Bacteria thrive on cooperation.

[rug]

- snip -

And, maybe not surprisingly, the bacterial species' evolution with company turned out to be quite a bit from their evolution alone. Left alone, most of the species evolved a faster growth rate. This is a common result in experimental evolution, because the process of transferring evolving bacteria to fresh growth medium—"serial transfers" that were performed fifteen times over the course of the experimetn—can create natural selection that favors fast-growing mutants. But, grown all together in the same tube, species that had evolved faster growth rates in the solo experiment evolved slower growth instead.

To find out what had evolved in the multi-species tubes, the team tested the growth of the bacterial species on beech tea that had been used to grow one of the other species, then sterilized. The original, ancestral strains of bacteria generally had negative effects on each others' growth—they lived on similar compounds in the beech tea, and so their used tea wasn't very nourishing for the other species. The same thing occurred with the strains that had evolved alone, only stronger, which makes sense in light of the increased growth rates, which would've depleted the growth medium faster.

But the interactions among the strains of the different bacterial species that had evolved together was strikingly different. Many of them actually made the tea more nutritious for other species in the evolved community. That is, some of the bacteria had evolved the capacity to eat the waste products of another species that was evolving with them. Using the NMR method to track changes in the presence of different carbon compounds in the tea before and after use provided confirmation that the co-evolved species were using, and producing, complementary sets of resources.

In short, the evolving community didn't simply become more diverse—it evolved new kinds of mutually beneficial relationships between species that began as competitors.

- snip -

http://www.denimandtweed.com/2012/05/ecological-complexity-breeds.html

http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.1001330

Just as I suspected.

[surrealAmerican]

1. k & r

When I read the title, I expected this to be metaphorical, and about bipartisanship. Literally, it makes a lot of sense.

[trotsky]

2. If there is a ecological niche to be found, evolution will find it.

And populate it. We should guard against trying to anthropomorphize this phenomenon, and acknowledge it's just what life does.

[Jim__]

3. I'm not sure cooperation is the best label for this.

It sounds more like evolution leading to adaptations to fill environmental niches. The more diversity within the environment, the more ecological gaps are available. It would be interesting to know what types of changes took place within the populations.

[rug]

4. There's a lot of data at the second link.

Most of it out of my depth.