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_AlreadyTaken_ t1_j2fmtd4 wrote

Reply to comment by theCumCatcher in How much does the liquid magma of the Earth affect it's surface temperature? by tripperfunster

I'll toss out one more thing to think about. Life clearly evolved on earth before there was any ozone layer and ultraviolet light was bombarding the surface because it appeared before photosynthesis did so there was no free oxygen (or very very little) in the atmosphere to make ozone. So life can develop in spite of UV light, probably in water too deep for UV light to penetrate. Did photosynthesis evolve from mechanisms to protect against UV light in shallow water? Who knows...

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theCumCatcher t1_j2fnzk5 wrote

about the origin of photosynthesis.

I think there is something there.

if we look at the visible spectra of the sun,

https://www.sunlightinside.com/wp-content/uploads/2017/09/Sunlight_spectrum_Fiji_July.jpg

green and red are its largest components.

the protective pigments in leaves that reflect this red light (carotenoids) become visible when the chlorophil dies in the fall.

suspiciously, chlorophil reflects the remaining green part of the spectra almost perfectly

https://s3.amazonaws.com/microsite-cuny-prod/media/courseware/openstax/m66474/Figure_08_02_05abcd.jpg

it could be the chlorophylls evolved from one of these pigments.

thats really neat

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_AlreadyTaken_ t1_j2fp8nf wrote

I even read that purple bacteria appear to be older than chlorophyll photosynthesis. So either absorbing green, the peak of the solar spectrum is TOO much energy (heat can disable the enzymes) or that part of the spectrum was already filled by organisms so the green ones took what was left.

Chlorophyll is also composed of many subunits that likely have been added as enhancing features over time, like energy transmitting antennae structures that funnel the photon energy to the reaction center.

I used to date a woman who was researching the dna structure of photosynthetic bacteria. :D

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