• Question: How did plants develop photosynthesis

    Asked by Little M to Ahmed, Francesca, George, James, Nitheen on 17 Nov 2014.
    • Photo: James Sullivan

      James Sullivan answered on 17 Nov 2014:

      Hi Little M –

      great question – and the clearest answer is it evolved.

      The first life to make their own food probably did it by taking electrons from chemicals that lose electrons easily – hydrogen perhaps, and when a lifeform evolved that could take electrons from water (which is a really rate limiting step in photosynthesis) they had a competitive advantage over the others organisms and they flourished.
      this is a nice link for this.


    • Photo: Francesca Paradisi

      Francesca Paradisi answered on 17 Nov 2014:

      Can’t beat Wikipedia or James!

    • Photo: George Dowson

      George Dowson answered on 17 Nov 2014:

      With all questions about fundamental evolution we don’t know the exact answer but we can build a good idea of the process. It would have started with a mico-organism which used some amount of sunlight to do some process inside its cell. This would have been a big advantage over other organisms that needed to use food to do the same process. The light using bugs would have breeded more easily passing on this skill to their offspring. Next the skill would have developed over generations using sunlight to do more and more for the cell until a rudimentary form of photosynthesis is developed, where the only thing the organism still needs apart from light is water, CO2 and trace minerals.
      Evolution simply requires each step on this process to be better than the last and voilà, you have the first photosynthetic plants!

      I find it amazing to think that huge mighty trees are made almost entirely of sunlight and gas (carbon dioxide)!

    • Photo: Ahmed Osman

      Ahmed Osman answered on 17 Nov 2014:

      when energy from light is absorbed by proteins called reaction centres that contain green chlorophyll pigments. In plants, these proteins are held inside organelles called chloroplasts, which are most abundant in leaf cells, while in bacteria they are embedded in the plasma membrane.
      hope this helps