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by pdl410 529 days ago
The endosymbiosis that resulted in the harnessing of mitochondrial energy production appears to have only happened once (see work by Nick Lane) and resulted in a ~20 fold increase in available energy to the cell was followed very closely by the Cambrian explosion. We could still all still be bacteria today without it.

https://nick-lane.net/wp-content/uploads/2017/05/Lane-J-Theo...
2 comments
baq 529 days ago
Once in a billion years is some very long odds bet. Drake’s equation should include this as a separate factor.
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sandworm101 529 days ago
If it happened by chance, then we are alone in the universe. If literally trillions of bacteria all living and dying (ie evolving) with generations measured in hours ... and it still took a billion years to happen, then there is no hope for multicellular life elsewhere. There would have been more bacteria in earth's ancient ocean than there are planets in the visible universe. Hope of ever contacting multicellular aliens is over.

OR ... the switch to multicellular life was triggered by some sort of event, an evolved response to an environmental change. In that case then it is reasonable to think that it would happen on other planets too. So I really do hope that it wasn't a matter of pure chance. I want us to meet or at lease hear someone else some day.

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PittleyDunkin 529 days ago
> an evolved response to an environmental change.

This is still a "by pure chance" event, yea? Otherwise we're just back to intelligent design. Surely the issue is that we have fundamentally few ways of analyzing how probable that single event is/was.

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sandworm101 529 days ago
Mutations occur by chance. With trillions of bacteria, mutations are a constant. Each possibly mutation is happening somewhere. Natural selection then dictates which mutations thrive when the environment favors them to do so. Evolution is a system, not a lottery.

There is also a meta layer to evolution, that organisms can "evolve to evolve", that the rate of "random" mutations can itself be an evolved trait. An organism unable to evolve, say with locked-in genetic code, will not adapt. Sexual reproduction arguably is such a system: an evolved system that regulates future evolution. So even base mutations may not be totally random.

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PittleyDunkin 529 days ago
> Evolution is a system, not a lottery.

Sure, if you chuck the concept of a lottery out the window. It's literally a genetic lottery. C'mon we can do better than this bullshit.

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sandworm101 529 days ago
Evolution and genetic lotteries are different concepts, like ball bearings and automobiles.
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pdl410 529 days ago
https://www.quantamagazine.org/scientists-re-create-the-micr...
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