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On the first day of class, we discussed multiple interpretations concerning the definition of evolution.  Some people described evolution as a random process, while others considered it an organisms’ “struggle to achieve perfection.”  Although I sensed strongly from other biology classes that the “struggle for perfection” was an inaccurate representation, I couldn’t articulate any counterpoint.  The answer didn’t occur to me until we were discussing the concept of observations last Thursday.  “Evolution does not maximize efficiency,” Professor Grobstein said.  Exactly, I thought.  While the rest of the class trailed off onto a new topic, my mind was still focused on that simple but accurate observation.  Here is an example that I think reinforces this observation.  Let’s think about plants.  Without getting dragged down in detail, there are two main categories of plants: C3 and C4 (the majority being C3).  C3 refers to the Calvin cycle (part of photosynthesis).  This cycle takes CO2 and with the help of an enzyme called Rubisco catalyzes it into sugar.  But the thing is, Rubisco is totally suboptimal for several reasons.  First, it works really slowly.  Second, it can catalyze in the opposite direction at the wrong temperatures.  When I first learned this I got really frustrated and confused.  Shouldn’t evolution have been able to correct for this inefficient enzyme?  Why hasn’t evolution been able to make this cycle more “perfect?”  But, as my teacher explained, although Rubisco is suboptimal, it just so happens to be the most abundant protein in the biosphere.  Meaning, plants have a lot of it and that allows the process to happen at an appropriate speed.  But even more importantly, (and what directly relates back to the discussion) photosynthetic organisms are doing just fine!  The process works well enough, there is no need to change it.  I just think that is a really important and also really cool aspect of Evolution.

~EB