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Complexity Theory in Icky Action: Meet the Slime Mold

Slime_mold_undermulch There are few creatures more remarkable than the lowly slime mold.

But is the slime mold really a creature? Or is it a fungus? If it’s not a fungus, is it a single entity — or millions? Or both?

Hence its remarkability.

Slime molds start life as single, amoeba-like cells. Eventually they find mates and produce offspring that grow into so-called plasmodia — structures that are full of cell nuclei, but without any dividing cellular walls.

These are large enough to be seen, usually on rotting logs rich in bacterial food, and can spread for meters, rolling slowly across the ground. But when food runs out, they come together and form a stalk;in a "fruiting body" at the top of the stalk, cell walls form around new nuclei. These are released as spores, alighting elsewhere and starting the cycle over again.

So sometimes a slime mold is single. Somtimes it’s plural. And somehow it/them coordinates this for itself/themselves.

How? That’s the big question.


2829x2slimemoldsporangia According to microbiology titan and evolution maverick Carl Woese, there’s some sort of emergent property inherent to the communications networks of the individual cells, which are capable of sending molecular signals to each other.

He likes to cite slime molds as living examples of the concept of saltations — jumps in organismal and ecosystem complexity that can’t be explained through the neo-Darwinian mechanisms of genetic mutation and natural selection.

So slime molds could hold the secret to how a few billion years turned single-celled organisms into you and me — and if that sounds academic, watch the video. You’ll see that it’s also pretty freaking cool.

Be forewarned, though: once you start seeing parallels between this and a macroscopic view of human civilization, it’s hard to go back.

Note: To learn more about slime molds, look up the works of J.T.
Bonner — one of the most interesting scientists you’ve never heard of.
Also a very cool BBC video here.

Images: Purdue University, University of Winnipeg

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