Proud to be curly

As we head into winter, which the climatologists say will be colder and wetter than usual, I wondered about why we have so little bodily hair to keep us warm.. We wear clothes, layers of it during winter, while my dogs have thick curly fur that trap the air and therefore keep their bodily heat to themselves for longer, much like the ozone layer traps the earth’s heat.

Hair does not fossilise easily. It is very difficult therefore to establish from the fossil record when and how we lost our bodily hair. Our closest living relative the Chimpanzee may provide some clues. About 6.2 million years ago we shared a common ancestor with the Chimp and went our separate ways since.

Vitner's delight

Carole Meredith is a grape geneticist in the world of wine science. She works at the University of California at Davis, an institution noted for its excellence in agricultural science. Along with researchers from France, in 1999 Meredith found that the celebrated Chardonnay grape has modest beginnings of roughly 1,700 years ago.

The DNA technology for tracing human ancestry and our historical patterns of divergence is now well established. As all living things share the same basic DNA, Meredith used a similar technology developed for animals and human beings to confirm that Chardonnay is the offspring of one of the Pinot family of grapes believed to have originated in Burgundy 300 AD.

Meredith also found traces of a more obscure grape in Chardonnay’s ancestral pedigree. The Romans brought a variety called Gouais Blanc from Croatia and to France during the 3rd century. It is a more obscure grape variety and likely spread prolifically on the Burgundy plains. A hybrid of Pinot and Gouais Blanc emerged during the Middle Ages.

Evolutionary artifact

Richard Dawkins writes in River out of Eden about research showing ‘how the first living photocell came into being by step-by-step modification of an earlier, more general-purpose cell.’

He speaks about skin as tissue, as is the lining of the intestine, muscle and liver. Like the rest of our physiology ‘tissues can change in various ways under the influence of random mutation. Sheets of tissue can become larger or smaller in area. They can become thicker or thinner. In the special case of transparent tissues like lens tissue, they can change the refractive index (the light-bending power) of local parts of the tissue.’ [New York, Basic Books, 1995, pp.77-83]

The beginning of the human eye likely evolved from the ever-thinning skin membrane of an underwater being. J. Craig Venter, who voyaged the world like Charles Darwin did in The Beagle about 150 years ago, was surprised to find so many underwater beings having light-sensitive membranes.

Our salty tears are a reminder of an oceanic origin now long gone. The first animals with anything resembling an eye lived about 550 million years ago and that it would have taken about 364,000 years, not terribly long in evolutionary terms, for a camera-like eye as we have to have evolved from a light-sensitive patch or membrane. Many animal species see with their ears – like dolphins and bats - observes Diane Ackerman in her Natural History of the Senses – ‘but for us the world becomes most densely informative, most luscious, when we take it in through our eyes. It may be', she speculates with literary license ‘that abstract thinking evolved from our eyes’ elaborate struggle to make sense of what they saw.’[New York, Vintage, 1995, p.230].