Sunday, 21 February 2016

Evolution In The Everyday

The February Stockport meeting saw Adam Benton give a presentation entitled Evolution in the Everyday: How the past 7 million years influences everything we do.  Adam studies evolutionary anthropology at Liverpool University and runs a blog  He is a long time attendee of Skeptics in the Pub but has never asked a question. This was his first public speaking engagement. For someone new to speaking in public he gave a very impressive performance.

To Adam evolution is everything. Living things change over time, animals reproduce with variation and, as some variants are better able to survive, more children are born to them and those variants become more common. Humans evolve because we’re animals too.
Working backwards in time Adam first considered the present day to 66 years ago (basline 1950). Just like all primates we have good vision (on the whole), the same basic body plan, opposable thumbs and nails instead of claws. Just like apes we have no tails but we do have some unique features: we walk upright, we’re (mostly) hairless, extensive tool users and super smart. Chimps, gorillas, orangutans and Gibbons all share a common ancestor with us.

50,000 years before the present our great (x1660) grandparents were what we now call cave dwellers. They were still primates, still apes and still fully human. They were bipedal, hairless, tool users and smart. They were able to plan and had specialised tools. They also mass produced tools implying ability to teach. They were flexible enough to use new materials and they used symbolism in the form of cave art. They were hunter-gatherers and built houses out of mammoths, presumably bones and skin. Caves were sacred places. Like us they met up with friends. It is thought that Venus figurines were a sort of secret handshake.

Nothing much was different in the life of Cro-Magnum man, except we had a lot of friends: Hobbit, Neanderthals, Denisovans, and Hominin-X.  For the most part Neandertal man was similar to humans but shorter and squatter to preserve heat. They had old-fashioned skulls with brow ridges no forehead and no chin.

Everyone has their roots in Africa, but non-Africans have 3% Neanderthal DNA. In total 30% of Neanderthal DNA lives on in us. Some of these genes have aided survival giving rise to different shades of white skin and an immunity boost. Some have been harmful leading to Lupus, biliary cirrhosis, Crohn’s disease, smoking behaviour and type 2 diabetes.

A million years ago our great (x33,330) grandparents were categorised as Homo Erectus as represented by Narikotome boy. His skeleton is very modern but his skull isn’t. Homo erectus started with a 600ml brain, (cf, chimps 400 ml and Humans 1.3 litres) but was still capable of making tools such as the multipurpose hand axe. Their brains doubled in size before extinction. Living in groups requires brain power to remember relationships. Humans are good runners particularly over distance but can over heat in midday sun. The need to keep cool led to our being naked.

Two million years ago our great (x66,000) grandparents were living more like apes. Handy Man had a body adapted for life in the trees. He was smaller, had longer arms and more-curved fingers. His brain was only slightly bigger than a chimp. But he was still doing human stuff. Making tools, even simple flakes of rock, requires much skill and dexterity. These evolved into hand axes with much the same height/width ratio as a modern mobile phone. The hand evolved very early on. Some apes make tools and some modern apes have been trained to make flakes.

Three million years ago our great (x100,000) grandparents, as typified by Lucy, were well adapted for life in the trees with long arms and fingers but stared to spend a  lot of time on the ground. Traits which evolved to help were a non-grasping toe and changed to the knees to bring the centre of gravity over the legs. 

Paranthropus, a more heavily built species, was an actual grazer eating grass and bushes.

Five million years ago we come to the start of our story. Early hominins share many similarities with modern apes. They lived in trees, had grasping toes and long arms. There were several species living at this time. They were upright but in the trees, and needed arms for swinging, which is the reason we can raise ours. Climate change broke up the rainforests forcing them on the ground.

Adam had some very interesting replica skulls, from each of the periods discussed, which he handed round for us to examine. 
He also discussed the problems of dealing with creationists who attempt to undermine evolution when they can. Many of them are racist, quoting bible accounts of Shem, Japheth and Ham to justify slavery and servitude.

Evolutionary psychology could be amazing but is too often WEIRD (Western Educated Industrialised, Rich, Democratic), and can be falsified by non-weird studies.

“You have been and are being evolved. There is grandeur in this view of life. . . “
“. . . from so simple a beginning endless forms most beautiful and most wonderful have been and are being evolved “ 
“We are risen apes not fallen angels”

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