A revolutionary thinker
Darwin’s Big Idea
The Natural History Museum exhibition, until April 19
Admission: £8-80
Reviewed by
Andy Hammond
THIS EXHIBITION is part of this year’s celebrations
marking Charles Darwin’s 200th birthday. His theory of evolution stands
alongside Karl Marx’s work on capitalism and Albert Einstein’s theory of
relativity in the impact it has had on society. An exhibition poster
correctly calls him a ‘revolutionary thinker’. Marx agreed, arguing that
Darwin’s ideas on evolution gave a firm materialist footing to biology
and therefore gave support to his and Friedrich Engels’ ideas.
The displays are of the high standard you always
find at the Natural History Museum. Scattered throughout are some of
Darwin’s letters and notebooks, and facsimiles of others. There are also
some specimens from his collection that, though well over 100 years old,
are in remarkably good condition. Even so, the design of the exhibition
sometimes makes it confusing as to what order to look at the displays.
This could have been avoided by a leaflet or booklet explaining the
layout and the main points being made – something strangely missing.
The exhibition has three parts. The first looks at
the different types of evidence for evolution that Darwin gradually
thought through from his experiences on the HMS Beagle expedition
to South America. The second looks at how his famous book, On the
Origin of Species, came together. The third part deals with developments
in evolutionary theory since Darwin.
To understand just how radical in the mid-1800s were
the ideas you need to appreciate how entrenched in the establishment was
the idea of all species being created by God, and their fixity. This was
heavily political. The Anglican Church was very much a political power
within the reactionary establishment in England: God put it in charge
and the poor should not try to remove it. Special creation, as part of
the Anglican faith, was heavily linked to the established capitalist
order. So a large number of biologists and geologists, being from
privileged backgrounds, vehemently opposed any theory of evolution, not
just Darwin’s version. This is touched upon towards the end of the
exhibition but should have been emphasised earlier to do justice to
Darwin as ‘revolutionary thinker’.
Example after example is used to lead to the same
small set of questions. Although not following strictly how Darwin’s
thoughts on evolution developed, it is in the spirit of his approach –
producing example after example to back up his arguments. Firstly, new
species appear where extinct but similar species used to live. If God
had created a species as a perfect fit to an environment then why was it
replaced by another species? Could it be that older species evolved into
newer ones? An impressive example used here was a specimen of a modern
dwarf armadillo next to its possible evolutionary ancestor, the much
larger glyptodont.
Secondly, why did the same species not appear in
similar environments? Put another way, why would God wastefully create
different species for slightly different environments when one species
would do? Darwin found two different species of rhea, flightless
ground-dwelling birds, living in neighbouring areas in South America.
Could they have had a common ancestor inhabiting the whole area but they
had evolved in different ways, dividing the area up between them?
Thirdly, many species only found on the Galapagos
Islands were similar to species in South America. Among the most famous
and strange of these creatures are the various species of iguana. Again,
why would God create separate species when the same would fit equally
well in both places? Surely a better explanation would be that the
ancestors of the Galapagos species came from South America and over time
evolved in a different direction to their South American cousins? Darwin
came to realise that these differences were due to species adapting to
the different environments they now inhabited in the Galapagos Islands,
even if the new was not that different to the old environment.
Fourthly, Darwin became interested in geology and,
by reading the new theory of Charles Lyell, started to see that the
earth was constantly changing. So if species were constantly adapting to
their environments, and those environments were constantly changing,
then species would have to be constantly changing to keep up with their
environment.
The point is made that Darwin moved from detailed
observations of various species to ‘pondering connections between them’.
This dialectical point was even more striking at the time because most
biologists still thought that all species were unchanging and completely
separate from each other.
As a bridge between the first and second parts,
there is a short film, a potted history of the life and times of Darwin.
It mentions earlier evolutionists, and introduces various influences on
Darwin and the reception of his big idea. At the end it comments that,
although religious objections are still made to evolution, it is central
to biology, evidence has confirmed it over and over again, and there are
historical evolutionary connections between all creatures, including us.
Essentially, what separated Darwin’s theory from
earlier evolutionary theories was his idea of natural selection. Some
varieties within a species are better adapted to their environment.
Because of this they survive longer and raise more offspring than the
others. Over many generations the more successful variety becomes so
much greater in numbers that it becomes the standard type for the
species: the species has changed. Because the environment is always
changing, this process of selecting the better adapted is always going
on. So species are always changing. Over long periods of time enough
changes happen to a species that its members no longer resemble their
distant ancestors. This is a remarkably dialectical view that has
remained central to biology.
There is no one reason why Darwin delayed publishing
his big idea until he absolutely had to. Apart from feeling the need to
muster more evidence, he spent a lot of his time and energy establishing
his career as a scientist when he got back to England after the Beagle
expedition. For some time he concentrated on establishing himself in
geology, gradually moving into publishing in biology. He also feared the
ridicule of respected scientists who opposed any idea of evolution. And
he worried that his ideas would be seen as an attack on religion and the
establishment, that they would encourage atheism and revolutionary
ideas.
The final part of the exhibition also begins with
short films: on natural selection and the evidence for evolution. The
second film emphasises that evolution is scientific because it is
testable, but creationism, relying on an untestable assumption, is not.
Creationism and intelligent design appeal to "a cause [God] that lies
outside our powers of observation" and, therefore, cannot be science.
Among the developments in evolutionary theory since
Darwin, DNA is highlighted as a tool for investigating how different
species are related. The role of mass extinctions is also mentioned.
Darwin insisted that all evolution must happen at a very slow rate with
no major upheavals or disruptions. This reflected his politics and his
fear of revolution. Ultra-slow evolution was akin to slow, mild
political reform of capitalism. Evolutionists now accept that major
disruptions have occurred in the past, wiping out huge numbers of
species. The most famous of these wiped out the dinosaurs. It also
destroyed many other creatures (65% of all life on earth). This view is
much more dialectical, these events being a massive qualitative change
in the history of life.
Other post Darwin developments displayed include the
famous example of the evolution of the horse and the increasing evidence
for how humans evolved from other animals. Finally, I should mention the
display on the evolution of viruses and bacteria. This is probably the
only field of biology in which we can see evolution as it happens. Since
evolution depends on changes through the generations, it will happen
faster with some creatures than with others. Humans (and elephants) live
for 70 years. Individual bacteria may live only for 20 minutes. In 70
years, bacteria will go through many more generations than humans and
any changes being selected for can be observed by us. HIV is a good
example – a virus only known since the 1980s but studies have already
shown how new strains have evolved that are resistant to current drugs.
There are some shortcomings to this exhibition. For
example, the part on Darwin’s life before the Beagle would have made
more sense at the beginning of the exhibition (his amateur interest in
natural history, awareness of earlier evolutionary theories, etc).
Nonetheless, it is well worth the visit and with so much to see and take
in you should give yourself a good two hours to get round it!
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