Close
Damn Dirty Apes – CPS talk 05/11/13
By Penny Carmichael, on 20 November 2013
– Article by Jack Humphrey
And now for something completely different. The CPS welcomed the geneticist and award winning science writer Professor Steve Jones whose talk was entitled “Is Man Just Another Animal?”. This question has been present since the creation of modern evolutionary theory by Charles Darwin and Alfred Russel Wallace. Humanity sharing a common ancestor with all living animals is a cornerstone of evolutionary thought. So does evolution somehow reduce the stature of humans by bringing us down to the level of the apes?
In its simplest form evolution is descent with modifications due to the imperfect transmission of genetic information through successive generations. Natural selection drives the accumulation of these modifications in response to environmental pressures. Professor Jones argues that if anything we humans are the inferior animal when compared with our closest relatives the great apes – gorillas, chimpanzees and orangutans. They are stronger and hairier than us with better digestive systems. Our lack of thick body hair is probably thanks to a single genetic mutation. This can be seen in hairless cats and dogs. We also have much weaker muscles due to a unique deletion in the gene coding for the muscle fibre protein myosin. Our jaw muscles are also much smaller and weaker and this co-occurs with our remarkably poor digestive abilities. Humans have much shorter intestines compared to the other apes and this requires us to pre-digest our food before eating it – in a microwave or pan. The invention of cooking is believed to have had a major effect on human history as we became able to consume more calories. There’s even more bad news: humans also produce less sperm compared to other apes and our penises lack spines, due to a missing receptor for androgen hormones.
But what we’ve lost in jaws, guts and genitals we make up for in our huge brains. We lead in both number of neurons and the level of connectivity between each neuron. The size difference is most apparent in the neocortex, the outermost part of the brain that deals with complex behaviour. One of the more apparent abilities we have that no other does is the ability for complex language. The genetics behind this are now coming to light. A family were discovered in west London with a severe speech and language disorder that appeared to be inherited. A mutation was subsequently found in the foxp2 gene. This gene has been dubbed “the speech gene” due to its link to language. Mice that lack this gene vocalise less. Songbirds and parrots have a more active form compared to non-vocal birds. Humans have two unique mutations in it that make us unique from other animals.
The same evolutionary ideas can be applied to uniquely human concepts like language. The realisation that the Indian language Sanskrit shared similar words with Latin and Greek led to the the theory that the languages of Europe and Central and Southern Asia all originate from a common ancestral language. This created the field of comparative linguistics and it is now possible to construct a family tree based on shared characteristics of individual words. This tree points to the original or proto Indo-European language emerging in Anatolia, part of modern day Turkey. This is believed to be where farming was first developed leading to a larger and longer lived population.
Professor Jones stressed that evolutionary biology is a comparative science – it works by comparing shared traits between species. But it falls down on understanding things unique to humans such as complex language or cooking as it is very easy to extrapolate conclusions but very difficult to prove them.
Subscribe to this blog!