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A Unified Theory of Animal Locomotion

ScuttleMonkey posted more than 8 years ago | from the how-much-wood-can-a-woodchuck-chuck dept.

Math 229

Roland Piquepaille writes "You probably already know that there is a master equation for all life processes based on metabolism. Now, physicists from Duke University have applied the so-called 'constructal theory' to explain how running, flying and swimming modes of locomotion are similar even if they're apparently unrelated. This single unifying physics theory explains how fast animals get from one place to another and how rapidly and forcefully they step, flap or paddle in relation to their mass. In other words, these scientists argue that the characteristics of animal shape and locomotion are predictable from physics."

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229 comments

... it has t o be said ... (-1, Offtopic)

Anonymous Coward | more than 8 years ago | (#14381823)

Duke Sucks!

Your MOM sucks... (-1, Troll)

Anonymous Coward | more than 8 years ago | (#14382021)

...my dong that is!

An open letter to CmdrTaco (1)

Fecal Troll Matter (445929) | more than 8 years ago | (#14382058)

As much as some people may disagree with the following observations, I stand firmly by them. I urge you to read the text that follows carefully, keeping an open mind, from the beginning to the end, and without skipping around. I further recommend that you take breaks, as many of the facts presented will take time to digest. Unfortunately, the English language contains so few words of reprobation and invective that I cannot satisfactorily describe Slashdot's impolitic rejoinders. At least our language's lexicon is sufficiently voluminous for me to explain that it is more than a purely historical question to ask, "How did Slashdot's reign of terror start?" or even the more urgent question, "How might it end?". No, we must ask, "Whatever happened to community standards?" I'll tell you what I think the answer is. I can't prove it, but if I'm correct, events soon will prove me right. I think that if Slashdot opened its eyes, it'd realize that its objectives run contrary to even the most cursory observation of the real world.

To be sure, Slashdot is the spawn of Satan, but those of us who are still sane, those of us who still have a firm grip on reality, those of us who still think that our country is being destroyed by belligerent poltroons, have an obligation to do more than just observe what it is doing from a safe distance. We have an obligation to keep its bedfellows at bay. We have an obligation to push the envelope on our knowledge of the world around us. And we have an obligation to build a sane and healthy society free of its destructive influences. It must be pointed out over and over again to Slashdot's buddies and, in a broader sense, to unstable wastrels that Slashdot uses the very intellectual tools it criticizes, namely consequentialist arguments rather than arguments about truth or falsity. Slashdot can go on saying that academicism brings one closer to nirvana, but the rest of us have serious problems to deal with that preclude our indulging in such sinister dreams just now.

In the past, it was perfectly clear to everyone with insight and without malice that Slashdot's bootlickers are blissfully ignorant of its flippant strictures. Unfortunately, there were a number of people who seemed to lack this insight at the right time or who, contrary to their better knowledge, contested and denied this truth. It is reasonable to infer that every time Slashdot gets caught trying to squeeze every last drop of blood from our overworked, overtaxed bodies, it promises it'll never do so again. Subsequently, its acolytes always jump in and explain that it really shouldn't be blamed even if it does, because, as they insist, the kids on the playground are happy to surrender to the school bully. Do you really want Slashdot to impose ideology, control thought, and punish virtually any behavior it disapproves of? I think not. Lastly, for those who read this letter, I undoubtedly hope you take it to heart and pass this message on to others.

Hold on a minute... (0)

Anonymous Coward | more than 8 years ago | (#14381826)

Isn't Will Wright doing this in Spore? (generating creature animations procedurally)

SP (-1, Troll)

Anonymous Coward | more than 8 years ago | (#14381828)

Second post. Suck my balls

More like TP. (-1, Offtopic)

Anonymous Coward | more than 8 years ago | (#14381883)

Not toilet paper...but third post!

Real animals only (3, Funny)

MarkusQ (450076) | more than 8 years ago | (#14381831)


the characteristics of animal shape and locomotion are predictable from physics

They must be using real animals only. I know for a fact that the Pegasus's shape (to cite just one famous example) isn't predictable from physics.

--MarkusQ

Re:Real animals only (0)

Anonymous Coward | more than 8 years ago | (#14381846)

I'm speechless.

Re:Real animals only (0, Offtopic)

bl4nk (607569) | more than 8 years ago | (#14381851)

What about a liger? [cracksmokingmonkeys.net]
It's pretty much my favorite animal.

Roland Piquepaille (5, Interesting)

Anonymous Coward | more than 8 years ago | (#14381833)

Re:Roland Piquepaille (0)

Anonymous Coward | more than 8 years ago | (#14381933)

Umm.. direct link to the article? Maybe it's an impostor.

Re:Roland Piquepaille (0)

slavemowgli (585321) | more than 8 years ago | (#14381955)

This time, though, the link provided doesn't go to his blog, so he doesn't get ad money for it. :)

Re:Roland Piquepaille (2, Informative)

Anonymous Coward | more than 8 years ago | (#14382013)

Apprently you didn't look very well. Two links go straight to his blog.

Allow Me (0, Troll)

TubeSteak (669689) | more than 8 years ago | (#14382019)

To point you to a previous post i've made on this subject
http://slashdot.org/comments.pl?sid=172700&cid=143 77094 [slashdot.org]

For those to lazy to click, the important part is that Roland Piquepaille has been submitting articles since 2002 and people have probably been bitching about it since.

Y'all need to simmer down. AC's and registered users alike.

It seems like the most important thing said... (2, Interesting)

gbutler69 (910166) | more than 8 years ago | (#14382030)

...in this article is, "...with a given gravity and density of their tissues, the same basic patterns of their design would evolve again."

This is important because it would suggest that were humans ever to travel to an "Earth-like" planet, we would likely find life-forms that would appear quite familiar to us. We would not likely find "exotic" life-forms that were nothing like what we'd seen before.

Re:Roland Piquepaille (2, Funny)

Anonymous Coward | more than 8 years ago | (#14382039)

In related news, scientists also discovered the unified theory behind the ratio of Roland Piquepaille accepted articles to submissions. Applying the so-called 'covetousness theory,' these scientists developed the formula describing the miraculous amount of articles from a single submitter, regardless of merit or ripped-off content. The answer, contrary to popular belief is not 42 but rather one. This ratio therefore implies that every article submitted has been and will be accepted. The reasons for this still remain unclear.

However, these same scientists are hoping to answer the latter question by applying the same theory to the variables of slashdot editor kickbacks and Roland Piquepaille advertising money. More information on this research can be found In related news, scientists also discovered the unified theory behind the ratio of Roland Piquepaille accepted articles to submissions. Applying the so-called 'covetousness theory,' these scientists developed the formula describing the miraculous amount of articles from a single submitter, regardless of merit or ripped-off content. The answer, contrary to popular belief is not 42 but rather one. This ratio therefore implies that every article submitted has been and will be accepted. The reasons for this still remain unclear.

However, these same scientists are hoping to answer the latter question by applying the same theory to the variables of slashdot editor kickbacks and Roland Piquepaille advertising money. More information on this research can be found here [slashdot.org]

Swimming Fish = Flying Bird? (2, Interesting)

jackb_guppy (204733) | more than 8 years ago | (#14381844)

This is question I have asked my daughter from time to thing about... Are Bird and Fish the same or different?

This article starts to show that yes they are.

For me thought the answer is yes they are. They both can move 3 dimentally in they fuild mediums... Air and Water. Just one is just more dense then the other.

Best example of this is Penguin. They "fly" in water.

Re:Swimming Fish = Flying Bird? (5, Funny)

Anonymous Coward | more than 8 years ago | (#14381856)

Yes, they are the same or different. I could have told you that without a research paper.

Re:Swimming Fish = Flying Bird? (4, Insightful)

Murphy Murph (833008) | more than 8 years ago | (#14381862)

Forget the penguin for a moment.

Are birds buoyant in their fluid?
That right there is a big difference.

Re:Swimming Fish = Flying Bird? (2, Insightful)

Anonymous Coward | more than 8 years ago | (#14381909)

Of course they are, just not nearly enough to stop them from plummeting downwards.

Re:Swimming Fish = Flying Bird? (0)

Anonymous Coward | more than 8 years ago | (#14381919)

Good one, pedant. :-)

Re:Swimming Fish = Flying Bird? (4, Funny)

dsanfte (443781) | more than 8 years ago | (#14381913)

You have obviously never hooked a bird up to a tank of hydrogen. I assure you, they're quite buoyant before they explode.

Re:Swimming Fish = Flying Bird? (1)

Servants (587312) | more than 8 years ago | (#14381990)

Are birds buoyant in their fluid?
That right there is a big difference.


The article explains that swimmers still have to fight gravity proportional to their body size, because the water they push out of the way while swimming effectively raises the surface of the fluid. I don't know that I entirely understand this, but that seems to be the authors' argument that it isn't such a big difference at all.

Re:Swimming Fish = Flying Bird? (1)

Breakfast Pants (323698) | more than 8 years ago | (#14382151)

Look at it this way:


|
|
|
#
|


Say the | is water and the # is a fish. Now let's assume (this simplifies the situation, but it is still quite accurate) that one | weighs the same as a #. Now consider that somehow that system moved on to this state:


|
#
|
|
|


There is no energy difference between the two systems. The only thing the fish had to work against was friction (and building up his own inertia). He doesn't fight the gravity of the water--well he does but for each bit he fights he is pushed up by an equivalent bit! From a physics standpoint the vertical movement of a fish is the same as its lateral movement. Now look at that diagram again and pretend |'s are air but #'s are birds. The change between the two states now takes some energy.

Re:Swimming Fish = Flying Bird? (1)

MaXiMiUS (923393) | more than 8 years ago | (#14382145)

One word: Helium :)

Re:Swimming Fish = Flying Bird? (3, Informative)

Ruff_ilb (769396) | more than 8 years ago | (#14381868)

As far as I'm aware, fish have gills and lay squishy (scientific term) eggs, while birds lay solid eggs and have lungs. Birds also have feathers, and I'm not aware of any feathered fish.

And heck, if you're going to define our atmosphere and our ocean as a fluid medium, then you're saying that ALL animals are the same - name a single animal that travels through a completely SOLID medium.

Re:Swimming Fish = Flying Bird? (1)

kfg (145172) | more than 8 years ago | (#14381904)

name a single animal that travels through a completely SOLID medium.

I wish I was a mole in the ground
I wish I was a mole in the ground
If I's a mole in the ground
I'd root this mountain down
I wish I was a mole in the ground

And parent poster is right about penguins flying in water. You only have to watch them for a few minutes to see it. They are birds and move like birds. They simply require a denser medium than air to fly in. A bit of bouyency doesn't hurt, but isn't strictly relevant to the way their wings produce propulsion and lift.

KFG

Re:Swimming Fish = Flying Bird? (1)

Ruff_ilb (769396) | more than 8 years ago | (#14381928)

Moles and related animals create holes in the solid medium to move through - they don't travel through the solid medium, they make room for them to travel and then they travel through the empty room.

Regardless of how penguins fly through water, that doesn't make penguins fish.

Re:Swimming Fish = Flying Bird? (1)

kfg (145172) | more than 8 years ago | (#14381953)

Moles and related animals create holes in the solid medium to move through - they don't travel through the solid medium, they make room for them to travel and then they travel through the empty room.

What on earth do you think animals that move through air and water do? You've never designed a boat or a car, have you?

Maybe while driving or bicycling you've drafted a truck or something? The truck displaces air. Welcome to the hole.

Regardless of how penguins fly through water, that doesn't make penguins fish.

Regardless of their differences that doesn't make them entirely dissimilar.

KFG

Re:Swimming Fish = Flying Bird? (1)

Ruff_ilb (769396) | more than 8 years ago | (#14381997)

Exactly - the parent poster is implying that birds and fish are the same, but not other organisms; the logical extension of his arguments would be that all animals are the same. Perhaps there are intrinsic similarities between locomotion between animals (which is what the OP is saying), not what the Parent Poster is saying, that is:
Are Bird and Fish the same or different?
... For me thought the answer is yes they are [the same]. They both can move 3 dimentally in they fuild mediums... Air and Water. Just one is just more dense then the other.
He implys that animals are the same if they move 3 dimensionally through fluid mediums. We have both shown that ALL organisms move 3 dimensionally through fluid mediums. I'm not saying that penguins and fish are entirely dissimilar, I'm saying that a penguin is != a fish, that's all. And even if you don't buy the transportation argument, there are a host of other criteria that prove birds and fish aren't the same.

Re:Swimming Fish = Flying Bird? (0, Troll)

kfg (145172) | more than 8 years ago | (#14382028)

Exactly - the parent poster is implying that birds and fish are the same, but not other organisms

No he isn't.

Are Bird and Fish the same or different? ... For me thought the answer is yes they are [the same].

Here you have editorialized (a polite way of saying "put words into the mouth of") what the OP said to fit your claim by changing it's meaning rather dramatically.

Here is what the OP said:

Are Bird and Fish the same or different? ... For me thought the answer is yes they are.

"Would you like to go the mall or would you like to go to the library?"

"Yes."

It is a not uncommon rhetorical ploy when when presented with apparently exclusive choices to answer in the singular to imply agreement with both options.

KFG

Re:Swimming Fish = Flying Bird? (4, Funny)

BorgCopyeditor (590345) | more than 8 years ago | (#14381925)

name a single animal that travels through a completely SOLID medium

The Horta [ericweisstein.com] ?

Re:Swimming Fish = Flying Bird? (1)

Ruff_ilb (769396) | more than 8 years ago | (#14381957)

I'm sorry, my failure to include The Horta is only due to my best attempts to uphold the Prime Directive.

Seriously though, even there, they're corroding things first and then moving through the hole or the goop left where they've melted whatever else away.

WORMS? (1)

spineboy (22918) | more than 8 years ago | (#14382112)

title says all

Re:Swimming Fish = Flying Bird? (1)

Xarius (691264) | more than 8 years ago | (#14381978)

Penguins don't have feathers and they are birds. Just something to think about there ;)

And worms travel through a solid medium!

Re:Swimming Fish = Flying Bird? (1)

Ruff_ilb (769396) | more than 8 years ago | (#14382005)

See what I said earlier: "Moles and related animals create holes in the solid medium to move through - they don't travel through the solid medium, they make room for them to travel and then they travel through the empty room."

Even if you don't buy that, the medium becomes a liquid by definition if the earthworm/mole/whatever can move through it. I know what you're thinking: "But dirt isn't a liquid!" - True, but earthworms couldn't move through dirt if it were JUST dirt, i.e. no air. The air allows it to act like a liquid when the earthworm moves through it.

Re:Swimming Fish = Flying Bird? (1)

hazem (472289) | more than 8 years ago | (#14382027)

But dirt isn't a liquid"

Ahh... but it can be: http://www.ce.washington.edu/~liquefaction/html/ma in.html [washington.edu]

The more I understand, the less I really know. Science has this nasty habit of taking things that make perfect sense, "dirt is a solid", and turn that sense on its head. Eventually, I think scientific advances will bring us all back to the philosophical perspective, "all things are one".

Re:Swimming Fish = Flying Bird? (2, Insightful)

EvanED (569694) | more than 8 years ago | (#14382012)

And heck, if you're going to define our atmosphere and our ocean as a fluid medium, then you're saying that ALL animals are the same - name a single animal that travels through a completely SOLID medium.

You're missing the point. He's not saying they're related because they move through fluids, he's saying they're related because they have three dimensional control of where they are.

And to some extent, that is something exclusive to them. Land animals have to do a lot more work than them in order to move in anything but the "plane" of the Earth.

Re:Swimming Fish = Flying Bird? (1)

Ruff_ilb (769396) | more than 8 years ago | (#14382060)

That is a good point - it makes me wonder how much dynamic 3d control an average bird, say, a swallow (That is, an unladen, European swallow) can exercise as compared to say, a goldfish.

How would one measure that, anyway?

Re:Swimming Fish = Flying Bird? (1)

EvanED (569694) | more than 8 years ago | (#14382080)

My somewhat educated guesses are as follows:

1. In general, I'd say fish have more control than most birds
2. Fish can pretty much stop if they like and move very little; almost no birds can (I think the hummingbird may be the only one able to hover)
3. Birds can dive very quickly because they have gravity to assist them; fishs' climb and descent speeds will be a lot more equal
4. A fish needs to expend energy to move forward; some birds have very very high glide ratios and can soar for quite some time while rarely beating their wings (not that sitting there with your wings outspread doesn't take energy)

Re:Swimming Fish = Flying Bird? (1)

Ruff_ilb (769396) | more than 8 years ago | (#14382122)

So it basically comes down to density and coef of viscosity, no?

And what if we're comparing a fish to a bird to an earthworm or a mole?

Could we say

1. In general, I'd say fish have more control than most birds, but less than moles
2. Fish can pretty much stop if they like and move very little; almost no birds can (I think the hummingbird may be the only one able to hover), but moles can stop dead whenever they like
3. Birds can dive very quickly because they have gravity to assist them; fishs' climb and descent speeds will be a lot more equal, moles' will be identical
4. A fish needs to expend energy to move forward; some birds have very very high glide ratios and can soar for quite some time while rarely beating their wings (not that sitting there with your wings outspread doesn't take energy), moles expand almost the same amount of energy going in any direction, except probably slightly less when going down and slightly more when going up

So is it possible to expand the Fish :: Bird analogy to Fish :: Bird :: Mole, for example? I don't see why not.

Re:Swimming Fish = Flying Bird? (2, Interesting)

aussie_a (778472) | more than 8 years ago | (#14382083)

Land animals have to do a lot more work than them in order to move in anything but the "plane" of the Earth.

But they can still do it (for instance moving down through the ground can be easier then moving up, but in some cases it can be easier to move up then down, and near cliffs or other walls it is just as easy to move up or down, then it is to move forward or side to side).

Re:Swimming Fish = Flying Bird? (1, Insightful)

Anonymous Coward | more than 8 years ago | (#14381885)

This is question I have asked my daughter from time to thing about... Are Bird and Fish the same or different?

This article starts to show that yes they are.

Yes, they are what ? That wasn't a yes or no question. The answer was "same" or "different". How the fuck does someone screw up answering their own question?

MOD PARENT UP OR GRANDPARENT DOWN (1)

QuantumG (50515) | more than 8 years ago | (#14382032)

I was thinking the exact same thing.

Re:Swimming Fish = Flying Bird? (2, Interesting)

Akaihiryuu (786040) | more than 8 years ago | (#14381977)

Stingrays "fly" in water too (I mean the larger kind that have "wings", not the smaller ones that look like fish frisbees). They are very interesting to watch. They're also very curious...they don't act like fish at all. They act more like puppies than fish actually.

Re:Swimming Fish = Flying Bird? (1)

slashdotnickname (882178) | more than 8 years ago | (#14381981)

This is question I have asked my daughter from time to thing about... Are Bird and Fish the same or different?

Enjoy that playful moment while you can, for one day the question will be about the Birds and the Bees, at which point you'll want to quickly say "Game Over" and pretend the lawn needs mowing.

Re:Swimming Fish = Flying Bird? (2, Interesting)

Deadstick (535032) | more than 8 years ago | (#14382050)

No. Fish receive most of their vertical support from hydrostatic buoyancy; if a fish doesn't move a muscle, it will neither rise nor sink very quickly. All the muscular energy it expends goes into overcoming the drag that resists its forward movement.

Birds have to expend some energy just to stay aloft, plus more to travel. If a bird doesn't move a muscle, assuming it's holding its wings in the gliding position, it will continuously lose altitude. Its drag has two components: parasite drag which resists its forward motion and induced drag which results from the lift-producing process.

When a penguin (or other diving bird) swims underwater, it has to expend energy just to avoid floating up, because it's positively buoyant in water -- in effect, it's flying upside down.

rj

Re:Swimming Fish = Flying Bird? (1)

mattwarden (699984) | more than 8 years ago | (#14382115)

Are Bird and Fish the same or different? This article starts to show that yes they are.

Is the meaning of your comment easy or hard to decipher?

I'd say that yes, it is.

Re:Swimming Fish = Flying Bird? (2, Informative)

Vellmont (569020) | more than 8 years ago | (#14382136)

As another poster pointed out, fish are boyant in water. They take advantage of this through an organ designed to control positive and negative boyancy (gas bladder). They use it to ascend and descend in depth without swiming. That's quite a major part of how fish move in water that's vastly different from how birds fly.

That's not to say that fish and birds aren't similar in how they move through fluids, but to say they're the same is a vast misunderstanding of fish and birds.

Science gibberish (5, Funny)

Piroca (900659) | more than 8 years ago | (#14381845)


these scientists argue that the characteristics of animal shape and locomotion are predictable from physics

I wonder who could expected the outcome to be the other way around.

Re:Science gibberish (-1, Troll)

Anonymous Coward | more than 8 years ago | (#14381859)

Really, this is just a logical extension of the notion of Convergent Evolution: "Form follows function."

Now watch some nitwit tout it as proof of "intelligent design".

Re:Science gibberish (1)

Fractal Dice (696349) | more than 8 years ago | (#14381998)

I for one did indeed expect that physics would be predicted by characterics of animal shape and locomotion :)

Re:Science gibberish (1)

Ruff_ilb (769396) | more than 8 years ago | (#14382015)

A soviet russia joke is quite accurate here:

In Soviet Russia, Physics predicts YOU!

Re:Science gibberish (4, Funny)

jackb_guppy (204733) | more than 8 years ago | (#14382120)

I wonder who could expected the outcome to be the other way around.

Intelligent Design?

Look Ma, no hands! (1)

Ruff_ilb (769396) | more than 8 years ago | (#14381850)

and how rapidly and forcefully they step, flap or paddle in relation to their mass.
Can't we do that already, as in... Oh look, the animal weighs 100 lbs and has two legs on the ground at any given point, so each leg has an average of 25 lbs of force on it?

Broken math... (1)

Ruff_ilb (769396) | more than 8 years ago | (#14381871)

"Can't we do that already, as in... Oh look, the animal weighs 100 lbs and has two legs on the ground at any given point, so each leg has an average of 50 lbs of force on it?"

*Fixed*

Sorry.

Re:Broken math... (1)

EvanED (569694) | more than 8 years ago | (#14381967)

Okay, that's find and dandy until they move. Now, as you run, what are the various stresses that your leg endures? Is there any point at which your full weight is on just one foot? More than your full weight? Is there any point it which there is almost no weight on a foot? What is the range of weights? How 'bout for a bird's wings? How much does a bird have to flap its wings in order to hover (for birds that can) in relation to the range of fores on the wing? Fly forward? What about for a fish?

Wake me up when... (0, Offtopic)

Anonymous Coward | more than 8 years ago | (#14381853)

...they've come up with A Unified Theory of Female Behavior. Meanwhile, back to yanking another one off.

Their "design"? (0)

Anonymous Coward | more than 8 years ago | (#14381854)

A single unifying physics theory can essentially describe how animals of every ilk, from flying insects to fish, get around, researchers at Duke University?s Pratt School of Engineering and Pennsylvania State University have found. The team reports that all animals bear the same stamp of physics in their design.

Oh sweet Christ. Why, oh why, did they have to imply some sort of design? Is this some sort of attempt to get funding from the Creationist Institute?

Wow...never would have guessed. (1)

jmcmunn (307798) | more than 8 years ago | (#14381864)


Wow, I never would have guessed that you could predict the charactaristics and shape of an animal by the physics. When's the last time you would have guessed a bird was shaped like a cube? Or maybe a fish shaped like a donut? I hardly think it is amazing that you can predict the shape of an animal from it's physics. But hey, maybe these guys don't get out much...

Re:Wow...never would have guessed. (2, Insightful)

rbarreira (836272) | more than 8 years ago | (#14381884)

Maybe, but maybe you didn't understand the article too... (judging from your post)

Three legs? (1)

TubeSteak (669689) | more than 8 years ago | (#14382073)

How come there aren't three/five/seven limbed critters running around? (star fish don't count)

Is symmetry that important?

I wouldn't claim a monkey's tail or an elephant's nose is a fifth limb, even though they're very functional.

Re:Wow...never would have guessed. (0)

Anonymous Coward | more than 8 years ago | (#14381894)

Assume all cows are spherical...

All fish are donuts but not all donuts are fish (3, Informative)

TapeCutter (624760) | more than 8 years ago | (#14382045)

"Or maybe a fish shaped like a donut?"

I hate to break this to you but most animals (including fish and humans) are shaped like donuts (tube surrounded by the organisim). This is not the only "body plan", there are ~30 others still around today, (eg: Jellyfish have only one orifice). All body plans that have ever existed hail back to (or before) the Cambrian explosion [wikipedia.org]

Re:All fish are donuts but not all donuts are fish (4, Funny)

EvanED (569694) | more than 8 years ago | (#14382057)

You need to spend less time reading topology books

Some robot guys already discovered that (4, Insightful)

Anonymous Coward | more than 8 years ago | (#14381867)

Robotics researchers already knew that something like 'animal' locomotion could be implemented based on the principles of physics. ie. given the right mechanical setup, locomotion is almost automatic and takes no supervision by a computer.

Actually, it's what you'd expect. Animals would naturally evolve to move in an efficient manner. It would give them an evolutionary advantage. What the bleep did these guys expect?

www.sciencenews.org/articles/20050806/bob8.asp

Re:Some robot guys already discovered that (0)

Anonymous Coward | more than 8 years ago | (#14382042)

What the bleep did these guys expect?

Lots of extra beer money when the grant check cleared to do the study?

Re:Some robot guys already discovered that (2, Interesting)

qray (805206) | more than 8 years ago | (#14382061)

Actually, it's what you'd expect. Animals would naturally evolve to move in an efficient manner.

I be they were pretty funny to watch before they started moving in an efficient manner.

Watching my dog chase its tail gives me a glimpse of what it must have been like.
--
Q

Some IP guys already discovered that (0)

Anonymous Coward | more than 8 years ago | (#14382064)

"Robotics researchers already knew that something like 'animal' locomotion could be implemented based on the principles of physics. ie. given the right mechanical setup, locomotion is almost automatic and takes no supervision by a computer."

Hey look everybody! Intelligent Physics!

Unrelated huh? (1)

jhines (82154) | more than 8 years ago | (#14381876)

It is the same thing, swimming through a liquid, just many orders of magnitude different in viscosity.

Re:Unrelated huh? (1)

Jeremi (14640) | more than 8 years ago | (#14381962)

It is the same thing, swimming through a liquid, just many orders of magnitude different in viscosity.


I'm no physicist, but intuitively I'd think that the fact that air is compressable (and water is not) would have some effect on the process...

Orders of magnitude (1)

John Hawks (624818) | more than 8 years ago | (#14381879)

"From simple physics, based only on gravity, density and mass, you can explain within an order of magnitude many features of flying, swimming and running," added James Marden, professor of biology at Penn State. "It doesn't matter whether the animal has eight legs, four legs, two, even if it swims with no legs."

I'm pretty sure that my own running speed is within an order of magnitude of almost anything with legs, regardless of its mass. That leaves a lot of biological interest within these simple physical parameters.

Re: Max weight on a exoskeleton (0)

Anonymous Coward | more than 8 years ago | (#14381932)

So my two ton exoskeleton will let me fly?

The Terrorists are putting Dumb in the water? (0)

Anonymous Coward | more than 8 years ago | (#14381903)

Good God this article, posted at Duke university, is at the intellectual level of a 5 year old. In print and in person, seems like people are getting really dumb. How can such tripe make it to slashdot? I mean, theres always been a lot of drivel, but this thing, doesnt anybody notice...its gawdawful dumb?

Re:The Terrorists are putting Dumb in the water? (1)

Jeng (926980) | more than 8 years ago | (#14381964)

I have begun to wonder if perhaps the dumb articles are getting posted just so we can discus the level of dumb out there.

As a nerd though I would much prefer to read people discussing smart.

Re:The Terrorists are putting Dumb in the water? (0)

Anonymous Coward | more than 8 years ago | (#14382081)

There are limits to smartness at any given time, dumb has no limits that i can find.

Re:The Terrorists are putting Dumb in the water? (0)

Anonymous Coward | more than 8 years ago | (#14382150)

As a geek, I feel compelled to tell you that the difference between a geek and a nerd, is that nerds are socially inept.

Some solutions missing. (0, Offtopic)

Fortress (763470) | more than 8 years ago | (#14381905)

Evolutionarily, one of the constraints on what features are successful is the physical ruleset. If the feature is to be successful, to some degree it must work reliably and efficiently within the rules of physics.

That said, we have discovered solutions for locomotion that take better advantage of physics principles than those developed by life. Rotary motion, almost entirely missing from biology, is the basis for some of our simplest and most efficient devices, such as the wheel and the screw. If such methods are better, why has no animal evolved them?

Re:Some solutions missing. (4, Interesting)

Jeremi (14640) | more than 8 years ago | (#14382002)

If such methods are better, why has no animal evolved them?


It could be just "bad luck" -- evolution isn't guaranteed to find the best solution to anything, only a solution that is "good enough" to guarantee survival of the species (otherwise the species would have gone extinct). But putting that aside, there are probably structural reasons why animals never evolved wheels -- for example, how would do you connect nerves or blood vessels to an appendage that needs to be able to rotate freely?


Finally, it could be that in nature wheels aren't actually "better" after all. There wouldn't be much use in being able to roll down a freeway at 50MPH if there are no freeways, and your snazzy evolved bio-wheels keep getting stuck in the mud...

Re:Some solutions missing. (1)

node 3 (115640) | more than 8 years ago | (#14382025)

If such methods are better, why has no animal evolved them?

We have.

Re:Some solutions missing. (1)

SheeEttin (899897) | more than 8 years ago | (#14382031)

Because they either did not need them, or evolved more efficient methods.

Take the horse. It moves very fast, by pushing against the ground in four places.
Also, take the bird. It is very light and pushes against the air.

In both of these, wheels would be useless. Horses usually are on rough terrain, not smooth roads. Birds could not use wheels, as there is nothing for them to use them on.

Howver, in The Amber Spyglass (a book), the author describes an animal that did evolve the wheel. They secrete a lubricant from their u-shaped hooves (no jokes), and place their front and back pairs of feet on cylindrical protrusions from large nuts from the trees above. They use these nuts to roll along hardened lava flows at high speeds. Nowhere on Earth are there these lava flows serving as roads. This could be why no animal uses the wheel.

Some choice counterexamples (1)

PIPBoy3000 (619296) | more than 8 years ago | (#14382092)

Some bacteria have a neat rotary motor [annualreviews.org] . There's way more flagellated bacteria than humans on the earth, so I wouldn't classify it as "almost entirely missing".

Even better, sperm has a rotary joint [wikipedia.org] . Just think, you could be holding a counterexample to the above post in 5-10 minutes (well, male Slashdotters anyway - female ones might have to drive a bit).

Re:Some solutions missing. (1)

aussie_a (778472) | more than 8 years ago | (#14382095)

Because God didn't invent them, only godless heathens after they became impure invented them.

Re:Some solutions missing. (1)

Antique Geekmeister (740220) | more than 8 years ago | (#14382126)

Because ball bearings are a bitch and a half to maintain from organic tissue: there are very few free-spinning joints in nature because making them smooth, round enough to spin, and not attached between the "wheel" and the "axle" to that it can actually spin is amazingly difficult.

A few animals roll effectively for short distances, but it's terribly inefficient because the you have to get the angular thrust from somewhere: if you're going to bother to have legs, why not just walk with them?

DURR (4, Funny)

ClamIAm (926466) | more than 8 years ago | (#14381942)

This single unifying physics theory explains how fast animals get from one place to another

Well if they're fast animals, and they're going from one place to another, perhaps they do it by moving quickly? Ever considered that?

This would really only be interesting... (0)

Anonymous Coward | more than 8 years ago | (#14381945)

... if "physics" predicted a shape of an animal that doesn't exist, suggesting a style of locomotion we haven't seen before.

In Other Words... (1)

GWSuperfan (939629) | more than 8 years ago | (#14381951)

In Nature, as in many other things- Form follows function.

And what about... (0)

Anonymous Coward | more than 8 years ago | (#14381968)

the duckbilled platipus. I don't think physics could've put together that frankenstein of an animal, or quite describe it's shape/locomotion relationship.

Finally, learning how to swim. (1)

chug2k (942834) | more than 8 years ago | (#14381994)

Bejan finally realized the answer. Although fish are neutrally buoyant, they still have to push water out of the way to move forward, he said. So THAT'S what I've been doing wrong! Push water OUT of the way to move forward...thank you Bejan. Thank you. God this article was dumb.

Animal, Vegetable, and Mineral Locomotion (0)

Anonymous Coward | more than 8 years ago | (#14382018)

This Unified Theory also applies to piston engines and sand flows.

Fish lift their weight in water? (0)

Anonymous Coward | more than 8 years ago | (#14382072)

I don't think that makes sense. What if the fish sat partly above the water like a ship does? Is it still lifting anything? Isn't it just regular friction that slows a fish?

Simulating walking motion (1)

chroma (33185) | more than 8 years ago | (#14382086)

For doing software simulations of walking creatures or robots, I've used the Yobotics Simulation Construction Set [yobotics.com] . It's reasonably easy to get started, given the complexity of physics simulations. Also, they have a free trial download, so it's great if, like me, you just want to play around.

Bumbling Theories ??? (1)

Dark_Archemedes (942838) | more than 8 years ago | (#14382090)

I don't get it. First, these glorious physicists tell us the laws of physics dictate that a Bumble-Bee can't possibly fly, then they tell us there's an equation that shows us how fast he can go, and how far. (flying, at that.) Somebody let me know what I'm missing here.... I'm not Sherlock Holmes, ya know?

Re:Bumbling Theories ??? (1)

Antique Geekmeister (740220) | more than 8 years ago | (#14382147)

Of course you're not Sherlock Holmes! He wrote "The Practical Handbook of Bee Culture", after his retirement to Sussex Downs, and tended to ignore physics in favor of direct observation of his surroundings.

Re:Bumbling Theories ??? (1)

MikeURL (890801) | more than 8 years ago | (#14382152)

Most people can understand the following line from TFA and how it likely has profound implications:

"All the organisms he tested -- birds, bats, insects -- could all lift approximately the same amount of weight in relation to the size of their flight muscles regardless of their many other biological differences."

A category of readers this article needs: (1)

Hosiah (849792) | more than 8 years ago | (#14382103)

Science fiction writers! Yes, SF writers, never again hand me your alien in the form of a flaming flying football, or a man crayola'd green with spikes taped to his ears, or an 80-ton katydid. If you have one of those, it belongs in the *fantasy* section. In science fiction, I should be able to picture the whole chain of evolution for the species, and if it's sentient, I should be able to marvel at it's natural design and be able to appreciate how it must have become the dominant species on it's planet.

Dinosaurs (1, Interesting)

samkass (174571) | more than 8 years ago | (#14382110)

I'm curious what his equations would reveal about dinosaur locomotion. I've seen a lot of people claim that dinosaurs could never move under today's Earth gravity, or that pterodactyls could never fly. Wouldn't this guy's equations tell us not only whether or not they could, but how fast they'd likely travel and what they're walking, swimming, and flying capabilities might have been?

Re:Dinosaurs (2, Insightful)

Stevyn (691306) | more than 8 years ago | (#14382141)

Gravity? I could understand if the atmosphere was thicker back then it may help the pterodactyls fly, but how was the gravity different? I'm not saying you're wrong, I've just never heard of this idea.
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