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Author Topic:   How come evolution never developed the wheel?
caffeine
Member (Idle past 87 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


(1)
Message 26 of 37 (846322)
01-04-2019 6:45 AM
Reply to: Message 25 by Tanypteryx
01-03-2019 11:06 PM


Eukaryotic flagella like those of Volvox do not work on a wheel and axle principle, they flail around like whips. The International Society of Protistologists recommends that they should instead be called cilia, since they are homologous with cilia rather than with bacterial flagella. Etymologically it would make more sense the other way round, since flagella should flail, not rotate, and I think the eukaryotic examples were described first anyway.

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 Message 25 by Tanypteryx, posted 01-03-2019 11:06 PM Tanypteryx has responded

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caffeine
Member (Idle past 87 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


(2)
Message 29 of 37 (846340)
01-04-2019 2:10 PM
Reply to: Message 28 by AZPaul3
01-04-2019 12:33 PM


You two are talking this thing, yes?

That's the bacterial one that rotates like a wheel, yes. Many eukaryotes have a structure that looks superficially similar, but is unrelated and completely different structurally. It doesn't rotate, but is bent back and forth by the movement of the microtubules inside (pic below); kind of like how muscle fibres work.


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caffeine
Member (Idle past 87 days)
Posts: 1800
From: Prague, Czech Republic
Joined: 10-22-2008


Message 34 of 37 (847363)
01-21-2019 3:46 PM
Reply to: Message 33 by Tangle
01-21-2019 3:24 PM


I'm interested in why there are no tripods - now why do you think that is?

There are lots of tripods in nature. The most obvious example would be ipnopids (tripodfish):

Maybe I'm misunderstanding your meaning here.


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