What I say about Lamarck in “Lamarck’s Due, Darwin’s Luck”:
What Buffon actually believed in private is anyone’s guess, so it is difficult to assess how much influence he had upon the views of a young man he took under his wing called Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (1744-1829), who would become generally regarded as the author of the Theory of Descent even though, technically, he didn’t fully believe in it in its modern form.
An eleventh child, Lamarck had been destined by his father to go into the church but he quit seminary at 17, after his father died, and joined the army until an injury forced him to abandon a military career and find other ways to earn a living in Paris. His passions became botany and meteorology and he eventually got a minor position at the Jardin du Roi, where he spent most of his working life. With Buffon’s assistance, he had his first book, “Flore francaise” (French Flora), published and was also admitted to the French Academy – a distinguished body of scientists. One of his early duties, in 1781, was to accompany Buffon’s young son, nicknamed Buffonet, on his travels around Europe. This afforded Lamarck the opportunity to study foreign plants, though he apparently did not get on with Buffonet. He also gave regular lectures throughout his working life and developed his passion for meteorology into an interest in geology and the environment. In doing so, he certainly took on board Buffon’s views about the age of the earth; in his 1802 book, “Hydrogéologie”, he wrote, “Oh, how very ancient the earth! And how ridiculously small the ideas of those who consider the earth’s age to be 6,000 odd years.”
At the same time, he also coined the term ‘biology’ as the science of all living things, though there are other claimants to that title. He was undoubtedly an unconventional man whose interest in biology extended to having six children by a woman whom he only married on her death bed, and going on to have three more wives and two more children. His main work was as a taxonomist, classifying species into families and genera, and he approached the subject methodically and scientifically. As Buffon had done, he saw natural progressive relationships between species, from simple to complex. Perhaps his most revolutionary claim was that there is no such natural thing as species; they are merely useful man-made concepts. From 1793, he turned his attention more to animals and continued writing essentially taxonomic books about both plants and what he called ‘invertebrate’ animals. In doing so, he collaborated with a Swiss-born, French botanist, Augustin Pyrame de Candolle (1778-1841), who not only coined the term ‘taxonomy’ but also provided the following, widely-accepted, definition of a species:
A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by mutual fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one individual.
Philosophically, Lamarck had known and admired Rousseau, who had played some part in getting him interested in botany, but he became more influenced by Étienne Bonnot de Mably de Condillac (1715-1780), whose Sensationalism was the French equivalent of Empiricism. In religious terms, Lamarck believed that nature would be understandable on the basis of natural laws and that there was no need for recourse to an interfering God or Vitalism. It was from that standpoint that Lamarck would make his major contribution to the history of science. Though the Revolution had a disastrous effect upon the resources available to scientists, and Napoleon was not very sympathetic to intellectual pursuits, the Enlightenment had brought about a sufficient liberalisation of thought at the start of the 19th century to allow Lamarck to develop, write and publish his masterpiece, “Philosophie Zoologique” (Zoological Philosophy, an Exposition with Regard to the Natural History of Animals) in 1809. In it, he expounded his theory of transformism, which means mutability of species. We simply do not know where he got the theory from or how long he had privately believed it, though it had been included in his lectures since 1800. Quite simply, it was the first comprehensive, rather than merely speculative or hypothetical, theory of the development of living organisms from simple origins:
I shall show that the habits by which we now recognise any species are due to the conditions of life under which it has for a long time existed, and that these habits have had such an influence upon the structure of each individual of the species as to have at length modified this structure, and adapted it to the habits which have been contracted.
A few paragraphs later, we find:
What, then, can be the cause of all this? Surely the following: namely, that when individuals of any species change their situation, climate, modes of existence, or habits, their structure, form, organisation, and in fact their whole being becomes little by little modified, till in the course of time it responds to the changes experienced by the creature.
In the same climate differences in situation, and a greater or lesser degree of exposure, affect simply, in the first instance, the individuals exposed to them; but in the course of time, these repeated differences of surroundings in individuals which reproduce themselves continually under similar circumstances, induce differences which become part of their very nature; so that after many successive generations, these individuals, which were originally, we will say, of any given species, become transformed into a different one.
Let us suppose that a grass growing in a low-lying meadow gets carried by some accident to the brow of a neighbouring hill, where the soil is still damp enough for the plant to be able to exist. Let it live here for many generations, till it has become thoroughly accustomed to its position, and let it then gradually find its way to the dry and almost arid soil of a mountainside; if the plant is able to stand the change and to perpetuate itself for many generations, it will have become so changed that botanists will class it as a new species.
The same sort of process goes on in the animal kingdom, but the animals are modified more slowly than plants.
In simple terms, what Lamarck maintained was that, over many generations, the environments in which any organisms existed had transformed them into the different species. This had also occurred in animals as a result of organs which were used becoming developed and enhanced, and organs which were disused becoming atrophied:
The bird which is drawn to the water by its need of finding there the prey on which it lives, separates the digits of its feet in trying to strike the water and move about on the surface. The skin which unites these digits at their base acquires the habit of being stretched by these continually repeated separations of the digits; thus in course of time there are formed large webs which unite the digits of ducks, geese, etc., as we actually find them. In the same way efforts to swim, that is to push against the water so as to move about in it, have stretched the membranes between the digits of frogs, sea-tortoises, the otter, beaver, etc.
We find in the same way that the bird of the water-side which does not like swimming and yet is in need of going to the water’s edge to secure its prey, is continually liable to sink in the mud. Now this bird tries to act in such a way that its body should not be immersed in the liquid, and hence makes its best efforts to stretch and lengthen its legs. The long-established habit acquired by this bird and all its race of continually stretching and lengthening its legs, results in the individuals of this race being raised as though on stilts, and gradually obtaining long, bare legs, denuded of feathers up to the thighs and often higher still.
We note again that this same bird wants to fish without wetting its body, and is thus obliged to make continual movements to lengthen its neck. Now these habitual efforts in this individual and its race must have resulted in course of time in a remarkable lengthening, as indeed we actually find in the long necks of all water-side birds.
A few paragraphs further on, he makes the only reference he ever made to the giraffe:
It is interesting to observe the result of habit in the peculiar shape and size of the giraffe (Camelo-pardalis): this animal, the largest of the mammals, is known to live in the interior of Africa in places where the soil is nearly always arid and barren, so that it is obliged to browse on the leaves of trees and to make constant efforts to reach them. From this habit long maintained in all its race, it has resulted that the animal’s forelegs have become longer than its hind legs, and that its neck is lengthened to such a degree that the giraffe, without standing up on its hind legs, attains a height of six metres.
Over aeons of time, transformism had changed primitive life forms into complex species. The two most important factors were the direct effects of the environment upon an organism and the habitual behaviour of an organism in response to its environment. For those changes to cause the development of a species, rather than just an individual in its own lifetime, they have to be accumulative. That requires the inheritance of acquired characteristics, whereby every organism can build on the achievements of its ancestors. For example, if, during his gestation and growth, a male hominid developed a bigger brain due to a rich diet than he would have done without the rich diet, that is an acquired characteristic. If he got together with a similarly-affected female hominid and any of their offspring had a bigger brain than it would have done if its parents had not had rich diets, that is the inheritance of an acquired characteristic, however slight the increase in brain size was. Similarly, if a group of stooping, hairy apes became more upright and less hairy as a consequence of standing in sea water, and any of their offspring were naturally more upright or less hairy than they would have been if their parents had not spent time standing in sea water, that is the inheritance of acquired characteristics. If a group of hominids moved to an environment where they were exposed to less strong sunlight than they had been, and they became lighter-skinned as a consequence, with an incremental accumulative effect over the generations, that is due to Lamarckian inheritance.
Ironically, in the light of what he would become famous (or infamous) for, Lamarck attached little importance to the inheritance of acquired characteristics; that was just a necessary assumption. His emphasis was upon the acquisition of characteristics, which is not now seriously disputed in principle, rather than their inheritability, which is. He was certainly a gradualist, so he did not believe that significant changes would occur over one generation, but changes were accumulative:
……..Now we shall easily discern how the new needs may have been satisfied, and the new habits acquired, if we pay attention to the two following laws of nature, which are always verified by observation.
In every animal which has not passed the limit of its development, a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, and gives it a power proportional to the length of time it has been so used, while the permanent disuse of any organ imperceptibly weakens and deteriorates it, and progressively diminishes its functional capacity, until it finally disappears.
All the acquisitions or losses wrought by nature on individuals, through the influence of the environment in which their race has long been placed, and hence through the influence of the predominant use or permanent disuse of any organ; all these are preserved by reproduction to the new individuals which arise, provided that the acquired modifications are common to both sexes, or at least to the individuals which produce the young.
It could indeed be argued that the second law is self-evident from the first, since, if the effects of use or disuse have any evolutionary significance at all, the inheritability of those effects, in some degree, is an absolute prerequisite.
Another reputation Lamarck was to acquire was that of a progressionist. In evolutionary terms, progression is generally taken to mean ‘improvement’ or ‘attainment of superiority’. If an amoeba is inferior to a human being, then the process of transformation of an amoeba into a human being is a progression. That is the sense in which I believe Lamarck meant it and that is the meaning I ascribe to it. He certainly believed that all lineages became more complex over generations, which may also be seen as progression. However, one connotation that ‘progression’ has is with teleology or ‘leading towards a goal’, for which I shall use the word ‘purposive’. When Lamarck came to the attention of the general public, long after his death, his progression would become assumed by many to mean purposiveness. This was accentuated by his paying a great deal of attention to the nervous system, as an indicator of the superiority of higher animals, and his regular references to the needs and wants of those animals, as indicated by the included extracts. Some latter-day Evolutionists would take this to mean that Lamarck’s progression took place through an Act of Will. In fact, Lamarck gave no indication that an animal’s conscious will did any more than determine its actual behaviour patterns, as may be shown by the following passage concerning human vocalisation:
Certain apes approach man more nearly than any other animal approaches him; nevertheless, they are far inferior to him, both in bodily and mental capacity…….
Surely these facts should reveal man’s origin as analogous to that of the other mammals, if his organisation only be looked to. But the following consideration must be added. New wants, developed in societies which had become numerous, must have correspondingly multiplied the ideas of this dominant race, whose individuals must have therefore gradually felt the need of fuller communication with each other. Hence the necessity for increasing and varying the number of the signs suitable for mutual understanding. It is plain therefore that incessant efforts would be made in this direction.
The lower animals, though often social, have been kept in too great subjugation for any such development of power. They continue, therefore, stationary as regards their wants and ideas, very few of which need to be communicated from one individual to another. A few movements of the body, a few simple cries and whistles, or inflexions of the voice, would suffice for their purpose. With the dominant race, on the other hand, the continued multiplication of ideas which it was desirable to communicate rapidly, would exhaust the power of pantomimic gesture and of all possible inflexions of the voice – therefore by a succession of efforts this race has arrived at the utterance of articulate sounds. A few only would be at first made use of, and those would be supplemented by inflexions of the voice: presently they would increase in number, variety and appropriateness, with the increase of needs and of the efforts made to speak. Habitual exercise would increase the power of the lips and tongue to articulate distinctly.
The diversity of language is due to geographical distribution, with consequent greater or less isolation of certain races, and corruption of the signs originally agreed upon for each idea. Man’s own wants, therefore, will have achieved the whole result. They will have given rise to endeavour, and habitual use will have developed the organs of articulation.
Part of the reason for Lamarck’s insistence on progression was based upon his belief in the spontaneous generation of life. Like many of his predecessors and contemporaries, he believed that primitive organisms (like moulds, algae and infusorians) were spontaneously generated from dead matter:
All living forms upon the face of the globe have been brought forth in the course of infinite time by the process of generation only. Nature has directly created none but the lowest organisms; these she is still producing every day, they being, as it were, the first sketches of life and produced by what is called spontaneous generation. Organs have been gradually developed in these low forms, and these organs have in the course of time increased in diversity and complexity. The power of growth in each living body has given rise to various modes of reproduction, and thus progress, already acquired, has been preserved and handed down to offspring.
You may well laugh but, before the invention of decent microscopes, no-one had cause to believe in the existence of organisms which were invisible to the naked eye, so it was only natural to assume that any life forms that emerged in places where there had previously not been life (like earth, food and dirty underwear) had to have been spontaneously generated. The French chemist, Louis Pasteur (1822-1895), who would prove the existence of micro-organisms, refute the spontaneous generation of life and have his name preserved in milk, had not been born yet. Besides, though no instance of spontaneous generation of life has ever been observed, the majority of scientists believe that it did once happen here on Earth. Many biologists aim to achieve it (even though it would not actually be spontaneous if they did).
Lamarck believed that seeds and eggs were made of dead matter which was so arranged that, when life was spontaneously generated in them, they grew in certain ways. The simplest forms of life were spontaneously generated from dead matter which became naturally organised. Since life was constantly being generated, different lineages had been evolving separately for different lengths of time. For instance, moulds and worms and lichen had not been evolving for anything like as long as toadstools, elephants and oak trees. Consequently, not all organisms were related to each other. It is this respect that Lamarck was not technically in accord with the modern version of the Theory of Descent. Complex organisms had undergone much more transformism, over a longer period of time, than simple ones. Consequently there was progression, from simple to complex. Given the right sequence of environmental circumstances, a worm’s eventual descendants could be elephants, though present-day elephants would have progressed to better things by then. Implicit in this progression is the notion that all changes are improvements, thus obviating the need for any quality control. Lamarck saw life as a long cycle in which simple living organisms were spontaneously generated from dead matter and became transformed through descent into more complex organisms, leaving the corpses of all the individual organisms to become the dead matter from which new life became spontaneously generated. He would have been delighted to learn of the Nitrogen and Carbon Dioxide cycles.
For the purposes of the rest of this book, the three most important assumptions that Lamarck made, expressed in my words, were as follows:
1. That living organisms are physico-chemical machines which do not require any outside agency in order to exist, which is known philosophically as Mechanist theory.
2. That all inheritable characteristics are derived only from parents, which is implicit in the meaning of ‘inheritable’ and fits with the Theory of Descent.
3. That acquired characteristics are inheritable in some degree, which is also known as progressive heredity or Lamarckian inheritance.
In the 20th century, it would appear to be the case that those three assumptions are incompatible. One of them would have to go.
Though he attached little significance to it, Lamarck was certainly aware of the part survival plays in nature:
In consequence of the extremely rapid rate of increase of the smaller, and especially of the most imperfect, animals, their numbers would become so great as to prove injurious to the conservation of breeds, and to the progress already made towards more perfect organisation, unless nature had taken precautions to keep them down within certain fixed limits which she cannot exceed…….
The strongest and best armed for attack eat the weaker, and the greater kinds eat the smaller.
Between 1815 and 1822, Lamarck kept up his total dedication to transformism in his 7 Volume “Histoire Naturelle des Animaux sans Vertèbres”, the last two volumes of which were dictated to one of his daughters, since he had gone blind and been forced to retire in 1819. Lamarck’s theory and books did not create much of a furore during his lifetime. They probably only came to the attention of a few scientists and natural historians, amongst whom he had supporters and opponents. One of his principal opponents was Léopold Chrétien Frédéric Dagobert Cuvier, usually known as Georges Cuvier (1769-1832), who also worked at the Museum as an anatomist and fossil expert. Cuvier was undoubtedly the most powerful, influential and formidable figure in the field of biology at the time. He had achieved that status by ingratiating himself with his superiors, for which trouble he was eventually made a Baron. He did not believe in the mutability of species and maintained that fossils were just species that had been destroyed in the Flood, or several floods. Napoleon had brought many mummified animals back to France from Egypt and they closely resembled their latter-day counterparts. Cuvier had seen them as further evidence that species were fixed, and dismissed Lamarck’s views as speculative. Lamarck had responded with the following passage, which also refutes the frequent criticism of Lamarckism that it means all species would be constantly changing:
The skeletons of some Egyptian birds, preserved two or three thousand years ago, differ in no particular from the same kind of creatures at the present day. But this is what we should expect, inasmuch as the position and climate of Egypt itself do not appear to have changed. If the conditions of life have not varied, why should the species subjected to those conditions have done so?