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Comment by lisper | Hacker News Reader

Energy and entropy are not really the right metric here. The thing that is lost when a species goes extinct is information, and specifically, information that has been acquired by a process of parallel search that has been going on for literally a few billion years, so the odds of reproducing that information once it is lost is effectively zero. Imagine working on a term paper for a few billion years and then having your computer crash and not having a backup. That's what happens when a species goes extinct.

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More on information and evolution in chapter 19 of MacKay, http://www.inference.org.uk/mackay/itila/book.html

Would there be a way to use "information entropy" as the measurement? Late in the day so I'm struggling to finish my thoughts, but putting this here in case you can connect the dots. https://en.wikipedia.org/wiki/Entropy_(information_theory)

Yes, but it's tricky for two reasons. First, we don't really know how to quantify the relative value of two different species. It's kind of like trying to quantify the value of a book. Losing a volume of Aristotle's Poetics is probably worse than losing a Harlequin romance. And second, the information is not just resident in the genome. We can quantify how many bits of information is contained in DNA, but just knowing the complete gene sequence of a salamander is not enough to be able to make a salamander. You need to embed those genes in the right environment, and we have no idea how to quantify the information needed to describe that. So actually putting a number on it is hopeless. The best you can do is look at the effort it would take to reproduce that information once it's lost, which is essentially infinite.

Thank you, you are thinking much clearer than I

And when you put it like that, it's particularly upsetting that we lose up to 150 species a day

They can use genetics to make aproximate evolutionary trees since different species share a lot of common genetics.

https://en.m.wikipedia.org/wiki/Phylogenetic_tree

That being said changes are very slow and extinction is pretty tragic.

The more I learn about genetics, the less I feel like we know. It’s definitely fascinating, thanks for your perspective!

To extend on your analogy a bit: Imagine working on that term paper on GitHub and then having your repo deleted. The odds of reproducing that information completely is zero. But there might still be some forks (related species) around. So it's pretty hard to wipe out everything.

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