Life Cycle (also called Life History) is the developmental history of an organism.  Often, it refers to the sexual life cycle (gametes to zygote to development of other stages that produce gametes).  However, many organisms do not experience sexual reproduction, and those that do sometimes have asexual or vegetative stages.

Life cycle of Schistosoma

from Barnes, R. D. 1980. Invertebrate Zoology. Saunders College, Philadelphia.