Systems that reliably evolve in similar ways (like stellar evolution)

June 21, 2019 1:29 PM

Hivemind! :) I'm looking for examples of nature producing structure out of randomness, but especially in a complex, evocative, beautiful evolutionary process that reliably occurs, where you have initial conditions; based on those, X happens; based on X, Y happens; based on Y, Z happens, and so on. The best example I can think of is the evolution of stars: you have a molecular cloud which undergoes a particular evolutionary trajectory depending on its mass, and this happens reliably across the universe. Thanks in advance :)
posted by mrmanvir to Science & Nature (17 answers total)

River Deltas are similar, a river carrying sediment reaches a larger body of water forming a characteristic set of patterns.
posted by gregr at 1:39 PM on June 21, 2019

I would take a look at Wolfram's book 'A New Kind of Science' and Mandelbrot's book 'The Fractal Geometry of Nature.'
posted by Dmenet at 1:54 PM on June 21, 2019

Crystallization
posted by vacapinta at 2:28 PM on June 21, 2019 [1 favorite]

Before Alan Turing died, he published research into how organisms develop seemingly complex colors, patterns, and shapes from simple inputs.
posted by They sucked his brains out! at 2:29 PM on June 21, 2019 [3 favorites]

Here's a paper on modeling pigmentation patterns in organisms, where complex patterns fall out of applying simple rules. The references may be a useful jumping point, as well.
posted by They sucked his brains out! at 2:37 PM on June 21, 2019 [2 favorites]

If you want to dig deeper into the idea that Turing launched, check out The Making of a Fly or The Coiled Spring.

I've had my mind blown by learning how neural development involves cells crawling around this way and that way, picking up knowledge about who they're supposed to become at each stop along the way, until they finally end up in the right place knowing who they are and what to do. I'll keep trying to find a reference for that. In the meantime, here's some Alberts on Universal Mechanisms of Animal Development.
posted by clawsoon at 2:45 PM on June 21, 2019

Basically every controlled chemical reaction, more or less.

Beer brewing (industrial scale) is very stringent and produces very uniform results.
posted by porpoise at 2:51 PM on June 21, 2019

You might be interested in Dictyostelium discoideum, in which single cells band together to make a worm-like thing, then turn into a plant-like thing, then go back to being single cells. (Previously.)
posted by clawsoon at 2:53 PM on June 21, 2019

I immediately thought of human (really, any organism) development. People basically always end up with two arms and two legs, and the right number and kinds of organs, etc. And they don't start with much, although maybe it's not quite chaotic enough for you. It's remarkable.
posted by dbx at 2:56 PM on June 21, 2019 [2 favorites]

Bird flocking has been an area of complexity research that might fit.
posted by clawsoon at 2:59 PM on June 21, 2019

Weather might be a good source, e.g. the growth of a cumulonimbus storm cell.
posted by clawsoon at 3:04 PM on June 21, 2019

The development of an ecosystem (though this example isn't quite so unmanaged as the impression given in the first link).

Biofilms are tiny ecosystems that evolve in different ways depending on initial conditions.
posted by clawsoon at 3:32 PM on June 21, 2019

D'arcy Thompson's "On Growth and Form" is my go-to reference for stuff like this. Turing cites it as one of the few references in his paper that TheySuckedHisBrainsOut links to. I think PDF copies are still available online with a little searching. Project Gutenberg also has it as an ebook.
posted by NotAlwaysSo at 3:43 PM on June 21, 2019 [2 favorites]

The Krebs cycle
posted by rhizome at 4:47 PM on June 21, 2019

Rivers again* but at the scale of the sand, gravel and rocks making up the bed. This is a nice graphical place to start (and most pages have pictures rather than functions):
Patterns and processes of sediment sorting in gravel-bed rivers

Pages 36-37, 39 of Scaling down hyporheic exchange flows: from catchments to reaches explain how river patterns emerge mainly from different materials and land slope. A series of tables from page 30 also helps one see the pattern consequences of various stream catchment factors.

I did a river mechanics paper back in the '90's which really opened my eyes to natural systems, you can tell a lot about a river from looking at it's bed material - particles from rock flour to house-size. Once you've immersed yourself in this thinking these patterns emerge whenever you're near a flowing water body.
posted by unearthed at 11:21 PM on June 21, 2019

Ira Livingston argues that culture is like this and that is why alien life may be more similar to us than otherwise thought... Between Science and Literature.
posted by Buddy_Boy at 8:03 AM on June 22, 2019

Might look at L-systems, Lindenmayer systems.

Lindenmayer and Prusinkiewicz (who's cited above by They Sucked His Brains Out!) wrote a beautiful book, The Algorithmic Beauty of Plants
posted by at at 10:43 AM on June 23, 2019 [1 favorite]