bluefugue

Well, organisms are very good at decoding various frequences of EM waves (light), and some animals (bats and dolphins, for instance) can also decode various sound-wave frequencies while filtering out extraneous noise. But then, of course, so can we, as speech is nothing more than sifting through encoded soundwave frequencies, is it not? (Well, okay, there are other factors than frequency -- sibilance, pauses, timbre, that sort of thing. In fact, come to think of it, pitch/frequency may be one of the least information-content-carrying aspects of speech. We are still very good at perceiving relative pitch, though, hence our appreciation of music. And we are good at filtering out extraneous noise, hence our ability to carry on a conversation in a crowded and noisy room.)

Offhand I can't think of any particular reason why you couldn't have a biological equivalent of a radio transmitter... but I don't know much about the logistical intricacies of the question. And yes, the fact that it *doesn't* exist in that form among terrestrial organisms might be a strike against it, given how many "engineering innovations" evolution has managed to produce...

[ June 06, 2002: Message edited by: IesusDomini ]</p>

Mr.Kitchen

I think the reason that organic radio communication never developed on earth is that auditory communication, and visual communitcation made it redundant. Add to this the fact that visual and auditory systems have other uses such as finding food and avoiding being food I don't expect to see it in anyform that isn't in an environment where sound waves are higly useful.

The Lone Ranger

It seems to me that there would be a serious problem with building an organic radio-wave detector.

If I recall my college physics correctly, for a detector to absorb radiative energy with any kind of efficiency (that is, in such a way that patterns in that radiation can be detected), it must be about the size of the wavelength of radiation that it can detect. It's no coincidence that our eyes detect radiation of about 300 - 800 nanometers in wavelength, for example -- this happens to be the approximate size of the photoreceptors we have available.

To detect microwave-wavelength radiation would require photoreceptors at least a few centimeters in diameter, and it seems unlikely that natural selection could or would produce such structures. To detect radio-wavelength radiation would require photoreceptors up to several meters in diameter. (This is one reason why radiotelescopes, which detect very long-wavelength radiation, must be so big.)

Cheers,

Michael

LogicMania

Ok ok, now I'm positively content with your explanations that natural selection would not have adapted organisms for radio wavelengths in the sense that to detect such radiation you'd need biological features meters long. What's more, it's redundant. Life could have simply adapted to utilizing sound to avoid predatory species. Once again, thank you guys for your comments.