Download Background At Cambridge

Welcome to the Geological Society of London, one of the organisations participating
in the ‘Charles Darwin: A Genius in the Heart of London’ project.
Darwin is famous throughout the world for his theory of evolution through natural
selection, and so is principally remembered as biologist. One of his earliest interests,
however, was geology; a science which drove much of his thinking throughout his
career.
Background
As Darwin grew up, the predominant theory in geology was catastrophism – the
idea that the Earth changes by sudden, short-lived, violent events like floods and
earthquakes. This was closely related to the church’s view of creation – animals and
plants were created, and only disappeared when they were wiped out in a
catastrophe, and replaced with new species.
Darwin’s family, by contrast, was strongly in favour of an alternative paradigm
called uniformitarianism. Uniformitarians held that the processes that shaped the
Earth are still happening now, and by observing the Earth now, we can infer what
happened to it in the past. Although the idea had been around for centuries, in
Darwin’s time it was made popular by Charles Lyell, whose book, ‘Principles of
Geology‟ popularised the famous term ‘the present is the key to the past‟.
At Cambridge
Darwin’s interest in geology began even before his journey on
The Beagle. At Cambridge, he met the geologist Adam
Sedgwick (1785 – 1873). In August 1831 he accompanied
Sedgwick on a geological mapping tour of Wales.
Statue of Darwin as a student at his college, Christ‟s.
The Voyage of the Beagle
Between 1831 and 1836, Darwin travelled as a naturalist on HMS Beagle; a journey
that was to change his life. As a welcoming gift, the ship’s Captain, Robert FitzRoy,
presented him with a copy of Charles Lyell’s recently published Principles of Geology.
Lyell’s ideas were a huge influence on Darwin. From the ship, Darwin wrote home
to his sisters that he “literally could not sleep for thinking over my [geology]”
During the five year voyage, Darwin wrote 1,383 pages of notes about geology –
compared to a mere 368 pages of notes on plants and animals.
Chilean earthquake
On February 20 1835, Darwin was in the town of Valdivia, Chile. At 11.30 in the
morning, a massive earthquake struck:
“I happened to be on shore, and was lying down in the wood to rest myself. It came on
suddenly, and lasted two minutes, but the time appeared much longer. The rocking of the
ground was very sensible”.
They spent the next few days surveying the damage. On 4 March, Darwin was
dropped off at the island of Quiriquina, where he found that parts of the coastline
had been raised up as a result of the earthquake.
He also noticed raised shell beds on the cliffs above – evidence that the Andes
mountains were slowly rising above the ocean. These discoveries supported Lyell’s
theory that land masses rise in tiny increments over geological time.
Coral reefs
Darwin’s observations of the aftermath of the Chilean earthquake allowed him to
hypothesise, before having seen them, how the coral reefs of the Pacific were
formed.
“No other work of mine was begun in so deductive a spirit as this; for the whole theory was
thought out on the west coast of S. America before I had seen a true coral reef”.
Because he had seen evidence for
the elevation of land, Darwin
hypothesised that land must also
subside. His theory was that if
coral reefs develop on the margins
of subsiding land masses, they
will grow upwards as the land
subsides so that the organisms
have enough sunlight. Eventually,
as the land sinks beneath the
surface, only the coral is visible.
Coral reefs were a subject of some
controversy at the time, and one of the Beagle‟s objectives was to find out more about
how they formed. In Principles of Geology, Lyell suggests that atolls (circular reefs)
grew up from the craters of sunken volcanoes.
When Darwin shared his alternative theory with him, Lyell is said to have been so
excited that he danced around the room, shouting and laughing.
Darwin eventually published his theories on coral reefs in The structure and
distribution of coral reefs (1842) – a copy of which is on display in the cabinet. He was
eventually proved right with deep borings were carried out on Bikini Atoll in the
1950s.
Fossil samples
Darwin collected many things on his travels, including numerous fossil samples.
Fossils were crucial to his ideas about evolution. In Punta Alta, a city in Argentina,
he discovered a fossil that was unlike anything living he had seen before. This led
him to consider extinction, and the impact of environmental change.
Whilst walking along the shoreline during his stay in the Falkland Islands, he noted
how different the fossils here were to those he had found on the coast of South
America. He carried out comparative studies of the samples he had collected from
various locations. This was the beginning of his thinking about different species
adapting to different environments.
Darwin sent many of the samples he collected back to England, where they were
beginning to make his name famous in scientific circles. Many were described and
illustrated by the naturalist and illustrator, G. B. Sowerby. Some of Sowerby’s
drawings are displayed in the cabinet, along with a selection of fossils that Darwin
would have come across on his journey.
„Most of the arguments which have convinced me that all the existing species of the same
group are descended from a single progenitor, apply with equal force to the earliest known
species. For instance, it cannot be doubted that all the Cambrian and Silurian trilobites are
descended from one crustacean, which must have lived long before the Cambrian age, and
which probably differed greatly from any known animal.‟
-
C. Darwin, ‘On the Origin of Species’
Evolution
It is for his theory of evolution by natural
selection that Darwin is now chiefly
remembered. Without his insight into geology,
as well as many other branches of science, his
theory might not have been developed. If it had,
it would certainly have been less convincing - it
was the breadth of Darwin’s research and his
ability to draw on such variety of evidence that
made his theory so compelling.
From the diversity of fossils he saw, he was able
to consider how species evolve differently in
different environments. The earthquake he
witnessed made him think about whether the
Earth is as solid as it appears, and how it might
be constantly changing under our feet. Coral
reefs allowed him to think about how
movements of the Earth affect the lives of creatures that live on it.
Most importantly, the study of geology taught Darwin that, although the Earth
seems static, it is constantly changing so slowly that we hardly notice it. In the same
way, living creatures are constantly changing in tiny ways which, over geological
time scales, give rise to entirely new species.
About the project
‘Charles Darwin: A Genius in the Heart of London’ is a Heritage Lottery funded
project that brings together the various organisations in Westminster with which
Darwin was associated.
Led by the Linnean Society of London and the Westminster Archives, the project
brings together the Geological Society, the Zoological Society, the Royal Society, the
Royal Geographical Society and Westmister Abbey.
The project focuses on the many facets of Darwin’s life and scientific work which
linked him to London. In Darwin’s lifetime, London, and more specifically
Westminster, was the main hub of the scientific world.
Over the course of the project a wide range of activities have been held for all ages,
particularly for young people in Westminster schools. Activities have ranged from
animation to art, tapestry to songwriting, debate to drama; all with Darwin as the
focus.
For more information, visit the project website, www.darwininlondon.co.uk.