Would it be at all possible for a species to evolve the ability to send and receive radio signals?
I don’t know if any species will be able to evolve into a radio transmitter, but receiving radio signals on dental work is a known, if poorly understood, phenomenon. I don’t think anyone’s been able to choose stations though - their teeth just pick up whatever’s strong and at the natural frequency of their fillings.
Nah, frequency is almost entirely irrelevant. It only happens on AM, which has wavelengths on the order of a hundred feet. You’d have to have a pretty big mouth…
Anyway, what’s going on there is some sort of nonlinear rectification; similar to a point-contact diode. I can’t see why this would be biologically impossible to evolve. A sufficiently powerful biological transmitter, on the other hand, seems extraordinarily unlikely to me.
Electric eels and other animals produce electric shocks, and electric shocks create EM (radio) waves, so you could say that a basic transmitter has evolved. Very simple structures can detect this discharge at a distance, so it is conceivable that organisms could use this for communication. But that’s just a burst of energy - it might be a good alternative to yelling out “hey!”
On the other hand, actually modulating information on a radio signal would be far, far more complex, and therefore much less likely to evolve. It hasn’t come close to evolving on earth, that’s for sure.
We know that specialized biological tissue can generate significant electrical current - see the electric eel and similar creatures. But to make a transmitter you need more than current, you need a way to generate oscillation at megahertz frequencies. Some kind of specialized tissue that acts as a semiconductor would be needed. I don’t know enough biology offhand to know if that’s feasible, but if you can make an AM transmitter using a strip of galvanized steel, there’s probably a way to do it biologically.
It seems to me that the biggest difficulty would be producing a good conductor organically. If you’ve got a length of conductor, and some way of generating electric potential (which a few species already have), then making a radio is pretty straightforward. You might not be able to modulate it all that much, but you should be able to do something equivalent to Morse code or so.
But would it be playing anything good? And I’m not talking JT and Britney, either… 
S^G
Why megahertz? Let’s ask it another way: could life evolve to transmit EM in a band that we consider to be radio? We have ELF frequencies already; those aren’t in megahertz.
It’s not that you need oscillation, per se, it’s that you need EM oscillation. Something like a cross between the biological “batteries” of an electric eel, and some mechanical system that varies the current going through them?
I also have to wonder what environment would select radio over other forms of communication. Radio doesn’t give you much extra for short distances, I think. We have to consider the energy expended versus the benefit, for a type of communication that is best for long distances and wide areas.
I think it’d be possible.
Don’t assume that the mechanism would have to have electronic circuit behaviors in it. Radio differs from light, X-rays, thermal infrared, and other EMR in wavelength only. We can detect those things by means not involving circuits. (the X-ray reference may sound pretty obscure, but I am sure other hairy dopers will back me up when I remark that the sudden removal of electrostatic forces on body hair caused by ionizing radiation is detectable). Various animals have also evolved some mechanisms for generating light.
Ammonia absorbs a certain frequency of microwaves, which was the basis for the molecular clocks that were attempted before atomic clocks caught on. No doubt there are many absorptions that could be taken advantage of by evolution.
It is hard to picture an incremental path that leads to radio transmission and reception - what would be the advantages each step along the way? But, not being able to imagine a thing happening is poor proof that it can’t.
Ok electric eels and some other aquatic animals DO communicate with their electric fields but at low frequency (up to about 700 Hz in the ghostfish) so in principle they could have evolved higher frequency radio signals. However I think there are many reasons why they did not.
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High frequency requires fast conduction - electrical impules in nerves do not travel that fast - (there might be another way of generating the waves at RF speed but it makes it harder to develop in a evolutionary sense).
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There is no need to communicate long distances for most small animals
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Radio does not work well underwater where all the electrical animals have developed
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Sound travels well underwater (and in air) and is 100x easier to generate
I think it is possible to come up with some way of generating radio waves in a biological organism, it is very unlikely to ever happen
Dragging out some numbers on that:
From Wikipedia on project Sanguine
That could be a useful range for fishes.
You really don’t need anything all that fancy for a transmitter. Early radios used spark gaps to generate the RF, and a spark gap really isn’t much more complicated than an electric eel.
Spark gap also has the advantage that it can “evolve”. You start out with something simple that splatters a wide range of RF all over the place. Your “receiver” would basically just be something that is electrically more conductive in one direction than the other. As it evolves, filtering structures (which could be as simple as just arrangements of electrically conductive material) would reduce the splatter and focus the energy on narrower frequency ranges, and the receivers could evolve to be more sensitive to those frequencies.
Man-made radios followed a similar “evolution” as RF became better understood.
Yeah, but antenna length might be a bit of a stumbling block. A fish with several hundred feet of conductive tissue trailing behind it is just asking to be caught.
It happened once. So yes, it’s possible.
Don’t some species (rattlesnakes) see into the infrared? That could be considered very short wavelenght RF.
Some (all?) sharks detect electric frequencies, don’t they? Granted that it’s short range, but still.
Not a biologist, but it doesn’t seem like such a big jump for a species like the eel or shark to develop a rudimentary radio communication ability, given the right evolutionary pressure. Not saying you’d get KROCK FM, but still…
Pardon my ignorance as I ask the following, but how does vision not fit this bill?
You are correct. Sharks and rays have structures called “ampullae of Lorenzini” which allow them to detect electric fields.
More info here: Ampullae of Lorenzini - Wikipedia
Hypothetical: How about an animal that uses strong muscles and leverage (like a jaw) to deform quartz crystals or some similar material and generate signals piezoelectrically?
(I saw the idea written up in passing someplace, can’t remember where, and it stuck in my brain. My guess is, it wouldn’t work for some reason, but I don’t know enough about these kinds of phenomena to say why or why not.)
Beware of Doug wins some sort of prize for being the first to spot the most correct and relevant answer. The rest of us, really, should be ashamed.
ArminE, vision doesn’t fit because light isn’t radio.
As far as rough-and-ready transmitters, think of a cricket rubbing its legs together to radiate sound, and then think of a cat rubbing things and generating static electricity sparks. That cat is most definitely transmitting radio. It makes the idea of evolving a receiver look slightly more motivated, I think.