Comment of the week, in response to a post about the Headline of the Week: "Success! Functioning Anal Sphincter Grown in a Petri Dish".

Otto says:
10 Aug 2011 at 11:46 pm

Question: How, exactly, do they know it's "functioning"? Ewwwwwwww….

jwz says:
11 Aug 2011 at 1:00 am

To quote Lauren Bacall, "You know how to whistle, don't you?"

The Big Blog Theory is written by David Saltzberg, the science consultant on The Big Bang Theory. He posts about each episode, explaining the scientific background to some plot point or throwaway comment. See, for example, the entry on The Wheaton Recurrence:

Giant ants were the terror of the movie Them! (1954). Tonight Rajesh and Howard realize giant ants would be a cool new method of transportation. But Sheldon Cooper is right: unfortunately physics determines that giant ants cannot exist on our planet as we know it.

The evolutionary biologist, J.B.S. Haldane, won this argument already in his 1926 essay "On Being the Right Size". In his essay, Handane did more than observe elephants are larger than mice but explained, using physics, how changes in size demand changes in form.

A typical ant we know and love is about 5mm long and has a mass of about 5 milligrams. The giant ants you might like to have around would be 1000 times longer. Not just longer, but 1000 times wider. Not just wider, but 1000 times taller. To calculate the new mass of the giant ant we have to multiply these all together – a billion times the volume. At the same density, a giant ant would weigh about 5 tons. But its legs would only be wider in two dimensions. They are a million times stronger, but that is not enough – for a creature a billion times heavier. Before taking their first step they would break all their legs, leaving them immoblile and harmless. While mass increases as the cube of size, the function of its structure improves only as the square, hence the name "square-cube law".

Note to bug spray companies: Just make a chemical that grows ants 1000-fold in every dimension. That will stop ants in their tracks. That's sure to be a best-selling item.

[Via MetaFilter]

David Fleming on the "Uh-oh" moment:

We can exhaustively explore every aspect of athletic life — victory, defeat, violence, racism, drugs, brain damage, paralysis, death — but nothing reveals as much about the physiology, psychology and sociology of sport as the excretory experience of athletes.

Of course, such is the sacredness of our relationship with our bowels that we're all programmed to pretend no one ever poops (or writes about it), despite the fact that every day on this planet, we humans produce 1.5 billion pounds of the stuff. The plain truth is, we all poop. Even athletes. Especially athletes. One of the sports world's last unspoken dirty little secrets is that this perfectly normal bodily function has a profound effect on all levels of competition. And the more you understand the way exercise impacts the intestinal tract, the more you'll wonder how any athlete ever manages to hold it in.

[Via Give Me Something to Read]

The life cycle of Symbion pandora is so outlandish it reads like something from the first draft of Ridley Scott's script for his Alien prequel:

Things start to get complicated when you consider their life cycle. Let's start with a feeding animal living on a lobster's mouthparts: this individual – it's hard to assign a sex – can then produce one of three kinds of offspring: a "Pandora" larva, a "Prometheus" larva or a female.

The Pandora larva develops into another feeding adult – a straightforward case of asexual reproduction. By contrast, the female remains inside the adult and awaits a male – but, attentive readers will be crying, what male?

The answer lies in the Prometheus larva [...]

[Via MetaFilter]

A creepy-looking blood-red waterfall in Antarctica.

It turns out that the H1N1 virus really is tiny but deadly:

So it takes about 25 kilobits – 3.2 kbytes – of data to code for [the H1N1 virus, which] has a non-trivial chance of killing a human. This is more efficient than a computer virus, such as MyDoom, which rings in at around 22 kbytes.

[Via Bruce Schneier]

Which is prettier: SARS, Swine Flu, Smallpox or HIV?

[Via MetaFilter]

What could go wrong?

After years spent hunting for the buried remains of prehistoric animals, a Canadian paleontologist now plans to manipulate chicken embryos to show he can create a dinosaur. Hans Larsson, the Canada Research Chair in Macro Evolution at Montreal's McGill University, said he aims to develop dinosaur traits that disappeared millions of years ago in birds. Larsson believes by flipping certain genetic levers during a chicken embryo's development, he can reproduce the dinosaur anatomy, he told AFP in an interview.

[Via James Nicoll]

Credit where it's due: Bruce Schneier certainly knows how to come up with an arresting post title. How can you scroll past a post entitled Security Considerations in the Design of the Human Penis?

(Shouldn't that be "Security Considerations in the Evolution of the Human Penis"?)

Never, ever annoy a mantis shrimp:

Mantis shrimps are aggressive relatives of crabs and lobsters and prey upon other animals by crippling them with devastating jabs. Their secret weapons are a pair of hinged arms folded away under their head, which they can unfurl at incredible speeds.

The 'spearer' species have arms ending in a fiendish barbed spike that they use to impale soft-bodied prey like fish. But the larger 'smasher' species have arms ending in heavy clubs, and use them to deliver blows with the same force as a rifle bullet.

[...]

With each punch, the club’s edge travels at about 50 mph

Wait, there's more…

[Each...] of the smasher's strikes produced small flashes of light upon impact. They are emitted because the club moves so quickly that it lowers the pressure of the water in front of it, causing it to boil.

[Via MemeMachineGo!]

Peter Ward and his colleagues reckon they might have figured out the cause of mass extinctions:

In the deep history of our planet, there have been at least five short intervals in which the majority of living species suddenly went extinct. Biologists are used to thinking about how environmental pressures slowly select the organisms most fit for survival through natural selection, shaping life on Earth like an artist sculpting clay. However, mass extinctions are drastic examples of natural selection at its most ruthless, killing off vast numbers of species at one time in a way that is hardly typical of evolution.

[...] An asteroid probably did kill off the dinosaurs, but the causes of the other four mass extinctions are still obscured beneath the accumulated weight of hundreds of millions of years, and no one has found any other credible evidence of impact craters.

But now, together with Mark Roth of the Fred Hutchinson Cancer Research Center in Seattle, I believe we have found a possible biochemical scar, present within living animals, that links Earth's greatest mass extinction to a single substance: hydrogen sulfide (H₂S). Hydrogen sulfide is a relatively simple molecule that gives rotten eggs their distinctive foul odor and is quite toxic — in high concentrations a single breath can kill. And it looks like that is what happened: Hundreds of millions of years ago, hydrogen sulfide probably saturated our oceans and atmosphere, poisoning nearly every creature on Earth. [...]

Fascinating.