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  Topic: More Woese, Evolution at the species level< Next Oldest | Next Newest >  
BWE



Posts: 1898
Joined: Jan. 2006

(Permalink) Posted: April 04 2008,04:14   

I know this didn't go very far last time so maybe it doesn't again this time but I've been following this wired series and am beginning to fall for his lilting tune. Where's the smiley with spiral eyes? Well, maybe not fall for it exactly. When I see the science I'll look at the M&M first. But there is a sort of poetic beauty to the idea.

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But to Woese and others, change and selection need to be studied at other levels: A honeybee colony, for example, is as much an individual as a single bee. And when explaining how interacting units -- bees, or bacteria, or cells -- produce the qualities of the whole, change and selection alone might not suffice. What's needed is an understanding of the dynamics of complexity....

Microbes make up much of Earth's biomass, and they also cast into relief the shortcomings of neo-Darwinian evolution. A bucket of seawater can contain 60,000 bacterial species, and to Woese, these must be seen as a collective rather than as disparate units.

At the collective level, said Woese, bacteria exhibit patterns of organization and behavior that emerge suddenly, at tipping points of population variation and density called "saltations." Natural selection still favors -- or disfavors -- the ultimate outcome of these jumps, but the jumps themselves seem to defy explanation solely through genetic changes or individual properties. ...

But as with bacteria and people, how can a sharp distinction be drawn between a honeybee colony and the flowers that both nourish them and rely on them for pollination? And between the flowers and organisms that in turn rely upon them?

"Selection probably happens at all scales, from gene to individual to species to collection of species to ecosystem to we don't even know what," said Maya Paczuski, head of the Complexity Science Group at the University of Calgary.

Paczuski's group sees evolution as taking place at all these levels, with what happens in ecosystems rippling down to individuals, back up to populations, across to other populations, and so on -- all simultaneously, and in tandem with the mysterious dynamics of networked complexity.

But does it all happen mechanically? Or does evolution obey some larger imperative?

University of Nevada evolutionary biologist Guy Hoelzer calls that imperative biospheric self-organization. "The idea of evolution is embedded within self-organization," he said. "It coordinates the ecological roles of species so that ecosystems persist and process a great deal of energy."

Woese expanded the concept. "Evolution is a better version of the second law of thermodynamics, of time-zero, which implies that things are going to degenerate until even the atoms fall apart. But maybe that's not the way it's going to play out."


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Who said that ev'ry wish would be heard and answered
When wished on the morning star
Somebody thought of that, and someone believed it
Look what it's done so far

The Daily Wingnut

   
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