The Voyage of the Beagle: 1831 to 1836
Before the voyage on the Beagle,
Charles Darwin was living an unfocussed life made possible by his
family’s wealth. However, his life was dramatically changed during the
five-year voyage, where he saw vast numbers of animals and geological
formations containing fossils in strata on the sides of mountains that
varied in modest ways. These experiences encouraged him to think in new
ways about how species came into existence.
He was offered the opportunity to sail on the Beagle by his friend
Professor Henslow, who sent him a letter from a Cambridge scholar
nominating Charles to the position of unpaid naturalist on board the ship.
At first Charles’ father discouraged the idea, but his
uncle-in-law Josiah Wedgwood supplied arguments that persuaded Charles’
father to support his participation in the voyage.
Charles Darwin, whose personal charm drew support from many people during his life, made a good impression on Robert FitzRoy, the Beagle’s captain. FitzRoy, who had a more conservative character than
Darwin, chose him in the hope that Darwin’s observations would uphold
the biblical view of creation by God, as described in Genesis. Darwin,
who had studied to be a clergyman, did not expect any problem with this
mandate from FitzRoy.
The Beagle
was one of six brig sloop ships that the British navy had built to do
surveying, using the recently developed accurate clocks that made it
possible to measure longitude. Only 90 feet long, this sailing ship
carried 74 people in very close quarters, and 22 clocks for accuracy in
surveying. The voyage was planned to be two years in length, but
ultimately lasted five years. Darwin shared quarters with Captain
FitzRoy and had a small room near the stern for his samples and
workspace.
On December 10, 1831, the Beagle
sailed out of Devonport, a district of Plymouth, England, but was
driven back by strong gale winds. A second attempt on December 21 had
the same result. Finally on December 27, the ship successfully left
Plymouth, heading for South American. A planned stop at
Teneriffe never occurred, because the island was quarantined in hope of
preventing the spread of cholera from arriving ships.
At
the Cape Verde islands Darwin saw a geological band of seashell
sediments far above the current sea level, yet covered by a layer of
lava from volcanoes that had been inactive for all of known history.
Darwin may have interpreted this as evidence of the Earth’s history
being far longer than estimates based on the Bible.
During an extended time on shore near Rio de Janeiro, Darwin was
horrified by the human brutality exhibited in the treatment of Negro
slaves. The Wedgwood family had been early opponents of slavery, and
Darwin’s reports supported their view. Captain FitzRoy and Darwin
disagreed violently over the issue of slavery, but eventually managed
to work together again.
At
Punta Alta, near Bahia Blanca, Darwin unearthed fossils of huge animals
that no longer lived. He and Captain FitzRoy struggled to figure out
how these creatures failed to be saved by Noah’s Ark during the
biblical flood. Darwin also noticed that they resembled in some ways
the current animals of this area, but clearly were also different from
the current animals.
At Tierra del
Fuego, the southernmost tip of South America, Captain FitzRoy delivered
three natives of the region back to their homelands, from which they
had been taken to England a year before. They were also supplied with
implements of civilization and a missionary, so that they could spread
Christianity to their people. The two cultures were radically
different, and neither really understood the other. After a year the Beagle returned, to find that the Fuegians had decided to live their lives without the benefits of English civilization.
For roughly a year the Beagle
sailed up and down the coast and nearby regions of the southern end of
South America. Darwin spent much time ashore, finding,
describing, collecting, and packaging the dried bodies of various
unidentified living things.
Finally, in the middle of 1834, the Beagle
sailed through the straights of Terra del Fuego, taking nearly a month
to pass through the icy passages near Cape Horn during winter in the
Southern Hemisphere. From Valparaiso Darwin took a six week trip up
into the Andes Mountains, where he observed a bed of seashells at
12,000 feet, above fossilized pine trees with marine rocks. He made the
reasonable deduction that the trees had been carried under the ocean
and later been raised high on the mountains. This incredible motion, if
it occurred at the rate of modern geological changes, suggested that
the Earth was older than he, or Captain FitzRoy, had originally
believed.
At Concepcion (and its port
city Talcahuano) there had been a very severe earthquake, which Darwin
and FitzRoy describe in detail. Darwin noted that the land had been
raised several feet, and suggested that repetitions of that raising
could account for the seashells in the Andes. FitzRoy and many
Christians believed that the earthquake was due to God; some natives
believed it was the work of an Indian woman who was a witch!
Again Darwin was able to make many exploratory journeys on land, meeting the Beagle
at prearranged locations. During this part of his life Darwin showed
great physical vigor, in contrast to later years when he often
complained of illness. Perhaps his later symptoms were from Chagas’ disease,
which he might have contracted from a Benchuga bug that he caught alive
and allowed repeated bites on his fingers. Sometimes curiosity can be
dangerous.
The Galapagos
Charles
Darwin’s discoveries of unique flora and fauna in the Galapagos Islands
are widely mentioned as being the source of his inspiration about
evolution: descent with modification. It would be more accurate to say
that what he found in the Galapagos only confirmed the explanation he
had been formulating for the previous three years of the Beagle’s
voyage, during which he had the opportunity to view a multitude of
amazing animals, plants, and land formations. It is also commonly
believed that he spent a long time in the Galapagos collecting samples.
In fact, his time sailing in and around the islands was a mere five weeks, from
September 17 to Oct. 20, 1835. Whenever the Beagle reached an
interesting point that was navigable, the ship dropped off a boatload
of men to explore. Darwin spent only 17 days onshore gathering
specimens of birds, animals, insects, plants, rocks, and fish.
To
provide a bit of background to Darwin’s arrival, the Galapagos are a
group of twelve small volcanic islands located on the equator 500 miles
off the coast of Equador. They were discovered by a Panamanian Bishop
in 1535. In Spanish, the word for giant tortoise is Galapago. They
are also referred to as “Las Encantadas” meaning the enchanted islands,
in acknowledgement of the amazing creatures that reside there. In the
1800s they were, as now, owned by Equador. In Darwin’s time, the
Galapagos were a refueling and refreshment stop for a fleet of 60-70
American whaling vessels. The endemic giant tortoises provided ships
with an easy-to-catch source of fresh meat that stayed alive onboard
ship for months while requiring very little maintenance.
Darwin spent much of his time in South America on land excursions. He would disembark at one port of call and rejoin the Beagle
at its next landing. On these treks he viewed incredible things that
could not be explained by the scientific and religious belief systems
of his time. The discoveries he made not only challenged current dogma
in biology, botany, zoology, and theology, they also held a huge impact
to the emerging discipline of geology. In his book The Voyage of the Beagle
Darwin writes of his delight and amazement at discovering such oddities
as fossils of sea shells and fish on exposed cliffs 12,000 feet up in
the Andes. He found living animals and fossil remains where the
structure of a species remained constant (e.g., armadillos with their
curved, segmented shells) but in sizes ranging from a under a foot long
to over 20 feet long depending on the habitat. Darwin wrote of seeing
living rheas and guanacos as well as their fossilized remains, noting
that they represented a variety of sizes and colors. While similar
enough to be classified as rheas and guanacos, each new group he
encountered had something unique that made them just a bit different.
He began to note the usefulness of these differences to the animals in
terms of their success at defending their territory and obtaining food
or mates.
With
these discoveries in mind, and having spent many months striving to
formulate a mechanism that might explain them, Darwin and the Beagle
landed in the Galapagos, after being at sea for over three and a half
years. In the Galapagos Darwin discovered barren, inhospitable, hot,
dry volcanic islands that were, quite to his amazement, sustaining a
multitude of creatures and plants. Although the islands are separated
by only a few miles of ocean and are within easy sight and sailing of
each other, the variety among similar species was stunningly apparent
to Darwin.
Each island had iguanas in
large numbers, yet they were different on each island. Some were black,
some were red, one island had iguanas with both red and green markings,
a few were brownish-orange; some ate cactus, others consumed algae off
submerged tidal rocks. The islands’ namesake tortoises varied in shape
from island to island. At one landing Darwin noted their long necks and
sharply-arched shells, and on a nearby island the tortoises had short
necks and nearly flat shells. On James Island (also called San
Salvador) Darwin counted 26 species of land birds, all unique,
and all incredibly tame.
Darwin
is perhaps most famous for collecting the Galapagos finches from
several of the islands he visited. While all similar in body size and
color, their beaks varied in size and shape. To Darwin, it was clear:
different foods were available on different islands and through
successive generations the birds with the most-useful shaped beak
flourished and those with less-useful beak shapes died out. There had
to have been a great principle or mechanism involved. While the finches
were noted in his journals without much more emphasis than other plant
and animal species he collected, many years later they would become one
of the biggest arguments in his theory of natural selection.
The
Galapagos Islands are spectacular in their topography and contain a
stunning variety of rare, unique, approachable, and vanishing species.
They are a sparkling jewel to be visited, admired, revered, and
protected.
Chronology of the Beagle in the Galpagos Islands, 1835:
Sept. 15: Arrive at the Galapagos Islands
Sept.17: Land on Chatham Island
Sept. 23-26: Disembark on Charles IslandSept.
Sept. 29-Oct. 3: Albemarle Island
Oct. 8-14: James Island
Oct. 20: Survey of Galapagos Archipelago completed, the Beagle heads towards Tahiti.
From the Galapagos Islands, the Beagle
sailed 3200 miles to Tahiti, where Darwin was very impressed with the
manners and skills of the natives. The next major stop was at New
Zealand, where Darwin judged the natives as far inferior to the
Tahitians. His observation of the missionaries in these areas lead to
one of his earliest signed publications: a 1936 pamphlet arguing for
more government support for Christian missionaries in the Pacific!
In Australia Darwin was again struck with sympathy for people in
servitude -- in this case the prisoners who had been sent to Australia.
Darwin also remarked upon the state of the native peoples of the
Pacific, who were dying out as the Europeans spread.
In the Cocos islands, Darwin made observations on how deep the coral
polyps, a kind of small creature, could live. Using that data, he
worked out how these creatures could build up reefs and atolls out in
the midst of oceans: as they died, new layers of polyps could grow on
top and build up new mass as the ocean floor subsided.
Toward the end of the voyage, Darwin, FitzRoy, and most of the crew
were very eager to return to England. But the British Navy’s need for
surveying accuracy required that the Beagle go first to South
America again. This requirement probably came from a need to
re-determine the position using the clocks at a previously surveyed
location to find the amount of longitudinal error on the whole trip and
then distribute that error through calculations, as if the error
occurred at a steady rate, which would probably be true for clocks.
Retracing their route north, the Beagle arrived back in England on October 2, 1836.
Sources and Further Reading:
Darwin and the Beagle, Alan Moorehead, 1969
The Beak of the Finch, Jonathan Weiner, 1994
Charles Darwin: Voyaging, Janet Browne, 1995
The Voyage of the Beagle , Charles Darwin, published 1839 and 1845
