As we are so often reminded by proponents of [Intelligent Design](http://www.ncseweb.org/resources/articles/996_intelligent_design_not_accep_9_10_2002.asp) creationism, we contain molecular "machines" and "motors". They don't really explain how these motors came to be other than to foist the problem off on some invisible unspecified Designer, which is a poor way to do science—it's more of a way to make excuses to _not_ do science.
Evolution, on the other hand, provides a useful framework for trying to address the problem of the origin of molecular motors. We have a theory—[common descent](http://www.talkorigins.org/origins/outline.html#evidence)—that makes specific predictions—that there will be a [nested hierarchy](http://www.talkorigins.org/faqs/comdesc/CDhierarchy.html) of differences between motors in different species. Phylogenetic analysis of variations between species allows us to reconstruct the history of a molecule with far more specificity than "Sometime [between 6,000 and 4 billion years ago](http://www.talkorigins.org/faqs/johnson.html), a [god or aliens](http://skepdic.com/intelligentdesign.html) (or aliens created by a god) conjured this molecule into existence by unknown and unknowable means".
Richards and Cavalier-Smith (2005) have applied tested biological techniques to a specific motor molecule, [myosin](http://www.mrc-lmb.cam.ac.uk/myosin/myosin.html), and have used that information to assemble a picture of the phylogenetic history of eukaryotes.
**Continue reading** ["Evolving motors" (on Pharyngula)](http://pharyngula.org/index/weblog/comments/evolving_motors/)