From: Durant Schoon (email@example.com)
Date: Mon Mar 05 2001 - 13:02:41 MST
Re: Vinge's discussion of bacteria
If you like that stuff I recommend "A Walk Through Time" (1998) which
chronicles the history of life on Earth. It is a very accessible book
based on a museum exhibit in which each foot represents a million
years of history (might be too simplistic for this audience though.
See Margulis for more in depth coverage - John Smart mentioned one
of her books).
"A Walk Through Time" chronicles the billions of years that bacteria
dominate(d) our planet. I thought I'd mention two snippets from the
book that seem very interesting, (since I didn't know them before):
1) Cellular Cities!
It is only recently that new techniques in microscopy (confocal
scanning laser microscopy) have allowed us to see cellular cities
(aka biofilms, mucilages).
"The cities are laced with intricate channels connecting the buldings
to circulate water, nutrients, enzymes, oxygen, and recyclable
wastes. Their diverse inhabitants live in different microneighborhoods
and glide, motor, or swim along roadways and canals." (p. 67)
Researchers cited: Microbiologist Bill Keevil (England),
Microbiologist Bill Costerton (US, Montana)
Also of note is that these bacteria turn on different sets of genes
than their identical counterparts. All bacteria give off small
amounts of homoserine lactone, and when enough of them get together,
concentrated amounts of h.l. turn them into city dwellers!
There was some speculation elsewhere in the book that bacteria might
have evolved viruses to pass information around. It all depends on how
you look at things, I guess.
2) Cells have skeletons!
"Until recently, we did not even know that such cell skeletons --
cytoskeletons -- exist, because the chemicals with which we prepared
cells for study dissolved them. We had assumed cells to be floppy
bags of organelles and a nucleus floating around in liquid cytoplasm"
(p. 84) - D'oh!
Researchers cited: Donald Ingber (Harvard / MIT) shows these
cytoskeletons to be "tensegrity structures" a la Buckminster Fuller
(imagine rigid straws connected with elastic to form flexible
geodesic domes that bend at the joints). So cool!
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