Aya hipotésis nu nyebutkeun yén kawatesna umur mangrupakeunmangrupa balukar tina [[évolusi]], sabab seléksi évolusionér ukur perlu nepi ka titik sawawa ([[baranahan]]); sanggeus éta, lian ti pikeun miara turunan, lumangsungna hirup téh pangaruhna leutik pisan kana kasalametan galur génna. Asumsi umum dina [[Hukum Kadua Térmodinamika]] nu nyebutkeun yén sistim kompléks must eventually deteriorate, so it is not likely that any species could ever be [[immortal]]. However, this aspect of the Second Law of Thermodynamics only applies to closed systems, which a living organism obviously is not.