The real Darwin

I'm reading Richard Leakey's annotated version of The Origin of Species. I can't help being struck by how much I misunderstood several aspects of Darwin's thought. Specifically, I viewed him as significantly different from other evolutionists, both before and since, even though he has more in common with them than I'd imagined.

In high school, I learned that Jean Baptiste de Lamarck presented the theory of the inheritance of acquired characteristics. This theory, of course, is wrong, and Darwin was given credit for correcting it by replacing it with his theory of evolution by natural selection. I think that Stephen Jay Gould once wrote an essay suggesting that Lamarck was closer to being on track than he's often portrayed. Still, I viewed Lamarck as believing acquired characteristics could be inherited, and Darwin as opposing him.

But Leakey corrects this view on page 19:

Darwin believed that the effects of habit and of use or disuse of an organ could be inherited, as did most biologists of his time. Although such ideas are often referred to as 'Lamarckism', the theory proposed by Jean Baptiste de Lamarck was rather different in that he believed in an inherent desire for improvement, besoin, which was the driving force of evolutionary change.

That is not at all the way I understood Lamarckism, and certainly it was news that Darwin favored the use or disuse theory that the high school textbooks associate with Lamarck.

Speaking of Gould, as I was earlier, even Leakey associates him with the theory of punctuated equilibrium:

But some paleontologists, notably Stephen Jay Gould of Harvard, think the fossil evidence suggests that at various stages in the history of life evolution has progressed unusually rapidly--in 'spurts'--and that the major branching in the evolutionary tree has occurred at these points.

Gould and Niles Eldredge developed this theory in 1972. In short, it says that things don't evolve continuously. They go through periods of stasis, when they have no reason to evolve because they're adequately adapted to their environment, and then change when their enviornment forces them to. This seemed like a significant improvement over Darwin's theory.

What puzzles me is that Darwin himself seemed to believe this, as we first see on page 88:

I must here remark that I do not suppose that the process ever goes on so regularly as is represented in the diagram, nor that it goes on continuously; it is far more probable that each form remains for long periods unaltered, and then again undergoes modification.

To my untutored eyes, that looks like something Gould or Eldredge might have written.

Moreover, Darwin repeatedly refutes those who believe organisms have an innate tendency toward development, pointing out that such a tendency is not natural selection at all. But such a tendency would imply continuous evolution. By rejecting this tendency, he supports the argument that things evolve only when they have reason to do so, whether by natural selection, sexual selection, or some other related form.

So how did Darwin come to be associated with favoring gradualism, or with opposing the use and disuse theory? I don't know. I think that's worth looking into.