|SocialismToday Socialist Party magazine|
A revolutionary thinker
Darwin’s Big Idea
The Natural History Museum exhibition, until April 19
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!