WordNet (r) 3.0 (2006):

life cycle
    n 1: a series of stages through which an organism passes between
         recurrences of a primary stage
    2: the course of developmental changes in an organism from
       fertilized zygote to maturity when another zygote can be
       produced

Moby Thesaurus II by Grady Ward, 1.0:

45 Moby Thesaurus words for "life cycle":
   anima, animating force, atman, bathmism, beating heart,
   biological clock, biorhythm, blood, breath, breath of life,
   divine breath, divine spark, elan vital, essence of life,
   force of life, growth force, heart, heartbeat, heartblood,
   impulse of life, inspiriting force, jiva, jivatma, life breath,
   life essence, life force, life principle, life process, lifeblood,
   living force, pneuma, prana, seat of life, soul, spark of life,
   spirit, vis vitae, vis vitalis, vital energy, vital flame,
   vital fluid, vital force, vital principle, vital spark,
   vital spirit