Many people think that Charles Darwin proposed the theory of evolution. He didn't. What Darwin proposed was the theory of natural selection, the method by which evolution occurs. In fact, evolution was widely discussed in scientific circles long before Darwin published his ideas, and Darwin had a predecessor. That predecessor was Lamarck, who first expounded his own theory of evolution in 1800. He released his two-volume masterwork, Philosophie Zoologique, in 1809, but it never gained the popularity of Darwin's Origin of Species.
Born in 1744, Lamarck came from a family of professional soldiers, but his father decided that this child (his 11th) would stay away from combat, and sent the boy to a Jesuit school. The tactic failed. At 19, the young man left the school and joined a regiment in the Seven Year War. After years of service, he traded in a military life for a civilian one. He worked as a clerk in a bank, then turned to writing encyclopedias and almanacs, then became a tutor to Buffon's son while waiting for a more prestigious position. He eventually found work at France's newly formed natural history museum.
Lamarck has been largely laughed out of the textbooks for proposing a bad theory, but he may have been too easily dismissed. By examining fossils, Lamarck realized that some species had remained the same over millennia and others had changed. Cuvier seized upon Egyptian ibises to claim that species never change. Lamarck recognized what Cuvier couldn't (or wouldn't): Just because ibises hadn't changed since Egyptian times didn't mean they couldn't evolve on a much longer time scale. Like Darwin, Lamarck concluded that species change over time by adapting to new environments. Like Darwin, Lamarck concluded that parents pass their traits on to their offspring. He also founded the principle of use and disuse: If an organ is used, it will become stronger, and if it is not used, it will weaken and may disappear in future generations. He argued that evolution tends toward greater complexity, but not always. Where Lamarck's theory fell short was in his supposition that parents could pass on acquired characteristics achieved through a kind of "inner striving," e.g., a longer neck developed by a lifetime of stretching to eat from higher branches. The idea seems silly now, but nobody understood genetics until after Lamarck's death. One set of experiments that disproved this notion involved cutting the tails off generations of poor little mice — who only produced more mice with tails destined for untimely ends.
Although the notion of acquired characteristics being passed down to offspring has been rejected, Lamarck's reputation has been somewhat improved — at least in the eyes of some modern biologists — by a new field of research: epigenetics. Epigenetics is the study of gene expression independent of DNA mutations. Acting in a fashion that contradicts Mendelian inheritance, epigenome changes result from genes being turned off or on by certain environmental factors. This appears to be especially apparent in plants, which produce cells that lead to the next generation late in their life cycles. Lab animals have offered up evidence, too. Underfeed a lab rat, and it will give birth to undersized pups. Feed those pups well, and they will, like their malnourished mother, still give birth to puny pups.
What is less well known about today than Lamarck's belief in the inheritance of acquired characteristics is his system of first and second causes. He believed that all life was governed by a first cause of increasing complexity, arranging organisms in a neat ladder with man (of course) at the top. Environmental adaptations could cause organisms to branch out from the main ladder, but the ladder of progress was predominant. Lamarck would eventually give up this idea in light of new evidence.
After a career in botany, Lamarck began studying invertebrates. In fact, the research change was a demotion. He had been a protégé of Buffon, but Buffon was now dead. The post-benefactor demotion proved to have its benefits, however, in that Lamarck now worked with a growing collection of specimens, and had to explain his findings to students.
When he started his new job, all invertebrates were believed to fall into just two groups: insects and worms. He quickly began reorganizing, and among his many new classifications, he split the group of worms into annelids (such as earthworms) and flatworms (such as tapeworms). While annelids had fairly complicated internal organs, flatworms, he found, were much simpler. Yet because flatworms were bilateral, they were considered superior to "radial" life forms (now classified as cnidarians and echinoderms). This was a problem because the more lowly-seeming radial forms had internal structures far more complicated than those of flatworms. So in one sense, flatworms deserved a higher rung on life's ladder, but in a different sense, radial forms were superior. What to do? Abandon his old classification system, which Lamarck eventually did. He instead adopted a branching view of life in which adaptation was the primary cause of change.
Lamarck's evolutionary theories raised eyebrows, not only for their religious implications, but also because they could be used as a rallying cry by the lower classes; if life could progress and improve, why couldn't they? Beyond upsetting the upper crust, Lamarck had the very bad luck to attract the disdain of Georges Cuvier.
Scientists at the natural history museum were able to live on site with their families. Lamarck took advantage of this opportunity, and was still struggling to support his family while in his 60s. He had three unmarried daughters with no incomes of their own, a son who was partially deaf, and another son who was mentally ill. Lamarck, meanwhile, was losing his sight. After his eyesight was completely gone, Lamarck fielded a public taunt from Cuvier. Perhaps, Cuvier said, Lamarck had lost the use of his own eyes through the principle of disuse. After Lamarck's death, Cuvier wrote him such a scathing eulogy that it was rejected for publication. Even without the final indignity of Cuvier's eulogy, Lamarck died blind, despairing and destitute, surrounded by unsold copies of his books. Poverty even chased him out of his grave; five years after his burial, his rented plot was turned over to someone else and his remains were exhumed and dispersed.
Narrative text and graphic design © by Michon Scott - Updated July 5, 2012