in taxon capable of capable of existence ends during circulatory system process Acoelomorpha Bilateria Cnidaria Platyhelminthes Nematoda fully formed stage anatomical system circulatory system http://upload.wikimedia.org/wikipedia/commons/2/29/Circulatory_System_en.svg Anatomical system of ion binding, a pumping mechanism, and an efficient vascular system; consisting of the blood, heart, and blood and lymph vessels, respectively.[AAO] Organ system that passes nutrients (such as amino acids and electrolytes), gases, hormones, blood cells, etc. to and from cells in the body to help fight diseases and help stabilize body temperature and pH to maintain homeostasis[WP]. AAO:0000959 systema cardiovasculare the cardiovascular system and the lymphatic system are parts of the circulatory system MESH:D002319 VHOG:0001248 Wikipedia:Circulatory_system CALOHA:TS-2103 UBERON:0001009 We should divest ourselves of the view that earlier vertebrate groups were 'on their way' to becoming mammals, as clearly they were not such visionaries. Neither were their systems 'imperfect' as earlier anatomists thought. Instead, their circulatory systems served them well to address the ecological demands arising from their lifestyles.[well established][VHOG] nervous system gustatory system skeletal system musculoskeletal system biliary system exocrine system hematopoietic system immune system integumental system hepatobiliary system entire sense organ system excretory system