Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
Two days ago I interviewed Richard Dawkins about his latest book: Flights of Fancy: Defying Gravity by Design and Evolution. The Center for Inquiry’s video is already up, and if you missed the live version you can watch it below. The discussion is about 45 minutes long with another 15 minutes for questions. At the end of the discussion, Richard describes the book he’s writing now.
I haven’t watched this one; like many, I can’t bear to see myself on video.
I found this directed to me on the Internet (original spelling preserved). It’s a new theory of how religion evolved.
I read your article on the war between religion and science as im trying to find an avenue to put my theory of the evolutionary basis of religion. It involves harmonic vibrations of the skull occuring as we speak (felt best on the top of your head). The vestibular system is located excellently to pick up the vibrations and cause a feedback loop with the parietal vestibular insular cortex located around the audiocortex and the muscular and sensory sections of the mouth to improve speech. I find the journal process to be too slow and haphazard as i have sincerely no patience with it. There are too many journals! if you know of an appropriate journal or any other location that might be interested i would be happy to send you a copy of the manuscript.
Reminder: this evening/afternoon/night, depending on where you live, Richard Dawkins and I will have an hourlong discussion (I envision 45 minutes with 10-15 minutes of questions from the viewers) about Richard’s new book on flight. Readers can type in questions, which will be curated, and I will chose what I think are the good ones. You can get the details by clicking on the screenshot below; the show begins at 6 pm U.S. Eastern time.
And if you can’t make it, a video of the show, sponsored by the Center for Inquiry, will eventually be put on YouTube.
See you there!
UPDATE: In a comment below, Randolph Nesse, one of the founders of “Darwinian medicine,” cites a book I’d forgotten:
If only everyone interested in this topic could read “Mother Nature: Maternal Instincts and How They Shape the Human Species”, Sarah Hrdy’s 2020 book on the topic. And if only the NY Times would review such excellent science books so people would know about them! I am tempted to send Conaboy a copy.
Hrdy is a highly respected anthropologist, and you can order her book by clicking on this screenshot:
I highly doubt that Hrdy sees maternal instincts as pure social constructs designed to hold women down. I’m going to read it, and I hope Conaboy does, too. Then we can expect her to retract her article (LOL).
______________________
Lately there have been a lot of articles trying to deny scientific evidence because, the authors claim, that evidence buttresses inequality. (One example is the widespread denial that sex in humans is a binary.)
The recent article below, from the New York Times (of course), is one of the worst of the lot. It bespeaks a lack of judgment on the part of the author—who ignores biology because of her ideology—as well as on the part of the newspaper, which failed to hold the author’s feet to the scientific fire. Let this post be my rebuttal.
Click on the screenshot to read.
Author Conaboy, who apparently hasn’t done enough scientific research, maintains that “maternal instinct” doesn’t exist, but is a social construct devised by men to keep women subordinate.
The immediate problem is that Conaboy never defines “maternal instinct”. It could mean any number of things, including a greater desire of women than men to have children, a greater desire of women than of men to care for those offspring, the fact that in animals mothers spend more time caring for offspring than do fathers, a greater emotional affinity of women than of men towards children (including offspring), or the demonstration of such a mental difference by observing a difference in caring behavior.
I will define “maternal instinct” as not only the greater average tendency of females than males to care for offspring, but also a greater behavioral affinity towards offspring in females than in males. The term involves behavioral response, not “feelings”, which are demonstrable only in humans. Thus one can look for difference in “parental instincts” across various species of animals.
But even in this sense, Conoboy is partly (but far from wholly) correct when she discusses humans. It’s undoubtedly true that women were socialized into the sex role as offspring breeders and caretakers, with men assuming the “breadwinning” role. It’s also true that women were often denied access to work or education because their vocation was seen as “reproducer”, or out of fear that they would spend less time working and more on children, or even that they’d get pregnant and would leave jobs. Further, it’s also true that this role difference was justified by being seen as hard-wired” (i.e., largely the result of genes, which, I argue below, is true), and that “hard-wired” was conceived as “unable to be changed.” The latter construal, however, is wrong, and that is what really held back women. The socialization of sex roles, which still occurs, goes on from early ages, with girls given dolls and boys toy cars, though, as society has matured, we’re increasingly allowing girls to choose their own toys and their own path through life. I of course applaud such “equal opportunity.”
But to claim that women don’t have a greater desire than men to care for offspring, or have a greater emotional affinity towards offspring, is to deny biology, and evolution in particular. (I freely admit that many men love their kids deeply, and that some men care for them as much or more as do mothers, but I’m talking about averages here, not anecdotes.)
There are two reasons why Conaboy is wrong, and both involve evolution.
The first is theoretical, but derived from empirical observations. It thus explains the second, which is wholly empirical and predictive. How do we explain the fact that, across the animal kingdom, when members of only one sex do most of the childrearing, it’s almost invariably the females? (Yes, in many species males share the duties, and in a very few, like seahorses, males provide more parental care; and there are evolutionary reasons for that.)
The reasons for the statement in bold above involves the biology of reproduction. It is the female who must lay the eggs or give birth, and there is no way she can leave her genes behind unless she does that. It’s easier for males to take off after insemination and let the females care for offspring. Given that females are constrained to stick with the fertilized eggs, their best strategy is to take care of the gestation and resultant offspring, which of course allows males to seek other mates. Not only must females carry the fetuses, lay the eggs, and so on, but they are also constrained to see out the pregnancy until offspring are produced and then suckle or tend them in other ways. In some cases it’s the best evolutionary strategy for a male to stick around and share the child-rearing, but often it’s not.
This disparity in behavior holds not just in humans, of course, but in many animals: it’s a prediction—largely verified—of evolutionary psychology.
The difference in the amount of parental care given by females and males is seen throughout the vertebrates, as well as in many invertebrates (squid and some insects come to mind; see here for a summary in the latter group).
It is the female lion who takes care of the cubs (and hunts for them) while the males are indolent; most often it is the female bird who not only incubates the eggs but feeds the offspring; it is the mother elephant who tends to her young; it is the female primate who holds, cares for, and nurtures her offspring. This difference alone, caused by the constraints of different reproductive roles, will, over time, select for mothers to be more attentive to offspring than are the fathers, more worried about them, and more attached to them. As all of us know, it’s the mother bear who tends her young, and woe to those who get between a mother and her cubs! But where is Papa Bear? Well, he’s long gone. In my ducks, if you approach a young brood, the mother will attack you, but the father, even if he’s around, does nothing.
Note that I am just talking about behavior, not “feelings” here, as we can’t really know what a mother bear or a mother duck experiences in her brain. But these behaviors are clearly seen in primates like gorillas and chimpanzees, and here we can start advancing hypotheses about emotions. Since I’m using maternal instinct as a behavioral phenomenon, it doesn’t really matter. What matters is that there is a strong regularity of behavior across the animal kingdom, one so pervasive that it demands explanation. And since animals don’t have humanlike culture, you can’t explain it by socialization. But can you deny, watching a female chimp cradle her young, that she feels something akin to love?
Of course to claim that a difference in sex and sex roles can cause a difference in behavior or emotions is anathema to “blank slaters” and those on the Left who flatly reject evolutionary psychology. And although Conaboy doesn’t go into the biology, this appears to be her view: there is no evolved difference in caregiving between men and women. Rather, differences in maternal and paternal behaviors must be the result of socialization.
And this brings us to the empirical point. Why, if “maternal instinct” is due entirely to socialization, is it is nearly ubiquitous among animals, causing female-specific nurturing and protective behaviors of offspring? Why, if Conoboy be right, are we the only species of animal in which those sex differences are due entirely to socialization? The parallels between humans and other animal species—especially other primates—is so strong that it would be foolish to deny that it says something about evolution. What it says is that human “maternal instincts” are partly hard-wired, and only partly socialized. As far as human emotionality is concerned, there are plenty of studies showing a difference in maternal vs paternal care due to hormones (here is one example), and they’re in the direction that evolution predicts.
Another example are studies showing that, when given a choice of toys, young female rhesus monkeys have a significantly greater preference for human “female” toys than do young male rhesus monkeys. (The toys are dolls vs trucks.) This preference of course is seen in human children, yet that could be, and has been, dismissed as a result of socialization. But rhesus monkeys don’t have that kind of socialization! The most parsimonious explanation is that monkeys, like us, have an evolved sex bias towards maternal instincts.
As I said, there are good evolutionary reasons to expect differences in maternal and paternal behavior, and we see those differences. While we can’t suss out “feelings”, it is likely that these behavioral differences are due to hormones, and in other apes we can guess that their “feelings” are not completely different from ours.
Conaboy, however, cavalierly dismisses the Darwinian explanation because of Darwin’s own sexism, as well as that of other evolutionists. Yes, it’s true that Darwin shared the sexism of his time, as have other evolutionists, but do we dismiss phenomena completely because of this? That would be foolish. Nonetheless, Conaboy does:
In the 1800s, Charles Darwin and other evolutionary theorists upended how we thought about human nature, shifting the focus from faith to biology.
And while one might have expected such a shift to dispel longstanding chauvinistic ideas about women and motherhood, the very opposite happened. Within his revolutionary work, Darwin codified biblical notions of the inferiority of women and reaffirmed the idea that their primary function is to bear and care for children.
“What a strong feeling of inward satisfaction must impel a bird, so full of activity, to brood day after day over her eggs,” Darwin wrote in “The Descent of Man, and Selection in Relation to Sex” in 1871. Observant as he was, Darwin apparently ignored the hunger of the mother bird and the angst of having mouths to feed and predators to fend off. He didn’t notice her wasting where wing meets body, from her own unending stillness.
Women are specialized to care for other humans and men to compete with them, he explained. By that basic fact, he argued, men achieve “higher eminence” in virtually all things, from the use of their senses to reason and imagination.
As more women demanded their own identities under the law, social Darwinists seized on this idea as justification for continued male dominance. Among them was the English philosopher Herbert Spencer, who wrote that childbearing extracts “vital power” from women, stunting them emotionally and intellectually.
Note that Conaboy challenges Darwin by pointing out the travails that beset a mother as opposed to a father (this is also a big part of her objection to “maternal instincts” in humans). But she fails to point out that there are costs to child-rearing, but there are also costs to abandoning or ignoring children, and the former costs are greater than the latter. Yes, a mallard hen loses up to 30% of her body weight while incubating her eggs over a month, but she gets a healthy brood from that behavior. If she leaves the nest to eat and drink, she loses her brood entirely. Genes that favor maternal care and concern will be favored. The notion of evolutionary tradeoffs—that a behavior can have costs and benefits, but will evolve if the reproductive benefits outweigh the costs—is something that apparently didn’t cross Conoboy’s mind.
Why is Conaboy so dead set against the idea of a “hard wired” (i.e., partly genetic) difference between men and women? For the expected reasons: she sees such differences as buttressing sexism, and so biological facts must take second place to her ideology. And, as I said, it is the case that scientists and others have used biology to justify sexism. But that doesn’t mean that the facts are wrong, or don’t give us insight into the evolution of sex-role differences.
Here are a couple of Conaboy’s statements showing the ideological basis of her objection to biologically based maternal instincts:
Where did the idea that motherhood is hard-wired for women come from? Is there a man behind the curtain?
In a sense, there is a man behind the curtain. Many of them, actually.
The notion that the selflessness and tenderness babies require is uniquely ingrained in the biology of women, ready to go at the flip of a switch, is a relatively modern — and pernicious — one. It was constructed over decades by men selling an image of what a mother should be, diverting our attention from what she actually is and calling it science.
Yes, sex role differences and behaviors, like the existence of two sexes themselves, must be dismissed because they go against what is an antiscientific, liberal, blank-slate ideology. When the facts are inconvenient, deny them and invoke bigotry.
Conaboy brings in religion, too, which of course has buttressed sex-role differences:
Modern Christian archetypes of motherhood were shaped by two women. There was Eve, who ate the forbidden fruit and in doing so caused the suffering of every human to come. And there was the Virgin Mary, the vessel for a great miracle, who became the most virtue-laden symbol of motherhood there is, her identity entirely eclipsed by the glory of her maternal love. Mary’s story, combined with Eve’s — unattainable goodness, perpetual servitude — created a moral model for motherhood that has proved, for many, stifling and unforgiving.
But religion’s own stereotypes aren’t independently contrived, but themselves come from sexism built by humans into a faith that is seen to create a harmonious society.
Others to blame for the “myth” of the maternal instinct are conservatives, another reason to dismiss the reality of that instinct:
Today, many proclaim that motherhood is neither duty nor destiny, that a woman is not left unfulfilled or incomplete without children. But even as I write those words, I doubt them. Do we, collectively, believe that? Maternal instinct is still frequently invoked in science writing, parenting advice and common conversation. And whether we call maternal instinct by its name or not, its influence is everywhere.
Belief in maternal instinct and the deterministic value of mother love has fueled “pro-family” conservative politicians for decades. The United States, to its shame, still lacks even a modest paid leave policy, and universal child-care remains far out of reach.
. . . Belief in maternal instinct may also play a role in driving opposition to birth control and abortion, for why should women limit the number of children they have if it is in their very nature to find joy in motherhood? A 2019 article published by the Ethics and Religious Liberty Commission of the Southern Baptist Convention, a Christian anti-abortion policy group, claimed that “the ultrasound machine has been the pro-life movement’s strongest asset in recent years” because once a woman is informed of her pregnancy, “her maternal instinct will often overpower any other instinct to terminate her pregnancy.” Why, then, should the law consider the impact of pregnancy on the life of a person who has the full force of an instinct stronger than “even fear itself” to gird her in the task?
I am course am not defending these statements, which do derive from sexism and misogyny. What I am saying is that Conaboy uses this kind of ideological and political argument to dismiss biological explanations for maternal instincts.
I won’t go into Conaboy’s description of the difficulties attending human childbirth, including postpartum depression, physical pain, and sleeplessness. Every mother knows what Conaboy is talking about. But it has no bearing on whether maternal instincts are a myth or a social construct of the patriarchy.
Finally, I want to bring up one other misrepresentation by Conoboy: the idea that there’s a big difference between “hard-wired” differences between the sexes versus differences that emerge later, after life experience. Here’s what she says:
The science of the parental brain — much of it now the work of female scientists who are mothers themselves — has the potential to pull back the curtain, exposing old biases and outdated norms, revealing how they are woven throughout our individual and societal definitions of mother or parent or family, and offering something new.
Using brain imaging technology and other tools, and building on extensive animal literature, researchers around the globe have found that the adaptation of the human parental brain takes time, driven as much by experience — by exposure to the powerful stimuli babies provide — as by the hormonal shifts of pregnancy and childbirth.
But surely environmental cues, like exposure to one’s own child, which is “experience,” can also activate hard-wired genetic differences between male and female behavior. (Let me emphasize that by “hard-wired” I do not mean that a behavior is always seen in one sex or the other; what I mean is that there are influences of genes on an average behavioral difference between men and women.) It is entirely possible that the sight of one’s own infant can activate other evolved pathways that produce “maternal instincts”. (See here for one paper on this topic.) This is similar to human children born with the genetic ability to learn semantic language, but they can’t express that ability until they actually hear spoken language. Thus we have an evolved trait that requires experience to be expressed.
In the end, in her attack on sexism and its attendant limitation of women’s opportunities (a view I share), Conoboy is forced to deny all the facts of biology, even dragging in the much beleaguered Darwin for a good drubbing. But she hasn’t done her homework. If she had, she’d see that maternal instincts are not limited to humans, but are widespread among animals. And she’d see that there are good evolutionary reasons for such instincts—reasons that, in our species, could lead to a difference in feelings towards infants.
I’m sick to death of people either ignoring or denying the facts of biology when they’re ideologically inconvenient. But that whole strategy fails for two reasons. First, the truth will out. In fact, we already know that Conaboy is wrong.
Second, it’s a terrible strategy to dismiss empirical data on ideological grounds. Far better for Conaboy to admit that sexism plays a role, but so does biology. There is nothing shameful in admitting that much of the “maternal instinct” is evolved. That admission does not force us to view women as inferior, nor to treat them as inferiors.
Finally every woman who chooses not to have a child because she has other priorities demonstrates that evolved tendencies need not compel our behavior. They can explain it, but that’s different from making it into an “ought”.
Much of Darwin’s work and thought was on plants, and today’s submission, by Philip Griffiths, has a Darwinian theme. His notes are indented, and you can enlarge the photos by clicking on them.
I enclose some pictures of Purple loosestrife, Lythrum salicaria, which is plentiful in my local park in central Newcastle upon Tyne (UK) at this time of year. Not only is it a beautiful flower with rumpled purple purple petals that look as though somebody forget to iron them, but it should be significant to readers of Why Evolution is True.
Charles Darwin wrote to Asa Gray I am stark staring mad over over Lythrum. For the love of heaven have a look at some of your species and if you can get me some seed, do! He wrote this after voyages to the Galápagos Islands and after his major work on orchids, so it must have been something that really caught his attention. Also, Purple loosestrife is pretty ubiquitous now, so I wonder if that was not the case in Darwin’s day.
What caught Darwin’s attention was the presence of three morphs, with each flower having one:
1) A short styled morph that has medium length stamens with yellow anthers and long stamens with greenish anthers. [Stamens are the pollen-produce male parts of a flower.]
2) A medium styled morph which has short stamens with yellow anthers and long stamens with greenish anthers.
3) A long styled morph with short and medium stamens.
The short-styled morph:
Medium-styled morph:
Long-styled morph:
To sum up, there are three different lengths of style [the female organ that receives the pollen for ferilization], and each is accompanied by two sets of five stamens that are of different length, so you never see a flower whose style and stamens are of the same length.
Darwin realised that this was a mechanism to encourage outcrossing. Each style is preferentially fertilised by stamens of the same length as itself and they are not to be found in the same plant. Thus a seed must be produced by pollen from a different flower.
Perhaps the three morphs (rather than two as in Primroses) increase the probability of successful outcrossing because two out of three morphs can pollinate a given flower rather than simply one out of two.
I am conscious I am ‘teaching my my grandmother to suck eggs’ here and I know the story is more complicated than I have outlined. Anyway, the flowers are beautiful this time of year and it is worth looking closely with magnification.
I’ve finished reading Richard Dawkins’s new book Flights of Fancy: Defying gravity by Design and Evolution, and quite enjoyed it, for it incorporates many of the principles he’s emphasized in his books—the gene’s-eye view, coevolution, arms races, step-by-step adaptive evolution, evolutionary convergence, and so on—into a discussion about a single adaptation, flight. Well, not a single adaptation, since he discusses gliding animals like flying squirrels and flying fish, the true flight of animals like birds and bats, and the “flying” of pollen via their insect vectors or of seeds via dispersal mechanisms.
And the “design” in the title refers to a convergence between what natural selection has done to facilitate aerial movement and how humans through deliberate design have mimicked many of nature’s contrivances in aircraft.
One of the pleasures of the book is discovering odd but fascinating bits of flight-related natural history that show us the power and “cleverness” of natural selection. Her are two examples he discusses.
The first is the Javan cucumber, Alsomitra macrocarpa, found on the tropical islands of East Asia. It disperses its seeds from a gourd that disgorges remarkable gliding seeds with two wings that look like this:
From Wikipedia:
The seed or samara of this species is unusual in having two flat bracts extending either side of the seed to form a wing-like shape with the seed embedded along one long edge and the wings angled slightly back from it. As the seed ripens the wings dry and the long edge furthest from the seed curls slightly upwards. When ripe, the seed drops off and its aerodynamic form allows it to glide away from the tree. The wing spans some 13 cm and can glide for great distances. The seed moves through the air like a butterfly in flight — it gains height, stalls, dips and accelerates, once again producing lift, a process termed phugoid oscillation. In the past it was often found on the decks of ships at sea.
You can see that dipping and stalling in the second video below.
By the way, Richard has a great discussion about why it’s adaptive for plants to disperse their seeds. If your parents are growing in a good place, why send them many meters away to a place that might not be as good? But you can read about that yourself.
The remarkable aspects of these seeds is how far they glide, ensuring that many of them find themselves well away from their parent. Here are two videos, one from Attenborough, showing the phenomenon. These features are certainly evolved as adaptive for the plant.
The Attenborough introduction:
. . . and a video from YouTube showing the remarkable gliding power of these seeds, which resemble plantlike albatrosses in their ability to glide very far without flapping:
This next one is remarkable. I’ve taught about “pseudocopulation”, a trait that some orchids use to spread their pollen using wasps as surrogate genitalia. There are many orchids that resemble female wasps, and randy males try to copulate with them. (Some of these “wasp orchids” even produce pheromones resembling those of female wasps.)
The “intent” of the orchid (I’m speaking in evolutionary jargon, of course) is to affix its pollen sacs, or pollinia, onto the wasp. After a fruitless attempt at copulation, the wasp, with a sac of pollen stuck to its body, eventually makes its way to another orchid, tries to bonk it, and transfers the pollinia to the female’s stigma, effecting fertilization. (These wasp-mimicking orchids almost never produce nectar to lure the insects; they save their energy and just act sexy.)
One remarkable orchid that tricks wasps this way is the “hammer orchid“; or rather orchids, as there are ten species in the genus Drakaea found in western Australia. A wasp, lured by a part of the flower that looks like a female wasp (it also smells like one), lands on that bit and tries to copulate with it. (The Attenborough video below shows the similarity between flower and female wasp.) At some point, the female-mimicking part of the flower folds over, hammering the male wasp against the pollinia. The pollen sticks to its body, and fertilization is halfway there. The act is completed when the frustrated wasp tries copulating with a different orchid, and the hammer then puts the pollina in contact with the stigma.
Females of these species are wingless (see below) and the orchid has evolved (unknowingly, of course) to look like them. The resemblance is facilitated by the female wasps’ habit of hanging atop a step to lure the males, which is just what the orchid does.
Note that only males can pollinate these orchids (or any wasp-mimicking orchid), so the flower potentially loses half its pollinators. But since females can’t pollinate anyway, being wingless, it’s not that big a loss. What puzzles is me is why the wasp nevertheless persists trying to copulate with the flower. If it ever learned not to waste its time, the flower would go extinct.
Have a look. There are even more remarkable tactics that orchids use to fertilize each other, but I’ll save those for later.
Denis Noble (born 1936) is a British physiologist highly regarded for his work in that field (he has an FRS). Wikipedia notes his accomplishments:
He is one of the pioneers of systems biology and developed the first viable mathematical model of the working heart in 1960.
What the article doesn’t discuss is that Noble has spent the last period of his life attacking neo-Darwinism, asserting that its most important foundations are either wrong or overemphasized. Noble is regarded by colleagues I respect as a bit of an enthusiast, bordering on an unhealthy obsession, though he’s much admired by the “Third Way of Evolution” group who argue that neo-Darwinism either needs a serious revision or a trip to the garbage can. Noble shows us that you can be a great physiologist but a lousy evolutionary biologist.
In an earlier post I wrote, “Famous physiologist embarrasses himself by claiming that the modern theory of evolution is in tatters“, I emphasized five assertions Noble made in a 2013 paper in Experimental Physiology, and then I criticized them as being either deeply misguided or flat wrong. Noble’s claims:
Wrong, partly right but irrrelevant, wrong, almost completely wrong, and totally wrong (speciation is my own area).
And yet Noble continues to bang on about “the broken paradigm of Neo-Darwinism,” which happens to be the subtitle of his new article (below) in IAI News, usually a respectable website run by the Institute of Art and Ideas.
Noble is especially excited because he sees himself in a war for the soul of biology, a soul currently occupied by the modern theory of evolution. And so, in this article (see below), Noble once again raises the specter of Lamarckian evolution: the idea—which he sees as both very important and unduly neglected—that adaptations can arise from modifications of an organism’s heredity directly by the environment. (The classic example is a giraffe stretching its neck to reach leaves on trees, and that usage elongates the neck, an environmentally-induced change that somehow worms its way into the mechanism of inheritance so that giraffes eventually evolve long necks)
Darwin himself held a form of Lamarckism, positing that cells of organism, induced by the environment, could feed “pangenes” thoughout the body in a way that could modify its inheritance. That’s why Darwin was always emphasizing “changed conditions” as a source of heritable variation. The problem with this view is that tests of environmental modification as a source of inherited variation have almost never succeeded, and even when they do, they have not created adaptations. The idea that Lamarckian inheritance is an important cause of adaptation is, to put it mildly, ridiculous. (I note here that DARWIN WAS WRONG about inheritance.)
Nevertheless, Noble persists—in the face of all the facts—to make the same tired old assertions. Click to read, and shame on IAI!
First Noble argues that environmental modifications can produce traits that become inherited, though only for a short while. This is true, but the phenomenon is rare.
Noble:
Modern physiology has vindicated Darwin’s idea. The small vesicles, called exosomes or extracellular vesicles, poured out by all cells of the body can function precisely as Darwin’s idea proposed. They have now been proven to communicate such acquired characteristics as metabolic disorders, and sexual preferences, to the germ-line via small regulatory RNA molecules. We can therefore be sure that Lamarckian use-disuse memory can be passed across generations. Weismann’s assertion that the inheritance of acquired characteristics is impossible was therefore incorrect. The debate now centres on two questions: “how often this happens and, when it does, for how many generations do the changes persist?”
The standard neo-Darwinist defense against this clear break of the Weismann Barrier has been to suggest that it only happens in unimportant circumstances and persists for very few generations. There is assumed to be no permanent transmission. The DNA continues “hard” transmission while “soft” inheritance inevitably dies away.
Yes, and soft inheritance can also be mediated by epigenetic (environmentally induced) modification of the DNA, usually by putting methyl groups (−CH3) onto the DNA bases. As Noble admits, these forms of inheritance gradually go away, with nearly all epigenetic modifications erased during the process of reproduction. That’s one reason why this kind of inheritance can’t be the basis of long-term adaptation. But wait! Noble says that short-term adaptation is of great value!
This defence fails to recognise the great virtue of “soft” inheritance, which is precisely the possibility that it can be temporary.
Yes, and so can adaptation based on genes (think of the increase in beak size of the Galápagos finches, which was reversed in a single generation when the size-inducing drought went away). If there’s substantial variation, these reversals can be fast. But Noble fails to recognize that most adaptations hang around for many generations, and those cannot be based on “Lamarckian” inheritance. It’s almost as if Noble is claiming that this form of inheritance, by some kind of group selection, has been installed in the organism to facilitate short term adaptation!
Here’s one example that people like Noble trot out when attacking modern evolutionary theory:
Consider a species under extreme environmental stress, such as the Dutch population during the starvation winter of the 1940s in the Second World War. The inherited signs of that stress have now been passed down three generations, to the great-grandchildren of the 1940s population. The chances are that it will progressively die out as the later generations experience good nutrition. And so it should!
The “Dutch famine syndrome” was caused by epigenetic modification of fetuses in utero when their mothers were starving during the Dutch “hunger winter” of 1944-1945. I’m not sure about the three generations, but I’ll let that pass. What we know for sure is that these offspring show DNA methylation changes probably due to starvation.
BUT this was not adaptive! The epigenetic changes reduced the health of their carriers, as this article shows. From its abstract (my emphasis):
This paper describes the findings from a cohort study of 2414 people born around the time of the Dutch famine. Exposure to famine during any stage of gestation was associated with glucose intolerance. We found more coronary heart disease, a more atherogenic lipid profile, disturbed blood coagulation, increased stress responsiveness and more obesity among those exposed to famine in early gestation. Women exposed to famine in early gestation also had an increased risk of breast cancer. People exposed to famine in mid gestation had more microalbuminuria and obstructive airways disease. These findings show that maternal undernutrition during gestation has important effects on health in later life, but that the effects on health depend on its timing during gestation. Especially early gestation seems to be a vulnerable period. Adequate dietary advice to women before and during pregnancy seems a promising strategy in preventing chronic diseases in future generations.
Now is that, on top of the inherited stress, an adaptive change? I think not.
It is intellectually irresponsible for Noble to suggest that the Dutch Famine syndrome has anything to do with adaptive change, much less evolution. In fact, I know of not a single adaptation that rests on epigenetic modification. I may have missed one or two, but when adaptive genetic changes in animals (including humans) are localized, they invariably are found to rest on base-pair changes in the DNA. When you map adaptations in humans, like changes in lactase persistence or adaptive skin color, you find that they are based not on methylation or episomes or micro-RNAs, but on good old-fashioned mutations that change the sequence of DNA. And so they must be, because these changes have lasted for many generations.
It’s intellectually irresponsible of Noble not to mention that, too.
Further, Noble cites the well-known phenomenon of “genetic assimilation,” in which an environmental change exposes genetic variation that can then be subject to selection, as if this were some kind of refutation of neo-Darwinism. (One hypothetical example: if you starve plants, it may, by stunting them al, hide genetic variation for height.) Noble says that studies of genetic assimilation, which are in all the textbooks, are actually discouraged by evolutionists who don’t like their non-Darwinian implications:
Given the importance of the question, why have so few attempts been made on the genetic assimilation of “soft” inheritance since Waddington’s work? The answer is that funding organisations would not be willing to support such work. If you submit a Lamarckian inheritance project to standard grant bodies, you will be almost certain to receive a firm rejection. Such is the hold of the Neo-Darwinian paradigm on innovative ideas in evolutionary biology.
Get this straight, Dr. Noble: GENETIC ASSIMILATION IS NOT LAMARCKIAN INHERITANCE! As every evolutionist with more than a handful of neurons knows, in these cases the environment exposes standard DNA mutations, allowing them to be selected in the classical neo-Darwinian fashion.
One clue that genetic assimilation depends on genetic variation and not changes in the environment becoming genetic variation is this: Conrad Waddington, who popularized the phenomenon of genetic assimilation using experiments in Drosophila, had a student repeat those experiments with an inbred strain of flies, a strain that had almost no genetic variation. Voilà: no genetic assimilation, no change in the trait. If the Lamarckian theory were correct, there should still have been changes in the character in inbred lines.
Once again we smell the odor of intellectual mendacity in Noble’s prose.
At the end, Noble beefs about how a 2016 Royal Society symposium he organized, on “New trends in evolutionary biology: biological, philosophical, and social science perspectives,” was protested by 20 other fellows of the Royal Society. He couches this as censorship against discussing new ideas, but he’s wrong. Many of the speakers at the symposium were touting ideas that had already been already refuted, and the purpose of the meeting was to show that neo-Darwinism is dead. It’s as if there were to be a Royal Society symposium on Intelligent Design (the ID people, by the way, loved that symposium). Of course one would object if someone who knows jack about evolutionary biology organizes a symposium designed to dismantle its modern form. It’s like a fox organizing a symposium on how to breed chickens.
I’m not saying that Noble has no right to weigh in on modern evolutionary biology simply because he was a physiologist. No, I’m asserting that Noble’s claims about the death of modern evolutionary biology should be ignored because there is virtually no data to support them. His claims should be ignored because he is ignorant, and willfully so. (Others have corrected him many times.)
I’m through with Noble; he says the same thing over and over again, tilting at the windmill of modern evolutionary biology with a soda straw. I probably should have ignored Noble’s mush, but the laws of physics compelled me to write. At least the readers here can be aware of his numerous errors and misstatements, even if Noble plays the same tune until he’s underground.
