Freethought & Rationalism Archive

Gooch's dad · 04-18-2002, 01:53 PM

I seem to remember seeing a web page about a year ago, on an experiment that showed a bacteria evolving into a multicellular aggregate.

A biologist friend on chat gave me the reference, and I didn't save it. I've done several google searches and found nothing.

IIRC, the bacteria, in the presence of some antibiotic or other harsh environmental condition, started aggregating into 8-cell groupings, and stabilized in this new form. It was considered especially interesting because it showed a case of evolution into what we would call a different phylum.

Does this sound familiar?

-Kelly

liquid · 04-19-2002, 12:24 PM

Yep, the experiment exists, and you have the results correct. I can't tell you the details though - heard about it a year or two back. I can't remember if the aggregation behaviour was genetically inhertied. The idea wasn't to actually evolve multicellularity, but to demostrate clustering behaviour that could lead to the evolution of permanent clustering.

04-19-2002, 02:23 PM

Look up slime moulds (or molds, if you're American).

Gooch's dad · 04-22-2002, 05:39 AM

Actually, I found my answer <a href="http://www.talkorigins.org/faqs/faq-speciation.html" target="_blank">on this talk-origins page.</a>

Down in section 5.9.1 it describes the experiment by Boraas involving Chlorella Vulgaris:

Quote:

Within five days a colonial form of the Chlorella appeared. It rapidly came to dominate the culture. The colony size ranged from 4 cells to 32 cells. Eventually it stabilized at 8 cells. This colonial form has persisted in culture for about a decade. The new form has been keyed out using a number of algal taxonomic keys. They key out now as being in the genus Coelosphaerium, which is in a different family from Chlorella.

Cheers,

-Kelly

04-18-2002, 01:53 PM	#1
Gooch's dad Veteran Member Join Date: Oct 2000 Location: Madison WI USA Posts: 3,508	single to multi-cell experiment? I seem to remember seeing a web page about a year ago, on an experiment that showed a bacteria evolving into a multicellular aggregate. A biologist friend on chat gave me the reference, and I didn't save it. I've done several google searches and found nothing. IIRC, the bacteria, in the presence of some antibiotic or other harsh environmental condition, started aggregating into 8-cell groupings, and stabilized in this new form. It was considered especially interesting because it showed a case of evolution into what we would call a different phylum. Does this sound familiar? -Kelly

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04-19-2002, 12:24 PM	#2
liquid Veteran Member Join Date: Jan 2001 Location: UK Posts: 1,440	Yep, the experiment exists, and you have the results correct. I can't tell you the details though - heard about it a year or two back. I can't remember if the aggregation behaviour was genetically inhertied. The idea wasn't to actually evolve multicellularity, but to demostrate clustering behaviour that could lead to the evolution of permanent clustering.

04-19-2002, 02:23 PM	#3
DMB Guest Posts: n/a	Look up slime moulds (or molds, if you're American).

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