Jean-Baptiste de Lamarck

Jean-Baptiste Pierre Antoine de Monet, knight of Lamarck (1744, Bazentin, Somme - December 18th 1829, Paris) is a biologist French.

Biography

Childhood and formation

He was born in the Bazentin-the-Small village of from an old noble family, cash of many soldier.

He continues studies at the Jésuites of Amiens, of 1755 with 1759, before starting a military career in 1761, under the name of Chevalier of Saint Martin's day . He becomes officer on the field of Bataille of Villingshausen, on July 16th of the same year.

Obliged to leave the army in 1765, following an accident, he works during some time for an accountant, then he devotes himself to studies of Médecine and impassions himself for the Botanique. In 1778, royal Printing works publishes its French Flore , where it gives dichotomic keys making it possible each one to identify the plants. This work brings an immediate notoriety to him, and is worth to him to be elected with the Academy of Science the following year, with the support of Georges-Louis Leclerc, count de Buffon. Initially associated member, it becomes titular about it in 1783 then, finally, boarder in 1790, year when, specialist in botany, it does not hesitate, at fifty years, to reconvert itself successfully, while being named professor of Natural history of the Insects and the Worms to the Garden of the King.

He takes part, in 1793, with the transformation of the Garden of the King into national Muséum of natural history, under the impulse of Lakanal. He becomes there professor of Zoologie, charged to teach the zoology of the Invertébré S: it is him which invents the word “biology” to indicate the science of the living beings ; it also founds the Paléontologie invertebrates.

It will spend several years to establish a Classification reasoned of the animal Invertébré S.

Two works enable him to be regarded as the founder of the theories of the spontaneous Generation and the theory which one went called a few years later the Transformisme, bases of the Lamarckisme: zoological Philosophy (1809) and Natural history of the animals without vertebrae (1815 - 1822).

It was four times widower and became blind during the ten last years of its life.

End of its life

During more than one century, the majority of the historical texts evoke the misery of the end of the lifetime of Lamarck. For Jean-Henri Humbert (1887-1967), Lamarck “stripped of resources” must yield its herbarium to the German botanist Johannes August Christian Roeper (1801-1885). More close to us, for Jaussaud and Brygoo, “is poor death in its home of the Natural history museum”. The study of Michel Guédès on the incomes of Lamarck shows that this one cumulated various incomes (like its treatment of professor of the Natural history museum, its incomes of, the sale Academy of Science of its works, etc) which reached the sum of 9.500 F of the time. Its incomes did not certainly equalize those of Cuvier (since those reached 41.200 F), but enabled him to live in a completely correct way.

He dies the December 18th 1829, at the 85 years age, in his house with the Natural history museum. Its remainders are thrown to the common grave of the Cimetière Montparnasse. As evoked above, it is for certain authors the sign of his misery. For Laurent, it is necessary to put that “on the lack of filial devotion” of his son, Auguste.

The theory of the transmission of the acquired features

One of the many legends which enamel the history of the biology made of Lamarck the author of a “theory of the transmission of the acquired features”. However it of it is nothing. The transmission of the acquired features was allowed like an obviousness since Aristote and until August Weismann which at the end of the 19th century will rejetera it more for theoretical reasons than he will not refute it in experiments. Lamarck does not have, not more than these predecessors, theorized this transmission, it made only integrate it into its own theory of the evolution. On the other hand, it is Charles Darwin in the origin of the species which will theorize this transmission of the acquired features.

By examining small Mollusque S Fossile S it notes a modification during the ages of their physical characteristics. It is one of the first to be wondered officially about this factor.

Its thesis on the evolution is that the individuals adapt during their life in particular by using more or less certain organic functions, which develop or attenuate in connection with the use or nonthe use of the bodies.

The incomprehension of the principle of adaptation, i.e. amalgamates it between the acquired features and undergone plays against him, and one sees appearing questions as for example what occurs for some Ethnie S or civilizations which pratiqu (A) ent systematic body modifications on their individuals whereas we note that these modifications are not transmitted to their descent.

Lamarck was also a large innovator by affirming, in 1809, in zoological Philosophie , delivers where it develops his theory transformist, that the organizations evolved/moved . However Charles Darwin did little case of the ideas of Lamarck. With others darwiniens which will succeed to him, it will largely contribute to discredit Lamarck with the eyes of the biologists and to forge the legends which surround it. However, it is in Lamarck that one owes the first true Théorie of the evolution of the species formalized and not with Darwin who will explain the mechanism of the random variation and the Natural selection from which the scientists was going to forge the theory that one will apply to all living it.

One of the errors of Lamarck on its version of the theory of the evolution was to state that the heredity of the acquired features was done as follows: a giraffe which stretched its neck all its life to reach the branches of a tree would have a descent with a longer neck. Here what Lamarck writes on this subject:

Relative with the practices, it is curious to observe of it the product in the particular form and the face of the giraffe (camelo-pardalis): it is known that this animal, largest of the mammals, lives the interior of Africa, and that he lives in places where ground, almost always arid and without pasture, obliges it brouter the foliage of the trees, and continuously to endeavor to reach there. It is resulted from this practice, supported, for a long time, in all the individuals of its race, that its legs of front became longer than those of behind, and than its collar lengthened so much, than the giraffe, without drawing up itself on the legs of behind, raises its head and reaches with six meters height (nearly twenty feet). |Lamarck| p. 256

Appendices

List partial of the publications

Here the selective list of works and works available on line to the format text:

the Illustration of the kinds (1783),
the botanical Encyclopedia (1783-1796),
Memory on the matter of the sound (1799),
zoological Philosophy (1809).

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