Rosio Pavoris

After watching a few more videos by and about creationists on the YouTube, I realised that not only do I have more computing power at my fingertips than most scientists in history could ever have dreamed of and a greater-than-average ability to use said power, I also have a neat, educational, and easily implemented project to use it for.

Perhaps you remember the weasel program, but in case you don’t, here’s how my implementation worked:
The user enters a string consisting of characters from a certain pool (in our case, just capital letters and spaces). The program generates a random string of character from that pool, of the same length as the string the user entered. Every “generation”, the program takes one character in that string at random, and replaces it with another random character from the pool; it then compares the new (offspring) string and the old (parent) string to the target string the user entered, and discards the string that’s least like the target. The other one goes on to be the parent in the next generation.
This continues until the program’s own initially random string matches the user’s.

It’s a very simplistic example of Darwinian evolution, and while the point of it can be missed by people aiming to miss it, it demonstrates the power of evolution quite well.

Of course, casually running the program, seeing the number, and nodding absent-mindedly before forgetting all about it is no way to treat a nice algorithm, so I decided to drive the point home by modifying it a bit.

I decided to do a series of tests with successively longer strings (starting with one character, working up to fifty), and record how long it took on average to get from the random starting string to the target string (which is now just a series of As; I hope you realise why this doesn’t matter). The pool of characters was brought down from 27 possible characters to 10, to speed up execution times¹, and each test was then run five thousand times, to get rid of statistical artifacts.
The results were then plotted on a graph:

The X axis is the length of the string. The Y axis is the number of generations it took to get from a random starting string to the target. The blue line is the results my program found. The red line is how long you’d expect to take on average if you just rerolled the string entirely, which is how most creationists seem to think evolution works (the “tornado through a junkyard” fallacy).
For a string of length 50 this number is (10⁵⁰)/2, so forgive me for cutting it off the graph pretty early on.

There are some odd spikes the large sample size should have gotten rid of, which I blame on java.util.Random crapping out², but the trend is pretty clear all the same. (Edit: yeah, the problem was indeed that, and specifically how Java caches things in ways that breaks seeding random number generators. I fixed the issue as best I could and ran the program again; the results are here, and the spikes are indeed gone.)
It took about half an hour to run on my laptop, and the results are even clearer than I expected. Rather than the exponential growth in the number of generations needed so many creationists “predict”, there’s a linear one, which is much healthier.

You can debate how directly this applies to real-life evolution, since organisms tend to have genomes rather larger than fifty base pairs (though their pool of characters is only four, not ten), but they also tend to have more than one kid, and evolution is a trend over an entire population, not just one lineage, and they tend to have more than one mutation per generation (not to mention a bunch of other ways to stir things up, like chromosomal crossover), and sexual reproduction makes a whole new mess of everything.
The point, though, is to show the power of the Darwinian process; specifically, that it’s not just random chance, but something much, much more powerful.

Of course, people can show you all kinds of graphs and give you all kinds of programs to run, but it’s much more satisfying if you do it yourself and understand what you’re doing.
So I’m not going to post my code. Do it yourself. You have the algorithm (and if you think it sucked, improve on it (and post in the comments)), write your own code. It’s simple enough, it’s fun, and it’s quite gratifying.

¹ I also made a multi-threaded version of the program which works with a pool of fifty characters and goes up to string lengths of 500, and it’s been running on my reasonably pathetic cluster for the past two hours. I expect it to finish in a few weeks, unless the fans give out again and the entire cluster shuts down.

² ENTERPRISE TURKEY SOLUTIONS

This took a while to finish. In part because I’m reading too many books at once, but also because it’s so depressing I had to put it down a few times.
Silent Spring, by Rachel Carson, published in 1962, is single-handedly responsible for revitalising the environmental movement around the world. I wanted to read it just for historical context, but the message is so powerful and important that it’s still a very important book.

The book is mainly concerned with indiscriminate pesticides (biocides) such as DDT and various chlorinated hydrocarbons. The book is, of course, famous for inspiring a movement that would very quickly get most of these banned, and it’s very obvious why.
She describes the various projects in the ’50s and ’60s that used these biocides, and how they have a tendency to not just affect the insects or plants targetted, but also, through a process of bioaccumulation in which the pesticides get stored in the bodies of animals in greater and greater doses as they travel up the food chain (that is, a single insect may contain X amount of DDT; a bird that eats twenty of those insects would contain 20X, and because it passes from the system only very slowly, it will remain there while that bird keeps eating insects, or while it is eaten itself), with the result that in the end, applications of these biocides end up killing enormous numbers of larger animals; several projects she described have been successful in wiping out all birds, squirrels, and fish in the (generally very large) treated areas, while not affecting the target insects very much at all, except by removing its natural predators, which, of course, is rather counterproductive.
And of course it’s not just dangerous to birds and the like. She documents a number of cases of human casualties; hardly surprising, given the toxicity of the products involving. Even if death doesn’t occur, permanent brain damage is far more common than it should be, in people handling or just being casually exposed to these supposedly safe products.
And even forgetting the immediate toxicity, there are long-term effects to be considered. Many of the products she talks about (including DDT) are powerful carcinogens. And speaking of long-term effects, insects, with their short generation times, are, of course, going to build up a resistance (and already have), so people will only keep using more and more dangerous pesticides.

She ends the book with alternative approaches to insect control, mostly through introducing natural predators of the insects involved. This has the advantage of being much cheaper and species-specific, and there’s no danger of developing resistance. Or, of course, poisoning your cat.

It’s all very, very depressing to read. If nothing else, it destroyed the myth that “if it’s bad for you, the government wouldn’t allow it!”. Fortunately, Carson’s book made a difference and got all of the products she discusses essentially banned; DDT was banned in the US in 1972, and in most of the rest of the world over the next few decades. Dieldrin, aldrin, endrin, chlordane, heptachlor, and its ilk soon followed.
Regulations on biocides and pest control became stricter and more sane, and most of the projects Carson describes would now be immediately dismissed as retardedly reckless.

Still, it’s alarming how many assholes are out to reverse the DDT ban. The meme that a DDT ban caused thousands/millions/billions of preventable deaths due to malaria is still out there, and for some inexplicable reason gaining support, even though it’s complete nonsense.
It’s important to remember that these people, regardless of their motivation (be it Kool-Aid-flavored ignorance or outright malice (well, greed; same thing)), are very directly working to kill your children.
This is only barely hyperbolic.

(If Rachel Carson and the things she cares about interest you, Deltoid is a very interesting blog that often deals with DDT nutjobs.)

This is something that’s been annoying me recently.
If you’ve ever had a discussion with a creationist (not, like, a run-of-the-mill creationist whose only argument is “evolution is false because my pastor says it is”, but a creationists who thinks his views are defensible), chances are that at one point, they said something like “evolution is false because it can’t even explain how life began”, or something along those lines.

And if this was on a public forum, chances are also good the very next reply was from a non-creationist, saying that evolution doesn’t deal with the origin of life, only with how life behaves when it’s already there, and that what he’s thinking of is abiogenesis, and this has nothing to do with evolution one way or the other.
That possibly annoys me more than the actual creationist, because it shows that the person either doesn’t understand evolution, or that he’s copping out.

Evolution isn’t separable from abiogenesis; it doesn’t have to be. This is because evolution doesn’t just apply to living things (unless you specifically define life as “that which evolves”, which is probably too permissive a definition, in my opinion), and there is no clean break between life and non-life anyway.
The break between evolution and abiogenesis is artificial and contrived.

Evolution

How do you define (Darwinian) evolution?
There have been many definitions over time, but for the most part, they require randomly variable heritable traits on the one hand (genes, for example), and a (non-random) selection process on the other.

Does something have to be alive for evolution to apply to it?

When you’re talking about life, viruses always seem to come up.
By most accounts, they aren’t alive. They’re strands of genetic material in a simple protective coat of protein. They don’t eat, they don’t drink, they can only reproduce by literally being copied by a host cell’s copying apparatus, which is a relatively simple chemical reaction.
They’re large but simple aperiodic crystals, and they aren’t alive.

But evolution obviously applies to them. They grow resistant to medication used against them, they adapt to changing host environments, and they even speciate (though virus speciation isn’t entirely comparable to speciation of higher organisms, because they’re so damn simple).¹

Abiogenesis

Abiogenesis is simply about evolution applying to prebiotic molecules similar to viruses (but even simpler) and the chemical reactions they go through.²
It’s not something that magically happened before evolution kicked in. It’s inextricably intertwined with evolution, and evolution is a very important tool in understanding how it worked.

Now, it’s true that if we didn’t have any clue how abiogenesis could possibly have happened, evolution is still a fact, in the same way that umbrellas don’t stop working because we don’t know where rain comes from, but that’s no reason to claim rain and umbrellas are unconnected.

I can see the appeal of separating them. It catches the creationists off guard, and often destroys their entire argument. They don’t have a logical basis for their beliefs, so they often can’t adjust to that new bit of information by themselves.
It also gives theistic evolutionists something to feel good about, by allowing God to move into another gap. “See, evolution is real, but God still created life!”

However, when creationists say evolution is false because it can’t account for the origin of life, the mistake they’re making isn’t that they’re conflating evolution and abiogenesis—it’s that they assume we don’t have a clue how life started.

If you don’t want to explain the whole thing to them, or you don’t know enough about the whole thing to explain it to them in the first place, saying they should be separated is a handy cop-out, but a cop-out is all it is.

¹ If you do want to define life as “that which evolution applies to”, then yes, viruses are alive. But then you have to deal with things like the Weasel program also being alive.

² Darwinian evolution isn’t the only force that applied to these things, obviously—non-Darwinian selection played its part as well. But then, it still does.

Here’s another argument I’ve seen come up a few times—I don’t intend to correct every single misconception I run into on the intertron, but this one is basic and common enough it’s worth addressing.

Have humans stopped evolving?

The argument tends to go something like “normally the weak die out and the strong survive, and that’s evolution, but humans have the technology to let the weak survive so clearly we aren’t evolving anymore!”, though usually the spelling is worse than that.
This reflects some fundamental misunderstanding of evolution, and natural selection’s place in it.

Selection and Evolution

Selection (be it natural or artificial) isn’t what makes species evolve. You could say that it guides evolution, but it doesn’t drive it.
The distinction is rather important if you don’t want to make an ass out of yourself by asking stupid questions.

The real driving force—the only driving force¹—of evolution is mutation.
This is obvious if you think about it. Selection (of any kind) doesn’t produce variety, and Lamarck, obviously, was wrong.

What selection does is prune out the harmful mutations (because yes, most mutations that have phenotypic effects are harmful), and get rid of the “less fit” organisms.
“Less fit” for what? To survive and successfully breed in their habitat.

This means that if the habitat of an organism hasn’t changed in a long time, it’s likely to be relatively close to ideally suited to thriving in it, which means that the overall effect of natural selection will be to maintain the traits of the parents in the offspring.
To most people who ask this sort of question, natural selection would seem to be the opposite² of evolution in these cases.^{3 4}

If the environment the organism has to survive in has changed recently, a species can undergo very dramatic changes in relatively short periods of time, but it’s important to realise natural selection is not the driving force here—mutation is.

Selection can only act a brake on evolution. If technology enabled mankind to be free of any of the pressures of selection, we’d be evolving faster than ever.⁵

Selective Pressures on Humanity

That was the first thing I wanted to get out of the way. Next, the claim that technology enables mankind to be free of any of the pressures of selection.

It’s bullshit.

Have we cured all diseases? Malaria alone still kills between one and three million people a year, and that one we supposedly know how to cure. Even the goddamn measels claim hundreds of thousands of people each year.
And forget diseases—what about our own bodies? Cardiovascular disease is still the most common cause of death worldwide, and cancer is responsible for 13% of all deaths.
And don’t forget that most pregnancies end in miscarriage; that’s some powerful selection right there.

And technology has brought us another very potent source of natural selection: pollution.
Air pollution means that suddenly a mild asthma that wouldn’t necessarily kill you in the past becomes life-threatening. Water pollution kills over five million people a year. Soil pollution degrades the quality of our food and threatens our health. Radioactive pollution renders us sterile. Noise and light pollution increase stress levels, which leads to increased blood pressure and heart problems.

And what about sexual selection? Or will you just have kids with anyone?

Conclusion

To sum up, yes, humans are still evolving, and yes, we’re still under selective pressures.
We’ll be subject to natural selection for a long, long time, and there’s no reason to believe we won’t be subject to artificial selection for a long time after that. And even if we weren’t, we’d still evolve. I’m sure technology affects natural selection (and by extension evolution), but it doesn’t stop it.

Obviously asking questions is always a good thing, but if you’re going to base your assumptions regarding evolution on Pokémon, it might be a good idea to just pick up a book in the future.
There are plenty of good, readable books out there that will help you think about evolution. Personally, I’d recommend Richard Dawkins’ The Selfish Gene (obviously), and Daniel Dennett’s Darwin’s Dangerous Idea.

¹ Yes, sexual recombination helps, but if you only had sexual recombination as a source of variety, your total population would shrink rather exponentially; and even sexual recombination requires variety to start with, and the only source of that is random mutations.

² “Devolution” isn’t a term that makes sense, shut the fuck up. The opposite of evolution is a lack of evolution, not devolution.

³ Obviously this is related to Eldredge and Gould’s punctuated equilibrium, which predicts rather long periods with no real change interspersed with quick periods of rapid change (arms races aside), and should be distinguished from saltationism or quantum evolution. The idea of gradualism isn’t bullshit as such, it’s just a lot rarer.

⁴ Yes, I’m essentially an adaptationist. No, that doesn’t mean I don’t think neutral phenotypic effects (like the African rhinoceros’ second horn) can’t be fixed, à la spandrels. Grow up.

⁵ I like footnotes.

Perhaps you’re already familiar with the idea behind METHINKS IT IS LIKE A WEASEL; it’s a simple program designed by Dawkins to demonstrate the enormous power of Darwinian evolution. He originally mentioned it in his book The Blind Watchmaker, and gave a demonstration of it in the accompanying BBC programme.
He also explains it in this shorter video (using a different phrase, but the idea is obviously the same):

(Earning that Public Understanding of Science badge. Near the end he also explains the title of another one of his books, Climbing Mount Improbable.)

Because I was bored, I’ve written a similar program (bytecode here, if you’re too lazy to compile) just now. It differs from Dawkins’ original design in a few ways.

First off, there’s only one offspring per generation, and rather than picking the best of the pool of kids, it simply picks the best of the kid or the parent.
Secondly, rather than each letter having a given chance to mutate, it just changes one letter per generation. This slows down the improvements early on, but it reduces the chances of reproduction severely messing up a nearly-correct string (my first test using random mutations took over six thousand generations just to get the final letter right; real evolution doesn’t work towards a goal it needs to get just right, so it’s not under that kind of restriction).
Thirdly, it actually kind of sucks, because you can’t really see it change as it goes. It just dumps data into the output window, and it scrolls too fast to actually follow. Still, you can scroll back a bit once it’s done.

I ran it a few times, and it seems to take about two or three thousand generations (that is, a few seconds; since this is kind of like bacterial asexual reproduction, that’s actually next to no time at all) to get from the random starting string to METHINKS IT IS LIKE A WEASEL. I could calculate how long it takes on average, but I’ll leave that as an exercise to the reader.

People have been talking about this recently, mostly sparked by some creationists calling it an example of Darwinian fundamentalism, followed by some atheist evolutionary biologists going “lol i dont believe it”.

Let me start by saying that evolutionary psychology, as it stands today, is indeed almost entirely pseudoscientific bullshit. This seems to be because psychology in general is pseudoscientific bullshit, and this is because people don’t really seem to know how to approach cognitive science.
The most obvious bullshit in psychology seems to derive from Freud and Jung, which is quite embarrassing, since their flaws should be immediately apparent to anyone who’s ever had the misfortune of sitting through a lecture on their ideas.

I’m not saying (Scientology-style) that psychologists are necessarily useless because of this, and that people should instead rely on dianetics/prayer/meditation/magic potions. Psychologists have value as a person for people with genuine problems to talk to, which helps more than most people realise, and like it or not, psychology is still the best we have, even if it isn’t very good.
Evolutionary psychology, of course, is doomed to inherit these flaws.

I do believe, however, that if we are ever going to make sense of human behavior, it has to be through the lens of our evolutionary history.
Obviously, I’m not a strict genetic determinist; some animal species’ behavior is clearly directly influenced by their genes (the case-building of caddisflies is a classic example, but there are countless more, and not just in the insect world), but humans are by their very nature generalists. There is very little behavior that’s hardwired (PZ wrote about this earlier, though he seems to be attacking a straw man at one point), and most specifically human behavior seems to be taught, not inherited.
This is (part of) the nature versus nurture debate again.

But it’s insane to deny that our genes play a very large part in determining who we are and what motivates us. Things like the desire to reproduce and raise children aren’t taught, and they’re a very fundamental part of what it means to be human; and they’re inescapable.
I know there are always those who want to pretend evolution doesn’t apply to humans, and that we stand outside nature, but that’s just chauvinistic nonsense.

There’s always a danger in making sweeping generalisations and jumping to conclusions (I’ll be the first to admit that my own foray into this area a while ago was an embarrassing failure), but knee-jerk dismissals of anything that looks like evolutionary psychology seem to me to be far more harmful than a few well-intentioned but ultimately ill-advised assertions.

I don’t know. Maybe there are fewer people disagreeing with this than seems to be the case, and I’m just preaching to the choir, but I wanted to get this out in the open just in case. Comments plz.

I don’t think I’ve posted this before. Carl Sagan on evolution and selection both artificial and natural. (06:24)

I finished this one a while ago, but I guess I never got around to reviewing it. What is Life? is, of course, a famous work by Erwin Schrödinger, of cat fame.
In it, he argues that chromosomes behave according to physical laws classical physics can’t really approach, since classical physical laws are statistical, and only hold for large numbers of molecules, while a chromosome is in essence just one very large molecule. He speculates that DNA is, in fact, a large aperiodic crystal, and muses about the ways in which it could encode hereditary information.

And yes, it’s all speculation. This was written in 1944, well before the actual structure of DNA became known, and, indeed, long before much of anything was known about genetics. It still speaks about DNA as being the carrier of heredity in the hypothetical, even.
What is Life? was a visionary work, and its influence is undeniable. Even today, it can still inspire people because of the intense sense of curiosity it conveys (Schrödinger was, after all, a theoretical physicist first, but he didn’t let that stop him from delving into this alien field of biology).
As a source of accurate information, though, it’s much more likely to misguide than to educate, at this point, so it really isn’t a book uninformed laypeople should be reading. Still, if you know a bit about genetics and molecular biology, it’s a very interesting read for its historic value.

This edition also contains Mind and Matter, an essay I didn’t bother reading since I figured it would make me angry (especially since Roger Penrose wrote the introduction), and Autobiographical Sketches, in which Schrödinger talks about his life.
This is particularly interesting, since Schrödinger was, after all, a scientist during the World Wars (which is always an interesting topic; just look at Richard Feynman). Moreover, he was Austrian, so he spent much of his time on the side we never really hear first-hand accounts from. It’s nice to hear someone talk about this without the off-hand demonisation we’ve become so used to.

The Naked Ape, by Desmond Morris, is about humans, from the perspective of a zoologist.
I mostly read it because my mom loves the guy, but I’d been meaning to read it because I’d been told he touches on the neotenous ape hypothesis too. (Turns out he doesn’t say anything new.)

While the zoologist perspective is refreshing even now, forty years after it came out, most of the actual information in it is either very obvious (to anyone with half a brain) or very outdated.
The fact that a lot of religious people were apparently outraged by it, though I really doubt most were because “it places man in nature”. The sections on sex and sexuality were often just gratuitous (and if I noticed, you know it has to be bad), and a much more likely source of outrage.

It really is quite outdated, though, and likely to give inexperienced or casual readers completely wrong ideas about a number of things, including some basic facts of evolution.
My copy was a new edition released in 1994, and the preface made it clear Morris thought everything he wrote still applied perfectly, and wasn’t in need of updating, even though his editor had asked him to, so I’m not inclined to cut him much slack on that account. The Naked Ape just isn’t a very good book.

The Double Helix, by James Watson, is an account of Watson and Crick’s part in the discovery of the structure of DNA, and of the people involved.

A lot of people have called this a brilliant work of non-fiction, and an important step in de-mystifying science for the general public, but to me it mostly demonstrated that James Watson is a arrogant, prejudiced asshole and a condescending sexist, who has a ridiculously poor understanding of his own field, but managed to ride the coat-tails of his betters (almost all of the work had already been done long before Watson turned his attention to it, and he still had to depend on the insights of Crick, Donohue, Franklin, and others to get there in the end) and convince himself that he’s the center of the universe in the process.

It was written fifteen years after the fact, so even it’s factual accuracy isn’t something I’d put too much faith in. If it’s supposed to give people an idea of how “creative science really happens” (as one of the cover endorsements suggests), it’s no wonder most people are distrustful of scientists.

The same book written by Francis Crick (or Maurice Wilkins, or Rosalind Franklin, or anyone besides Watson) would’ve been infinitely more interesting.

Today is the 125th anniversary of Charles Darwin’s death.
Why didn’t he just evolve immortality, eh, if he’s so great? Hur hur hur.

Anyway. Pharyngula has a bit about his final moments.

As part of her blog tour, Lynn Margulis (mostly known for being Carl Sagan’s first wife, I guess) was doing Q&A in #pharyngula today.
It just ended ten minutes ago, and I thought it was rather underwhelming. I missed parts of it, but Margulis strikes me as a stopped-clock-is-right-twice-a-day type of “revolutionary”, for various reasons.
It’s a pity nobody asked her about the HIV/AIDS thing (she seems to deny there’s any connection).

If anyone’s interested in logs, there’s one here (unedited, so somewhat noisy).

(No, this isn’t an un-hiatusing.)

Roy Zimmerman appears to be awesome.

(Via this person.)

I still haven’t managed to find a paper copy of Charles Darwin’s On The Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life (seriously, that’s the title; I think I’ll end up having to order it online), but LibriVox, a website that creates and makes available public domain audiobooks for free, has recently put up a set of recordings of it.
If you’d rather read, of course, Project Gutenberg has had it for a while now.

This is why I love the public domain, and the internets.

The term “just-so story” goes back to Rudyard Kipling’s 1902 collection of short stories titled, surprisingly, Just So Stories. (Thanks to Larry Moran for that link.)
The stories were aimed at children, and “explained” certain features of the world. Most of them dealt with animals.

Perhaps the most famous one is The Elephant’s Child, in which Kipling explains how the elephant got its trunk.

‘Come hither, Little One,’ said the Crocodile, ‘and I’ll whisper.’

Then the Elephant’s Child put his head down close to the Crocodile’s musky, tusky mouth, and the Crocodile caught him by his little nose, which up to that very week, day, hour, and minute, had been no bigger than a boot, though much more useful.

‘I think,’ said the Crocodile–and he said it between his teeth, like this–’I think to-day I will begin with Elephant’s Child!’

At this, O Best Beloved, the Elephant’s Child was much annoyed, and he said, speaking through his nose, like this, ‘Led go! You are hurtig be!’

Then the Bi-Coloured-Python-Rock-Snake scuffled down from the bank and said, ‘My young friend, if you do not now, immediately and instantly, pull as hard as ever you can, it is my opinion that your acquaintance in the large-pattern leather ulster’ (and by this he meant the Crocodile) ‘will jerk you into yonder limpid stream before you can say Jack Robinson.’

This is the way Bi-Coloured-Python-Rock-Snakes always talk.

Then the Elephant’s Child sat back on his little haunches, and pulled, and pulled, and pulled, and his nose began to stretch. And the Crocodile floundered into the water, making it all creamy with great sweeps of his tail, and he pulled, and pulled, and pulled.

Nowadays, “just-so story” is mostly used in academic contexts, particularly in anthropology, sociology, and evolutionary biology, for a narrative explanation of a certain cultural practice or behavior or biological feature that is (perhaps just perceived to be) unfalsifiable.

Consider, for example, this story on how birds may have gotten their wings, from Richard Dawkins’ Climbing Mount Improbable:

Here’s one guess as to how flying got started in birds. The hypothetical ancestor, which we can imagine as a small, agile, dinosaur, runs fast after insects, leaping in the air with its powerful hind legs and snapping at the prey. Insects had evolved into the air long before. A flying insect is perfectly capable of taking evasive action, and the leaping predator would benefit from skill in mid-course correction. To some extent you can see cats doing this today. It seems difficult because, since you are in the air, there is nothing solid to push against. The trick is to shift your centre of gravity. You can do this by moving bits of yourself relative to other bits. You could move your head or tail, but the obvious bits to move are the arms. Now, once the arms are being moved for this purpose, they become more effective at it if they develop surfaces to catch the air. It has also been suggested that the feathers on the arms originally developed as a kind of net for catching insects. This is not so far-fetched as it sounds, for some bats use their wings in this way. But, according to this theory, the most important use of the arms was for steerage and control. Some calculations suggest that the most approppriate arm movements for controlling pitching and rolling in a leap would actually resemble rudimentary flapping movements.

Just-so story? Perhaps.
But it helps teach the reader how to think about evolution as a gradual process, and it also throws in the concept of exaptation. It’s a valid and valuable teaching tool.

That isn’t the only use for just-so stories, however. They can also help researchers by giving them a new angle from which to approach a certain subject.
For example, Cairns-Smith’s clay hypothesis is now generally accepted not to have been the exact mechanism behind abiogenesis, but it’s still quoted a lot as an example of the kind of mechanism that could have caused it.

Yes, it’s possible to get too caught up in just-so stories and give them more credit than they deserve (evolutionary psychology in particular seems to suffer from this), and there’s a good reason “just-so story” is often used as harsh criticism, but they’re more valuable than many people are willing to admit.

(Of course, another important problem with the concept is that it’s pretty easy for creationists (and such) to take just-so stories out of context and claim they’re evidence of poor science, or that well-tested and uncontroversial hypotheses (such as the development of the eye, still) are nothing more than just-so stories themselves.)

I don’t remember how I came across this, but it’s made of epic win.
If you have several days to spend on improving yourself, watch all of those videos. All of them. Reading his books would be better, of course, but still.
I think the biology videos are more interesting than the religion ones, but it’s all good. (Well, except for the BBC profile, which starts out promisingly enough, but then just runs itself face-first into the ground by completely misunderstanding both the entire premise of the selfish gene and the function of religion.)

Richard Dawkins makes me happy in the pants.

I was reading Daniel Dennett’s Consciousness Explained (so far it hasn’t been very impressive, though I’m only on the fourth chapter), and I saw this passage.

There is a species of primate in South America, more gregarious than most other mammals, with a curious behavior. The members of this species often gather in groups, large and small, and in the course of their mutual chattering, under a wide variety of circumstances, they are induced to engage in bouts of involuntary, convulsive respiration, a sort of loud, helpless, mutually reinforcing group panting that sometimes is so severe as to incapacitate them. Far from being aversive, however, these attacks seem to be sought out by most members of the species, some of whom even appear to be addicted to them.
We might be tempted to think that if only we knew what it was like to be them, from the inside, we’d understand this curious addiction of theirs. If we could see it “from their point of view,” we would know what it was for. But in this case we can quite sure that such insight as we might gain would still leave matters mysterious. For we already have the access we seek; the species is Homo sapiens (which does indeed inhabit South America, among other places), and the behavior is laughter.
No other animal does anything like it.

Quite apart from the point he goes on to make, this just isn’t true. Aristotle may have observed that “only the human animal laughs”, but Aristotle was wrong about a lot of things.

All four extant genera of great apes (which is to say, humans, chimpanzees, gorillas, and orangutans) laugh, though the laughter of non-humans may not always be immediately recognisable to humans. Their laughter sounds more like regular panting than actual laughter, possibly because of differences in their vocal cords.
There is evidence to suggest many non-ape primates laugh as well.

Further up the genetic stream, but probably more familiar to most people, are dogs. Their laugh sounds a lot like excited panting as well, but spectrographic analysis reveals that it’s actually quite distinct. Anyone who’s owned a dog for a while will generally be able to recognise it as well.
Experiments have been performed where dogs were exposed to a recording of a laughing dog, and its effects on their behavior was monitored. The dogs exposed to the recording were found to be more playful, and their stress levels seemed to be reduced. This suggests laughter has much the same role in dogs as it does in humans.

And finally, rats seem to laugh as well. Their laughter is ultrasonic, so humans can’t hear it, and they mostly seem to laugh while playing or being tickled.
Apparently some scientists manage to get research grants for tickling rats.

Either way, humans are far from the only animals that laugh. Some people would argue that self-awareness or the ability to identify with somebody else’s predicament are prerequisites for laughter, so animals are not really laughing in the same way that we do, but that’s just species chauvinism.

Edit: Coincidentally, John Wilkins quotes Daniel Gilbert on a topic quite relevant to this.

Evolution is an entirely uncontroversial idea, at this point, but how could it get started? Life begets life, but where did the first life come from?
If we want to explain the origin of life without invoking a deity (which, contrary to popular belief, creates a lot more questions than it could possibly answer), it must have come from non-life at some point: abiogenesis.

Let’s start by saying what abiogenesis is not: it’s not spontaneous generation.
Spontaneous generation is the idea that complex life forms can appear fully formed, and that’s what Pasteur disproved (kind of; you can’t prove a negative, obviously). The important part about abiogenesis is that it’s gradual, like evolution itself. Early life would have been less complex than even modern viruses.

Now, the exact details of abiogenesis are still far from certain, so what I’ll do is first describe the best guess we have so far, and then describe a model that takes it from there, and is probably similar to the kind of mechanism that led to abiogenesis.

Primordial soup

The primordial soup hypothesis states that prebiotic Earth had oceans that formed a type of warm soup with tons of simple organic molecules (such as CO₂) dissolved into them. In this soup, these simple molecules combined into more and more complex molecules, eventually forming the amino acids which form the basis of life.

In 1936, Aleksandr Ivanovich Oparin demonstrated that organic molecules could be created in an oxygenless atmosphere, under the influence of sunlight.
He suggested these molecules would combine in growing complexity until they dissolved into a coacervate droplet.
These droplets could then fuse with other droplets and break apart into more droplets, and whatnot. A simple form of reproduction with partial inheritance.
Favorable attributes such as increased durability in the structure would survive more often than nonfavorable attributes, so they’d become dominant. So there’s a basic selection as well.

Influenced by this idea, and by the work of J. B. S. Haldane, Stanley L. Miller and Harold C. Urey formulated and carried out the now-famous Miller-Urey experiments, in which they attempted to recreated the chemical conditions the primitive Eart would have had. They started out with methane, ammonia, water vapor, and hydrogen, mostly. An external energy source was provided in the form of electric sparks, simulating lightning.
Within two weeks, thirteen of the twenty amino acids used in life had formed spontaneously. Very impressive results.

It’s worth pointing out that larger organic molecules probably wouldn’t have been stable, and would have fallen apart relatively quickly under most circumstances.
Still, perhaps not.

Clay theory

This was first suggested by Graham Cairns-Smith. The idea is simple and elegant.
Clay crystals form naturally from silicates in solution, and like all crystals, they preserve their structure as they grow. When bits snap off from the main crystal, they continue to grow, preserving the structure of the main crystal. This is a simple form of reproduction with inheritance. Nobody would say this is life, though.
There is a simple selection as well: crystals of forms that grow more easily will eventually dominate.

From here, it’s not hard to imagine some structures might happen to influence their environment in ways that are condusive to more efficient replication. A stickier clay crystal is more likely to silt a stream, perhaps, thereby creating an environment that’ll make further sedimentation, and thus growth, easier.
It’s conceivable that some crystals could find ways to trap certain kinds of molecules (perhaps, indeed, the amino acids of the Miller-Urey experiment, or even simpler organic molecules) on their surface to replicate even more efficiently, perhaps arranging them in certain combinations. This could create rather complex (comparatively speaking) organic molecules, catalysed by the surface properties of the silicates.

Eventually, these organic molecules learn to replicate on their own: they’ve become proto-DNA.
They no longer depend on the clay for their reproduction, and because they need so much less space and time to reproduce than the clay crystals do, they become the dominant type of “life” (the cut-off between life and non-life being, of course, mostly arbitrary). Clay crystals might continue to reproduce, but they’re a dead end.

Now, while this is a good model of the kind of process that might have been involved in the prehistory of DNA, it’s very unlikely that this was the exact mechanism.
Still, it’s useful to help us think about abiogenesis.

Interesting desu.
If you want to know more, TalkOrigins has a section on abiogenesis as well.
It should be noted that I’m not an expert, so if got anything wrong, feel free to point it out. We’re all here to learn~

Time for another installment of Weird Creatures. I’m only going to be doing one per week now, I think, because of classes.
This is another group of species rather than just one, like the leafcutter ants. And like the leafcutter ants, they’re also insects: the fig wasp!

Fig wasps are wasp species in the Agaonidae family. There are almost eighty of them, and they can be roughly divided into two groups: symbiotic and parasitic.
The parasitic ones aren’t very interesting, but the symbiotic ones are. Let’s take a look at those.

Their life starts when they hatch as larvae, and eventually turn into tiny, tiny wasps inside the flowers their eggs were deposited in. They leave the flowers, and find themselves in a type of small cave. If they’re males, they often won’t have wings. If they’re female, they always do.
There are relatively a lot more males than females, as is often the case, and most males never get to mate. As soon as a female has mated, the male (and some males who won’t get to mate) start digging their way out of the cave, clearing the way for the female. While they’re doing that, the female goes around and fills up specialised pouches on her body with pollen.

They make their way out, and burst out into the world. The males die quickly, but the female flies off. If she looks back, she sees what she just came out of is a fig. What she has to do now is find another fig, preferably on another tree.

If the fig doesn’t have any other wasps in it yet, it’ll be soft enough for the female wasp to squeeze through one of the pores on the skin, though it’s still a tight enough squeeze that she’ll probably lose her wings in the process.
Once she’s in, though, she’ll generally find three types of flowers: male, short female, and long female.
The male flowers will hold pollen for the next generation of female wasps to carry. The long female flowers are too long for the wasp to deposit her eggs into, but she can still pollinate it with the pollen she carried from her home fig.
The short female flowers are the one she lays her eggs in. She’ll pollinate the flowers, but the larva growing in it will destroy the reproductive capabilities as far as the fig tree is concerned.

Once she has laid her eggs, she dies, and the cycle starts over.
If she has laid eggs in too many flowers (because she found a way to lay eggs in the long female flowers, perhaps), the fig will shrivel and fall off, making sure any wasp taking advantage of the fig tree’s generosity (since it provides both protection and nutrition for the wasp larvae) doesn’t reproduce, and the tree cuts its losses (since it takes energy to provide food for the wasps).
And so, the balance is preserved~

Each species of fig wasp is specific to a species of fig, and some fig trees don’t have wasps. Still, the crunchy bits in your figs are about as like to be wasps as they are seeds. Enjoy that.

And this isn’t the whole story, of course. The parasitic wasps are a different story entirely (they also lay eggs in figs, but they don’t pollinate them; they’re harmful to both the fig tree and the symbiotic fig wasps), and what happens to the fig after it’s been pollinated is kind of complicated.
There are some types of ant that wait near likely exits for female wasps on figs, too, so life as a fig wasp isn’t entirely safe inside a fig. The picture below shows that. Also handy because you can compare scale, to see just how small these wasps are.

I talked about humans being neotenous apes before. Some people may have felt my labelling of religion as an example of psychological neoteny was a bit gratuitous, so maybe it needs a bit of elaboration.

The heavenly parent figure and the guy with all the answers central to almost every religion is an obvious one, of course, but there’s more.

One reason religion is so popular is because it tends to feed them easy answers, allowing—encouraging—them to accept feel-good dogma without having to critically examine any evidence themselves. Well, not just feel-good dogma; few would argue the xenophobia that comes with so many religions is a feel-good thing.
Why do people have this tendency to accept information without examining it, even when it contradicts reality?

There is an obvious evolutionary disadvantage to this. Blinding yourself to reality and blindly trusting fellow packmates when they’re clever enough to be able to lie (as is the case with—to my knowledge—all primates, and quite a number of other animals) is bound to bite you in the ass sooner or later.
In fact, it’s a very disadvantageous trait in all but one very specific group of individuals: learning children.

Parents (or other individuals charged with rearing a group’s kids) will often teach their young, since forcing them to figure everything out on their own is an inefficient and dangerous way of doing things. Learning on your own takes more time than being taught, and there are some things you can only find out once, after all.
For this reason, it’s advantageous to the young to accept their parents’ advice uncritically rather than to constantly be second-guessing them.

It makes sense that if somatic development is slowed, development of the brain and (more importantly) the general change of hormone levels over the course of a lifetime would be delayed as well.
The brain is still relatively poorly understood (not least by me), and I’m not sure how much of a correlation there is between certain hormone levels and religiosity. I’m sure research has been done in this field, and if there’s ever a third post in this neoteny series, it’ll be about that. Someone with more of a background in these matters would probably be better at this, though.
It’s still very interesting~

I think I should read this book. It’s quite amusing that the third Google hit for “religion neoteny” (and the first one that isn’t that book) is my previous post on the matter.