“I am not a number — I am a baby cuttlefish!”
Figure from Cephalopods: A World Guide (amzn/b&n/abe/pwll), by Mark Norman.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
Just wait — this one will be featured in some cheesy Sci-Fi channel creature feature in a few months. Paleontologists have dug up a fossil boa that lived 58-60 million years ago. They haven’t found a complete skeleton, but there’s enough to get an estimate of the size. Look at these vertebrae!
Just to put it in perspective, the small pale blob between a and b in the photo above is an equivalent vertebra from an extant boa, which was 3.4 meters long. The extinct beast is estimated to have been about 13 meters long, weighing over 1100 kg (for us Americans, that’s 42 feet and 2500 pounds). This is a very big snake, the largest ever found.
The authors used the size of this snake to estimate the temperature of this region of South America 60 million years ago. Snakes are poikilotherms, depending on external sources of heat to maintain a given level of metabolic activity, and so available temperature means are limiting factors on how large they can grow. By comparing this animal’s size to that of modern tropical snakes, and extrapolating from a measured curve of size to mean annual temperature, they were able to calculate that the average ambient temperature was 30-34°C (American cluestick: about 90°F); less than that, and this snake would have died.
From other data, they know that the atmospheric CO2 concentration at this time was about 2000 parts per million, and that the forests it lived in were thick, wet, and rainy. They also estimate that slightly later, about 56 million years ago, mean tropical temperatures would have soared to 38-40°C (102°F), and would have killed off many species.
So there you go…this is one place I think I’d avoid if I had a time machine. It was a thick-aired, muggy, sweltering oven, with giant snakes crawling about. They were likely to have eaten large crocodilians, so I suspect a time-traveling human would be nothing but a quick hors d’ouevre. They’re still interesting, though, especially as an example of evolution and climate science meeting in a mutually revealing fashion.
Head JJ, Block JI, Hastings AK, Bourque JR, Cadena EA, Herrera FA, Polly D, Jaramillo CA (2009) Giant boid snake from the Palaeocene neotropics
reveals hotter past equatorial temperatures. Nature 457(7230):715-718.
My teaching schedule this semester is a major time-suck; I’m teaching genetics and all of its associated labs (you really don’t want to know how much prep time goes into setting up fly labs), I’m doing some major revision of the content this year, and I’ve got this asymmetric schedule that packs everything into the first half of each week. So I simply have to protest when those evil (Stein was right!) scientists announce a major discovery on a Tuesday, which just happens to be the very worst day of the week for me. They’ve gone and found another important whale transitional fossil, Maiacetus, and I’m just going to have to tell you to go read a bunch of other fine blogs that already have it covered.
(A, B)- Dorudon atrox (5.0 m; 36.5 Ma) based on UM 101222 and 101215 [11] in lateral and dorsal views, respectively. (C, D)- Maiacetus inuus (2.6 m; 47.5 Ma) based on male specimen GSP-UM 3551 in lateral and dorsal views, respectively.
It’s beautiful. It’s clearly adapted for aquatic life, but it has another revealing feature: this specimen was pregnant at death, and the fetus is oriented for a head-first birth, which is not good for birth at sea (the head would pop out, baby would take its first breath, and drown before the tail emerged), so this animal would have had to give birth on land.
But like I said, you’ll have to read Carl Zimmer, Ed Yong, Brian Switek, or Greg Laden this time around for all the details. Or read the paper yourself! It’s freely accessible.
The NY Times ran an interesting article on sexology a short while ago, focusing on the differences in arousal between men and women. Like any guy, I read it hoping to discover the magic switch that turns women on, but as expected, the message is that female arousal is very, very complicated. This was not a surprise. One of the curious results, though, was that not only do men and women differ in the specificity of stimuli that induce arousal, but women’s brains (measured by self-reporting) and women’s bodies (measured by plethysmograph) don’t agree — vaginal arousal was measured when subjects saw video clips of mating bonobos and a variety of different sexual situations, while at the same time they reported a lack of interest.
It’s fascinating stuff, but I have to raise an objection. They try to use evolution to explain what’s going on.
Besides the bonobos, a body of evidence involving rape has influenced her construction of separate systems. She has confronted clinical research reporting not only genital arousal but also the occasional occurrence of orgasm during sexual assault. And she has recalled her own experience as a therapist with victims who recounted these physical responses. She is familiar, as well, with the preliminary results of a laboratory study showing surges of vaginal blood flow as subjects listen to descriptions of rape scenes. So, in an attempt to understand arousal in the context of unwanted sex, Chivers, like a handful of other sexologists, has arrived at an evolutionary hypothesis that stresses the difference between reflexive sexual readiness and desire. Genital lubrication, she writes in her upcoming paper in Archives of Sexual Behavior, is necessary “to reduce discomfort, and the possibility of injury, during vaginal penetration. . . . Ancestral women who did not show an automatic vaginal response to sexual cues may have been more likely to experience injuries during unwanted vaginal penetration that resulted in illness, infertility or even death, and thus would be less likely to have passed on this trait to their offspring.”
Evolution’s legacy, according to this theory, is that women are prone to lubricate, if only protectively, to hints of sex in their surroundings. Thinking of her own data, Chivers speculated that bonobo coupling, or perhaps simply the sight of a male ape’s erection, stimulated this reaction because apes bear a resemblance to humans — she joked about including, for comparison, a movie of mating chickens in a future study.
That all sounds very plausible, but plausibility isn’t enough — this is a perfect example of a just-so story. I’d want to see comparative data, but our closest relatives, the chimpanzees, are so different from us in sexual behavior that it would be difficult to generate an appropriate comparison. I’d want to see the causal and molecular basis for this behavior in women, but again, it’s going to be so complex that I doubt we’ll find simple relationships, let alone molecular evidence of selection. I’d want to see historical evidence that women who lacked a lubricity response to the prospect of unwanted sexual activity were more prone to injury that affected childbearing, but that doesn’t exist.
While not doubting the physiological relevance of the research, this too-willing cooption of evolutionary explanations just bugs me.
As an antidote, I have to recommend a book I’ve mentioned before, an excellent survey of evolutionary explanations for female sexuality, The Case of the Female Orgasm: Bias in the Science of Evolution(amzn/b&n/abe/pwll), by Elisabeth Lloyd. It steps through various proposed scenarios and shows the lack of legitimate evidence or, in quite a few cases, neglect of evidence that contradicts the hypotheses. It’s one of the best books around for demonstrating how rigorous evolutionary logic should be applied.
Unfortunately, that book doesn’t tell me what women want, either. The conclusion is that the female orgasm is probably an evolutionary byproduct, and that adaptive explanations are inappropriate and unjustified. I suspect the same answer applies to the work on female arousal.
It’s a bit too phenomenological, and definitely too animal-centric, but who cares? David Attenborough’s tree of life is very pretty and gets the gist of the story of life on earth across.
Jonathan Wells recently gave a talk in Albuquerque at something called the “Forum on Science, Origins, and Design”, a conference about which I can find absolutely nothing on the web. I wasn’t there, of course, and I don’t get invited to these goofy events anyway, but I did get a copy of Wells’ powerpoint presentation from an attendee. It’s titled “DNA Does Not Control Embryo Development” — shall we look at it together? It’s really a hoot.
A few of us wild and crazy evo people, including Richard Dawkins, wrote up pieces for an issue of the BBC Focus magazine. You’ll find me arguing with Steve Jones about whether evolution has stopped, Richard Lenski is highlighted, and Carl Zimmer makes an appearance. If you’ve got a flash player, you can read it online right now. It’s pretty good stuff, if I do say so myself.
A few people (actually, a lot of people) have written to me asking me to address Kirk Durston’s probability argument that supposedly makes evolution impossible. I’d love to. I actually prepared extensively to deal with it, since it’s the argument he almost always trots out to debate for intelligent design, but — and this is a key point — Durston didn’t discuss this stuff at all! He brought out a few of the slides very late in the debate when there was no time for me to refute them, but otherwise, he was relying entirely on vague arguments about a first cause, accusations of corruption against atheists, and very silly biblical nonsense about Jesus. So this really isn’t about revisiting the debate at all — this is the stuff Durston sensibly avoided bringing up in a confrontation with somebody who’d be able to see through his smokescreen.
If you want to see Durston’s argument, it’s on YouTube. I notice the clowns on Uncommon Descent are crowing that this is a triumphant victory, but note again — Durston did not give this argument at our debate. In a chance to confront a biologist with his claims, Durston tucked his tail between his legs and ran away.
Somebody is going to have to declare Jerry Coyne an official member of the “New Atheist” club and send him the fancy hat and instructions for the secret handshake. He has a substantial piece in The New Republic that is both a review of two recent books by theistic scientists, Karl Giberson (who really detests me) and Ken Miller, and a definite warning shot across the bows of those who believe science and religion can be reconciled.
First, let’s consider the reviews of the two books — they’re less interesting, not because they’re poorly done, but because Coyne’s opinion is almost identical to mine. The main point is that both books shine when they’re taking on the misconceptions of the creationists, but are weak and unconvincing whenever they move on to religious apologetics.
Giberson and Miller are thoughtful men of good will. Reading them, you get a sense of conviction and sincerity absent from the writings of many creationists, who blatantly deny the most obvious facts about nature in the cause of their faith. Both of their books are worth reading: Giberson for the history of the creation/ evolution debate, and Miller for his lucid arguments against intelligent design. Yet in the end they fail to achieve their longed-for union between faith and evolution. And they fail for the same reason that people always fail: a true harmony between science and religion requires either doing away with most people’s religion and replacing it with a watered-down deism, or polluting science with unnecessary, untestable, and unreasonable spiritual claims.
Although Giberson and Miller see themselves as opponents of creationism, in devising a compatibility between science and religion they finally converge with their opponents. In fact, they exhibit at least three of the four distinguishing traits of creationists: belief in God, the intervention of God in nature, and a special role for God in the evolution of humans. They may even show the fourth trait, a belief in irreducible complexity, by proposing that a soul could not have evolved, but was inserted by God.
That last paragraph in particular sounds like Larry Moran, who puts the theistic evolutionists on the same non-science side as the creationists. It’s going to grate on the authors, I’m sure, because both have clearly been strongly outspoken against creationism, and I don’t doubt the sincerity or honesty of either in their repudiation of creationism in any of its Intelligent Design, young earth, or old earth flavors, but they are both pushing a different flavor, a kind of weak tea flavored brand of theistic babble that is notable only its reliance on a diffuse vagueness instead of strong claims about the nature of the universe. They are equivalent in being equally unsupportable. They are equivalent in requiring their proponents to walk away from evidence and rigor in order to suggest that a peculiar entity was critical in creating the universe, life, and humanity — while at the same time, Miller and Giberson at least declaim the importance of scientific thinking honestly (the creationists who are a real problem also declaim the importance of science dishonestly, as they are doing their best to consciously undermine it.)
I also thought their unfortunate praise for superstitious dogma was the key flaw in both books — and their attempts to pin the blame for creationism on secularism instead of religion was disingenuous at best. The same could be said for another author with excellent scientific credentials, Francis Collins, who was even more outrageous in the way his logic lapsed whenever he introduced his deity into the discussion.
Criticizing an unfortunate turn in their books is one thing, but Coyne wins his New Atheist oak leaf cluster for taking it one step further, and making the case that religion and science are antagonistic. Readers here will know that this is also a view I share, and that I also think this pattern of trotting out yet more scientists who go to church is growing old. It does not argue that science and religion are compatible at all — all the coincidence of these ideas in single individuals tells us is that human beings are entirely capable of holding mutually incompatible ideas in their heads at the same time. The question is not whether a person is capable of swiveling between the church pew and the lab bench, but whether religion can tolerate scientific scrutiny, and whether science can thrive under dogma. I say the answer is no. Coyne agrees.
It would appear, then, that one cannot be coherently religious and scientific at the same time. That alleged synthesis requires that with one part of your brain you accept only those things that are tested and supported by agreed-upon evidence, logic, and reason, while with the other part of your brain you accept things that are unsupportable or even falsified. In other words, the price of philosophical harmony is cognitive dissonance. Accepting both science and conventional faith leaves you with a double standard: rational on the origin of blood clotting, irrational on the Resurrection; rational on dinosaurs, irrational on virgin births. Without good cause, Giberson and Miller pick and choose what they believe. At least the young-earth creationists are consistent, for they embrace supernatural causation across the board. With his usual flair, the physicist Richard Feynman characterized this difference: “Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.” With religion, there is just no way to know if you are fooling yourself.
So the most important conflict—the one ignored by Giberson and Miller—is not between religion and science. It is between religion and secular reason. Secular reason includes science, but also embraces moral and political philosophy, mathematics, logic, history, journalism, and social science—every area that requires us to have good reasons for what we believe. Now I am not claiming that all faith is incompatible with science and secular reason—only those faiths whose claims about the nature of the universe flatly contradict scientific observations. Pantheism and some forms of Buddhism seem to pass the test. But the vast majority of the faithful—those 90 percent of Americans who believe in a personal God, most Muslims, Jews, and Hindus, and adherents to hundreds of other faiths—fall into the “incompatible” category.
Coyne is admitting something that most of the scientists I’ve talked to (and I’ll openly confess that that is definitely a biased sample) agree on: we don’t believe, and we find no virtue in faith. At the same time, we’re struggling with an under- and mis-educated population that believes faith is far more important than reason. So what most scientists do is keep as quiet as possible about it all, or fall under the spell of ‘framing’…that is, lying about their position. That is changing.
This disharmony is a dirty little secret in scientific circles. It is in our personal and professional interest to proclaim that science and religion are perfectly harmonious. After all, we want our grants funded by the government, and our schoolchildren exposed to real science instead of creationism. Liberal religious people have been important allies in our struggle against creationism, and it is not pleasant to alienate them by declaring how we feel. This is why, as a tactical matter, groups such as the National Academy of Sciences claim that religion and science do not conflict. But their main evidence—the existence of religious scientists—is wearing thin as scientists grow ever more vociferous about their lack of faith. Now Darwin Year is upon us, and we can expect more books like those by Kenneth Miller and Karl Giberson. Attempts to reconcile God and evolution keep rolling off the intellectual assembly line. It never stops, because the reconciliation never works.
There is a way to make it stop, though…at least I believe it will work. And that is to stop hiding the facts, and show people that secular reasoning works and is far superior to faith-based delusions. Science will not and cannot adopt religious thinking without being destroyed, but citizens can learn about the power of secular reasoning, and become stronger and better people for it. That’s where our attention should be focused, not on trying to reconcile science with its antithesis, but on getting everyone to think.
I do have one quibble with the article. In it, Coyne defines four common traits of all creationists.
But regardless of their views, all creationists share four traits. First, they devoutly believe in God. No surprise there, except to those who think that ID has a secular basis. Second, they claim that God miraculously intervened in the development of life, either creating every species from scratch or intruding from time to time in an otherwise Darwinian process. Third, they agree that one of these interventions was the creation of humans, who could not have evolved from apelike ancestors. This, of course, reflects the Judeo-Christian view that humans were created in God’s image. Fourth, they all adhere to a particular argument called “irreducible complexity.” This is the idea that some species, or some features of some species, are too complex to have evolved in a Darwinian manner, and must therefore have been designed by God.
This is true for the vast majority of creationists, but it isn’t quite universal. I know a few atheist creationists, and they are just as incoherent as the necessary conflict between the two terms in that phrase implies. They do exist, however. There is a subset of creationists who are more like radical denialists: they reject evolution because the majority of scientists accept it, or in some cases because they are so egotistical that they reject anything they didn’t think of first, or because they have some other wild hypothesis that they have seized upon, or because, frankly, they’re nuts. Coyne’s generalization may be accurate in 99% of all cases, and is certainly true for the leadership of the creationist movements in the US, but saying “all” opens up the idea to trivial refutation when the DI makes a sweep of the local insane asylums or trots out David Berlinski to pontificate supinely.
Usually, Begley is reasonably good on science, but her latest piece is one big collection of misconceptions. It reflects a poor understanding of the science and of history, in that it confuses long-standing recognition of the importance of environmental factors in gene expression with a sudden reinstatement of Lamarckian inheritance, and it simply isn’t — she’s missed the point of the science and she has caricatured Lamarck.
Some water fleas sport a spiny helmet that deters predators; others, with identical DNA sequences, have bare heads. What differs between the two is not their genes but their mothers’ experiences. If mom had a run-in with predators, her offspring have helmets, an effect one wag called “bite the mother, fight the daughter.” If mom lived her life unthreatened, her offspring have no helmets. Same DNA, different traits. Somehow, the experience of the mother, not only her DNA sequences, has been transmitted to her offspring.
That gives strict Darwinians heart palpitations, for it reeks of the discredited theory of Jean-Baptiste Lamarck (1744-1829). The French naturalist argued that the reason giraffes have long necks, for instance, is that their parents stretched their (shorter) necks to reach the treetops. Offspring, Lamarck said, inherit traits their parents acquired. With the success of Darwin’s theory of random variation and natural selection, Lamarck was left on the ash heap of history. But new discoveries of what looks like the inheritance of traits acquired by parents–lab animals as well as people–are forcing biologists to reconsider Lamarckism.
She’s describing real and interesting phenomena, but it isn’t new and it isn’t revolutionary. These are results of plasticity and epigenetics, and we aren’t having heart palpitations over them (you’re also going to have a difficult time finding any “strict Darwinians” in the science community who are even surprised by this stuff). We load up pregnant women with folate and maternal vitamins and recommendations to eat well, and we tell them not to get drunk or smoke crack for a few months, because it is common sense and common knowledge that extra-genetic factors influence the health and development of the next generation. Genes don’t execute rigid, predetermined programs of development — they are responsive to the environment and can express radically different patterns in different contexts. The same genes build a caterpillar and a butterfly, the difference is in the hormonal environment that selects which genes will be active.
It’s the same story with the water fleas. Stressed and unstressed mothers switch on different genes in their offspring epigenetically, which lead to the expression of different morphology. It’s very cool stuff, but evolutionary biologists are about as shocked by this as they are by the idea that malnourished mothers have underweight babies. That environmental influences can have multi-generational effects, and that developmental programs can cue off of the history of the germ line, is not a new idea, especially among developmental biologists.
This is just wrong on evolution:
Water fleas pop out helmets immediately if mom lived in a world of predators; by Darwin’s lights, a population of helmeted fleas would take many generations to emerge through random variation and natural selection.
It misses the whole point. The population of water fleas have a genetic attribute that allows the formation of spines under one set of conditions, and suppresses them under others. This gene regulatory network did not pop into existence in a single generation! If it did, then Begley would have a big story, evolution would have experienced a serious blow, and we’d all be looking a little more carefully into this ‘intelligent design’ stuff. The pattern of gene regulation was the product of many generations of variation and selection; only the way it was expressed in a phenotype experienced a shift within a single generation.
It’s also not Lamarckism. It’s another of those short and simple-minded myths perpetuated by high-school textbooks that Lamarck and Darwin had competing explanations for the same phenomena. They did not. This story of giraffes stretching their necks is an example of the purported inheritance of acquired characteristics … and here’s some headline news, Darwin proposed exactly the same thing! Darwin did not have a solid theory of heredity, and he himself proposed a mechanism of pangenesis which permitted the inheritance of characters by use and disuse and by injury or malformation. The key difference is that Darwin proposed that these variations could lead to the formation of new species; Lamarck believed in the fixity of species, and thought that a species would merely express a constrained range of forms in differing environments.
Both were wrong. A concept called the Weismann barrier emerged in the late 19th century, which suggested that the only influences that can be transmitted across generations are those that affect the germ line, the cells that give rise to sperm and egg, and that modification of the somatic tissues alone would not propagate. This is correct, and it’s still true: nothing in these reports suggest anything but that when perturbed by environmental stressors, gametes can switch on different genetic programs.
I think epigenetics and plasticity are important and play a role in evolution, certainly, but these kinds of elaborations on how cells interact do not imply in any way that there is a revolution in evolution, or that evolutionary biology has had it all wrong, or that this is heresy in progress. It’s also annoying to see all the vague handwaving about discrediting a “Darwinian model” — what Darwinian model? These discoveries are about mechanisms of genetic inheritance, and Darwin didn’t have a valid mechanism in the first place. In that sense, the only real heresy that counted was Mendel’s.
