Sunday, May 02, 2010

On a Richard Dawkins review

In the Times Literary Supplement for 11 February 2009, Richard Dawkins reviews a book by Professor Jerry Coyne called Why evolution is true published by Oxford University Press.  Dawkins is sufficiently persuasive to have induced me to order a copy, so I might dare to say a bit more after I have read it.

While I have been happy since childhood to believe, alongside Professor Coyne, that evolution is true, I often feel that the leaders in the field are suggesting that nothing about the mechanisms of evolution remain unresolved.  It is encouraging therefore to read in a paper by Antónia Monteiro and Ondrej Podlaha (2010) from the Department of Ecology and Evolutionary Biology, Yale University "There is still much to do in order to fully understand how novel complex traits evolve. ....  it is important to continue exploring the full complement of genes that are shared across multiple traits to identify gene clusters that may be behaving as an integrated and context-insensitive network of genes."

Another remark in Dawkins review also puzzles me, though I am sure there is an explanation out there somewhere.  He wrote "One of Coyne’s graphs shows a genus of radiolarians (beautiful protozoans with minute, lantern-like shells) caught in the act, two million years ago, of “speciating” – splitting into two species."  Apart from the fact that it seems a bit odd for a genus (presumably of many species) to split into two species, I cannot quite grasp the evolutionary processes involved in this double take.  Did half the population of said radiolarian suddenly change into another species.  If so, the factor that triggered this was presumably endogenous and must have been present before the radiolarians changed.  And why didn't they all change?  Can a trait-changer spread throughout many individuals of a species before it goes live?  And if it can, would it be switched on simultaneously (like the flowering of the bamboo) across all individuals possessing it?  Or did just one example of the newly evolved species appear and successfully spread its genes down the generations by hybridising with its unevolved congenerics?

I would also humbly point out that there are many groups of species apparently speciating, or evolving, right now - no need to go back 2 million years.  Though why some groups are doing this, and others not needs some explaining.  "Right chaps, its a nice day, let's do a bit of evolving."

Dawkins also debunks belief in a moon god by saying that "science predicts, with complete certainty unless the end of the world intervenes, that the city of Shanghai will experience a total eclipse of the sun on July 22, 2009."

Although it is implied in Dawkins's remark, I don't think science can yet predict where evolution will have taken life on earth (if it survives) in a few million years time,  Predicting an eclipse involves a good data set, some geometry and arithmetic (plus faith in inductive reasoning).  It seems to me to be impossible to account for all the significant variables in areas like ecology and evolution with sufficient confidence to be able to predict the future accurately over even very short time scales.

REFERENCES

Coyne, J. (2009) Why Evolution is True.  Oxford University Press.

Dawkins, R. (2009)  Dawkins on Darwin.  Times Literary Supplement 11 February 2009.

Monteiro, A. & Podlaha, O. (2009) Wings, Horns, and Butterfly Eyespots: How do Complex Traits Evolve?  PLoS Biol 7(2): e1000037. doi:10.1371/journal.pbio.1000037

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