" 

 ::::Why is neutrality particularly challenging at this point? What bias is left to eliminate after the edits we've made in the course of the last two weeks? Remaining on Petter's list is an account of the replacement of pelycosaurs by therapsids, which will require presentation of both the competitive and the opportunistic theories of replacement, but both can be explained using the neutral terms ""pelycosaur"" and ""therapsid"".   "