The Life Cycle, Longevity, and Aging

  • Ralph Wichterman


Over a century ago, Ehrengerg (1838) came to the conclusion that the protozoa are potentially immortal. Later, Weismann (1891) stated that the protoplasm or cells of a metazoan animal could be classified into two groups, namely, the body or somatic protoplasm and the germinal protoplasm. He proposed the idea that the former is mortal but the germinal protoplasm is potentially immortal. Weismann contended that old age and natural death are penalties demanded of the metazoa, including man, because of their specialization and differentiation into somatic and germinal protoplasm, whereas the protozoa, without this protoplasmic specialization, are potentially immortal like the germ cells.


Sexual Process Fission Rate Isolation Line Clonal Aging Metazoan Animal 
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Copyright information

© Plenum Press, New York 1986

Authors and Affiliations

  • Ralph Wichterman
    • 1
    • 2
  1. 1.Temple UniversityPhiladelphiaUSA
  2. 2.Marine Biological LaboratoryWoods HoleUSA

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