Jean-Baptiste Lamarck (1744-1829)

by
Janet Russell
KIE Developer

Critique the influence of Lamarck

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"Do we not therefore perceive that by the action of the laws of organization . . . nature has in favorable times, places, and climates multiplied her first germs of animality, given place to developments of their organizations, . . . and increased and diversified their organs? Then. . . aided by much time and by a slow but constant diversity of circumstances, she has gradually brought about in this respect the state of things which we now observe. How grand is this consideration, and especially how remote is it from all that is generally thought on this subject!"

Text of a lecture given by Lamarck at the Musée National d'Histoire Naturelle, Paris, May 1803

Lamarck's scientific theories were largely ignored or attacked during his lifetime; Lamarck never won the acceptance and esteem of his colleagues Buffon and Cuvier, and he died in poverty and obscurity. Today, the name of Lamarck is associated merely with a discredited theory of heredity, the "inheritance of acquired traits." However, Charles Darwin, Lyell, Haeckel, and other early evolutionists acknowledged him as a great zoologist. Charles Darwin wrote in 1861:

This justly celebrated naturalist first published his views in 1801. . . he first did the eminent service of arousing attention to the probability of all changes in the organic, as well as in the inorganic world, being the result of law, and not of miraculous interposition.

Who was this man, and why did he inspire such conflicting attitudes?

Biography of Lamarck

Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck was born on August 1, 1744, in the village of Bazentin-le-Petit in the north of France. He was the youngest of eleven children in a family with a centuries-old tradition of military service; his father and several of his brothers were soldiers. The young Lamarck entered the Jesuit seminary at Amiens around 1756, but not long after his father's death, Lamarck rode off to join the French army campaigning in Germany in the summer of 1761; in his first battle, he distinguished himself for bravery under fire and was promoted to officer. After peace was declared in 1763, Lamarck spent five years on garrison duty in the south of France, until an accidental injury forced him to leave the army. After working as a bank clerk in Paris for a while, Lamarck began to study medicine and botany, at which he rapidly became expert; in 1778 his book on the plants of France, Flore Française, was published to great acclaim, in part thanks to the support of Buffon.

On the strength of the Flore Française (and Buffon's patronage), Lamarck was appointed an assistant botanist at the royal botanical garden, the Jardin des Plantes, which was not only a botanical garden but a center for medical education and biological research. Aside from a stint as tutor to Buffon's son during a tour of Europe in 1781, Lamarck continued as an underpaid assistant at the Jardin du Roi, living in poverty (and having to defend his job from cost-cutting bureaucrats in the National Assembly) until 1793. That year, the same year that Louis XVI and Marie Antoinette went to the guillotine, the old Jardin des Plantes was reorganized as the Musée National d'Histoire Naturelle (National Museum of Natural History), which was to be run by twelve professors in twelve different scientific fields. Lamarck, who had called for this reorganization, was appointed a professor -- of the natural history of insects and worms (that is, of all invertebrates), a subject he knew nothing about.

To be fair to Lamarck, we should mention that since the time of Linnaeus, few naturalists had considered the invertebrates worthy of study. The word "invertebrates" did not even exist at the time; Lamarck coined it. The invertebrate collections at the Musée were enormous and rapidly growing, but poorly organized and classified. Although the professors at the Musée were theoretically equal in rank, the professorship of "insects and worms" was definitely the least prestigious. But Lamarck took on the enormous challenge of learning -- and creating -- a new field of biology. The sheer number and diversity of invertebrates proved to be both a challenge and a rich source of knowledge. As Lamarck lectured his students in 1803, after ten years of research on invertebrates:

. . . we perceive that, relative to the animal kingdom, we should chiefly devote our attention to the invertebrate animals, because their enormous multiplicity in nature, the singular diversity of their systems of organization, and of their means of multiplication, . . . , show us, much better than the higher animals, the true course of nature, and the means which she has used and which she still unceasingly employs to give existence to all the living bodies of which we have knowledge.

Lamarck published a series of books on invertebrate zoology and paleontology. Of these, Philosophie zoologique, published in 1809, most clearly states Lamarck's theories of evolution.

But Lamarck's works never became popular during his lifetime, and Lamarck never won the respect or prestige enjoyed by his patron Buffon or his colleague Cuvier. While Cuvier respected Lamarck's work on invertebrates, he had no use for Lamarck's theory of evolution, and he used his influence to discredit it. Most of Lamarck's life was a constant struggle against poverty; to make matters worse, he began to lose his sight around 1818, and spent his last years completely blind, cared for by his devoted daughters (he had been married four times). When he died, on December 28, 1829, he received a poor man's funeral (although his colleague Geoffroy Saint-Hilaire gave one of the orations) and was buried in a rented grave; after five years his body was removed, and no one now knows where his remains are.

Lamarck's Scientific Thought

Beginning in 1801, Lamarck began to publish details of his evolutionary theories. Where men like Buffon had hinted at the possibility of evolutionary change, Lamarck declared it forthrightly. In 1801 he wrote:

. . . time and favorable conditions are the two principal means which nature has employed in giving existence to all her productions. We know that for her time has no limit, and that consequently she always has it at her disposal.

What was the mechanism for evolution? "Lamarckism" or "Lamarckianism" is now often used in a rather derogatory sense to refer to the theory that acquired traits can be inherited. What Lamarck actually believed was more complex: organisms are not passively altered by their environment, as his colleague Geoffroy Saint-Hilaire thought. Instead, a change in the environment causes changes in the needs of organisms living in that environment, which in turn causes changes in their behavior. Altered behavior leads to greater or lesser use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas disuse would cause it to shrink or even disappear. This rule -- that use or disuse causes structures to enlarge or shrink -- Lamarck called the "First Law" in his book Philosophie zoologique. Lamarck's "Second Law" stated that all such changes were heritable. The result of these laws was the continuous, gradual change of all organisms, as they became adapted to their environments; the physiological needs of organisms, created by their interactions with the environment, drive Lamarckian evolution.

While the mechanism of Lamarckian evolution is quite different from that proposed by Darwin, the predicted result is the same: adaptive change in lineages, ultimately driven by environmental change, over long periods of time. It is interesting to note that Lamarck cited in support of his theory of evolution many of the same lines of evidence th