"Under these doctrines, patentability is specific to the particular art in which the invention is made. Thus courts measure patentability against a benchmark that varies by industry and by technology. There is overwhelming evidence that the results vary by industry, leading for example to fewer, but broader, valid software patents and more, but narrower, biotechnology patents."
Source: http://www.law.com/jsp/nlj/PubArticleNLJ.jsp?id=1202430534638&Dont_tailor_make_patent_act&slreturn=1