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First Mechanical Gear Found in a Living Creature

popularmechanics.com

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Re: First Mechanical Gear Found in a Living Creature

#151

Post by gizmo686 »

jerf wrote: post #132
zdean wrote: 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…

Regarding your footnote, there are already several examples of evolution evolving itself more efficient ways to evolve. The first example that comes to mind is sex, then passing knowledge between generations through non genetic means (IE a parent teaches its offspring).

Re: First Mechanical Gear Found in a Living Creature

#152

Post by thwest »

muyuu wrote: post #130
m-photonic wrote: post #88

"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.

Almost every complex AND specialized adaptation has an advantage. In this case it seems pretty obvious that gears can be better than friction at transmitting torque.

> every complex AND specialized adaptation

The ones that stay around long enough to be studied perhaps.

Re: First Mechanical Gear Found in a Living Creature

#153

Post by Asterick6 »

jonnathanson wrote: post #70
niels_olson wrote: post #56

Earlier quoted context omitted.

> All things that move are mechanical. How is that blurry? > 'Organic' is a similarly blurry category I thought "organic" was restricted to carbon chemistry. Seems pretty specific to me. > The terms you're looking for are 'natural' and 'artificial,' It may be that his choice of words conflicts with his meaning, or at least conflicts with your interpretation of his meaning, but doesn't make his original word choices l…

When I'm talking about "blurry" categorizations, I'm talking about how connotation has blurred what was once a very clear denotation . As in, the literal meanings of words like "organic" and "mechanical" -- which, as you've put it, are not ambiguous in the least -- are being challenged by modern associations of these words outside their original definitions. (A good case in point would be the grandparent comment, whi…

No, it's not unfortunate at all. Please continue this kind of explanation and clarification [in the future]. Accurate and precise usage of terms helps maintain specific definitions for each idea/term, and retaining specific denotations (and reducing connotations) for more words will allow one to express more easily and clearly, so there won't be multiple connotations or inspecific, colloquial terms that dilute the meaning of what one wants to say.

Re: First Mechanical Gear Found in a Living Creature

#154

Post by petsos »

upquark wrote: post #150
jk4930 wrote: post #143

Earlier quoted context omitted.

There's another term from the mentioned "Selfish Gene" (which is a book by the same title): https://en.wikipedia.org/wiki/Memetics It's a view on how ideas spread and use hosts (e.g., human brains) as carriers. They mutate, they're selected, they compete for "brain space". One funny perspective is that we're the slaves to genes and memes, both using us to survive. We're just carrying out their orders. :) (In the end…

Wouldn't it be in the best interest of memes to never let us figure them out though? To never obtain this view of the world where memes are exposed for the parasites that they are? Maybe "theory of memetics" is a next-generation meme that took over our collective consciousness to exterminate all the other primitive memes and gain world domination :)

They are only parasites only if you also think that genes are parasites too.

Re: First Mechanical Gear Found in a Living Creature

#155

Post by BrandonMarc »

upquark wrote: post #146
jerf wrote: 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…

Awesome post. About the "fantastic two-gene change": can't there ever be a force pushing for a species to obtain two independent mutations more or less simultaneously? What I mean by that is pressure on a species to maintain / promote a few existing mutations in the population (each individual may carry one, or the other, or none, but the offspring of carriers is likely to end up with more than one). I imagine in ver…

Kevin Kelly wrote about "co-evolution" in his book [0] Out of Control. Great book, by the way. I don't think he coined the term, but co-evolution regards how relationships between different kinds of species can effect the adaptations that each species undergo. So in your example, wolves have a definite effect on the sheep population's genepool, but the truth is the sheep have a similar effect on the wolves.

[0] http://www.kk.org/outofcontrol/

Re: First Mechanical Gear Found in a Living Creature

#156

Post by milkshakes »

ByronT wrote: post #142
stcredzero wrote: post #129

> In 2 milliseconds it has bulleted skyward, accelerating at nearly 400 g's—a rate more than 20 times what a human body can withstand. This is entirely incorrect. 9g is the limit that someone can stay conscious, but the body can withstand a lot more. Experimental subject John Stapp withstood 46.2 g. http://en.wikipedia.org/w/index.php?title=G-force#Horizontal...

I think it depends on the direction of the acceleration. The John Stapp experiment was horizontal acceleration, right? Right above that: "... if g-forces are not quickly reduced, death can occur. Resistance to "negative" or "downward" g, which drives blood to the head, is much lower. This limit is typically in the −2 to −3 g (about −20 m/s² to −30 m/s²) range."

relevant: https://en.wikipedia.org/wiki/Euthanasia_Coaster

Re: First Mechanical Gear Found in a Living Creature

#158

Post by smosher »

m-photonic wrote: post #88

"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.

I wonder whether you're responding to the the journalist or the person they're quoting.

If you read the rest of the article, that idea does become more compelling since the creature loses those gears at its final stage in life.

Re: First Mechanical Gear Found in a Living Creature

#159

Post by upquark »

BrandonMarc wrote: post #155
upquark wrote: post #146

Earlier quoted context omitted.

Awesome post. About the "fantastic two-gene change": can't there ever be a force pushing for a species to obtain two independent mutations more or less simultaneously? What I mean by that is pressure on a species to maintain / promote a few existing mutations in the population (each individual may carry one, or the other, or none, but the offspring of carriers is likely to end up with more than one). I imagine in ver…

Kevin Kelly wrote about "co-evolution" in his book [0] Out of Control . Great book, by the way. I don't think he coined the term, but co-evolution regards how relationships between different kinds of species can effect the adaptations that each species undergo. So in your example, wolves have a definite effect on the sheep population's genepool, but the truth is the sheep have a similar effect on the wolves. [0] http…

Cool, thanks for the link.

Re: First Mechanical Gear Found in a Living Creature

#160

Post by Kliment »

ocharles wrote: post #45
mrb wrote: post #43

Why do they say the gears "look nothing like what you'd find in your car"? They look very similar to me.

To me it appears that there are teeth on one "side" of the gear, but on the back of it is a flat surface. The valley between the teeth is sloped from front to back, going from a deep valley to no valley at all. At least, that was what I took from that picture.

Just like herringbone gers you find in old sewing machines, designed to self-align in one direction.
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