Feigned Lamarckism

A chance-mutation gives the individual a certain advantage.

Why does it also increase the opportunities for its being?

To reveal this mechanism let the environment be schematically described as an ensemble of favourable and unfavourable circumstances.

Among the first are food, drink, shelter, sunlight and many others, among the latter are the dangers from other living beings (enemies), poisons and the roughness of the elements. For brevity we shall refer to the first kind as ’needs’ and to the second as ‘foes’.

Not every need can be obtained, not every foe avoided. But a living species must have acquired a behaviour that strikes a compromise in avoiding the deadliest foes and satisfying the most urgent needs from the sources of e’asiest access, so that it does survive.

A favourable mutation makes certain sources more easily accessible, or reduces the danger from certain foes, or both. It thereby increases the chance of survival of the individuals endowed with it, but in addition it shifts the most favourable compromise, because it changes the relative weights of those needs or foes on which it bears.

Individuals which - by chance or intelligence - change their behaviour accordingly will be more favoured, and thus selected. This change of behaviour is not transmitted to the next generation by the genom, not by direct inheritance, but this does not mean that it is not transmitted.

The simplest, most primitive example is afforded’ by our species of flowers (with a habitat along an extended mountain slope) that develops a hairy mutant. The hairy mutants, favoured mainly in the top ranges, disperse their seeds in such areas so that the next generation of ‘hairies’, taken as a whole, has ‘climbed up the slope’, as it were, ’to make better use of their favourable mutation’.

In all this one must bear in mind that as a rule the whole situation is extremely dynamic, the struggle is a very stiff one. In a fairly prolific population that, at the time, survives without appreciably increasing, the foes usually overpower the needs - individual survival is an exception. Moreover, foes and needs are frequently coupled, so that a pressing need can only be met by braving a certain foe.

(For instance, the antelope has to come to the river for drink, but the lion knows the place just as well as he.) The total pattern of foes and needs is intricately interwoven. Thus a slight reduction of a certain danger by a given mutation may make a considerable difference for those mutants who brave that danger and thereby avoid others. This may result in a noticeable selection not only of the genetic feature in question but also with regard to the (intended or haphazard) skill in using it. That kind of behaviour is transmitted to the offspring by example, by learning, in a generalized sense of the word. The shift of behaviour, in turn, enhances the selective value of any further mutation in the same direction.

The effect of such a display may have great similarity with the mechanism as pictured by Lamarck. Though neither an acquired behaviour nor any physical changes that it entails are directly transmitted to the offspring, yet behaviour has an important say in the process. But the causal connection is not what Lamarck thought it to be, rather just the other way round. I t is not that the behaviour changes the physique of the parents and, by physical inheritance, that of the offspring.

It is the physical change in the parents that modifies - directly or indirectly, by selection - their behaviour; and this change of behaviour is, by example or teaching or even more primitively, transmitted to the progeny, along with the physical change carried by the genom. Nay, even if the physical change is not yet an inheritable one, the transmission of the induced behaviour ‘by teaching’ can be a highly efficient evolutionary factor, because it throws the door open to receive future inheritable mutations with a prepared readiness to make the best use of them and thus to subject them to intense selection.

GENETIC FIXATION OF HABITS AND SKILLS

One might object that what we have here described may happen occasionally, but cannot continue indefinitely to form the essential mechanism of adaptive evolution. For the change of behaviour itself is not transmitted by physical inheritance, by the hereditary substance, the chromosomes. At first, therefore, it is certainly not fixed genetically and it is difficult to see how it should ever come to be incorporated in the hereditary treasure. This is an important problem in itself.

For we do know that habits are inherited as, for instance, habits of nestbuilding in the birds, the various habits of cleanliness we observe in our dogs and cats, to mention a few obvious examples. If this could not be understood along orthodox Darwinian lines, Darwinism would have to be abandoned. The question becomes of singular significance in its application to man, since we wish to infer that the striving and labouring of a man during his lifetime constitute an integrating contribution to the development of the species, in the quite proper biological sense. I believe the situation to be, briefly, as follows.

According to our assumptions the behaviour changes paral- lel those of the physique, first as a consequence of a chance change in the latter, but very soon directing the further selectional mechanism into definite channels, because, according as behaviour has availed itself of the first rudimentary benefits, only further mutations in the same direction have any selective value. But as (let me say) the new organ develops, behaviour becomes more and more bound up with its mere possession. Behaviour and physique merge into one.

You simply cannot possess clever hands without using them for obtaining your aims, they would be in your way (as they often are to an amateur on the stage, because he has only ficti tious aims) . You cannot have efficien t wings wi thou t attempting to fly. You cannot have a modulated organ of speech without trying to imitate the noises you hear around you. To distinguish between the possession of an organ and the urge to use it and to increase its skill by practice, to regard them as two different characteristics of the organism in question, would be an artificial distinction, made possible by an abstract language but having no counterpart in nature.

We must, of course, not think that ‘behaviour’ after all gradually intrudes into the chromosome structure (or what not) and acquires ’loci’ there. It is the new organs themselves (and they do become genetically fixed) that carry along with them the habit and the way of using them.

Selection would be powerless in ‘producing’ a new organ if selection were not aided all along by the organism’s making appropriate use of it. And this is very essential. For thus, the two things go quite parallel and are ultimately, or indeed at every stage, fixed genetically as one thing: a used organ - as if Lamarck were right.

It is illuminating to compare this natural process with the making of an instrument by man. At first sight there appears to be a marked contrast. If we manufacture a delicate mechanism, we should in most cases spoil it if we were impatient and tried to use it again and again long before it is finished. Nature, one is inclined to say, proceeds differently.

She cannot produce a new organism and its organs otherwise than whilst they are continually used, probed, examined with regard to their efficiency. But actually this parallel is wrong. The making of a single instrument by man corresponds to ontogenesis, that is, to the growing up of a single individual from the seed to maturity. Here too interference is not welcome.

The young ones must be protected, they must not be put to work before they have acquired the full strength and skill of their species. The true parallel of the evolutionary development of organisms could be illustrated, for example, by a historical exhibition of bicycles, showing how this machine gradually changed from year to year, from decade to decade, or, in the same way, of railway-engines, motor-cars, aeroplanes, typewriters, etc. Here, just as in the natural process, it is obviously essential that the machine in question should be continually used and thus improved; not literally improved by use, but by the experience gained and the alterations suggested.

The bicycle, by the way, illustrates the case, mentioned before, of an old organism, which has reached the attainable perfection and has therefore pretty well ceased to undergo further changes. Still it is not about to become extinct!