Everything about Jean-baptiste Lamarck totally explained
Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (
August 1,
1744 –
December 18,
1829) was a
French soldier,
naturalist,
academic and an early proponent of the idea that
evolution occurred and proceeded in accordance with
natural laws. Lamarck was born as the eleventh child in an impoverished noble family of soldiers in
Picardie. Lamarck was forced into enrollment in a
Jesuit college in
Amiens, but after his father's death in 1760, Lamarck joined a
company of soldiers. He fought in the
Pomeranian War with
Prussia, and was awarded a commission for his bravery on the battlefield. At his post in
Monaco, Lamarck became interested in natural history and resolved to study medicine. He retired from the army after being injured in 1766, and he returned to his medicine studies. Lamarck showed a particular interest for botany, and he studied the subject under
Bernard de Jussieu for nearly ten years. He was one of the main contributors to the Cell Theory.
After publishing a respected three-volume work
Flore Français, he gained membership into the
French Academy of Sciences in 1779, with the help of
Georges-Louis Leclerc, Comte de Buffon. Lamarck became involved in the
Jardin des Plantes and was appointed to the Chair of Botany in 1788. When the
Muséum national d'histoire naturelle was founded in 1793, Lamarck was appointed as a professor of zoology. In 1801, he published
Système des Animaux sans Vertebres, a major work on the classifications of invertebrates. In an 1802 publication, he became one of the first to use the term
biology in its modern sense. Lamarck continued his work as a premier authority on invertebrate zoology.
In the modern era, Lamarck is remembered primarily for a theory of "
inheritance of acquired characters", called "soft inheritance" or
Lamarckism. His descriptions of soft inheritance were accepted by most natural historians (until
Charles Darwin in his
Origin of Species). Lamarck's contribution to
evolutionary theory consisted of the first truly cohesive theory of 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.
Biography
Lamarck was born in
Bazentin,
Picardie, northern France, as the eleventh 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 teenage 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
Pomeranian 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 fourteen men - with no officers. One of the men suggested that the puny, seventeen year-old volunteer should assume command and order a withdrawal from the field; but although Lamarck accepted command, he insisted they remain where they'd 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 underwent a complicated operation, and continued his treatment for a year. He was awarded a commission and settled at his post in
Monaco. It was there that he encountered
Traite des Plantes usuelles, a botany book by James Francis Chomel. Under Jussieu, Lamarck spent ten years studying French flora. After his studies, in 1778, he published some of his observations and results in a three-volume work, entitled
Flore Français. Lamarck's work was respected by many scholars, and it launched him into prominence in French science. On
August 8,
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
April 22,
1781, and he made 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
January 7,
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
April 21 of the following year, Charles Rene, 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 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 didn't imply such a close association with King
Louis XVI. 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
September 27,
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
October 9, he married Charlotte Reverdy, who was thirty years his junior. 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
Museum de'Histoire Naturelle in which he first outlined his newly developing ideas about evolution.
In 1801, he published
Système des Animaux sans Vertebres, 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 the class
Crustaces, Lamarck proposed two orders. The first group was
Crustaces pediocles, classified by the animals' two distinct stalked eyes. This categorization included crabs, shrimps and hermit crabs. The second group
Crustaces sessiliocles were classified by the animals' distinct pair of eyes, or single,
sessile eyes. Members of this order included
amphipods,
isopods,
cyclops,
cladocerans,
xiphosurida and amymones.
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 Vivans, 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.
During his lifetime he became controversial, attacking the chemistry proposed by
Lavoisier and criticising
palaeontologist Georges Cuvier’s anti-evolutionary stance. After his death, Cuvier used the forum of a eulogy in an attempt to discredit Lamarck's scientific beliefs, painting a picture of Lamarck as the equivalent of a philosopher or poet (in fact, Lamarck was a strict materialist).
Lamarck died in
Paris on
December 18,
1829. When he died, his family were so poor they'd to apply to the Academie for financial assistance. Lamarck's books and the contents of his home were sold at auction, and he was buried in a temporary lime-pit.
Lamarckian Evolution
Lamarck stressed two main themes in his biological work. The first was that the environment gives rise to changes in animals. He cited examples of blindness in moles, the presence of teeth in mammals and the absence of teeth in birds as evidence of this principle. The second principle was that life was structured in an orderly manner and that many different parts of all bodies make it possible for the organic movements of animals.
Lamarck is usually remembered for his belief in the inheritance of acquired characteristics, and the "use and disuse" model by which organisms developed their characteristics. Lamarck incorporated this belief into his theory of evolution, along with other more common beliefs of the time, such as spontaneous generation.
The inheritance of acquired characteristics (also called the theory of
adaptation or "
soft inheritance") was rejected by
August Weismann when he developed a theory of inheritance in which "germ-plasm" (the hereditary material passed from parents to offspring) remained separate and distinct from "soma" (the material composing the body of an organism); thus nothing which happens to the soma may be passed on with the germ-plasm. This model underlies the modern understanding of inheritance. Weismann is famous for an experiment in which he cut the tails off mice, demonstrating that the injury wasn't passed on to the offspring; but historians of science such as Stephen Jay Gould argue that this experiment had far less effect on the acceptance of
Lamarckism than Weismann's more comprehensive theoretical framework
(Believers in Lamarckian inheritance didn't count injury or mutilation as a true acquired characteristic: only those which were initiated by the animal's own needs, that were beneficial, were expected to be passed on. This Lamarckian view is consistent with
Charles Darwin's theory of natural selection).
Lamarckism is used as an analogy to describe the action of other "evolutionary" concepts in the modern era. For example, the
memetic theory of
cultural evolution is sometimes described as a form of "Lamarckian" inheritance of non-genetic traits.
The
honeybee subspecies
Apis mellifera lamarckii is named after Lamarck. Likewise, the bluefire
jellyfish (Cyaneia lamarckii) has been named after him.
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