History of Oceanography
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Darwin and the Voyage of the Beagle
Charles Darwins scientific career began humbly.
In 1831, and in the teeth of a gale, the HMS Beagle, a British warship,
left Devonport, England, for an expedition to map the South American
coastline and to carry out chronometer surveys all over the globe.
Darwin embarked as a naturalist, although he had no formal training
and had recently left Cambridge University because he grew disinterested
in his studies. But he was a very sharp observer of the natural world, and
he lived at a time when a revolution in thinking was going on. Scientists
were feverishly re-examining age-old questions, such as how old was
the Earth? How did various features of the planet form? How old and
diverse was Earths animal life?
drawing of the HMS Beagle. Taken from Darwins book The
Voyage of the Beagle
Darwin was also fortunate that the Beagle took him
to the Galapagos Islands, where he observed various animals and birds
that had evolved in an isolated environment. His observations led
him to his famous theory of natural selection. According to Darwins
theory, variations within species occur randomly and the survival
or extinction of an organism is determined by its ability to adapt
to its environment. (Another young naturalist of the time, Alfred
Russell Wallace, had independently come to similar conclusions about evolution
and natural selection.) Darwin also made important observations about the geology of the islands
and coastlines he visited. He proposed a theory about the formation
of atolls. Atolls are coral reefs that form small islands that enclose
a lagoon. They are found mostly in the Pacific. An example is Bikini
Atoll located northwest of Hawaii. Darwin proposed that the foundation
for the atoll was a volcano that was sinking because of its weight.
As the volcano sinks, coral reefs that rim the volcano grow upwards.
As long as the rate at which corals grow kept up with how fast the
island was sinking, then small coral islands would remain in a ring
around the now sunken volcano.