E-Letter responses to:

essays: Daniel E. Koshland Jr. SPECIAL ESSAY: The Seven Pillars of Life Science 2002; 295: 2215-2216 [Summary] [Full text] [PDF]

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Published E-Letter responses:

Reproduction Not for Regeneration

Anthony H. Notario   (16 May 2002)

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Muhammad Shahabuddin   (16 April 2002)

Reproduction Not for Regeneration 16 May 2002
Anthony H. Notario Respond to this E-Letter: Re: Reproduction Not for Regeneration	The author argues that reproduction is the ultimate regeneration of an organism -- the solution to the accumulated, and inevitable, effects of aging. However, degeneration and death due to aging is a process engineered to remove the adult population so it does not compete with successive generations for resources. Reproduction is actually a mechanism for adaptation. It is through the turnover of generations that mutation and natural selection can take place allowing a species to adapt to environmental change. The ability to fully regenerate itself (immortality), while allowing potentially unlimited life for an individual organism, is not a survival characteristic for the species as a whole. Such a characteristic is arguably detrimental to a species' survival.
Untitled 16 April 2002
Muhammad Shahabuddin, Research Scientist Center for Biologics Evaluation and Research, US Food and Drug Administration, Respond to this E-Letter: Re: this article	This article provides an excellent definition of life here on earth. There is a multiplication error in the 'Regeneration' section for the annual heart beat calculated for heart muscles of a normal human. The corrected numbers would be approximately 31.5 million times a year and 2.2 billion times a lifetime (approximately 70 years). It is amazing that a human heart is so durable.