Why are plants green?


I woke up this morning puzzling about this… The Sun is green and I’ve wondered for years about why plants reflect the most intense light from the Sun rather than absorbing it. Leaves are green because plants absorb more red and blue light than they do green light. 

Why are they being inefficient?

Turns out the answer – only recently determined – is pretty interesting.

at least sometimes — evolution cares less about making biological systems efficient than about keeping them stable.

If plants were purple or black (absorbing all the green light from the Sun) then any change in intensity (flickering light from shadows) would make the photosynthesis process too variable. It would work great sometimes and it was fail at others. By using the outside light of the spectrum, the process is able to create more stability and essentially correct for fluctuations.

More here, Quieting a noisy antenna reproduces photosynthetic light-harvesting spectra which summarized here: Why Are Plants Green? To Reduce the Noise in Photosynthesis.

This is worth thinking about for a bit… The most efficient answer is, in this important case, the least useful.

Perhaps a church that insists on comprehension rather than clarity has some important reason for existing.

The Author

Episcopal bishop, dad, astronomer, erstwhile dancer...


  1. Thank you!
    Fascinating! Informative! Thought provoking! I am delighted that you shared this!

  2. Jere says

    I loved the conversation Wednesday about how this relates to Richard Hooker’s view of the via media! Thank you so much!

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