Oh, no, not the Aquatic Ape Hypothesis again!

I think BAHFest — the festival of Bad Ad Hoc Hypotheses — has been made entirely redundant. It’s an event to mock the absurdly adaptationist hypotheses put forward by some scientists, and it’s intended to be extravagantly ridiculous. But then, you look at some ideas that are inexplicably popular among scientists, and you realize…it’s a little too close to reality.

I’m speaking of the Aquatic Ape Hypothesis.

The Guardian is running yet another article on the goofy idea that we evolved from swimming apes, and that all of the unique features of our species are a product of adaptations to an aquatic lifestyle. It’s complete nonsense: there is no evidence of long-term residence of our species in the water, and the proponents tend to invent the most outrageous panglossian explanations, fitting data to the hypotheses instead of the other way around. At least this story has one new contrivance I’d never heard before. Take it away, Rhys Evans!

“Humans have particularly large sinuses, spaces in the skull between our cheeks, noses and foreheads,” he added. “But why do we have empty spaces in our heads? It makes no sense until we consider the evolutionary perspective. Then it becomes clear: our sinuses acted as buoyancy aids that helped keep our heads above water.”

<stunned silence>

But…but…but every mammal, as far as I know, has a head full of sinuses! Have you ever taken a mouse skull apart? They’re amazingly spongy. Here are some sections through a mouse skull to show you what I mean:

mousesinuses-3
Coronal sections. There is a distinct osteomeatal complex within the nose that drains the true maxillary sinus as well as ethmoids. The true maxillary sinus is located lateral to the osteomeatal complex, and unlike the other sinuses, is lined by submucosal glands. This true maxillary sinus has a single ostium. Each nasal passage is separated by nasal septum. The posterior septum is deficient along its inferior aspect, and the two nasal passageways communicate freely just anterior to nasopharynx.

Isn’t that just beautiful? It’s fairly typical, too: mammals have these elaborate spaces to lighten the skull, humidify inspired air, and in some provide expanded surface area for olfaction — but I suspect the slight contribution of sinuses to those functions means that they’re actually a consequence of conserved developmental programs to build the skull. They’re there as a byproduct of developmental processes in which a scaffold is assembled first, and then thickens and fills in over time. The density of the skull is relatively easily regulated by modifying the timing of its development.

Just because they’re pretty, here’s another image of mouse skulls:

mousesinuses-4
Plates 1 and 2 display three-dimensional computed tomography (CT) reconstructions of mouse skull in axial and lateral-oblique views. Plates A to F display coronal fine cut CT scan images, confirming our histologic planes of section.

So, did mice have an aquatic ancestor? Doesn’t this hypothesis imply that every mammal descended from an aquatic ancestor? (I shouldn’t ask that: my experience with AAH fanatics is that they joyfully answer “yes” to the question.)

I also wonder if these people ever go swimming. Somehow, my sinuses don’t seem to work very effectively as water wings.

Michael Crawford offers a familiar absurdity: the nutritional argument from docosahexaenoic acid (DHA). DHA is one of those omega-3 fatty acids that is used to build brains, and it’s found in high concentration in lots of seafood. The true zealots consider this indisputable proof that we evolved by eating lots of clams.

“It boosts brain growth in mammals. That is why a dolphin has a much bigger brain than a zebra, though they have roughly the same body sizes. The dolphin has a diet rich in DHA. The crucial point is that without a high DHA diet from seafood we could not have developed our big brains. We got smart from eating fish and living in water.

“More to the point, we now face a world in which sources of DHA – our fish stocks – are threatened. That has crucial consequences for our species. Without plentiful DHA, we face a future of increased mental illness and intellectual deterioration. We need to face up to that urgently. That is the real lesson of the aquatic ape theory.”

An experiment: let’s feed zebras bucketloads of DHA, and watch their brains expand to 3-5 pound blobs that give them advanced communications abilities!

Oh, wait. It won’t work. There’s such a thing as neuroplasticity, but brains aren’t quite that flexible. I’m willing to believe that increased availability of the building blocks of brains might remove a constraint on growth, but not that it’s causal, as Crawford claims. Even feeding many generations of zebras DHA isn’t going to affect brain size much at all…and there’s no evidence that terrestrial herbivores are in any way limited by the availability of DHA.

For one thing, they synthesize it. We humans synthesize it, too. We also get it from the herbivores we eat, and certain plants are rich in the precursors to DHA. Vegans have to pay attention to get their DHA requirements met, but it’s not particularly difficult, and you don’t see lifelong vegetarians walking around with itty-bitty pinheads.

There are good reasons to be deeply concerned about declining fish stocks, but preserving a resource vital to the formation of our brains isn’t one of them. There are many people around the world who don’t eat seafood — there are entire ethnic groups who haven’t touched the stuff for generations. There are big-brained primate species that virtually never eat fish. How do they survive? How do they avoid “mental illness and intellectual deterioration”? They get it from other dietary sources.

Mammals in general are larger brained than other animals, are we to use that as an argument that all mammals went through an aquatic stage in their evolution…oh, wait. I did it again. The True Believers will just say “YES!” to that.

Fortunately for Matt Yglesias, Lindsay Beyerstein only leaves him in a metaphorical smoking crater.

A couple of commenters here have persisted in defending Matthew Yglesias’ odious bleat that life is cheaper in Bangladesh because it ought to be because reasons, and that any anger we Westerners might feel about the horrendous loss of life in the recent factory collapse ought more helpfully be directed to buying clothes made in those collapsing sweatshops so that eventually the people making a few hundred dollars a year will have flat screen televisions just like us.

Yglesias is doubling down. In a followup post, he stands by his conclusion that poor countries need to have less stringent workplace safety standards, and adds, as a prelude to accusing his critics of “poisoning the atmosphere,” [see update at end of post]

I’m not really sure what Americans can constructively do to get better enforcement of building codes in Bangladesh

As it turns out, Lindsay Beyerstein has a possible answer:

A group of Bangladeshi and international trade unionists put forward a bold plan to make the garment industry in Bangladesh safer. A surcharge of 10 cents per garment over 5 years would raise $600 million a year, enough to radically transform the infrastructure of the garment industry in Bangladesh. Walmart and the Gap rejected the proposal in 2011.

So that’s pretty handy: All America has to do to make sweatshops in Bangladesh safer is to stop fucking obstructing their being made safer. It’s win-win!

Oh, and a protip to Yglesias: If you persist in discussing the worker safety aspects of US investment in South Asia, you might want to consider not using “poisoning the atmosphere” as a way to tone-troll your critics. We have a 30th Anniversary coming up late next year that will turn that phrase a bit unfortunate.

Updated: in comments, nialscorva correctly points out that I misread Yglesias’ reference to “poisoning the atmosphere.”  My bad. Leaving the post as it was for transparency’s sake.

Bruce Alberts, failure

This is not a very exciting video, but I might just inflict it on my cell biology students in the fall. We got a fair amount of flak from students last time around who were frustrated when labs didn’t work like a recipe from a cookbook — yet that’s how science usually proceeds, with lots of tinkering and frustration and repetition.

I also like his point about how teaching is important for science (although the students won’t really care about that.) I don’t think I really got the breadth of my discipline until I had to master it in order to teach it — there’s nothing quite like the panic behind “I’ve got to lecture for an hour on vesicle transport tomorrow!” to focus the mind wonderfully on a subject you might have found of only passing interest previously.

(via Sandwalk.)

Musings from the mind of a mouse

Casey Luskin is such a great gift to the scientific community. The public spokesman for the Discovery Institute has a law degree and a Masters degree (in Science! Earth Science, that is) and thinks he is qualified to analyze papers in genetics and molecular biology, fields in which he hasn’t the slightest smattering of background, and he keeps falling flat on his face. It’s hilarious! The Discovery Institute is so hard up for competent talent, though, that they keep letting him make a spectacle of his ignorance.

I really, really hope Luskin lives a long time and keeps his job as a frontman for Intelligent Design creationism. He just makes me so happy.

His latest tirade is inspired by the New York Times, which ran an article on highlights from the coelacanth genome. Luskin doesn’t think very deeply, so he keeps making these arguments that he thinks are terribly damaging to evolution because he doesn’t comprehend the significance of what he’s saying. For instance, he sneers at the fact that we keep finding conserved elements in the genome, because as we all know, there are lots of conserved elements.

Hox genes are known to be widely conserved among vertebrates, so the fact that homology was found between Hox-gene-associated DNA across these organisms isn’t very surprising.

[Read more…]

Yankee brainlessness

The craven tools in congress can’t get up the nerve to increase gun control so our kids won’t be as likely to be shot in school, but that just creates opportunity for capitalists. You can now buy bulletproof backpacks.

Lined with ballistic material that can stop a 9mm bullet travelling at 400 metres per second, the backpack is only one of a clutch of new products making their way into US schools in the wake of Newtown school massacre. As gun control legislation grinds to halt in Washington, a growing number of parents and teachers are taking matters into their own hands.

The Denver company that supplied Jaliyah’s rucksack, Elite Sterling Security, has sold over 300 in the last two months and received inquiries from some 2,000 families across the US. It is also in discussion with more than a dozen schools in Colorado about equipping them with ballistic safety vests, a scaled-down version of military uniforms designed to hang in classroom cupboards for children to wear in an emergency.

Parents “taking matters into their own hands” in the most selfish and stupid way imaginable. If only that effort could be focused on getting assault rifles out of the hands of self-righteous assholes…but there is no money for Elite Sterling Security in improving actual security, but there’s a lot in increasing fear.

Is this some kind of test for creeps?

I watched this ad for a new service unbelievingly. Who at Virgin America thought this was a good idea?

Maybe it’s a kind of psychological test — a kind of video gom jabbar. If you’re watching it and thinking that this is a wonderful idea for all involved — the men get to be generous and charming, the women get free alcohol and compliments — then you’re an animal. If you watch it and are appalled at the attempt to use access to unwilling, trapped women as an enticement to use his commercial airline, you pass the humanity test.

If you don’t see it yet, read this account of a woman who was harrassed on a flight without Richard Branson’s facilitation. Are you getting a little closer to humanity yet?

If not, one more thought. Watch the video. Imagine yourself buying a ticket to get access to hot chicks on the flight. Imagine all the hot chicks watching this same video, and immediately rebooking their flights to a different airline. Imagine boarding the flight to discover it’s entirely occupied by leering lechers who are peering around the cabin looking for the available women.

I know I don’t want to be on that flight. I’m not going to be on that flight. Virgin America won’t be getting my business.

It’s another exam day!

I’ve been terrible about updating everyone about my class the last few weeks — we’re coming up on the end of the semester, so I’ve been going a little bit mad. We’ve been focusing on vertebrate development lately, and right now we’ve got a few dozen fertilized chicken eggs sitting in an incubator and developing embryos. Maybe. It is always a real pain to get these things delivered to remote Morris, Minnesota — I delayed this part of the lab to the very end of the semester, hoping the sun would emerge and warm the hemisphere enough that when UPS took their sweet time getting them to me, they wouldn’t freeze in the back of the truck. As usual, though, next day delivery turned into two day delivery, and we haven’t seen Spring yet. So we’ll soon know whether they survived their harrowing journey through the frigid Northlands, and if they haven’t, I’ll have to throw up my hands and cry.

Or I could torture my students to ease my frustration. Yeah, that’s the ticket. So it’s exam day.

Developmental Biology Exam #3

This is a take-home exam. You are free and even encouraged to discuss these questions with your fellow students, but please write your answers independently — I want to hear your voice in your essays. Also note that you are UMM students, and so I have the highest expectations for the quality of your writing, and I will be grading you on grammar and spelling and clarity of expression as well as the content of your essays and your understanding of the concepts.

Answer two of the following three questions, 500-1000 words each. Do not retype the questions into your essay; if I can’t tell which one you’re answering from the story you’re telling, you’re doing it wrong. Include a word count in the top right corner of each of the two essays, and your name in the top left corner of each page. This assignment is due in class on Monday, and there will be a penalty for late submissions.

Question 1: One of Sarah Palin’s notorious gaffes was her dismissal of “fruit fly research” — she thought it was absurd that the government actually funded science on flies. How would you explain to a congressman that basic research is important? I’m going to put two constraints on your answer: 1) It has to be comprehensible to Michele Bachmann, and 2) don’t take the shortcut of promising that which you may not deliver. That is, no “maybe it will cure cancer!” claims, but focus instead on why we should appreciate deeper knowledge of biology.

Question 2: There is an interesting tension in evo devo: on the one hand, we like to talk about the universality of molecular mechanisms, but on the other hand, we’re also very interested in the differences, both in phenotype and genetics. This is an old debate in evolutionary theory, too, so it’s not unique to development, but how do you reconcile unity and diversity simultaneously?

Question 3: When I told you about axis specification in Drosophila, the story was relatively straightforward: maternal factors switch on a chain of zygotic genes that set up the pattern. When I told you about the same process in vertebrates, though, I didn’t give you the same level of detail—I gave you buckets of transcription factors and said they had various roles. Dig deeper. Pick ONE of these vertebrate dorsalizing factors out of the bucket and tell me more about it: noggin, chordin, frizbee, goosecoid, pintallavis.