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Cell Life

By | November 2012
Page 1 of 3
Agelessness has three main drawbacks as a survival strategy. First, on a changing planet the problems and opportunities for living organisms vary over the years in unpredictable ways. Climate shifts, dry land becomes flooded, new predators evolve. Such unforseen threats can be answered only by providing opportunities for trial changes in the organism. These changes arise from sexual reproduction, which confers on the next generation a new assortment of genetic combinations and mutations. Among the offspring the failures die out, but those that succeed in the new environment survive to reproduce their better adapted genes. Second, ageless parents would compete for food and mates with their offspring, which would jeopardize the survival of future generations. A third drawback of agelessness is that living matter deteriorates. In particular, the genes are under the constant bombardment of background radiation from space, and the resulting damage accumulates over a period of years. The probability of birth defects in humans increases with the age of the mother. Exposure to 20 extra years of radiation distinguishes the 40-year old mother from the 20-year old, and often results in damaged genes and inferior offspring. A population of immortal mothers would give birth to an appalling number of deformed children and genetic misfits. There are still other factors that favor the evolution of senescence and death, which we shall discuss in the more detailed treatment of evolutionary theory.

We next explain the workings of multi-cellular organisms, beginning with development and growth: the journey from a one-celled fertilized egg to a mature organism consisting of from thousands to trillions of cells. The emphasis is on the diversity of systems that life has devised to propagate itself, to acquire raw materials and energy, to transport substances from one part of the organism to another, and to integrate and control its activities, including behavior....

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