Evolution is literally just the observation that there are lots of things that self-replicate.

That's it. That's the entire thing. Plus some nuance about things that self-replicate faster than other things...

It occurs at all levels. Amyloid protein in Alzheimer's patients is self-replicating. So are cells. So are individual parts of cells. Sometimes things replicate by being parts of a larger thing that replicates, sometimes they don't. It's all one big chaotic tangled mess with no particular purpose or design. Human cells evolve, so do humans, so do human societies. So do rocks.

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cwillu 2 hours ago | parent | next [-]

Rocko can't have kids, because Rocko is just a stupid rock.

	▲	card_zero an hour ago \| parent [-]
		Possibly a reference to A.G. Cairns-Smith, who speculated about evolving clay crystals. (They can sit in a stream and accumulate minerals, and reproduce that way.)

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dekhn an hour ago | parent | prev [-]

No, evolution is not an observation that there are things that replicate. Darwin's view, which has survived mostly intact, is that there is replication with variation and that more fit individuals replicate at a higher rate ("survival of the fittest" isn't a correct description; plenty of less fit individuals do replicate, but they contribute very little to the population genetics in the long run)

And amyloid protein doesn't self-replicate. An instance of the misfolded form causes other folded proteins of the same type to transition to the misfolded form. It's a form of catalysis, not self-replication.

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card_zero an hour ago | parent [-]

Seems like splitting a hair. In a world abundant with other amyloids, they'd self-replicate. Cells likewise need nutrients and a favorable environment.

	▲	dekhn an hour ago \| parent [-]
		In retrospect I conclude you're right (that it's splitting a hair). I went back and some literature does use the term self-replication although at least within my academic circles, we consider autocatalyzed template matching simpler than self-replication.