Before the modern evolutionary synthesis was established, Jean-Baptiste Lamarck posited that it was possible for an organism to pass on characteristics acquired during its lifetime to its offspring.
Lamarck’s popular example in Philosophie Zoologique was the idea of the giraffe that stretches its neck to eat from a tree, and thereby passes onto its immediate offspring longer necks, who in turn continue to stretch their necks even further.
Without any scientific evidence, Lamarck’s theory was abandoned. Mendelian genetics and Darwinian natural selection supplanted Lamarckism.
Unfortunately, one of the popular misconceptions that lingers about evolution today is that it is a Lamarckian process. Even laypersons who purport to “believe” in scientific explanations as against religious explanations of the origins of life often don’t understand the process of evolution. The popular March of Progress, through iconic oversimplification, conveys Lamarckism.
The graphic doesn’t depict any mechanism of selection pressure—it begs readers to misinterpret evolution as Lamarckian by just showing a progression of traits, absent of any other context.
Perhaps it’s the folk misunderstanding of evolution as Lamarckian that bolsters an intuitive belief in the SSSM. If the claims of evolutionary psychology were merely operating in a Lamarckian way, then central planners would be able to intercept the inheritance of behaviors, beliefs, and attitudes from parent to child, and instead reëngineer society by collectivizing child rearing to create a socialist New Man.
There’s been a curious resurgence of interest in Lamarckism. Guy Barry (2013) describes transgenerational epigentic inheritance in the brain as evidence of classic Lamarckian inheritance, but it’s post hoc reasoning. As T. Ryan Gregory pointed out,
Lamarck did not think that the environment imposed direct effects on organisms that were then passed on. He argued that the environment created needs to which organisms responded by using some features more and others less, that this resulted in those features being accentuated or attenuated, and that this difference was then inherited by offspring.
Epigenetics wasn’t the mechanism that Lamarck anticipated.