Evolution is junk science and as junk science goes, a spectacularly pernicious and dangerous flavor of it. Evolution was the philosophical corner stone of Nazism and Communism and the various eugenics movements. Worse, despite its having been thoroughly debunked over the last 100 years, its adherents still dominate discussions of it by sheer weight of numbers and decibel level.
You even see that on conservative forums like FR and in fact the argument you generally see is "Hey, you're making all of us (conservatives) look like kooks (by saying anything about evolution) and, funny thing, evolutionism appears to transcend left/right barriers. The evolutionist postings you see on FR or the Limbaugh or Coulter forums are basically indistinguishable from those you'd see on DU or anything else like that.
Sorry, I was addressing your concern about evil and its existence in our world.
It must have a purpose.