The Extended Phenotype today
January 21st 2009 09:46
While The Selfish Gene was to a large extent an exposition of a view that had been pioneered (albeit implicitly) by other workers, this book is Dawkins’ unambiguously original contribution to the study of animal behaviour and evolution. Building on the aforementioned work where the gene-centric view of evolution was made explicit, this edition, apart from clearing up some common misunderstandings about the 1976 classic, invites us to view genes as the centres of interlocking webs of power radiating out from the bodies of organisms and into the world. This is why genes have extended phenotypes, because their consequences reach out across animate and inanimate entities, beyond the bounds of the organism-proper they ride around in; they manipulate or otherwise influence “vehicles” and objects in ways conducive to their own propagation. A beaver’s damn is no less a part of the phenotype of the genes predisposing beavers to damn building than the limbs and neural circuitry that facilitate such activity. Perhaps most fascinating, there are certain phenomena that are puzzling if one were trying to interpret them from the point of view of individual-level selection. An example of such is meiotic drive. If one adopts the extended phenotype/gene-centric view, the puzzle disappears. Of course, it could be argued that meiotic drive is an example of unambiguous gene selection, while macro-level phenomena like the evolution of limb morphology are best left to the orthodox account. But the beauty of the extended phenotype is that all these things are seamlessly incorporated and come to be seen as manifestations of the same underlying thing: genes using the levers of power at their disposal. Sometimes they propagate themselves by programming animal brains and using these as their proxies, other times through the subversion of the meiotic lottery or replication throughout the genome.
This book, despite its difficulty in parts, should be read by anyone interested in evolution, from teachers to lay people (though they should prepare themselves by first reading The Selfish Gene); it should definitely be required reading for ecologists, professional biologists, and ethologists. This is, simply, because the book is extremely bold and extremely fascinating. It’s so fascinating that one often has to put it down and pause to consider whether it might all actually be the result of a misunderstanding. But the arguments are carried through with the clarity and passion that Dawkins so eloquently combines in all his writing. It is his most technical book, and some parts of it require serious mental exertion to extract the full message contained therein, but the effort is well worth it.
Personally, I learned an enormous amount from reading it. It escalated my interest in “ultra-selfish” DNA, and showed how the line between genomic parasites and viruses is a blurred one; it gave me more of a feel for the group selection controversy (admittedly, Dawkins is a partisan in that conflict), in which he convincingly demonstrates that, at least in some respects, it is much ado about nothing; it clarified aspects of evolutionarily stable strategies and game theory; it expanded my appreciation of coevolutionary arms races; it crystallised the notion of costs and benefits; it introduced me to the reasons for imperfections in organisms, and why some antagonistic relationships might see one side “winning” consistently; it raised the subtleties of kin selection and the different definitions of fitness; it increased my fascination with parasites, using them as a central case-in-point to show how the genes’ phenotype should be viewed as a combined host-parasite system; it hammered home the message that biological complexity and apparent design are the results of impersonal forces acting on unconscious entities which together impose an equivalent of teleological rationality on the world; it allowed me to see more clearly how the biosphere is a seething mass of countless interactions, conflicts, partnerships, and intrigues; in short, it allowed me to “rediscover the organism”. And it further opened up the possibility of there being entities other than genes that are subject to Darwinian (or quasi-Darwinian) processes, dependent upon their exhibiting certain qualities. The important current running through all this is the transfer and preservation of information; whether it happens to be carried through molecules or memes is incidental.
The book complements many of the ideas and concepts that are likely to form part of a course on animal behaviour, not so much from an empirical or experimental point of view but through the provisioning of a conceptual foundation to make these ideas all come together. It’s not just that adopting the extended phenotype orientation of the Necker Cube, so to speak, suggests new ways of interpreting phenomena. It’s that this orientation incorporates them more parsimoniously. Adopting such a view isn’t actually necessary, but it is extremely interesting. I can imagine many students of animal behaviour being inspired to carry out post-graduate projects to quantify some aspect of the extended phenotype associated with an organism of interest; personally, I would be moved to look into parasites but perhaps also animals that construct artefacts like nests.
Recently, the European Science Foundation organised a workshop on the Extended Phenotype, and it was agreed that the theory holds up well to this day, being consistent with some empirical discoveries as well as alternative ways of seeing ecosystem interactions. It was pointed out, though, that it doesn't actually have much in the way of predictive value, though it does have plenty of explanatory value. I can sort of see why: the theory says that genes will use the levers of powers at their disposal. That's a pretty broad statement, and it's easy to think of how that condition could be satisfied across a vast array of different environmental settings and contingencies.
An excerpt from an article in Science Daily talking about the workshop on the Extended Phenotype: "It was recognised that it has explanatory rather than predictive power," said David Hughes, convenor of the ESF workshop, from the Department of Biology, University of Copenhagen, now at Harvard. "It is a good way of looking at things but not necessarily the best approach when designing experiments."
Continue reading here.
This book, despite its difficulty in parts, should be read by anyone interested in evolution, from teachers to lay people (though they should prepare themselves by first reading The Selfish Gene); it should definitely be required reading for ecologists, professional biologists, and ethologists. This is, simply, because the book is extremely bold and extremely fascinating. It’s so fascinating that one often has to put it down and pause to consider whether it might all actually be the result of a misunderstanding. But the arguments are carried through with the clarity and passion that Dawkins so eloquently combines in all his writing. It is his most technical book, and some parts of it require serious mental exertion to extract the full message contained therein, but the effort is well worth it.
Personally, I learned an enormous amount from reading it. It escalated my interest in “ultra-selfish” DNA, and showed how the line between genomic parasites and viruses is a blurred one; it gave me more of a feel for the group selection controversy (admittedly, Dawkins is a partisan in that conflict), in which he convincingly demonstrates that, at least in some respects, it is much ado about nothing; it clarified aspects of evolutionarily stable strategies and game theory; it expanded my appreciation of coevolutionary arms races; it crystallised the notion of costs and benefits; it introduced me to the reasons for imperfections in organisms, and why some antagonistic relationships might see one side “winning” consistently; it raised the subtleties of kin selection and the different definitions of fitness; it increased my fascination with parasites, using them as a central case-in-point to show how the genes’ phenotype should be viewed as a combined host-parasite system; it hammered home the message that biological complexity and apparent design are the results of impersonal forces acting on unconscious entities which together impose an equivalent of teleological rationality on the world; it allowed me to see more clearly how the biosphere is a seething mass of countless interactions, conflicts, partnerships, and intrigues; in short, it allowed me to “rediscover the organism”. And it further opened up the possibility of there being entities other than genes that are subject to Darwinian (or quasi-Darwinian) processes, dependent upon their exhibiting certain qualities. The important current running through all this is the transfer and preservation of information; whether it happens to be carried through molecules or memes is incidental.
The book complements many of the ideas and concepts that are likely to form part of a course on animal behaviour, not so much from an empirical or experimental point of view but through the provisioning of a conceptual foundation to make these ideas all come together. It’s not just that adopting the extended phenotype orientation of the Necker Cube, so to speak, suggests new ways of interpreting phenomena. It’s that this orientation incorporates them more parsimoniously. Adopting such a view isn’t actually necessary, but it is extremely interesting. I can imagine many students of animal behaviour being inspired to carry out post-graduate projects to quantify some aspect of the extended phenotype associated with an organism of interest; personally, I would be moved to look into parasites but perhaps also animals that construct artefacts like nests.
Recently, the European Science Foundation organised a workshop on the Extended Phenotype, and it was agreed that the theory holds up well to this day, being consistent with some empirical discoveries as well as alternative ways of seeing ecosystem interactions. It was pointed out, though, that it doesn't actually have much in the way of predictive value, though it does have plenty of explanatory value. I can sort of see why: the theory says that genes will use the levers of powers at their disposal. That's a pretty broad statement, and it's easy to think of how that condition could be satisfied across a vast array of different environmental settings and contingencies.
An excerpt from an article in Science Daily talking about the workshop on the Extended Phenotype: "It was recognised that it has explanatory rather than predictive power," said David Hughes, convenor of the ESF workshop, from the Department of Biology, University of Copenhagen, now at Harvard. "It is a good way of looking at things but not necessarily the best approach when designing experiments."
Continue reading here.
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