Lately I've collected a file of stories and press releases claiming that some new biological finding vindicates French natural philosopher Jean Lamarck. The guy sure could use it. It's good to be famous, but Lamarck is remembered mostly as a court jester of evolution. When I hear the name Lamarck, I think of giraffes, since these are often used as an example of so-called Lamarckian evolution. In Lamarck's evolution, the story goes, giraffes acquired long necks over the generations by reaching for high leaves, thus stretching their necks and passing the stretched neck on to the next generation.
The scientific advances that are claimed to vindicate him are examples where some acquired traits can be inherited, not through DNA changes but through other mechanisms, such as alterations in the molecules that are attached to DNA. But these advances don't vindicate Lamarck because he wasn't the one to come up with the idea that acquired traits can be inherited. Inheritance of acquired traits has stuck to his name like a barnacle, but his error was not to invent this idea but to fail to see past it.
I learned this from further reading into Loren Eiseley's Darwin's Century. Pop history gives us an erroneous view of Lamarck, who was born in 1744. Lamarck's innovation was to see thought the entrenched concept that species of living things were immutable. Breeds and varieties could emerge, but a cat was always a cat and a dog a dog and it had been so since the beginning of time.
Lamarck's suggestion that evolution could transform one species into another was revolutionary and blasphemous. And he was proven right. Interestingly, the same idea was put forward by Erasmus Darwin, who was grandfather to Charles and a contemporary of Lamarck. But in Eiseley's opinion, the earlier Darwin doesn't have his name associated with a version of evolution because Lamarck was a more systematic thinker.
Both Lamarck and Erasmus Darwin wrote of a kind of directed evolution, in which new organs and other biological innovations came from "physiological need". If your species needs longer necks or bigger brains, or fins or eyes, evolution will grant them.
Eiseley consulted historians who told him both men were "working in the same climate of ideas," and the idea of inherited acquired characteristics was embedded in the popular consciousness. Lamarck also believed living things were hierarchical, arranged in a great ladder of being. But with evolution, "he transformed it into an escalator."
In the 1800s, Charles Darwin didn't refute the notion that acquired traits could be passed down. But he introduced something new, elegant and powerful that neither Lamarck nor his grandfather could see. Charles Darwin saw chance variability working in concert with the winnowing of natural selection. Those processes, he realized, would allow evolution to transform species into new ones, and for all life today to be related to common ancestors.
Lamarck didn't pick up on the importance of chance variation the way Darwin did. It's a frightening idea – that chance has so much power in shaping the world we live in. In Charles Darwin's evolution, no higher being decrees the need for horses or cattle, pine trees or humans. And so the element of chance is resisted to this day, as many people need to believe "everything happens for a reason." Scientists often try to correct people who balk at the randomness of evolution, by pointing out that natural selection is an ordering process. But Charles Darwin's evolution gives chance a big role. His evolution is not directed, has no overall goals, doesn't strive to make animals rise in a hierarchy and become closer to gods.
But Lamarckian evolution was scary enough to the English for shaking the idea of God-given immutable herarchies of things and people. It was no coincidence to Eiseley that Lamarck's breaking of the species barrier came in the wake of the French Revolution. The reaction in England was to label Lamarck as a "French Atheist", whose ideas were, "morally reprehsible." Does any of that sound familiar?