THE FUNDAMENTALS OF LIFE
SCIENCEPHOTO^ LIBRARY“Da Vinci took risks asking heretical questions. He may
have developed his mirror-writing technique to protect
the ideas in his notebooks from prying eyes”
THE KEY EXPERIMENT
5 conclusions, he was not that
interested in questions of species.
What da Vinci saw in fossils was
evidence to support his neo-Platonist
beliefs: that the human body was a
microcosm of the Earth and was
subject to similar laws. Da Vinci was
taking significant risks in asking such
heretical questions about the nature
of the Earth. Indeed, he may have
developed his mirror-writing
technique to protect the ideas in his
notebooks from the prying eyes of
inquisitors and priests.
Through the 18th century, the
publication of new works on insects
and the development of microscopes
inspired a generation of young men to
study the reproductive behaviour of
microscopic organisms. Occasionally
they discovered disturbing and
inexplicable things.
In the summer of 1740, Abraham
Trembley, a young Swiss tutor
educating the sons of the Count of
Bentinck in The Hague, sent his young
charges to collect pond water for the
microscope. He proposed that theyNatural selection was the most important milestone in the long history of evolution,
because it provided a mechanism to explain how the theory workedThe crucial breakthrough in the history
of evolution is a ‘convergent’ one. In 1858,
while suffering from malaria on the Malay
Archipelago, Alfred Russel Wallace came
up with the idea of natural selection: the
process by which some species survive
and others die out, encapsulated in the
phrase ‘survival of the fittest’.
Charles Darwin had already found
evidence for natural selection during
his travels around South America aboard
the Beagle during the 1830s. Darwin
understood that evolution worked
through a struggle for existence in which
favourable variations would tend to
be preserved and unfavourable ones
destroyed. The result of this would be
the formation of new species. From this
point on, Darwin committed himself
to gathering more evidence. This is one
of the reasons why it took him so long
to publish his landmark book On the
Origin of the Species.
When Wallace sent him his still-
unpublished essay on natural selection
in 1858, Darwin finished his book in a
matter of weeks and rushed it to press.
The Linnaean Society declared Darwin the
first to have discovered natural selection
because he was able to submit evidence
that he had defined the idea – though not
published it – many years before Wallace.An illustration from The Malay Archipelago by Alfred Russel Wallace (1874). The work described
Wallace’s thoughts that led to the idea of natural selection and a theory of evolutiondo some experiments on the creatures
(he called them polyps; we know them
as Hyd ra) t hey found in t he estate’s
ornamental ponds. Trembley was
astonished to discover that, when
he cut the organisms in half, they
regenerated themselves. Such a
phenomenon appeared to violate the
prevailing understanding of natural
laws: plants re-grow after cutting;
animals don’t. But the polyp did.
The polyp quickly became the
talk of Eu ropea n salons a nd were used
by materialists and atheists alike to