Timeline for Why aren't leaves black?
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5 events
| when toggle format | what | by | license | comment | |
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| Jul 6, 2020 at 19:49 | comment | added | Armadillo Jim | Circling back to this a loooong time later, here's another piece of the puzzle: it's hypothesized that eukaryotes engulfed cyanobacteria -- becoming chloroplasts -- and this event only happened once in all of evolution. (That is, no convergent evolution at play among all plants and algae.) All descendants of that common ancestor all have the same green appearance. | |
| Dec 30, 2018 at 1:02 | comment | added | Armadillo Jim | Another intriguing hypothesis is that the first successful photosynthesizer was purple (absorbed abundant green and reflected red and blue). The green algae then exploited a niche by doing the reverse (reflecting green and absorbing red and blue). Eventually the second comers out-competed the first movers, and began to dominate. There was never a need to re-adapt once dominant and absorb green. See this answer: biology.stackexchange.com/a/45335 | |
| Dec 29, 2018 at 16:06 | comment | added | Armadillo Jim | Thanks! If I can restate in my own words, it's two things. (1) Absorbing only red and blue light is good enough to dominate; why bother expending extra effort that isn't necessary (or if it ain't broke, don't fix it). And (2) green light is used for other purposes such as quenching chlorophyll (regulation) and fueling anti-oxidants. Neat! TIL carotenoids play both roles. The xanthophylls you mention assist quenching. Carotenes absorb shorter wavelength light, scatter longer wavelengths, and transmit what they do absorb to chlorophyll (to provide extra energy to the photosystem). | |
| Dec 29, 2018 at 15:58 | vote | accept | Armadillo Jim | ||
| Dec 26, 2018 at 16:27 | history | answered | aeffenberger | CC BY-SA 4.0 |