For Darwin Day on February 12th we were fortunate enough to have a talk by Professor Steve Jones - Professor of genetics, science writer and broadcaster, and a Patron (formerly Distinguished Supporter) of the British Humanist Association.
International Darwin Day marks the birth of British scientist Charles Darwin. It celebrates the contribution of Charles Darwin and the wider scientific community to human understanding and development. Co-organiser of the event, David Milne, explained: “International Darwin Day seeks to encourage us all to reflect on the principles of intellectual bravery, scientific thinking and hunger for truth demonstrated by Charles Darwin”.
Summary of Steve’s presentation: Darwin’s ‘Origin of Species’ is the real beginning of biology. Evolution equals genetics plus time; it is ‘descent with modification’. Natural selection is design without a designer. In fact ‘evolution makes me feel more important not less’.
We can observe evolution before our eyes in the development of the HIV/Aids virus. It spread rapidly from the early 1980s to infect 33 million today. Infection rates in some African countries such as Botswana reached 30/40% at one point. It is now thought the virus started in the 1910s/1920s when cities were developing in Africa. However, we would have been unaware of what it was until, with the advent of cheap air travel, it spread to American and European cities– leading to research and identification of the virus. The virus would have come from chimpanzees that, in fighting with other animals, spread it to bush animals. Eating bush meat would then have infected the human population. The origin is tracked to an area of Cameroon.
Humans split from chimpanzees about 7 million years ago, but were susceptible to viruses carried by them through being of the same genus. Humans have lost many of the genes that in chimpanzees produce big teeth, big muscles and thick hair. We cannot now survive without cooking food – if we ate only raw food we would eventually starve to death.
Humans are very similar genetically all over the world, whereas the DNA differences between chimpanzee sub-groups, which all live in Central or West Africa, are much more marked. However, humans adapted mentally by evolving large brains (more than half of a new baby’s metabolism is dedicated to the brain).
Language: as well as passing on DNA, humans pass on culture and learning through language. Other animals do not do this. Even chimpanzees do not teach their young – though the young may learn through imitating the adults. Our modern languages probably originated 60,000 years ago. Evolution in our DNA is not enough to explain the development of humans and all the differences between them. Humans uniquely developed large brains, languages, and the ability to cooperate which sets us apart from other life forms. Thus man is NOT just another animal.
There followed a lively Q & A session with Steve. Some of the topics touched on were: The recent mitochondrial debate; the fact that, though animals do display altruism, humans are the only species with a sense of self; we don’t know if our species killed off the other types of humans; we don’t need to evolve as much today as we have created environments that are more suited to our species (e.g. we don’t have to fight- off sabre toothed tigers); Dawkins vs EO Wilson. The origin of life is problematic, a unique event, not the same as evolution. It either happened once or many times. In 1400 there were probably about as many people with white skins as there were people with black skins. By 1900 there were twice as many whites as blacks. In 2015 there are about the same number again. By 2065 there will be twice as many blacks as whites. All people are getting taller (e.g. the Dutch have grown three inches since WW2); we don’t yet understand why this is.