In regards to aging, one should note that the germ lines do not exhibit any characteristics of aging nor do hydras show signs of aging, although they eventually die.
Irrespective of the fact that all things must die, why do most organisms age while some specices have seemingly eluded evolution?
References:
Kirkwood article in Nature volume 408
Martinez, Mortality patterns suggest lack of senescence in Hydra,
Experimental Gerontology, vol 33
Edited by albertng, : No reason given.