> even though evolution is contingent at a local level (such as a specific protein sequence or the shape of a flower), it is remarkably predictable at a global level (such as the very existence of proteins and flowers across many species)
to be fair... flowers are a very recent invention that appeared only after the dinosaurs got wiped out and clean slate allowed co-evolution of flowers and pollinators to occur
Flowering plants (angiosperms) appeared during the Cretaceous before dinosaurs got wiped out, and there is fossil evidence of insects pollinating non-flowering plants (gymnosperms) like ferns and confers even earlier than that: https://repository.si.edu/server/api/core/bitstreams/152b12d...
There are a few pictures of truncated icosahedra in the article, alongside several other shapes that are not icosahedra. The point is that they have icosahedral symmetry. The L is important.
I was going to comment pedantically that soccer balls were dodecahedrons not icosahedrons, but in reading the article, I came to realize that truncated icosahedrons are the same as truncated dodecahedrons.
This was such a delightful realization I felt the need to comment anyway.
Hmm. I'm sorry, but truncated dodecahedra are different from truncated icosahedra.
Truncated dodecahedra are made from twelve 10-gon and twenty triangular faces. Truncated icosahedra are made from twenty hexagonal and twelve pentagonal faces.
And that archetypal soccer ball design is called the Telstar and named for a communications satellite, fun fact. I think before 1968 the volleyball shape was more popular https://en.wikipedia.org/wiki/Adidas_Telstar
CO, CO2, carbonate salts like Na2CO3, or CaCO3, and cyanides like HCN, NaCN, and KCN are usually considered inorganic compounds instead of organic compounds, despite containing carbons. But the vast majority of carbon-containing compounds are considered organic, and there are no organic compounds that don't contain carbon.
> there are no organic compounds that don't contain carbon
It's very much nitpicking and an edge case but now you've got me wondering if some silicone hydrocarbon analogs might not qualify. Noting that we have plausible theories about the feasibility of silicone based life.
I mean, I don't think diamonds are considered "organic"; same for graphite. But that's where the term "organic" itself starts to break down as a category.
Yes! Not sure why you're asking- things don't have to be created by biological processes to be organic (this concept is totally unrelated to "organic" in the supermarket).
33 comments
> even though evolution is contingent at a local level (such as a specific protein sequence or the shape of a flower), it is remarkably predictable at a global level (such as the very existence of proteins and flowers across many species)
to be fair... flowers are a very recent invention that appeared only after the dinosaurs got wiped out and clean slate allowed co-evolution of flowers and pollinators to occur
>an estimated 70 percent of viral capsids known to date are icosahedral, shaped like tiny soccer balls.
Soccer balls are not icosahedra. The archetypal soccer ball is a truncated icosahedron: https://en.wikipedia.org/wiki/Truncated_icosahedron
This was such a delightful realization I felt the need to comment anyway.
Truncated dodecahedra are made from twelve 10-gon and twenty triangular faces. Truncated icosahedra are made from twenty hexagonal and twelve pentagonal faces.
> there are no organic compounds that don't contain carbon
It's very much nitpicking and an edge case but now you've got me wondering if some silicone hydrocarbon analogs might not qualify. Noting that we have plausible theories about the feasibility of silicone based life.
> we have plausible theories about the feasibility of silicone based life.
... Do we? Last I heard those weren't really viable due to some combination of being too stable or too unstable in all the available solvents.