Jean-Baptiste de Lamarck

Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck (1 August 1744 – 18 December 1829), often known simply as Lamarck (; ), was a French naturalist, biologist, academic, and soldier. He was an early proponent of the idea that biological evolution occurred and proceeded in accordance with natural laws.

Lamarck fought in the Seven Years' War against Prussia, and was awarded a commission for bravery on the battlefield. Posted to Monaco, Lamarck became interested in natural history and resolved to study medicine. Packard (1901), p. 15. He retired from the army after being injured in 1766, and returned to his medical studies. Lamarck developed a particular interest in botany, and later, after he published the three-volume work ''Flore françoise'' (1778), he gained membership of the French Academy of Sciences in 1779. Lamarck became involved in the Jardin des Plantes and was appointed to the Chair of Botany in 1788. When the French National Assembly founded the Muséum national d'Histoire naturelle in 1793, Lamarck became a professor of zoology.

In 1801, he published ''Système des animaux sans vertèbres'', a major work on the classification of invertebrates, a term which allegedly he coined. In an 1802 publication, he became one of the first to use the term "biology" in its modern sense. Coleman (1977), pp. 1–2. Lamarck continued his work as a premier authority on invertebrate zoology. He is remembered, at least in malacology, as a taxonomist of considerable stature.

The modern era generally remembers Lamarck for a theory of inheritance of acquired characteristics, called Lamarckism (inaccurately named after him), soft inheritance, or use/disuse theory, which he described in his 1809 ''Philosophie zoologique''. However, the idea of soft inheritance long antedates him, formed only a small element of his theory of evolution, and was in his time accepted by many natural historians. Lamarck's contribution to evolutionary theory consisted of the first truly cohesive theory of biological evolution, in which an alchemical complexifying force drove organisms up a ladder of complexity, and a second environmental force adapted them to local environments through ''use and disuse'' of characteristics, differentiating them from other organisms. Gould (2002), p. 187. Scientists have debated whether advances in the field of transgenerational epigenetics mean that Lamarck was to an extent correct, or not.

Biography

Jean-Baptiste Lamarck was born in Bazentin, Picardy, northern France, as the 11th child in an impoverished aristocratic family. Male members of the Lamarck family had traditionally served in the French army. Lamarck's eldest brother was killed in combat at the Siege of Bergen op Zoom, and two other brothers were still in service when Lamarck was in his teenaged years. Yielding to the wishes of his father, Lamarck enrolled in a Jesuit college in Amiens in the late 1750s.

After his father died in 1760, Lamarck bought himself a horse, and rode across the country to join the French army, which was in Germany at the time. Lamarck showed great physical courage on the battlefield in the Seven Years' War with Prussia, and he was even nominated for the lieutenancy. Lamarck's company was left exposed to the direct artillery fire of their enemies, and was quickly reduced to just 14 men—with no officers. One of the men suggested that the puny, 17-year-old volunteer should assume command and order a withdrawal from the field; although Lamarck accepted command, he insisted they remain where they had been posted until relieved.

When their colonel reached the remains of their company, this display of courage and loyalty impressed him so much that Lamarck was promoted to officer on the spot. However, when one of his comrades playfully lifted him by the head, he sustained an inflammation in the lymphatic glands of the neck, and he was sent to Paris to receive treatment. He was awarded a commission and settled at his post in Monaco. There, he encountered ''Traité des plantes usuelles'', a botany book by James Francis Chomel.

With a reduced pension of only 400 francs a year, Lamarck resolved to pursue a profession. He attempted to study medicine, and supported himself by working in a bank office. Lamarck studied medicine for four years, but gave it up under his elder brother's persuasion. He was interested in botany, especially after his visits to the Jardin du Roi, and he became a student under Bernard de Jussieu, a notable French naturalist. Under Jussieu, Lamarck spent 10 years studying French flora. In 1776, he wrote his first scientific essay—a chemical treatise.

After his studies, in 1778, he published some of his observations and results in a three-volume work, entitled ''Flore française''. Lamarck's work was respected by many scholars, and it launched him into prominence in French science. On 8 August 1778, Lamarck married Marie Anne Rosalie Delaporte. Georges-Louis Leclerc, Comte de Buffon, one of the top French scientists of the day, mentored Lamarck, and helped him gain membership to the French Academy of Sciences in 1779 and a commission as a royal botanist in 1781, in which he traveled to foreign botanical gardens and museums. Lamarck's first son, André, was born on 22 April 1781, and he made his colleague André Thouin the child's godfather.

In his two years of travel, Lamarck collected rare plants that were not available in the Royal Garden, and also other objects of natural history, such as minerals and ores, that were not found in French museums. On 7 January 1786, his second son, Antoine, was born, and Lamarck chose Antoine Laurent de Jussieu, Bernard de Jussieu's nephew, as the boy's godfather. On 21 April the following year, Charles René, Lamarck's third son, was born. René Louiche Desfontaines, a professor of botany at the Royal Garden, was the boy's godfather, and Lamarck's elder sister, Marie Charlotte Pelagie De Monet, was the godmother. In 1788, Buffon's successor at the position of Intendant of the Royal Garden, Charles-Claude Flahaut de la Billaderie, comte d'Angiviller, created a position for Lamarck, with a yearly salary of 1,000 francs, as the keeper of the herbarium of the Royal Garden.

In 1790, at the height of the French Revolution, Lamarck changed the name of the Royal Garden from Jardin du Roi to Jardin des Plantes, a name that did not imply such a close association with King Louis XVI. Damkaer (2002), p. 118. Lamarck had worked as the keeper of the herbarium for five years before he was appointed curator and professor of invertebrate zoology at the Muséum national d'histoire naturelle in 1793. During his time at the herbarium, Lamarck's wife gave birth to three more children before dying on 27 September 1792. With the official title of "Professeur d'Histoire naturelle des Insectes et des Vers", Lamarck received a salary of nearly 2,500 francs per year. The following year, on 9 October, he married Charlotte Reverdy, who was 30 years his junior. On 26 September 1794 Lamarck was appointed to serve as secretary of the assembly of professors for the museum for a period of one year. In 1797, Charlotte died, and he married Julie Mallet the following year; she died in 1819.

In his first six years as professor, Lamarck published only one paper, in 1798, on the influence of the moon on the Earth's atmosphere. Lamarck began as an essentialist who believed species were unchanging; however, after working on the molluscs of the Paris Basin, he grew convinced that transmutation or change in the nature of a species occurred over time. He set out to develop an explanation, and on 11 May 1800 (the 21st day of ''Floreal'', Year VIII, in the revolutionary timescale used in France at the time), he presented a lecture at the Muséum national d'histoire naturelle in which he first outlined his newly developing ideas about evolution.

In 1801, he published ''Système des Animaux sans Vertèbres'', a major work on the classification of invertebrates. In the work, he introduced definitions of natural groups among invertebrates. He categorized echinoderms, arachnids, crustaceans, and annelids, which he separated from the old taxon for worms known as ''Vermes''. Lamarck was the first to separate arachnids from insects in classification, and he moved crustaceans into a separate class from insects.

In 1802 Lamarck published ''Hydrogéologie'', and became one of the first to use the term biology in its modern sense. In ''Hydrogéologie'', Lamarck advocated a steady-state geology based on a strict uniformitarianism. He argued that global currents tended to flow from east to west, and continents eroded on their eastern borders, with the material carried across to be deposited on the western borders. Thus, the Earth's continents marched steadily westward around the globe.

That year, he also published ''Recherches sur l'Organisation des Corps Vivants'', in which he drew out his theory on evolution. He believed that all life was organized in a vertical chain, with gradation between the lowest forms and the highest forms of life, thus demonstrating a path to progressive developments in nature. Osborn (1905), p. 160.

In his own work, Lamarck had favored the then-more traditional theory based on the classical four elements. During Lamarck's lifetime, he became controversial, attacking the more enlightened chemistry proposed by Lavoisier