Evolution expert takes highest science award

By SIMON COLLINS

An evolutionary expert who says meat-eating made us human has been awarded New Zealand's top science prize, the Rutherford Medal.

Professor David Penny, a Massey University biologist, raised vegetarian hackles when he wrote in Nature this year that "an increased proportion of meat in the diet of early humans was important for an increase in brain size".

"Apes were mostly vegetarian," he said yesterday. When the early ancestors of humans ventured out of the trees a few hundred thousand years ago and started stalking wild animals, they took in new chemical compounds which enabled brain growth.

"The brain is a very costly organism. It requires a lot to grow it and keep it running," Professor Penny said.

"Since the domestication of peas and beans [a mere 10,000 years ago], we have probably got richer sources of proteins from plants, but of course that's really post-being human.

"Now you can be vegetarian and have all sorts of plants that have high amino-acid levels. But you probably couldn't have been a vegetarian 50,000 years ago."

Professor Penny, who turns 66 next week, was born in Taumarunui and raised on a sheep farm near Ohura in the remote southern King Country.

He is now a regular referee for Nature and other leading journals and is an expert on evolutionary issues ranging from the peopling of the Pacific to the spread of the hepatitis B virus.

In the late 1990s, he led the movement to ban experiments on our closest relatives - chimpanzees, gorillas and orang-utans - unless the research also benefited them.

"I think evolution is continuity," he said. "There must be a continuous series of common ancestors of chimps and humans, and the humans have been going out more into the open and have had to learn a whole lot more skills.

"If you look at the chimp and gorilla genomes, you find that the differences from humans are just the normal sorts of changes between any pair of species, so there is nothing special.

"We have pretty well all the same genes. It's often the timing that is different - our brain keeps on developing several years more. It's not that we are different, it's just that we have a much longer learning period."

After New Zealand passed the world's first law protecting the apes, other countries followed.

"New Zealand did it first. It's not that we actually have many great apes, but others have looked at it and said, 'New Zealand has done it, perhaps we should'."

The award coincided with publication of a paper by Professor Penny and colleague Matthew Philips yesterday arguing that birds and mammals displaced the dinosaurs gradually during the 20 million years before the disastrous asteroid impact which is traditionally blamed for the extinction of the dinosaurs about 65 million years ago.

"Although the asteroid at the end of the period was real, we think it's natural evolutionary processes that made the difference," he said.

"We think mammals and birds over 20 to 30 million years were starting to outcompete dinosaurs. From about 80 to 90 million years ago, the birds and mammals were diversifying."

Professor Penny is now delving back further into the past to work out how the first complex living cell with a distinct nucleus evolved about 1.5 billion years ago, producing what is called the "last universal common ancestor" of all plants, animals, amoebas and fungi.

Even further back, he is researching the origin of life itself, perhaps 3.5 billion years ago. It is a riddle he believes scientists will eventually solve.

"The general feeling is that the problem is solvable, and that in itself is quite an amazing statement," Professor Penny said.

The evidence so far suggested that life began in the sea, at a time when the atmosphere outside was inhospitable to any living thing. But earlier theories that life began in hot volcanic underwater vents were now discounted.

"We think there are lots of reasons why it was in a low-temperature place."

The Rutherford Medal

* The Rutherford Medal is awarded by the Royal Society of New Zealand.

* One previous winner was Nobel chemistry laureate Alan MacDiarmid in 2000.

* The 1991 winner, Professor Vaughan Jones, was the first person in the Southern Hemisphere to win the maths equivalent of the Nobel Prize.