Saturday, April 21, 2012


Somwhere in grammar school SRA Reading Laboratory was introduced. The 20+ leveles were color coded, and the names were different than the Crayola designations. This in itself fascinated me; I think I believed Crayola was based on some official color list, something venerable, like the periodic table. How else to explain a color such as

Burnt Sienna?

So SRA seemed suspicious right from the start, an arrogant upstart organisation which made up its own names for colors. The system also allowed you to work in only one color at a time - damn fascists.

On the plus side, it was free reading allowed during class time, and one got to choose which selections to read and which to skip within color. Provided you tested on to the next color before exhausting the possibilities, that is. Otherwise, I suppose you got stuck reading girl stuff at the end.

It may have been my first exposure to speculative reasoning. Most vividly, I remember an article (aqua, perhaps) explaining why creatures from other planets were unlikely to have six eyes or six arms; why they would not be giant-size or teensy. Looking back, I can see enormous failure of imagination on the part of the author, who essentially concluded that aliens would look something like us. I liked this whole process, however. A topic where no one knew the answer, but we might figure out which answers were possible or likely, versus impossible or unlikely.

In popular culture contact with aliens follows two forms (the SF writers have provided more variety if you dip into that): either we are meeting space others for the first time and so are they, or the universe has got lots of sentient creatures, among which earthlings figure prominently. That's because these make for better stories. These concepts have been around for quite awhile, and the narratives were already in place before we started thinking about intelligence elsewhere in the universe. The first bears similarity to folk tales of meeting with dwarves or the spirits of trees; the second is like the animal tales, where the human characters are the powerful, dominant ones..

That's ridiculous. Unless God designed some specific lower number of intelligences in the universe for unfathomable reasons of his own, the universe is either generally supportive of complex development sucking energy from a source - in which case there are thousands - or it's not, in which case we're it, by wild chance. There isn't going to be just one or two others. Preposterous.

Thus when they find us, they will be blase, and slightly annoyed at our childish wonder and questions. Then they will eat us and take all the earth's ammonia. Glad I could clear that up for you.


Sam L. said...

If we can tell each other dirty jokes, we'll be fine.

(Opinion expressed at end of a first-contact story, occurring in deep space.)

Texan99 said...

There could be lots of others, but so widely dispersed that we're the first "other" they've run across. But I'd guess it would be something more like the process of isolated human populations running into each other -- usually at least one side had run into foreign cultures before. It would be a bit of a fluke for both to be entirely new to the experience.

Or we could be the only ones. Who knows. As I was mentioning over at Grim's place, we don't know enough about how life started to have an informed opinion on how inevitable or fluky it was. We do know that some kind of life subsisted on Earth for a really long time -- perhaps over 3 billion years -- before the Cambrian explosion of fairly complex life got started. That suggests, if only faintly, that the development of complex life is nowhere near inevitable even on planets where some kind of life gets started. Single-cell life does just fine, more or less permanently, and still outnumbers the complex animals in a big way.

james said...

Every crevice, and even in boiling water and buried deep underground, seems to have something living there. My impressions hardly have the force of argument, but it seems as though God likes life and stuffs it everywhere, and that He has a sense of humor.

Texan99 said...

But everything we find here that's living uses the same RNA or DNA, even speaking the same code language, and therefore evidently has a single ancestor. If really different life ever evolved here, there is no trace of it. It may have been a system that started once and then radiated. There is nothing to suggest that it started independently at many spots or at different times.

james said...

True, but as per the argument above, there's no proof that life requires DNA.

Assistant Village Idiot said...

I have started thinking in terms of "intelligences" rather than "life," just because our definitions here, which include reproduction, for example, may not be necessary. I have to figure there is some use of energy, though.

Texan99 said...

It's true that intelligence needn't come with reproduction as an abstract matter, but it's a pretty good intellectual challenge to imagine how complexity and intelligence could have developed naturally without selection, or selection without reproduction.

Texan99 said...

James -- certainly there's no proof that life requires DNA, but we haven't found any examples of life here that pulled off the heritability trick in any other way. (And as I noted above, we don't know of any way to get complexity in living things without replication, variability, and selection.) If there was ever life here that used a different method, it got eaten up or something. If non-DNA life were still around, we could point to a counter-example as an argument that life can originate independently at different spots and different times. As things are, it's possible that that happens, but we don't have any evidence for it. We know that it happened here once. Beyond that we know nothing, so we're left not having any way to assess whether it's wildly likely or wildly unlikely for it to happen again.

Why do I say it happened only once? DNA is so complicated, and yet so similar in all Earth life, that it defies belief it could evolve spontaneously on separate occasions, especially when you consider that all DNA uses a code that is essentially abstract or arbitrary and is not simply a matter of molecular shapes that happen to fit together. The 3-base codon G-C-A means the amino acid "alanine" the world over, whether you're a streptococcus or a symphony conductor, but only because there are little tRNA molecules swimming around with anti-GCA on one end and alanine on the other. The tRNA could just have easily had anti-GCA on one end and leucine on the other, and in fact in the laboratory can be made to carry a different amino acid. But way back when, ancestral life settled on GCA for alanine, and everybody has done that way ever since. All twenty amino acid codes are like that, with very minor variations.

All life even uses the same 20 amino acids in its primary DNA/RNA fabrication system, though other amino acids can be and are synthesized in post-transcription reactions, and many more "unnatural" amino acids are available to be tossed in the mix, even one not naturally used by DNA. In laboratories, they can make up special tRNA with a codon on one end that currently is associated with a traditional amino acid, but they can attach a non-traditional amino acid on the other end instead, which can result in cool synthetic proteins with all kinds of new characteristics: photoreactive, metal-chelating, xenon-chelating, crosslinking, color-changing, spin-resonant, fluorescent, biotinylated, and redox-active.

The fact that DNA employs a specific code that is common to bacteria, archaea, and eukaryotes (that last one is us and all animals and plants) argues strongly that we all had a common ancestor with basically that type of DNA already in it. That is, the common ancestor obviously had different genes from us, but the genes already were using the same DNA mechanism and code that we have today.

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