Radial Symmetric creatures evolving Flight

[Zor]

This is something i was wondering about.

Lets say that we have a planet that is earthlike, but differs in a major respect, this is that starfish like lifeforms had an evolutionary edge in flexibility and congnative ability eary on that their earthborne counterparts did not, as such, eight apendaged Radial Symetric animals with a similer body plan to starfish (a central mass containing a brain with a mouth on the bottom, a ring of six eyes on top surrounded by flexible muscular apendages with digits at the end) developed complicated nervous systems, complex eyes and crawl out of the ocean to colonize the landmassed of this world. Now here is the question, could these radial creatures like this evolve the ability to fly, and if so, how?

Zor

[Darth Raptor]

I don't think there's any physical or biological reasons why they shouldn't. The first image to pop into my head was a sea star spinning and whirling through the air like a living shuriken, with broad, flat arms serving the role of rotary wings. And while it's not true flight a sand dollar-esque creature could feasibly glide while any number of lower animal species could produce sacs of lighter-than-air lifting gas.

Another point to consider is that any given species can deviate from its base anatomical symmetry. Like the flounder or fiddler crab. It's not unimaginable that two of the five arms on a hypothetical flying sea star could be overdeveloped in relation to the other three and serve as more conventional wings.

[Winston Blake]

I imagine it would be easy for membranes to form between those limbs, giving you a kind of jellyfish like motion where the limbs flap up and down and the wing-branes open and close. Very similar to a bat actually, if bats had eight wings and swung their arms vertically.

Or you could just have two limbs become wings while the others remain 'legs'.

[Einhander Sn0m4n]

I can imagine a cigar-shaped creature with two or more pairs of wings in a cruciform or radial arrangement that flap back and forth opposite their immediate neighbors. It would look a bit like a counterrotating propeller engine nacelle flying through the air.

[Starglider]

A rotary ornithopter is theoretically possible... you're essentially combining the stability issues of a flying wing, an ornithopter and a helicopter though, and spinning all your sensory organs at a few hundred rpm as well, so this is a nightmarish control problem.

[Junghalli]

I think the most plausible evolutionary development is for some of the creature's legs to evolve into wings, as happened with large flying creatures on Earth. It'll probably lose radial symmetry at this point because evolution will naturally push the flyer in the direction of the most aerodynamic shape, which is a vaguely missile-like shape. You'd probably end up with a planet with radially symmetrical land animals and "birds" in which bilateral symmetry is a relatively recent innovation concurrent with the development of flight.

[Admiral Valdemar]

A rotary mechanism simply doesn't work well given no biological bearings and we already have numerous examples of efficient and simple fixed-wing flight models arising independently anyway. You could probably engineer such an organism, but it'd be about as pleasant as grafting albatross wings to a human and twice as graceful.

KISS.

[Darth Raptor]

I drew a picture just for this thread (feel proud, Zor):

[Starglider]

A rotary mechanism simply doesn't work well given no biological bearings

You don't need bearings if you spin the whole organism.

and we already have numerous examples of efficient and simple fixed-wing flight models arising independently anyway.

I was assuming the parent poster wanted to maintain radial symmetry, otherwise the question is pointless.

[Rye]

I can imagine a cigar-shaped creature with two or more pairs of wings in a cruciform or radial arrangement that flap back and forth opposite their immediate neighbors. It would look a bit like a counterrotating propeller engine nacelle flying through the air.

There's a subset of UFO whackoes that believe they exist on Earth, but are outside human vision. Apparently, they would work, but the videos of these "rod" creatures are just insects that have gotten stretched out over a few frames. Wiki article.

[Admiral Valdemar]

You don't need bearings if you spin the whole organism.

That's the only real way, and it has major issues in itself. I was simply stating that while you could engineer such a thing, the fact is nature hasn't and for good reason.

It'd be a fun pet though.

[Starglider]

I was simply stating that while you could engineer such a thing, the fact is nature hasn't and for good reason.

Nature is a lousy engineer. If there isn't an incremental path, it doesn't evolve. If the selection environment isn't just so to concentrate fitness pressure on the incremental path, it doesn't evolve. If it requires even the tiniest bit of foresight to make multiple co-ordinated changes at once, it doesn't evolve. If you just get bad luck with your mutations, it doesn't evolve. If the species gets wiped out before creating a significant number of fossils, it evolves but we never find out about it.

But if you still subcribe to the notion that 'if it was a good idea it would have evolved' I suppose you must think that any and all alien life will look and function just like earth life existing in the same environment, because evolution is just so efficient at exploring the design space. I bet you're a popular panelist at Trek conventions.

[Broomstick]

You don't need bearings if you spin the whole organism.

That's the only real way, and it has major issues in itself. I was simply stating that while you could engineer such a thing, the fact is nature hasn't and for good reason.

Nature actually has "engineered" (actually, evolved) spinning parts - but only on a microscopic level. H. pylori for example.

Nothing larger than a single cell, though

[Admiral Valdemar]

Nature actually has "engineered" (actually, evolved) spinning parts - but only on a microscopic level. H. pylori for example.

Nothing larger than a single cell, though

Thank you, Mrs. Biology: 6th Edition by Campbell and Reece. However, as a microbiology major, I do know of the wonders of rotary motors long before humans invented them.

They just suck at scaling up. Unless we have super large atoms, but they are far too expensive.

[Broomstick]

You're welcome

And if you're a microbiology major, why didn't you mention it before the art major?

[Admiral Valdemar]

I'm lazy. Plus, I mentioned it every other post from 2002-2005.

*Shrug*

[Dooey Jo]

If the sea creatures have evolved some sort of propeller-like structure which they use for propulsion in the water, that could become adapted to air, and flight if the creatures get lighter (or develops a sack filled with hot air, or maybe helium or hydrogen), and it could use its arms for stabilisation. It could use anything from a sphincter-like muscle to an electrical motor (bioelectricity + magnetite = win) to drive the rotary shaft.

So yeah, have fun with your weird helicopter pods

[Shroom Man 777]

How about balloon animals? Some sort of creature that begins its life as a sea-dwelling plankton thing, but as it grows older, it somehow manufactures hydrogen or helium in its body and float off the surface of the water, and just keeps on growing bigger?

Hrm...what would these animals eat...surely they can't just subsist on sun and water alone?

Maybe they just temporarily metamorph into balloon creatures to migrate or spawn and disperse their seed/grotesque progeny.

Flying Sea Shrooms!