I want to start my exploration of evolution with an article The Not-So-Selfish Gene, by Bob Holmes in the New Scientist, 7 March 2009. Near the beginning, on page 36, he writes:
This relentless focus on the gene may not tell the whole story, however. A small but growing coterie of evolutionary biologists argue that it leaves us blind to crucial evolutionary processes at higher scales - among groups, species and even whole ecosystem. If they are right, the popular view of evolution and the biological world needs a radical shake-up.
My first response to reading this was 'too right it does'. What on earth is going on here?
Partly, it is entirely understandable caution on the part of the author and others. Higher level selection implies altruism and there is a basic premise that altruism has no role in natural selection.
One of my favourite sentences is this one: Finding out whether there is ecosystem selection or not isn't easy. The point the author is trying to make is whether selection acts upon ecosystems in a similar way to which it acts upon species. So, for example, would a more diverse ecosystem be more or less likely to survive as selection acts upon it.
Let's imagine we could separate out in the laboratory all the components of an ecosystem; animals in cages, plants in plant pots, bacteria in petri dishes, etc. Each single organism has evolved and is living, we can assume for the purpose of this illustration, with reasonable stability. Would it be possible to put the ecosystem together again? The answer is no. The ecosystem has evolved through interactions between the species within it.
The evidence that ecosystems evolve is there in front of all of us; ecosystems exist. Possibly the problem is that ecosystem evolution is conceived as selection acting on whole ecosystems, so some catastrophy might wipe out an ecosystem where a better equipped one might survive. An alternative way to think about it is ecosystems are subject to selection internally as species interact. This is how they grow and develop over thousands of years. Selection is likely to be subtle but no less real for that.
Finally, here is another gem from page 38:
The response of the Dawkins camp is that genes carry information in a stable form from one generation to the next, usually changing only slowly, while individuals flicker in and out of existence. It therefore makes more sense to study genes - the replicators - rather than their temporary vehicles.
I hope this paragraph does not do justice to Dawkins because it is balderdash from beginning to end. Individuals do not flicker in and out of existence. Precisely where is the gene when the individual flickers out of existence?
More fundamentally, selection does not act on genes. It acts upon the phenotype and most GCSE biologists know phenotype equals genotype plus environment. Genes are not replicators, they carry a code used in replication.
In future posts I will unpick this further. My aim is not to prove Dawkins wrong but to ask what assumptions underlie his work.
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