Sunday, October 31, 2010

Evolution as Fact

(Picture from here.)

Mostly I think evolution speaks for itself.

But I'd be remiss if I didn't talk at least a little about people's difficulty with it.

Personally, I think evolution has sufficiently proved itself to move from the scientific concept of theory to the scientific concept of fact. No scientist of any integrity disputes the fact that we got here by a natural mechanism that we call evolution. The component parts of the mechanism are in dispute, argument and enthusiastic debate. But no one disputes that evolution happened.

It's the same way the no one disputes the facts explained by Maxwell's Equations or Newton's Laws of Motion. Maxwell's equations explain the phenomenon he observed regarding electricity and Newton's equations explain the operation of the phenomenon of motion. That neither model is complete does not refute the fact that there is electricity or the fact there is motion.

Natural selection is the model. Evolution is the fact.

But unlike electricity and motion, evolution strikes at the heart of human exceptionalism-- not too terribly different from American exceptionalism which I spoke about here. Human exceptionalism is the belief that we are special beyond our natural endowments. It usually takes the form that humans are endowed of their abilities by God.

This should not be surprising.

A species by its definition must distinguish between like and not like, otherwise propagation is impossible. Arising from that, reproductive groups distinguish between mine and not mine-- horses, cows, lions and gorillas all make that distinction. Chimpanzees make war against other bands, showing that they have made the leap from reproductive group to societal abstraction. From mine to my people.

One of the human abilities we so prize is the ability to abstract-- the ability to simplify and categorize like things together. The ironclad concept of species itself is a human invention. Reproductive isolation in the wild is much more complex and interesting. (What's the nature of the species boundary between dog and wolf, for example?)

Abstraction is an enormously powerful tool. From it we have deduced cosmology, Euclidean geometry and evolution.

We apply this ability to ourselves and derive nations, states, political ideology and religion which, I submit, are all examples of human exceptionalism. Democrats are better than Republicans. Americans are better than Canadians. Southerners are better than Yankees. Christians are better than Moslems. On and on and on.

I wonder sometimes if we would benefit as a species if we would just stop thinking about ourselves all the time. We're a tiny piece of life on the world that through bizarre happenstance developed abilities that give us inordinate power.

We've been to the moon, cracked the atom and moved machinery with only the circuits of our brain. We've also not managed to make it back in thirty years, burn the atom like it was coal and are figuring out how to better manipulate our brain to make us buy more things from China.

Our view of our exceptional selves was advantageous for the last several thousand years. (For a fun view of this, see Milo Manara's Man. NSFW.) But at some point in the recent past we reached a tipping point, a point beyond which considering ourselves as the sole important group on the planet, made things worse instead of better. I'm not sure when it began but it is unmistakably true now.

The philosophical worth of human beings has been paramount throughout our history. The corollary of that is the worth of human effort has been valued over the natural world. James Watt said in an interview I heard years ago that it wasn't that he didn't value wildlife; it was that he valued human beings more. By extension, he valued human property as symbolic of human worth since he had no trouble developing public land for private interest. Humans, as exceptional creatures, have decided they have the moral right to exploit the living world as they see fit.

I think it's time to change that outlook. And I think it begins by not thinking of ourselves as a special creation outside the operations of nature but as something that evolved directly by the operations of nature.

I don't mean that we are part of everything in the world in some subjective spiritual way. I mean it in an objective mechanism. As Tom Lehrer sang in Pollution:

The breakfast garbage that you throw in to the bay,
They drink at lunch in san jose.
Or perhaps we should quote Benjamin Franklin:

We must all hang together, or assuredly we shall all hang separately.

Friday, October 29, 2010

There is so much disinformation and misinformation out there.

The current conservative talk about deficit presumes as if the deficit sprung full grown from the head of Democrats in January 2008. Look at the graph at left. This is a flat out bald faced lie. (Picture from here.)

There's another lie circulating around. That the debt is exclusively the problem of the Democrats and the Republicans have nothing to do with it.

See graphs at left. (From here. Another one here.)

The pink (Republican) and blue (Democrat) background colors indicate what presidential administration is in power. Two things should be immediately apparent to anyone whose brain is still consuming oxygen. 1) Debt slope crosses administration boundaries and 2) it accelerated the most under Republican administrations.

This is not, most emphatically not, a defense of Obama. You can make all sorts of arguments against what he's been doing in the last couple of years. But the current rhetoric about deficits and debt by Republicans is at best disingenuous abut more likely an outright lie.

Remember that when Clinton wanted to reduce the deficit and pay down the debt the Republicans lined up and voted against it. (See here.)

Okay, people are pissed. The economy is in the tank. A whole f*load of jobs have been sent overseas to the point that most of what we buy is made in China. It's not clear how we're going to get free of this mess-- especially since a lot of the jobs we exported to China were jobs that helped bring us out of past recessions. If you want to say that thirty years of crap didn't happen and Obama is responsible for it since he's right there now for the last 18 months, you can do so. It's a free country. You can vote with your adrenal glands if you want to.

Me, I'll vote with my brain.

Tuesday, October 19, 2010

RIP Benoit Mandlebrot

I have nothing sufficiently pithy to say about it. But here is a great good-bye.

Sunday, October 17, 2010

Baby Speculations

(Picture from here.)

There have been a lot of media attention on what makes us human. Alan Alda hosted The Human Spark. Nova did a series on it as well. I figure I'm at least as uninformed and ignorant as Fox (or as I like to say Faux) News. I'm going out on a limb today and put my oar in the water.

Much of the attention to where we came from is based on what we are now.

I'm not so sure this is a good way to think about it.

While that is interesting-- not many other primates blog, for example-- it's often putting the cart before the horse. I've seen a lot of shows, articles, books, that push who we are now back to what we were. Certainly, what we were was the enabling animal that became what we are. But we always have to remember in evolution a few things:

1. Selection is against individuals, not traits. The traits can enable successful selection but the whole organism has to reproduce.
2. What enabled successful selection in the ancestor may or may not be the same thing enabling successful selection in the descendant.
3. The ancestor was also a successful product of evolution.
4. Anything to be selected against had to be in place prior to the act of selection.
These are fairly critical points to make. For example, we have big brains. It's important to us. They have made us what we are. It's very easy to say that brains are what make us human so bigger brains four million years ago are a selective advantage to Hairy Joe the Australopithecus. Not necessarily. Brains are big and expensive and our big lump between the ears didn't happen overnight. Therefore, for a larger brain to be useful to Hairy Joe it had to be a enough bigger to be useful but not so big as to be unaffordable.

We know Hairy Joe was successful-- we're his descendants after all. But we need to remember that what made him successful isn't likely to be what has made us so successful.

So, what was it about Hairy Joe that was successful (or at least neutral) in its own right at the time that enabled him to evolve into us?

Well, there were a bunch of things: shoulders, hips, thumb, etc. But, because we like our brains let's dwell on that.

One of the characteristics of human development is how bloody long it takes. Human infants are born after a gestation period not too dissimilar to chimps (8 months to 9 months) . A chimp infant learns to hold on to the mother soon after birth. Humans can't even turn over prior to two months of age. We can safely presume that modern humans are born more immature than our closest relative.

Add in to the fact that human brains keep growing long after birth-- much longer than chimps. From one of the above shows I learned that chimp skulls fuse solidly before age five. Humans don't fuse solidly until they're thirty. Humans retain immature characteristics long after birth.

This is called

About 6-11% of human births are preterm-- prior to 37 weeks. I looked for statistics for other mammals but didn't find them. But I suspect that the human rate is higher. It makes sense. Unlike most other mammals humans are in a position to accommodate a variability in gestation period. After all, what's the difference between a baby born at 36 weeks and a baby born at 37 weeks? Both are pretty helpless. Apply the same logic to a pig or a cow where the animal be able to walk, follow the mother, etc., from birth. There's no way a cow can look after a helpless infant. Herbivores have to go where the food is and can't bring it back to the cave and give it back.

There's a significant advantage to neoteny-- birds do it all the time. The hatchlings aren't a lot more capable than a new baby. Predator babies (think kittens and puppies) can afford to be born a little helpless. The mother can bring food to the baby-- the same way birds do. If an animal is set up for it, neoteny is great. Smaller infants. More of them.

Not too small and helpless and not for too long. The mother is tied to the den where those puppies are and she can't wait forever. The cost of predation is high and most predators don't have a big support group.

Our long legged ancestors had a capability possessed by neither lion nor lamb: hands. Like chimps, our ancestors could carry an infant with them. They could carry their offspring to the food source. Gorillas do that now. When Hairy Joe went out on the savannah, he was already capable of rearing a less mature offspring than a lot of his neighbors.

Remember what I said about trains that can be selected against having to be in place before selection occurs. Hairy Joe had to have those traits available for selection. This meant a lot of those components we think are peculiarly human had to be present or latent.

There are a lot of things that helped us along: duplication of the genes for salivary amylase, modifications of the shoulder, the shift to upright posture (which also gave us our thumbs), several genes involved in brain development. But I think while these have aided in our evolution since we started on our path I'm not so convinced they started us on our path.

But I think neoteny is key.

Variability in birth timing is something that shows up in chimps as well as humans. We know we needed it to get here since selection for immature infants can't happen without it. The same social paradigms we share with chimps allows for some variability in infant maturity. An increase in this variability could be tolerated if it favors selection-- which it did in our ancestors.

I am not saying we didn't need the other things that have brought us where we are. Variability in brain size, enabling brain size to be selected for, was pretty nice to have. Nor am I saying that preterm birth is always good thing-- it isn't. Our species tolerates a variability in gestation that I don't think other species do. And it's not just because we have better technology. I think it's part of who we were and who we are. It's an evolutionary opportunity like any other pattern of variation.

I'm saying that out in the veldt Hairy Jolene gave birth to a child a little bit earlier than her sister and she cared for it just fine.

It took a little longer to mature than the other kids but when it was all grown up, it happened to be a little bit smarter.

Friday, October 8, 2010

Krugman on Rupert Murdoch

Krugman takes on Murdoch here. Finally.

Murdoch is pretty close to 10 on the Evil Scale as far as I'm concerned.

Thursday, October 7, 2010

News from BVC

Book View Café Publishes K. E. Kimbriel’s Fires of Nuala.

Book View Café has published Fires of Nuala from Campbell Award-nominated Katharine Eliska Kimbriel. Fires of Nuala concerns the people of the planet Nuala, a world cursed by radiation...and riches. Mutant microbes and high ground radiation make it a deceptive paradise, but wealthy planets always attract predators. This time, one predator may be Nuala's salvation. Originally published by Warner Books in 1988, Fires of Nuala garnered much praise and recommendations for reading from such entities as Locus Magazine. BVC is releasing the ebook version of the book in epub, mobi, pdf, and prc formats.

Buy the ebook for \$4.99 here.

Wednesday, October 6, 2010

Chili Peppers Forever

More video on the New Mexico State Chile Pepper Institute here.

Sunday, October 3, 2010

Spiderpunk

(Picture from here.)

I am not a steam punk writer. I enjoy it immensely. But it is a fantasy arena in which I do not participate. Partly this comes from my love of eighteenth and nineteenth century science and engineering, much of which is ignored or used as mere furniture in steampunk romances. My limitation, I suppose.

I work a great deal in systems and instrument control which is largely accomplished these days by the use of software and electronic mechanisms. The big advantage of software is you're instructing systems how to be have in a language.

In the nineteenth century this was done by mechanical means using hydraulic systems, and comprises the field of fluid mechanics and hydraulic engineering. This means that steam-- the nineteenth century's nuclear power-- was tamed and controlled by valves and whistles. The physical world was controlled by physical laws and physical mechanisms, not minute bits housed in silicon. Very different from what I do and, of course, therefore fascinating.

Hydrodynamics, from the view point of nineteenth engineering, was formalized by Blaise Pascal and canonized in Pascal's Law:
$\Delta P =\rho g (\Delta h)\,$
What this says is the hydrostatic pressure (the difference in pressure between two points in a fluid column: delta-P) is a function of the fluid density (p), the acceleration due to gravity (g) times the difference in height between the two points in the fluid column (delta-h). To reframe it, if you take a garden hose and hook it to a piece of four inch PVC pipe and fill them with water the difference in height of the two water columns is a function of the weight of the water between them.

Note that no additional pressure has to be attributed to get the difference in pressure. Therefore, one interpretation of Pascal's law is that any change in pressure applied to a point in a fluid is transmitted undiminished through the fluid. Similarly, since pressure is a function of the mass of the fluid (the pg part of the equation), if you apply pressure across a wide area it will be increased when the area is reduced. Like a lever where the mechanical advantage is a function of the difference between the lengths of the lever on either side of the fulcrum, you can achieve mechanical advantage by a difference between the difference in areas where pressure is being applied. (See here and here.) Area increases as a square function (πr2 in the case of a circle) where length increases linearly. A consequence of Pascal's law was the Age of Steam.

Pascal's law, like a lot of physical laws discovered by human beings, was already exploited in biological organisms. The vertebrate heart and circulatory system exploit Pascal's law in reverse; by increasing the total cross sectional area of the carrying tubes (arteries->arterioles->capillaries) they reduce the pressure in the blood vessels. Once blood reaches the actual cells the pressure is quite low.

But vertebrate circulatory physiology is a topic for another time. Now I want to talk about something more steampunk-ish.

Spiders.

Vertebrates and a large number of invertebrates have flexor muscles and extensor muscles. Flexors reduce the angle of a joint (flexion) and extensors increase it (extension.) Your biceps is a flexor and your triceps is an extensor. (See here.)

Spiders do not have extensor muscles.

This was discovered back in the early twentieth century but the thought was that there was resistance in the joint such that spider locomotion was a sort of pull-relax-pull mechanism. The relaxation of the flexors would allow the resistance to straighten the joint. Then, someone noticed that dead spiders curled up. If there had been a passive straightening force dead spiders would have spread out.

In 1959, Parry and Brown published The Hydraulic Mechanism of the Spider Leg, a lovely paper where they put house spiders in tiny harnesses and measured how much actual pressure was being created by the spiders. They came up with some fairly impressive numbers for such a tiny creature-- as much as 50 mm Hg-- about .06 atmospheres. Not bad for a creature that's about the weight of a paper clip, if that.

Spiders share the same phylum as insects and pillbugs: Arthropoda. They belong to the subphylum Chelicerata, which they share with horseshoe crabs and sea spiders. The class Arachnida contains scorpions, ticks and mites as well as spiders, which fill the order Araneae. The line that evolved into spiders began at least 400 million years ago. The first true spiders seem to appear about 300 million years ago.

Fluid pressures are generated by muscles in the abdomen and transmitted to the legs. It's likely a primitive condition since a similar mechanism has been shown in whip scorpions which diverged from true spiders prior to the Carboniferous period. (See here.) The heartbeat, however, does appear to have something to do with it since the heart rate changes under forced exercise. (See here.)

There are evolutionary problems with a hydraulic based system. An injury can reduce the effectiveness of the pressure by fluid loss. The animal can be prone to desiccation reducing the ability to move. In addition, use of a hydraulic system for locomotion and for the circulation of oxygen and food puts the two systems in competition. (Anderson and Prestwich discuss this at length in a paper here.) Not to mention there is the additional complexity of managing two separate systems for locomotion. But spiders are very successful. How come?

Wilson (mentioned in the Anderson and Prestwich paper) noticed that the spider mechanisms of predation using webs and poison were extremely efficient. He suggested that these mechanism were so successful that they were able to overcome the problems inherent in their design. Anderson and Prestwich suggested additionally and advantage to the hydraulic system itself. By using a power mechanism whose source resides in the abdomen rather than the legs, the legs were freed up to add more muscles for purposes of flexion, increasing power.

Spiderpunks, indeed.

More on spiders:
Space system based on spider locomotion and here
Ed Nieuwenhuys great articles on spiders of Europe and his microbook, The Spider
AMNH's World Spider Catalog
Wikipedia's Evolution of Spiders
Energy Storage in the Pedipalpal Joints