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First Mechanical Gear Found in a Living Creature

popularmechanics.com

131–140 of 191 posts

Re: First Mechanical Gear Found in a Living Creature

#131
post #128

"They're rather specialized, and there are lots of other jumpers that don't have them, so there must be some kind of advantage." Not necessarily. Evolution has a lot to do with path dependence and in no way guarantees the best of all possible adaptations.

Could you clarify/expound on this?

Perhaps the best option would be if you went out and grabbed a copy of 'Climbing mount improbable' - It will answer all your questions on this and then some

Re: First Mechanical Gear Found in a Living Creature

#132
post #128

"They're rather specialized, and there are lots of other jumpers that don't have them, so there must be some kind of advantage." Not necessarily. Evolution has a lot to do with path dependence and in no way guarantees the best of all possible adaptations.

Could you clarify/expound on this?

Evolution works by incremental changes, each of which to a first approximation must be at least neutral and preferably advantageous to producing offspring. In order for evolution to get from A to B, there must be a path of incremental advantageous changes to get from here to there. It can't magically leap from one optimum to another. So you see things like the way the same basic body plan is reused endlessly in the natural world; with only incremental changes available to create the next species, you can't create a whole new body plan from scratch, even if it would be completely appropriate due to, say, transitioning from land to water. It is also completely goalless; if there is a fantastic two-gene change that a species could make, even if both are individually advantageous, there's no particular force that will cause them to occur [1].

Evolution is both very powerful, with many people underestimating it, and profoundly stupid, with many people also overestimating it. Once humans really get cracking with the gene engineering (which has proved harder than we had initially hoped, but I'm still confident we'll get there), I'm sure we'll find a plethora of relatively simple changes we can make to natural organisms that may involve changing three or four genes simultaneously where no single change is advantageous, which is a thing that evolution essentially can't do.

[1]: Or at least, not yet... one bizarre-ish, "Selfish Gene" way of looking at human gene engineering is evolution evolving itself a way to make those multi-gene changes. Still not in a directed fashion, of course. But evolution will still apply to our own gene engineered creations, just possibly with a very different set of constraints, such as potentially severing the billion-year-old connection between fitness and direct biological reproduction... as I've said on HN before, you don't have to be a full-on "Rapture of the Nerds"-style Singulatarian to see that the future may get very weird....

Re: First Mechanical Gear Found in a Living Creature

#133
post #121
post #11

Earlier quoted context omitted.

Maybe it doesn't. The last paragraph of the article implies that wear eventually would compromise the gears, but that the insect molting and replacing the old gears with new ones (frequently?) prevents it from being a problem.

maybe self-healing? I am curious to know more

The creature sheds it exoskeleton at it grows. Adults don't have this gear "feature" apparently.

Re: First Mechanical Gear Found in a Living Creature

#134
post #132
post #128

Earlier quoted context omitted.

Could you clarify/expound on this?

Evolution works by incremental changes, each of which to a first approximation must be at least neutral and preferably advantageous to producing offspring. In order for evolution to get from A to B, there must be a path of incremental advantageous changes to get from here to there. It can't magically leap from one optimum to another. So you see things like the way the same basic body plan is reused endlessly in the n…

Whoa. That blew my mind.

So we're evolving in such a way to be able to make combinatorial multi-gene changes- by evolving brains big enough to be able to develop gene engineering?

Re: First Mechanical Gear Found in a Living Creature

#135
post #132

Earlier quoted context omitted.

Evolution works by incremental changes, each of which to a first approximation must be at least neutral and preferably advantageous to producing offspring. In order for evolution to get from A to B, there must be a path of incremental advantageous changes to get from here to there. It can't magically leap from one optimum to another. So you see things like the way the same basic body plan is reused endlessly in the n…

Whoa. That blew my mind. So we're evolving in such a way to be able to make combinatorial multi-gene changes- by evolving brains big enough to be able to develop gene engineering?

Remember, it's not directed. Evolution qua evolution hasn't got a problem going to the brink, then watching humanity wipe out, then never building another intelligent species on Earth again... of course it doesn't have a problem, since it isn't a human or even a living thing that could have a problem, or indeed have anything.

But observationally, humanity is currently in a place where that level of gene engineering is a decent bet, yes.

Re: First Mechanical Gear Found in a Living Creature

#136
post #99

Earlier quoted context omitted.

While I can't be certain, I believe it might not handle wear very well based on the article. Near the end they mention that it molts several times growing new, larger versions of the gears. When its an adult, it actually loses these gears entirely. Their theory is that when the insect is fully grown is gets rid of the gears since it can no longer molt and thus replace them if they become damaged.

What's interesting is that their replacement - essentially friction pads, IS expected to last the remainder of their life (and for other similar insects). I would have expected gears to last longer than something relying on friction, especially at those levels of energy.

Friction pads would probably have much more predictable wear (potentially in excess of the expected lifespan of the critter), whereas the discrete, stress-concentrating nature of gears would put them at higher risk of a single weak spot leading to cascading failure (then again, they'll still technically last almost a lifetime :)).

Re: First Mechanical Gear Found in a Living Creature

#137
post #49

Earlier quoted context omitted.

Isn't this the same as #4?

Top comment is pretty much, "this changes my whole theory of nonsense which I just invented." It's a pseudoscientific strawman and I can't believe it was upvoted. As a mechanical engineer I see tons of mechanical components in the human body. Diaphragm pumps, ball and socket joints, pinned joints, tensile supports. None of this makes you a cyborg. https://en.wikipedia.org/wiki/Not_even_wrong

> As a mechanical engineer I see tons of mechanical components in the human body. Diaphragm pumps, ball and socket joints, pinned joints, tensile supports.

The chemical engineer points at the vast complexity of enzyme catalysed reactions and intricate supply chains of nutrients.

The electrical engineer observes the networked structure of the nervous system, the myriad signal processing pipelines built all from similar, near-standard components, yet ultimately giving rise to consciousness.

...and the civil engineer gets the blame for routing a hazardous waste pipeline through a recreational area.

Re: First Mechanical Gear Found in a Living Creature

#138

Earlier quoted context omitted.

> if we were designed by something, why would the designer not use the optimal leg designs for all the jumping bugs? Because: - the designer is not that clever, - the designer likes to play with its creatures, - the designer is not alone, - the designer forgot to update its creations, - or simply because she does not care.

Yes, my personal pet theory is that something really smart made a 3D printer-like life machine, and then gave it to thousands of other not-so-smart individuals - who then came up with all these crazy and inconsistent life forms on Earth. Some designed Bengal Tigers, and others designed Aye Ayes.

I guess everyone would like to have a chat with the one who came up with the monkey idea.

Re: First Mechanical Gear Found in a Living Creature

#139
post #74
post #57

Earlier quoted context omitted.

"ADP and Pi are mechanically squeezed against each other in order to create the covalent bond." I have a PhD in Biophysics. If I ever said "ADP and Pi were squeezed together", I'd have been laughed out of journal club. The fine details of the reaction coordinate are still being argued about. I'll grant you there are no canonical gears as a mechanical engineer would recognize them. I wasn't talking about the motive co…

Doctor of medicine here, with basic notions of chemistry and biochemistry from courses I took 16 years ago. I sure know what I'm talking about! ;-) More seriously, I had inferred the squeezing from the videos I linked to. If I understand properly, the mechanical constrains on the ADP, Pi and AA residuals involved result in the formation of the high energy covalent bound between the two phosphates. Thus mechanical ->…

Protein-interaction videos often make molecular reactions seem "deterministic" when in reality everything is quite stochastic; the molecules are "bouncing" around like crazy and each step may go back and forwards several times before completing. That said, I love the videos--its really amazing to think about all these little proteins bending and folding around all the time!

Re: First Mechanical Gear Found in a Living Creature

#140
post #132

Earlier quoted context omitted.

Evolution works by incremental changes, each of which to a first approximation must be at least neutral and preferably advantageous to producing offspring. In order for evolution to get from A to B, there must be a path of incremental advantageous changes to get from here to there. It can't magically leap from one optimum to another. So you see things like the way the same basic body plan is reused endlessly in the n…

Whoa. That blew my mind. So we're evolving in such a way to be able to make combinatorial multi-gene changes- by evolving brains big enough to be able to develop gene engineering?

But the jury is still out on whether that ability is a net positive for our survival in evolutionary terms. And if it isn't, well, natural selection is quite merciless.
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