CONSERVATION VS DE-EXTINCTION. “We protect endangered species, conservationists retort (and most of the public agrees), in order to preserve the richest biodiversity we can, to retain creatures that have important ecological roles, or that people love … All those reasons apply to bringing back extinct species, plus some.”
http://e360.yale.edu/feature/the_case_for_de-extinction_why_we_should_bring_back_the_woolly_mammoth/2721/