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‘I do not propose to say anything new or original in these lectures. But I am a great believer in saying familiar, well-known things backwards and inside out, hoping that from some new vantage point the old facts will take on a deeper significance. It is like holding an abstract painting upside down; I do not say that the meaning of the picture will suddenly be clear, but some of the structure of the composition that was hidden may show itself
This is pernicious rubbish on an almost astrological scale.
‘satisficing’ as an alternative to optimizing. If optimizing systems are concerned with maximizing something, satisficing systems get away with doing just enough.
In many ways the word ‘meliorizing’ expresses a sensible middle way between optimizing and satisficing.
Of course the mathematics of biological currency-conversion, of evaluating the costs of wing muscle, singing time, predator-vigilance time, etc., in some common currency such as ‘gonad equivalents’, are likely to be very complex. Whereas the engineer is allowed to simplify his mathematics by working to an arbitrarily chosen minimum threshold of performance, the biologist is granted no such luxury. Our sympathy and admiration must go out to those few biologists who have attempted to grapple with these problems in detail (e.g. Oster & Wilson 1978; McFarland & Houston 1981).
for periodical cicadas (Simon, 1979, gives an entertaining recent account).
successful exploitation by means of a “super-stimulus”.’
Hamilton, in this case his paper on extraordinary sex ratios (1967).
In any animal, an inverted portion of chromosome may resemble a Y chromosome in being unable to cross over. The ‘experience’ of any part of the ‘inversion supergene’ therefore repeatedly includes the other parts of the supergene and their phenotypic consequences.
Approaching from a non-palaeontological direction, indeed in lamentable ignorance of the whole Eldredge/Gould theory, I once found the Wrightian/Mayrian idea of buffered gene-pools resisting change, but occasionally succumbing to genetic revolutions, satisfyingly compatible with one of my own enthusiasms, Maynard Smith’s (1974) ‘evolutionarily stable strategy’ concept:
Reductionism is a dirty word, and a kind of ‘holistier than thou’ self-righteousness has become fashionable.
‘neuro-economic’ and ‘software’ explanations of behaviour in preference to conventional neurophysiological ones (Dawkins 1976b).
The theory expects that, when p* is achieved in the population as a whole, digging and entering should be equally successful.
At equilibrium, therefore, we expect no correlation between a wasp’s digging probability and her success.
Thus a species must have many chromosomes if, when a distorter arises, selection at most loci is to favor its suppression. Just as too small a parliament may be perverted by the Cabals of a few, a species with only one, slightly linked chromosome is an easy prey to distorters’
Cosmides and Tooby (1981) coin the useful term ‘coreplicon’ for such a gang of genes that replicate together and therefore tend to work for the same ends.
One might make a similar argument for any substantial portion of a chromosome which, say because of inversion, did not cross over.
This idea was developed further and worked out more fully by molecular biologists in two stimulating papers published simultaneously in Nature (Doolittle & Sapienza 1980; Orgel & Crick 1980).
These hypothetical engineers, fragments of nucleic acid which might lie inside or outside the chromosomes, would have to achieve their own replication success as a byproduct of forcing meiosis upon the organism.
selfish DNA might evolve mimetic qualities that ‘make it more like ordinary DNA and so, perhaps, less easy to remove’
The idiotype of a rabbit turned out to be inherited by its children, although not shared by its clone-mates.
cells that did not risk their lives smothering antigens but selfishly left the task to their colleagues should, on the face of it, have a built-in advantage.
Unadulterated clonal selection should favour selfish cells whose behaviour conflicts with the best interests of the body as a whole.
Non-genetic anomalies that appear, or even that are surgically induced, in the cortex of ciliates, may be directly inherited.
This has been demonstrated by Sonneborn and others. By Bonner’s account, they cut out a small portion of the cortex of Paramecium and reversed it. ‘The result is a Paramecium with part of one row of basal bodies in which the fine structure and details are all pointed 180° away from the rest of the surface. This anomalous kinety is now inherited;
However, I had got no further than some brief remarks on ‘selfish mitochondria’ (now in Chapter 12), when two papers arrived (Eberhard 1980; Cosmides & Tooby 1981) which, independently, say everything I might have said and much more.
To give just one example, ‘The migration of egg mitochondria to cluster around the egg nucleus, so as to favor their inclusion
If I am descended from a particular individual male who lived a million years ago, it is virtually certain that you are descended from him too.
Hamilton (1964a,b), in a pair of papers which we can now see to have marked a turning point in the history of evolutionary theory, made us aware of an important deficiency in classical fitness[3], the
Together with Williams (1966), Hamilton could fairly be regarded as one of the fathers of gene selectionism in modern behavioural and ecological studies:
beetle larvae of the genus Tribolium, when infected by the sporozoan Nosema, usually fail to metamorphose into adults. Instead they continue to grow through as many as six extra larval moults, ending up as giant larvae weighing more than twice as much as non-parasitized controls. Evidence suggests that this major shift in beetle priorities, from reproduction to individual growth, is due to the synthesis of juvenile hormone, or its close analogue, by the protozoan parasite.
A protozoan is so small in comparison with a beetle larva that a single protozoan, on its own, could not muster a sufficient dose of hormone to affect the beetle. Hormone manufacture must be a group effort by large numbers of individual protozoa.
Maximizing the amount and diversity of DNA in the biosphere is the concern of nobody and nothing.
An animal’s behaviour tends to maximize the survival of the genes ‘for’ that behaviour, whether or not those genes happen to be in the body of the particular animal performing it.
The Gaia hypothesis is an extreme form of what, for old times’ sake although it is now rather unfair, I shall continue to call the ‘BBC Theorem’.
Hardin (1968) summed the problem up in his memorable phrase ‘The tragedy of the commons’, and more recently (Hardin 1978) in the aphorism, ‘Nice guys finish last’.
A master of restrained eloquence in biological writing is Ernst Mayr. His chapter on ‘The unity of the genotype’ (Mayr 1963) is often held up to me in conversation as deeply antithetical to my replicator-based viewpoint. Since, on the contrary, I find myself enthusiastically endorsing almost every word of that chapter, something must have been misunderstood, somewhere.
Much the same could be said of Wright’s (1980) equally eloquent article on ‘Genic and organismic selection’, which purports to be a repudiation of the genic selection view that I hold, yet almost none of which I find myself disagreeing with.
All I am saying is that there are two general ways in which harmonious cooperation can come about. One way is for harmonious complexes to be favoured by selection over dis-harmonious complexes. The other is for the separate parts of complexes to be favoured in the presence, in the population, of other parts with which they happen to harmonize.
There is no need to postulate a meta-population of populations,
Wickler (1968), in his fascinating review of animal mimicry,
In any given local area, once one colour starts to predominate at a majority of loci, selection works to increase the frequency of that colour at all loci. In a particular area, if all the loci save one are dominated by pink genes, the odd locus which is dominated by blue genes will soon be brought into line by selection. As in the case of the hypothetical cicadas, historical accidents in different local areas automatically set up selection pressures in favour of one or another of two evolutionarily stable states.
Ityraea nigrocincta, like I. gregorii, practises cooperative mimicry of lupin-like inflorescences, but it ‘possesses a further peculiarity in that both sexes have two morphs, a green form and a yellow form. These two morphs may squat together, and the green forms tend to sit at the top of the stem, especially on vertical stems, with the yellow forms below. The result is an extremely convincing “inflorescence”, because the true flowers of inflorescences often open progressively from base to apex, so that green buds are still present at the tip when the base is covered with open flowers’
(Wickler 1968).
We often speak of, say, the size of a bird’s tail as a compromise between the needs of aerodynamics and the needs of sexual attractiveness. I do not know what kind of mathematics are considered suitable for describing this kind of within-body conflict and compromise, but whatever they are, they should be generalized to cope with the analogous problems of genetic action at a distance and extended phenotypes.
When I say here that a behaviour pattern is maladaptive, I only mean it is maladaptive for the individual animal performing it. I am suggesting that the individual performing the behaviour is not the entity for whose benefit the behaviour is an adaptation. Adaptations benefit the genetic replicators responsible for them, and only incidentally the individual organisms involved.
I would not have been able to justify my position until I had read J. T. Bonner’s (1974) inspiring book On Development.
But he must show the same circumspection in this difficult theoretical field as Fisher (1930a), Williams (1975) and Maynard Smith (1978a) brought to the analogous suggestions about sexual reproduction being there because it speeds up evolution.
The replicators that exist tend to be the ones that are good at manipulating the world to their own advantage. In doing this they exploit the opportunities offered by their environments, and an important aspect of the environment of a replicator is other replicators and their phenotypic manifestations. Those replicators are successful whose beneficial phenotypic effects are conditional upon the presence of other replicators which happen to be common. These other replicators are also successful, otherwise they would not be common. The world therefore tends to become populated by mutually
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Bethell, T. (1978). Burning Darwin to save Marx. Harpers 257 (Dec.), 31–38 & 91–92.
