I am not a biologist. I am aware that photosynthesis is the main process for capturing electromagnetic energy from the Sun. Also, I am aware that some bacteria can capture energy from boiling water and others from certain chemicals.

  1. What are the known energy capturing processes in biological systems other than photosynthesis? I am looking for references or a good survey of all known mechanisms.

  2. Is there an explanation for the ingenuity of evolution in solving the energy capturing (transforming) problem via multitude of mechanisms?


2 Answers 2

  1. Apart from phototrophy, there is only chemotrophy (obtaining energy from redox reactions of chemical substances) and radiotrophy (obtaining energy from ionizing radiation such as gamma rays). However, radiotrophy as of now is only known to be a supplemental mode of energy and not a primary one.

  2. Diversity is a central theme of evolution. It would be interesting if there was a single common mechanism for all modes of energy-nutrition which is perhaps true for the case of the chemiosmotic energy generating mechanism (ATP-synthase like systems which generate energy from chemical gradients). Otherwise, diversity is expected as the organisms evolve to survive in different environments.

  • $\begingroup$ Nice answer. Can you provide an example organism for each mechanism under chemotrophy and raditrophy? $\endgroup$ Dec 16, 2015 at 15:01
  • $\begingroup$ @MohammadAl-Turkistany The link to the article gives the example of radiotrophic fungi. You can also check the other linked post. There are several chemotrophic bacteria. See the wikipedia link. $\endgroup$
    Dec 16, 2015 at 16:45


The only two sources of energy that I could find (not that there aren't any others that I couldn't find or that haven't been discovered) are from light (plants) and "abiological compounds" (some bacteria).



It seems you have to buy this book, but the website does provide a preview containing the answer to your question (in the first paragraph).


The likely explanation for having a multitude of ways of capturing energy is adaptive radiation. Having a different method of gathering energy would place the organism in a different ecological niche, which would have been otherwise unoccupied. This allows the organism to flourish. For example, heterotrophs evolved to metabolize a variety of compounds. Some digest mainly glucose, while others evolve to break down cellulose, amylose, protein, etc.

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