If you have studied evolution inside or outside of the classroom, you have no doubt encountered the figure of Jean-Baptiste Lamarck and the discredited notion of the inheritance of acquired characteristics attributed to him known as “Lamarckism.” This
But even if he did not invent the idea, what if Lamarck was right all along to believe, at least in part, that acquired characteristics can be passed along transgenerationally after all—perhaps not on the kind of macro scale manifested by giraffe necks, but in other more subtle yet no less critical components to the principles of evolution? That is the subject of Lamarck’s Revenge: How Epigenetics is Revolutionizing Our Understanding of Evolution’s Past and Present, by the noted paleontologist Peter Ward. The book’s cover naturally showcases a series of illustrated giraffes with ever-lengthening necks! Ward is an enthusiast for the relatively new, still developing—and controversial—science of epigenetics, which advances the hypothesis that certain circumstances can trigger markers that can be transmitted from parent to child by changing the gene expression without altering the primary structure of the DNA itself. Let’s imagine a Holocaust survivor, for instance: can the trauma of Auschwitz cut so deep that the devastating psychological impact of that horrific experience will be passed on to his children, and his children’s children?
This is heady stuff, of course. We should pause for the uninitiated and explain the nature of Darwinian natural selection—the key mechanism of the Theory of Evolution—in its simplest terms. The key to survival for all organizations is adaptation. Random mutations occur over time, and if one of those mutations turns out to be better adapted to the environment, it is more likely to reproduce and thus pass along its genes to its offspring. Over time, through “gradualism,” this can lead to the rise of new species. Complexity breeds complexity, and that is the road traveled by all organisms that has led from the simplest prokaryote unicellular organism—the 3.5-billion-year-old photosynthetic cyanobacteria—to modern homo sapiens sapiens. This is, of course, a very, very long game; so long in fact that Darwin—who lived in a time when the age of the earth was vastly underestimated—fretted that there was not enough time for evolution as he envisioned it to occur. Advances in geology later determined that the earth was about 4.5 billion years old, which solved that problem, but still left other aspects of evolution unexplained by gradualism alone. The brilliant Stephen Jay Gould (along with Niles Eldredge) came along in 1972 and proposed that rather than gradualism most evolution more likely occurred through what he called “punctuated equilibrium,” often triggered by a catastrophic change in the environment. Debate has raged ever since, but it may well be that evolution is guided by forces of both gradualism and punctuated equilibrium. But could there still be other forces at work?
Transgenerational epigenetic inheritance represents another so-called force and is at the cutting edge of research in evolutionary biology today. But has the hypothesis of epigenetics been demonstrated to be truly plausible? And the answer to that is—maybe. In other words, there does seem to be studies that support transgenerational epigenetic inheritance, most famously—as detailed in Lamarck’s Revenge—in what has been dubbed the “Dutch Hunger Winter Syndrome,” that saw children born during a famine smaller than those born before the famine, and with a later, greater risk of glucose intolerance, conditions then passed down to successive generations. On the other hand, the evidence for epigenetics has not been as firmly established as some proponents, such as Ward, might have us believe.
Lamarck’s Revenge is a very well-written and accessible scientific account of epigenetics for a popular audience, and while I have read enough evolutionary science to follow Ward’s arguments with some competence, I remain a layperson who can hardly endorse or counter his claims. The body of the narrative is comprised of Ward’s repeated examples of what he identifies as holes in traditional evolutionary biology that can only be explained by epigenetics. Is he right? I simply lack the expertise to say. I should note that I received this book as part of an “Early Reviewers” program, so I felt a responsibility to read it cover-to-cover, although my own interest lapsed as it moved beyond my own depth in the realm of evolutionary biology.
I should note that this is all breaking news, and as we appraise it we should be mindful of how those on the fringes of evangelicalism, categorically opposed to the science of human evolution, will cling to any debate over mechanisms in natural selection to proclaim it all a sham sponsored by Satan—who has littered the earth with fossils to deceive us—to challenge the truth of the “Garden of Eden” related in the Book of Genesis. Once dubbed “Creationists,” they have since rebranded themselves in association with the pseudoscience of so-called “Intelligent Design,” which somehow remains part of the curriculum at select accredited universities. Science is self-correcting. These folks are not, so don’t ever let yourself be distracted by their fictional supernatural narrative. Evolution—whether through gradualism and/or punctuated equilibrium and/or epigenetics—remains central to both modern biology and modern medicine, and that is not the least bit controversial among scientific professionals. But if you want to find out more about the implications of epigenetics for human evolution, then I recommend that you pick up Lamarck’s Revenge and challenge yourself to learn more!
Note: While you are at it, if you want to learn more about 3.5-billion-year-old photosynthetic cyanobacteria, I highly recommend this: