flagellum/cilium confusion
nickm...@gmail.com
1. bacterial flagella
2. archaeal flagella
3. eukaryotic flagella/cilia
The point was made that this has caused confusion before. Recently I
was writing a book review of E.O. Wilson's new book _The_Creation_,
and I came across this line on p. 166:
"[Intelligent Design's] logic is simply this: biologists have not yet
explained how complex systems such as the human eye or the spinning
bacterial ***cilium*** could have evolved by themselves; therefore a
higher intelligence must have guided the evoltuion."
So I guess we can say this one has confused even the world's leading
living biologist!
r norman
1) Who claims that E.O. WIlson is the "world's leading living
biologist"? He certainly is a fine biologist but there many such
fine biologists. He has gone rather overboard at various times.
Sociobiology generated extreme anti-Wilsonian reaction in a previous
era and his notion of "consilience" is not universally applauded.
2) Wilson is an old guy and old habits die hard. The modern
distinction to always use "flagellum" for the prokaryotic structure
and "cilium" for the eukaryotic, but that is relatively recent. In
the past, "cilium" meant a relatively short structure and "flagellum"
a relative long one without distinction to the details of their
organization. So bacteria really did used to have cilia even though
they really didn't, they were just small flagella.
John Harshman
I've never heard of this modern distinction. I've never heard of
bacterial cilia either, but I bow to your greater age. However, the only
practice I know that distinguishes between bacterial and eukaryote
flagella is Margulis' suggestion to call the latter "undulipodia" (and
to stop calling them either flagella or cilia, depending on length).
r norman
PubMed has several citations for "bacterial cilia":
[On certain methods of staining of bacterial cilia.]
G Batteriol Virol Immunol. 1959 Jul-Oct;52:320-7
Microstructure of bacterial cilia in Salmonella typhosa.]
Boll Soc Ital Biol Sper. 1957 Mar;33(3):284-6.
The role of bacterial cilia in the process of transmitting multiple
drug resistance in E. coli K-12. I. The transmission of R-factors by
bacteria stripped of cilia by treatment in a blendor]
Zh Mikrobiol Epidemiol Immunobiol. 1969 Mar;46(3):143-7
Admittedly, these are all translations of the titles, but they do
indicate that in previous epochs, the notion that bacteria have cilia
was acceptable.
Few people actually avoid using the term "flagellum" for the
eukaryotic structure and specifying "cilium" in place of
"undulipodium" seems to be a reaction against Margulis. I mentioned
it primarily because of the authority of truly the "world's greatest
biologist", Wikipedia.
Perplexed in Peoria
"r norman" <r_s_norman@_comcast.net> wrote in message news:iidev21icbu3n1s76...@4ax.com...
I would point out that "reacting against Margulis" is not at all silly
and petty in this context. Margulis proposed the term in the context
of a theory regarding their evolutionary origin which most people think
is wrong. So the word carries a connotation of crack-pottery, even
though there is nothing in the etymology that should raise anyone's
hackels.
Too bad there wasn't a reaction against Woese when he proposed the term
Archaebacteria (later changed to Archaea). The etymology there clearly
suggests that the Archaea are somehow 'more ancient' than ordinary
bacteria - something almost no one today believes is true.
r norman
I think there is a technical difference between naming organisms and
groups thereof and naming concepts or structures. The first has
international bodies recognizing precedence of naming, and the namer
has great latitude of choice, everyone recognizing that the meaning of
the words chosen for the name may bear little or no relationship to
the named object. John W. would have a technical term for this
notion.
Telling people that flagellated sperm or that flagellated protists
don't have flagella is rather another story. It is almost as bad as
telling people that dogs are wolves or that birds are dinosaurs except
that in this case the recalcitrant group is the scientific community.
I guess you could talk about the "macroundulapodified protozoa" such
as Euglena or the dinoflagell --- oops, the dinomacroundulipodia, as
opposed to the "microundulipodists" like Paramecium.
Merry Go Round the Sun
> "[Intelligent Design's] logic is simply this: biologists have not yet
> explained how complex systems such as the human eye or the spinning
> bacterial ***cilium*** could have evolved by themselves; therefore a
> higher intelligence must have guided the evoltuion."
>
I've heard the claim that a spinning cilium is free to rotate
and that evolution would never create such a thing.
A helicopter's blades rotate, but a helicopter not a living creature
that nature would have produced directly. Rather I would say
that the helicopter was produced indirectly by nature through man,
just as we would say that a bee hive was not a direct product
of nature but was produced indirectly via bees.
Are bees intelligent designers?
Some magnetotactic bacteria have long chains of
permanent magnets inside of them. They are used
for navigation.
Pictures of magnetotactic bacteria:
http://www.biophysics.uwa.edu.au/STAWA/TEM_images.html
The bacteria did not "invent" these magnetic compasses
any more than bees "invented" bee hives.
Are helicopters like bee hives or bird nests?
Are humans intelligent or are they just doing what
the birds and the bees are doing?
nickmat...@gmail.com
> On 13 Mar 2007 15:37:19 -0700, nickmat...@gmail.com wrote:
>
>
>
> >I was just reading a recent thread on confusion between:
>
> >1. bacterial flagella
> >2. archaeal flagella
> >3. eukaryotic flagella/cilia
>
> >The point was made that this has caused confusion before. Recently I
> >was writing a book review of E.O. Wilson's new book _The_Creation_,
> >and I came across this line on p. 166:
>
> >"[Intelligent Design's] logic is simply this: biologists have not yet
> >explained how complex systems such as the human eye or the spinning
> >bacterial ***cilium*** could have evolved by themselves; therefore a
> >higher intelligence must have guided the evoltuion."
>
> >So I guess we can say this one has confused even the world's leading
> >living biologist!
>
> 1) Who claims that E.O. WIlson is the "world's leading living
> biologist"? He certainly is a fine biologist but there many such
> fine biologists. He has gone rather overboard at various times.
> Sociobiology generated extreme anti-Wilsonian reaction in a previous
> era and his notion of "consilience" is not universally applauded.
Eh, I didn't really mean to start an argument on this, but really, who
else comes close? The list of others at his level of fame and
influence, both popular and academic, is pretty short, and they are
mostly deceased -- Ernst Mayr, John Maynard Smith, Francis Crick,
etc. I guess James Watson is a legitimate competitor.
> 2) Wilson is an old guy and old habits die hard. The modern
> distinction to always use "flagellum" for the prokaryotic structure
> and "cilium" for the eukaryotic, but that is relatively recent. In
> the past, "cilium" meant a relatively short structure and "flagellum"
> a relative long one without distinction to the details of their
> organization. So bacteria really did used to have cilia even though
> they really didn't, they were just small flagella.
AFAIK this usage of cilium/flagellum only applies to eukaryotes. E.g.
paramecium, with rows of short cilia/flagella, typically are said to
have "cilia." Sperm cells are said to have "flagella" -- longer and
usually only one or a few.
The bacterial organelles have always been flagella.
A substantial portion of biologists will say that this is confusing
because the eukaryotic cilia/flagella are all basically the same, and
so the eukaryotic organelles should be called cilia. This usage is
followed by e.g. Behe in Darwin's Black Box.
Then there is Margulis, who advocated for "undulipodium" to avoid the
above terminology issue, and to push her hypothesis that the
eukaryotic flagellum/cilium/undulipodium was derived from a spirochete
symbiont.
There are other terms floating around, i.e. kineto-something.
Even the "bacteria have flagella" idea is no longer pure, since
archaea/archebacteria have their own unrelated flagella.
So IMO, we should just call everything "flagella", and use the term
like we use the term "wing" or "tail", with no implication of detailed
similarity or relationship. And reserve cilia for the paramecium-type
situation.
Mark Isaak
Other contenders are Richard Dawkins and Jane Goodall. Goodall and E.O.
Wilson, like Stephen J. Gould, have written forewords to Gary Larson
books, but Dawkins has been depicted on Southpark. I guess it is a
judgment call which of those distinctions best qualifies one as
"foremost." Goodall has also been parodied (as "Joan Bushwell") on "The
Simpsons," which I would say gives her the clear edge.
--
Mark Isaak eciton (at) earthlink (dot) net
"Voice or no voice, the people can always be brought to the bidding of
the leaders. That is easy. All you have to do is tell them they are
being attacked, and denounce the pacifists for lack of patriotism and
exposing the country to danger." -- Hermann Goering
John Wilkins
Watson did One Big Thing and then made a career talking about it.
>
> Other contenders are Richard Dawkins and Jane Goodall. Goodall and E.O.
> Wilson, like Stephen J. Gould, have written forewords to Gary Larson
> books, but Dawkins has been depicted on Southpark. I guess it is a
> judgment call which of those distinctions best qualifies one as
> "foremost." Goodall has also been parodied (as "Joan Bushwell") on "The
> Simpsons," which I would say gives her the clear edge.
Dawkins is a populariser. Goodall is worthy, but hardly broad in her
contributions.
Some of the contenders in my book:
Joel Cracraft - ornithologist who has written extensively on everything
Alan Templeton - leading population geneticist and theoretical biologist
Franz de Waal - primatologist who has worked extensively on social
biology
Kevin Padian - dinosaurian paleontologist who also writes widely
Sergey Gavrilets - mathematician/population geneticist
Massimo Pigliucci - Ecologist and Evo-Devo specialist
Scott Gilbert - leading developmental biologist
Two or three of these guys rolled into one might approach Wilson.
--
John S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project
University of Queensland - Blog: scienceblogs.com/evolvingthoughts
"He used... sarcasm. He knew all the tricks, dramatic irony, metaphor,
bathos, puns, parody, litotes and... satire. He was vicious."
John Harshman
I think Templeton approaches Wilson in the breadth of his involvement.
None of the others. Pigliucci, ironically, is one of the people who have
confused flagella (eubacterial and eukaryote) in print. Why are we
keeping score this way, again?
Perplexed in Peoria
"John Wilkins" <j.wil...@uq.edu.au> wrote in message news:1hv29n2.1u72nj6n2xu2N%j.wil...@uq.edu.au...
The closest thing biology has to a Nobel is the Crafoord prize, awarded to
a biologist every three or four years.
http://en.wikipedia.org/wiki/Crafoord_Prize
The list of recent winners is:
1990 Paul R. Ehrlich and Edward O. Wilson
1993 William D. Hamilton and Seymour Benzer
1996 Robert May
1999 Ernst Mayr, John Maynard Smith, and George C. Williams
2003 Carl Woese
2007 Robert L. Trivers
Lots of ecologists, evolutionary theorists, and molecular-level people
on that list. Not many whole-organism biologists.
Trivers is an interesting choice. Not someone I would have thought of,
but deserving, I think.
I wouldn't call Woese a biologist, and maybe not Benzer. May, Maynard Smith,
and Williams strike me as theorists rather than 'real' biologists. Trivers
and Hamilton are/were primarily theorists, though they do/did a lot of field work.
And Mayr is (finally) dead. That leaves Erlich and Wilson. I don't particularly
like Erlich on political grounds, but he definitely did some good biology. But
not as much good biology as Wilson did.
Calling Wilson "the world's leading living biologist" may not be as absurd as
I first thought.
r norman
There is a little thing called Nobel Prize in Physiology or Medicine.
There are a large number of biologists who have won that prize.
Physiology does happen to be a part of biology. There is also a
little thing called Nobel Prize in Chemistry that has been won by a
number of biologists.
This list is exceptionally heavy on ecologists and evolutionary
biologists. There are a few people in biology who do work in
physiology or in development or in biochemistry and molecular biology
and cell biology that seem to be overlooked, here.