Jean-baptiste Lamarck Proposed That Organisms

Jean-Baptiste Lamarck (1744-1829)

"Do we not therefore perceive that by the action of the laws of organization . . . nature has in favorable times, places, and climates multiplied her outset germs of bestiality, given place to developments of their organizations, . . . and increased and diversified their organs? Then. . . aided by much fourth dimension and by a slow only constant diversity of circumstances, she has gradually brought about in this respect the state of things which nosotros at present observe. How grand is this consideration, and especially how remote is information technology from all that is generally idea 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 proper 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 and as a forerunner of evolution. Charles Darwin wrote in 1861:

Who was this human, and why did he inspire such alien attitudes?

Biography of Lamarck

Jean Baptiste Pierre Antoine de Monet, Chevalier de Lamarck was born on Baronial ane, 1744, in the hamlet of Bazentin-le-Petit in the due north of France. He was the youngest of eleven children in a family with a centuries-former tradition of armed forces service; his begetter and several of his brothers were soldiers. The young Lamarck entered the Jesuit seminary at Amiens around 1756, only not long after his father's expiry, Lamarck rode off to join the French ground forces candidature in Germany in the summer of 1761; in his beginning boxing, he distinguished himself for bravery under burn and was promoted to officer. After peace was alleged in 1763, Lamarck spent five years on garrison duty in the south of France, until an accidental injury forced him to get out the ground forces. After working every bit a banking concern 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 French republic, 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 banana botanist at the majestic botanical garden, the Jardin des Plantes, which was not merely a botanical garden but a eye for medical education and biological enquiry. Aside from a stint as tutor to Buffon'southward son during a bout of Europe in 1781, Lamarck continued as an underpaid banana at the Jardin du Roi, living in poverty (and having to defend his task from toll-cutting bureaucrats in the National Assembly) until 1793. That year, the aforementioned year that Louis 16 and Marie Antoinette went to the guillotine, the onetime Jardin des Plantes was reorganized every bit the Musée National d'Histoire Naturelle (National Museum of Natural History), which was to exist 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 zippo most.

To be fair to Lamarck, we should mention that since the time of Linnaeus, few naturalists had considered the invertebrates worthy of study. The give-and-take "invertebrates" did not even exist at the time; Lamarck coined it. The invertebrate collections at the Musée were enormous and chop-chop 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. Simply 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 enquiry 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 truthful grade 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 take cognition.

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. The first volume of Histoire naturelle des Animaux sans vertèbres was published in 1815, the second in 1822. Bated from Lamarck's contributions to evolutionary theory, his works on invertebrates stand for a great advance over existing classifications; he was the first to split up the Crustacea, Arachnida, and Annelida from the "Insecta." His classification of the mollusks was far in advance of anything proposed previously; Lamarck broke with tradition in removing the tunicates and the barnacles from the Mollusca. He too anticipated the work of Schleiden & Schwann in cell theory in stating that:

. . . no body can take life if its constituent parts are not cellular tissue or are not formed past cellular tissue.

Lamarck even constitute time to write papers on physics and meteorology, including some annual compilations of atmospheric condition data.

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'southward piece of 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 4 times). When he died, on December 28, 1829, he received a poor man'due south funeral (although his colleague Geoffroy Saint-Hilaire gave i of the orations) and was cached in a rented grave; later 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 alter, Lamarck declared it forthrightly. In 1801 he wrote:

. . . time and favorable weather condition 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 at present 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 non passively altered by their surround, 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 beliefs. Altered behavior leads to greater or bottom use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas decay would cause it to compress or even disappear. This rule -- that apply or disuse causes structures to overstate or compress -- Lamarck chosen the "First Law" in his book Philosophie zoologique. Lamarck's "Second Constabulary" stated that all such changes were heritable. The result of these laws was the continuous, gradual change of all organisms, equally they became adapted to their environments; the physiological needs of organisms, created past their interactions with the surround, drive Lamarckian development.

While the mechanism of Lamarckian evolution is quite unlike from that proposed past Darwin, the predicted outcome is the same: adaptive change in lineages, ultimately driven by environmental alter, over long periods of time. It is interesting to note that Lamarck cited in back up of his theory of evolution many of the same lines of evidence that Darwin was to use in the Origin of Species. Lamarck's Philosophie zoologique mentions the bully variety of animal and plant forms produced under human cultivation (Lamarck even anticipated Darwin in mentioning fantail pigeons!); the presence of vestigial, not-functional structures in many animals; and the presence of embryonic structures that have no counterpart in the adult. Like Darwin and later evolutionary biologists, Lamarck argued that the Globe was immensely old. Lamarck even mentions the possibility of natural selection in his writings, although he never seems to have attached much importance to this idea.

It is fifty-fifty more interesting to note that, although Darwin tried to refute the Lamarckian machinery of inheritance, he afterward admitted that the heritable effects of use and decay might exist of import in development. In the Origin of Species he wrote that the vestigial eyes of moles and of cave-domicile animals are "probably due to gradual reduction from disuse, simply aided perhaps by natural pick." Lamarckian inheritance, at least in the sense Lamarck intended, is in conflict with the findings of genetics and has at present been largely abandoned -- but until the rediscovery of Mendel'southward laws at the commencement of the twentieth century, no one understood the mechanisms of heredity, and Lamarckian inheritance was a perfectly reasonable hypothesis. Several other scientists of the day, including Erasmus Darwin, subscribed to the theory of use and disuse -- in fact, Erasmus Darwin's evolutionary theory is then close to Lamarck'south in many respects that it is surprising that, as far every bit is known now, the two men were unaware of each other's piece of work.

In several other respects, the theory of Lamarck differs from modern evolutionary theory. Lamarck viewed development as a process of increasing complexity and "perfection," non driven by chance; equally he wrote in Philosophie zoologique, "Nature, in producing in succession every species of animate being, and beginning with the least perfect or simplest to end her piece of work with the most perfect, has gradually complicated their structure." Lamarck did not believe in extinction: for him, species that disappeared did so because they evolved into unlike species. If this goes on for too long, it would mean the disappearance of less "perfect" organisms; Lamarck had to postulate that elementary organisms, such as protists, were constantly existence spontaneously generated. Yet despite these differences, Lamarck made a major contribution to evolutionarythought, developing a theory that paralleled Darwin's in many respects. Rediscovered in the centre part of the 19th century, his theories finally gained the attention they merited. His mechanism of evolution remained a popular alternative to Darwinian selection until the beginning of the 20th century; prominent scientists like Edward Drinker Cope adopted Lamarckianism and tried to apply information technology to their work. Though his proposed mechanism somewhen fell out of favor, he broke footing in establishing the fact of evolution.