In　distributed　sensor　networks,　which　have　limited　resources,　such　as　energy　and　storage,　and　work　in　a　dynamic　environment,　the　networks　should　effectively　allocate　some　real-time　tasks　on　those　limited　resources.　Additionally,　we　should　do　our　best　to　maximize　the　lifetime　of　wireless　sensor　networks　(WSNs)　and　the　accuracy　of　the　results.　Due　to　most　of　previous　works　focusing　on　static　task　allocation　for　WSNs　and　only　a　few　works　having　paid　attention　to　dynamic　resource　allocation　for　sensor　networks,　this　paper　present　an　effectively　adaptive　task　allocation　(EATA)　in　WSNs　which　applied　dynamic　alliance.　Instead　of　being　aid　of　manual　adjustment,　each　node　can　autonomously　adjust　its　parameters　and　state　by　means　of　EATA　according　to　tracking　the　change　of　environment,　such　as　energy　depletion.　By　comparing　with　static　task　allocation,　experiment　results　show　that　our　scheme　can　save　a　great　deal　of　energy　and　prolong　the　lifetime　of　the　network.　©　2010　IEEE.