Posts Tagged ‘evolution’

Evolution and Minister Lenihan

September 14, 2010 Leave a comment

There’ s been lots of comment about the welcome decision of Minister Lenihan’s to recuse himself (or be recused?) of further involvement in the launch of a book by a constituent of his that purports in some grandiose terms to disconfirm the theory of  evolution (Darwin’s one – not some of the other ones!). The story has spread widely – PZ Myers of Pharyngula (one of the most widely read science blogs on the planet) even carries the story.

I won’t link to the website of said constituent (do a search; a link is simply not appropriate here), but reading it and the sample material available is a remarkable experience. The theory of evolution by natural selection as presented bears little relation to anything that you might find in a contemporary textbook or indeed in the J Theor Biol (or wherever).

So what is the theory of evolution? Here is a simple and accessible statement by a major leader in the field:

RC Lewontin: ‘Darwinism is a population-based theory consisting of three claims. First, there is variation in some characteristics among individuals in a population. Second, that variation is heritable. That is, offspring tend to resemble their biological parents more than they do unrelated individuals. In modern Darwinism the mechanism of that inheritance is information about development that is contained in the genes that are passed from parent to offspring. Third, there are different survival and reproduction rates among individuals carrying different variants of a characteristic, depending on the environment inhabited by the carriers. That is the principle of natural selection. The consequence of differential reproduction of individuals with different inherited variants is that the population becomes richer over generations in some forms and poorer in others. The population evolves.’

This is a pretty straightforward set of claims. The contemporary theory of evolution makes the following (empirically-testable) assumptions:

  • Long periods of geological time (~ a billion or so years for the current speciation evident on Earth);
  • Cumulative selection;
  • Genotypic variation;
  • A mechanism for inheritance;
  • Variation in the environment over time driving evolution – ‘selection-pressure’ and ‘resource-pressure’.

What empirical observation would prove evolution wrong? Flippantly but profoundly, J.B.S. Haldane (discussed on this blog recently), replied when asked what empirical evidence disprove evolution “fossil rabbits in the Precambrian era“.

Said constituent is apparently offering a monetary prize for anyone who can demonstrate ‘biochemical evolution’. I’m not certain what this means, but I guess the famous citric acid metabolism experiments (see here for a wiki account) might entitle Richard Lenski to the prize. I presume the prize is offered in the belief that no-one can claim it, but I could be wrong…

From the wiki article above (but read the cited PNAS and other papers cited here – they are available for download):

The E. coli long-term evolution experiment is an ongoing study in experimental evolution led by Richard Lenski that has been tracking genetic changes in 12 initially nearly identical populations of asexual Escherichia coli bacteria since February 24, 1988.The populations reached the milestone of 50,000 generations on early 2010.

Since the experiment’s inception, Lenski and his colleagues have reported a wide array of genetic changes; some evolutionary adaptations have occurred in all 12 populations, while others have only appeared in one or a few populations. One particularly striking adaption was the evolution of a strain of E. coli that was able to grow on citric acid in the growth media.

This should qualify shouldn’t it?

[Update: The Irish Times story is worth reading; it notes the existence of the prize for ‘…prov[ing] evolution at a biochemical level’.]

Titans of science: David Attenborough meets Richard Dawkins | Science | The Guardian

September 13, 2010 Leave a comment

Titans of science: David Attenborough meets Richard Dawkins | Science | The Guardian.

A wonderful conversation.

A few quotes:

What is the one bit of science from your field that you think everyone should know?
David Attenborough: The unity of life.

Richard Dawkins: The unity of life that comes about through evolution, since we’re all descended from a single common ancestor. It’s almost too good to be true, that on one planet this extraordinary complexity of life should have come about by what is pretty much an intelligible process. And we’re the only species capable of understanding it.


What is the most difficult ethical dilemma facing science today?
DA: How far do you go to preserve individual human life?

RD: That’s a good one, yes.

DA: I mean, what are we to do with the NHS? How can you put a value in pounds, shillings and pence on an individual’s life? There was a case with a bowel cancer drug – if you gave that drug, which costs several thousand pounds, it continued life for six weeks on. How can you make that decision?