▁main ▁focus ▁of ▁system ▁theories ▁in ▁the ▁si xt ies , ▁as ▁convey ed ▁by ▁Julian ▁Ste ward , ▁was ▁acknowled gment ▁of ▁rec urrence , ▁cultural ▁patterns ▁or ▁" la ws ." ▁Ste ward ' s ▁e colog ical ▁anth rop ology ▁was ▁based ▁on ▁top ography , ▁climate , ▁and ▁resources ▁and ▁their ▁access ibility ▁to ▁define ▁culture . ▁While ▁Mar vin ▁Harris ' ▁cultural ▁material ism ▁observed ▁and ▁g aug ed ▁social ▁units ▁by ▁means ▁of ▁material ▁production . ▁Both ▁focused ▁on ▁culture ▁as ▁a ▁m alle able ▁cont ing ent ▁to ▁the ▁environment ; ▁a ▁social ▁unit ' s ▁characteristics ▁( techn ology , ▁politics , ▁modes ▁of ▁subs istence , ▁to ▁name ▁a ▁few ) ▁have ▁adapt ive ▁limitations . ▁Import antly , ▁those ▁limitations ▁are ▁not ▁considered ▁determin ants . ▁ ▁D iversity , ▁history ▁and ▁associations ▁ ▁The ▁new ▁focus ▁of ▁environmental ▁anth rop ology ▁was ▁cultural ▁variation ▁and ▁divers ity . ▁Such ▁factors ▁like ▁environmental ▁dis aster s ▁( f lo ods , ▁earth qu akes , ▁fro st ), ▁migr ations , ▁cost ▁& ▁benefit ▁ratio , ▁contact / ▁associations , ▁external ▁ideas ▁( tra de / ▁lat ent ▁capital ism ▁bo om ), ▁along ▁with ▁internal , ▁independent ▁logic ▁and ▁inter - connect ivity ' s ▁impact ▁now ▁were ▁observed . ▁Roy ▁A . ▁R app ap ort ▁and ▁Haw kes , ▁Hill , ▁and ▁O ' Con nell ' s ▁use ▁of ▁Py ke ' s ▁optimal ▁for aging ▁theory ▁for ▁the