Saturday, September 13, 2014

How Bacteria Relate to Memes

The last post suggested chemical signals used in quorum sensing by microbes could be labeled "chemical memes".  For some (maybe for you) this is stepping onto questionable ground.  These chemicals are derivatives of the genes--there is no line between genes and memes. And there should be a definite line...right?

There are many similar transitions in biology created by our need to catalogue and classify.  Where is the first human; how do we distinguish "first human" from "closely related hominid"?  The pursuit of that question is not as productive as "how did modern humans emerge from hominids?" or "how did modern humans survive while other hominids did not?".  Yet the pursuit of that first question is deeply engrained in our collective Western tradition.  Something seems incomplete without an answer, but this is a misleading sentiment.  Questions of origin are not evolutionary questions: Questions of development are.

When does a bacterial colony become a superorganism--or cease to be an independent organism?
Is the bacteria in our gut part of us, an individual organism or a colony inside us?  With microbial endocrinology we are learning it is not so easy to separate two species which have co-evolved quite so elegantly.  We are entwined.  But still, the distinction between species is useful in certain disciplines and as such, remains a useful tool, even if it is not wholly accurate from all perspectives.

Let's make a distinction then:   When chemical signals happen within an individual organism, it's a chemical signal triggered by genetic and environmental factors and is not a chemical meme.  When chemical signals are exchanged between two or more organisms, it's a chemical signal triggered by genetic and environmental factors and it is a chemical meme.  It is the transmission of information from one organism to another that makes the meme (this will be an important distinction later).

Continue to Comparison With Bacteria

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