2012, Day 172 - Toothy

Evolution is a strange beast.  Why is it that cacti have spines?  To keep predators from their rich  reservoirs of water presumably.  Why then do some lack such protection?  Do they have a bitter taste?  Perhaps they harbor a vicious guest within their folds.  A territorial arachnid or a jealous bird possibly.  Then you look at plants like the one pictured.  New growth starts small at the center and as it ages is pushed further away until it eventually withers at the ground.  It is a striking similarity to the teeth of sharks that are produced ad infinitum and constantly grow from the inside out, shedding with time and being replaced by new sharp pristine teeth.  It is reassuring to know that evolution recycles good ideas too...

Canon 5D Mark III, Canon 100/f2.8L IS
100mm, f8, 1/400 sec @ 400 ISO