Consider it your morning meditation. Or an opportunity to learn something about cell motility.
Pharyngula
Evolution, development, and random biological ejaculations from a godless liberal
Consider it your morning meditation. Or an opportunity to learn something about cell motility.
I like those little animations, they’re very well done, and have some good information too.
Very cool video. I hadn’t thought of applying the Reynolds number to the world of bacteria before.
And for your homework, go read John Bath’s “Night Sea Journey” found in his book “Lost in the Funhouse”.
This video is based on a very famous paper/talk by Purcell in 1977, as mentioned at the beginning. The paper is covered in pretty much any intro biophysics course! It has a very casual tone and might be legible to a semi-lay audience too, so check it out if you want more:
jila.colorado.edu/perkinsgroup/Purcell_life_at_low_reynolds_number.pdf
better link to the paper:
http://www.damtp.cam.ac.uk/user/gold/pdfs/purcell.pdf
“Water numbers outnumber you a thousand trillion trillion to one, so pushing past them with your gigantic body is easy” seems like kind of a non-sequitur. Some super-viscous fluid might have the same number of molecules but be difficult to get through. It’s kind of an over-simplification.
Otherwise, cool video. I didn’t know about sperm tails spiraling, essentially screwing their way to the destination.
I think Woody Allen had something about this in his documentary about sex.
I mainly use Reynolds numbers when evaluating water systems for prevention of biofilm formation. Reynolds numbers in excess of 20,000 are desirable for water for injection systems. Biofilms are a fascinating topic in themselves.
That is an AWESOME video and I’ll have to use it in class. But why the hell does the cow have six nipples???
If the biofilm does form, would it be a Reynolds wrap? ;-p
@9–The Cow With The Golden Gun??
Speaking about a Reynolds number, this is what chigau was mentioning.
Then I remember it was 40 years ago, gaaaack
This is also why (one reason among many) proteins like bacterial flagella and kinesins and so forth are not analogous to macro-scale machines and motors (that being a common ID talking point).
I am immediately reminded of “Mach 20” from Laurie Anderson’s “United States Live” [disk 4 – back when people still used disks – mine are the big black ones you used to pull a needle across – I think they used to call them “gramophones” or something like that…]
“Would they realize they were carrying information…”
[P. S. – speaking of Laurie A.: RIP, Lou Reed]
I’m pretty sure what this video says at ~3 minutes about sperm flagella is wrong. They don’t spin around; they undulate within a plane, a bit like an eel, or a snake on flat ground. Prokaryotic flagella are spinning corkscrews but eukaryotic flagella have a different structure and mechanism.
Oh no not again
Every time I look at this post, I get “The Penis Song” from Monty Python’s Meaning of Life stuck in my head.
“…and you won’t… a-come…. a-back.”
@17, Eric That, and not the “Every Sperm Is Sacred” song from the same movie? That’s just wrong.
@17, Eric: You forgot “uuuuuhthangyerverrehmuch”.