Jean-Baptiste Lamarck

French biologist

• Born: August 1, 1744; Bazentin-le-Petit, France
• Died: December 28, 1829; Paris, France

Jean-Baptiste Lamarck was a French botanist and biologist during the late eighteenth and early nineteenth centuries. He was one of the first scientists to advance a theory of evolution. Though later discredited by Charles Darwin and modern genetics, Lamarck’s ideas were revolutionary at the time.

Primary field: Biology

Specialties: Evolutionary biology; botany

Early Life

Jean-Baptiste Pierre Antoine de Monet, chevalier de Lamarck, was born in Bazentin-le-Petit, Picardy, France, on August 1, 1744. He was the youngest of eleven children. The Lamarck family had served in the French military for generations. Lamarck’s father wished for his youngest son to join the clergy and made him study in a Jesuit seminary. After his father’s death in 1760, however, Lamarck left the seminary and joined the French army, which was fighting in Germany at the time. He went on to serve in the South of France for five years, during which time he suffered an injury to his neck. After surgery failed to solve the problem, Lamarck was forced to resign his commission in 1768.

The military pension he received was not enough to support him, so Lamarck enrolled in medical school, hoping to become a physician. He often had to work in a bank to make ends meet. In the meantime, he studied botany and the natural sciences with increasing interest. Eventually, Lamarck became so interested in natural science that he abandoned his medical studies altogether in order to dedicate himself to botany. He traveled throughout France collecting specimens until finally, in 1778, he published a survey of the flowers of France entitled Flore française (French flora). The book was praised by the great French botanist Georges-Louis Leclerc, comte de Buffon, and soon Lamarck was invited to lecture and correspond with many premier French scientists.

In 1779, Lamarck was inducted into the French Academy of Sciences. Through the academy, he acquired a poorly paid position in the royal herbarium at the Jardin des Plantes. King Louis XVI sponsored Lamarck on a tour of Europe to search for new botanical specimens, but the small salary kept him in a state of poverty. The chaos of the French Revolution (1789–99) did not distract Lamarck from his studies; he published a series of works on botany, physics, and meteorology over the next several years. As he was tenured, he did not lose his position when the new republic came into power and the Jardin des Plantes was reorganized into a natural history museum.

Life’s Work

In 1794, Lamarck was put in charge of insects and worms at the natural history museum and soon realized that there was great potential for advancement in his new field. Since ancient times, Western scientists had done very little study of insects and worms. As he studied and categorized the museum’s vast collection, Lamarck came up with the term invertebrates (lacking vertebrae) to describe the insect specimens. He wrote a series of books classifying thousands of invertebrates, noticing in the process how much invertebrates vary from one another.

In 1809, after fifteen years at the museum, Lamarck published Philosophie zoologique (Zoological Philosophy, 1914), in which he set forth a bold new theory of evolution in the natural world. Through an examination of the fossil record, Lamarck had discovered that after millions of years, some species had physically changed from their original ancestors, and it was this fact of physical change over time that prompted his theory. While many scientists had discussed evolution, no one had yet advanced a comprehensive and detailed theory on the subject. Lamarck had hinted at evolution through his earlier studies in the invertebrate world, but it took him several more years of studying the wider natural world before he went public with his theory.

Lamarck’s theory was grand and all encompassing, based on a system of first and second causes. All natural life, according to Lamarck, could be categorized as a ladder of increasing complexity, with humans at the top. The first cause was that all organisms were attempting to “evolve” to the top of the ladder, and that nature wanted all organisms to reach the same state of perfection as humankind. The second cause, what enabled these organisms to evolve, was environmental adaptation; in other words, over the course of many years, the natural environment forced animals to evolve in order to achieve a better state.

According to Lamarck, the inheritance of acquired characteristics proved his theory. He argued that animals changed and evolved because parents passed onto their offspring the physiological changes they had undergone in their lifetime. For example, Lamarck believed that giraffes once had short necks close to their bodies, but by stretching to eat the leaves high up in trees, their necks eventually grew longer and longer, and adult giraffes then passed these long necks onto their offspring. Conversely, according to this theory, when animals did not use a limb or organ, it would eventually disappear; as an example, Lamarck cited snakes, whose legs he believed had eventually disappeared due to a lifetime of sliding on their stomachs.

In 1818, Lamarck was forced to retire from the museum due to ill health and failing eyesight. For the next ten years, blind and penniless, he was cared for by his daughters. He died in 1829, so poor that he was buried in a temporary grave. After five years, his body was exhumed and reburied somewhere in the catacombs of Paris, where vagrants and criminals were interred.

Impact

Lamarck’s theory of evolution was heavily criticized by his fellow scientists. Georges Cuvier, one of Lamarck’s most famous colleagues, made a point of publicly denigrating his ideas. Few scientists read or debated his work, because many thought the whole idea of evolution was impossible.

Lamarck’s importance has been debated among modern scientists, since he was correct on many subjects and wrong on many others. He was correct in assuming that species change over time by adapting to new environments and that parents pass on traits to their offspring. Later, Charles Darwin would borrow from Lamarck in describing his principle of use and disuse, which states that when an organ is not used, it is discarded. However, other parts of Lamarck’s theory were eventually disproved, such as the inheritance of acquired characteristics, proved incorrect during the nineteenth century. Also, evolution is not synonymous with direction. Despite Lamarck’s insistence to the contrary, most scientists agree that there is no perfect organism to which all other organisms aspire.

During his lifetime, Lamarck ignored evidence contrary to his theory, which did nothing to help his cause. He was highly defensive and would ignore the arguments of other scientists who contradicted him. In most modern science textbooks, Lamarck is derided for having proposed a bad theory. While his theory on the inheritance of acquired characteristics was incorrect, Lamarck was working at a time when the study of genetics and inherited traits was unknown to the scientific world.

Most importantly, Lamarck developed a theoretical framework for evolution. Forty years later, when English naturalist Charles Darwin first began his work, Lamarck was one of the writers he used to help build up his theory. Darwin’s idea of natural selection, the idea that favorable characteristics will allow some animals to survive and breed over others, could not have been advanced without Lamarck’s earlier work. Thus, although he was wrong about the details of evolution, Lamarck is noteworthy for being the first scientist to recognize it as an observable process.

Bibliography

Burkhardt, Richard. The Spirit of System: Lamarck and Evolutionary Biology. Cambridge: Harvard UP, 1995. Print. Examines Lamarck’s position within his scientific community, discussing his study of invertebrates and his resulting conclusions about evolution.

Lamarck, Jean-Baptiste. Zoological Philosophy: An Exposition with Regard to the Natural History of Animals. Rosamund, CA: Bill Huth, 2006. Print. A translated edition of Lamarck’s theory of evolution.

Shapiro, James A. Evolution: A View from the Twenty-First Century. Upper Saddle River: FT Press Science, 2011. Print. Situates Lamarck’s views on evolution within the history of early evolutionary science, while also providing an analysis of evolutionary theory in the twenty-first century.