16 December, 1832 Tierra del Fuego: native indians.
17 April, 1835 Chilean coast: earthquake.
16 September, 1835 Galapagos Islands: finches and turtles.
2 October, 1836 Return to Falmouth, England.
What impressed Darwin the most in the tropical rain forest of Brazil were the
great variety and number of species of animals and plants, and their adaptive
features, well suited for the constant struggle for survival.
As to the fossil bones of several species of rather large ground sloth he found
scattered on the seashore he remarked that these creatures had been extinct
for some time. He called them the remains of “antediluvian” animals
referring to the destroying flood mentioned in the book of Genesis.
Darwin was most impressed by the ability of the native indians to survive in the harsh climate of Tierra del Fuego. He realized that human beings and not only the plants and animals of the area have been endowed with special adaptations for survival.
As they arrived to the northern part of the Chilean coast, Darwin witnessed the effects of a tremendous earthquake. This brought home for him the truth that Lyell was trying to convey to him: the earth’s crust is constantly being formed by geological events.
And finally, on the islands of the Galapagos, some 500 miles west of Ecuador,
Darwin was greatly puzzled by the finches and the turtles found only there.
The turtles were rather species specific as to the individual islands. The various
species of finches looked very similar to each other and also similar to some
of the finches of the main land, and yet, they were well established diverse
species with different habits and habitats. At this time, Darwin did not know
it yet that he was actually observing was the results of evolution by means
of natural selection in the peculiar settings of a group of relatively new volcanic
islands.
Sources:
Encyclopedia Britannica on Line.
Alan Moorhead: Darwin and the Beagle. Harper and Row. 1969.