A Different Rulebook for Life.

August 31, 2012 § 1 Comment

What if life plays by other rules elsewhere in the universe?

In December, 2010, biologist Dr. Felisa Wolfe-Simon published a widely publicized paper claiming that she had discovered a type of bacterium in Mono Lake, California that was capable of thriving in high-arsenic, low-phosphorus environments by replacing phosphorus with arsenic in the building blocks of its molecular structures. Phosphorus plays a critical role in the formation of DNA; indeed, the phosphate functional group is responsible for stringing together the genes that make up these basic strands of life. Theoretically, arsenic could fulfill phosphorus’s role in this process because, being in the same group as phosphorus on the periodic table, it needs the same number of electrons to be stable. Therefore, the heavier element makes similar bonds and forms a similar functional group to phosphate called arsenate. The only significant difference between the two is obviously that phosphorus is at the center of one while arsenic is at the center of the other.

Unfortunately, Wolfe-Simon’s results have not been reproduced, and she is still working to prove the validity of her study to the scientific community after being refuted multiple times. However, if she were successful in duplicating her results, her research would have sweeping implications in the search to determine if we are alone in the universe. As of now, we understand that six basic elements must be present for life to exist: carbon, hydrogen, oxygen, nitrogen, sulfur, and of course, phosphorus. If Wolfe-Simon’s bacterium truly did substitute one of these basic elements for another, then it would show that these six fundamental elements really are not necessary for anything. I mean to say, they still are for life on Earth, but that could only be a function of the evolutionary process finding them the most suitable for this environment and atmosphere. On a different world with a different set of rules, could life evolve using its own set of necessary elements? Sidenote: this same line of thinking applies to the theoretical concept of “silicon-based life,” the reasoning being that silicon is capable of bonding together form similar skeletal structures to the carbon skeletons for which many organic molecules are known. Generally, the problems seen in these types of theories are that arsenic and silicon have significantly more mass than phosphorus and carbon, respectively, so incorporating them into molecules make the molecules to heavy to be sustainable.

Anyway, that was a long explanation of a plausible scientific advancement for the near future (the confirmation of Wolfe-Simon’s results), but I just get really fired up thinking about another planet inhabited by a species of beings that could potentially be made of completely different matter than ourselves. The concept has just the right balance of plausibility and implausibility to be an excellent candidate for a science-fiction story, and such a story could provide the willing suspension of disbelief that is necessary not only for the appreciation of science-fiction, but for the continuation of the search for extraterrestrial life in today’s world. With the countless number of seemingly random factors that allowed for life to develop on Earth, it seems that another planet could not have possibly undergone a similar sequence of events. Maybe our world truly was subjected to a unique set of circumstances, but maybe another world reached a similar result without the same circumstances.

Hadley Wilson



§ One Response to A Different Rulebook for Life.

  • scifisean says:

    The idea of alternate biochemistries is long-discussed throughout the development of modern organic chemistry. I really appreciate how you tied chemistry to extra-terrestrials and the questions over their existence.
    But moving away from speculation, can we right now – on paper – devise an entire alternate biochemical system? Try it!



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