phenotype affects entity obsolete animal organ senescence organ system development variant organ system morphology variant organ system physiology phenotype aging variant organ senescence variant WBPhenotype:0001740 C_elegans_phenotype_ontology organ senescence abnormal Any variation in the preprogrammed process that occurs in an organism that is associated with the dismantling of an organ and an overall decline in metabolic function compared to control animals. This may include variations in the rate or extent of morphological disarray and of the breakdown or organelles, membranes and other cellular components.