From: Terry W. Colvin (fortean1@mindspring.com)
Date: Tue Sep 02 2003 - 17:42:50 MDT
Science Frontiers, No. 149, Sep-Oct, 2003, p. 2
< http://www.science-frontiers.com >
BIOLOGY
Life's Lethal Quality Control?
Cancer is such a deadly scourge of life that one wonders why it was not
strongly selected against and totally eliminated from all forms of life
long ago. Does cancer's eons-long persistence among a wide spectrum of
living things imply that it has some purpose---some positive value that
we are blind to?
In SF#30, back in 1983, it was observed that the incidence of cancer is
strongly correlated with the complexity of organisms. It would seem
therefore that cancer tends to damp out any tendency life has (or is
given) to attain higher states of diversity and complexity. Some even
hold that cancer is the price that must be paid by higher forms of life!
But there is much more to be said about the potential roles of cancer in
the development of human life.
It must be recognized that the bulk of human cancers occur in individuals
beyond the age of reproduction. If old-age cancer has an evolutionary
purpose, it might be simply the reduction of the drain nonproducing oldsters
place upon society.
One can also speculate as do A. Leroi and J. Graham that cancer is one of
evolution' methods of quality control. To be effective in this role,
cancer must affect individuals capable of reproduction---before they
reproduce. However, there are only a few lethal childhood cancers
specifically associated with additions to human biological diversity. Two
such examples are: brain cancer and bone cancer.
These are interesting observations, but they alone can hardly account for
the strong correlation between cancer incidence and complexity.
J. Graham goes much further in his 1992 book _Cancer Selection_. There, he
claims that cancer is *the* driving force in the creation of biological
diversity. In other words, living things tend to evolve features that
reduce the incidence of cancer. One of the examples Graham proposes is
the evolution of shells by snails to protect themselves from cancer-inducing
solar ultraviolet light. His book contains many more examples.
(Watts, Geoff; "Life's Lethal Quality Control," *The Times Higher Education
Supplement*, April 11, 2003. Cr. J. Graham.)
Comment. Since cancer has survived the filtering action of natural
selection for hundreds of millions of years and attacks so many organs
in so many diverse species, we wonder if it has a single, simplistic
explanation.
-- “Only a zit on the wart on the heinie of progress.” Copyright 1992, Frank Rice Terry W. Colvin, Sierra Vista, Arizona (USA) < fortean1@mindspring.com > Alternate: < fortean1@msn.com > Home Page: < http://www.geocities.com/Area51/Stargate/8958/index.html > Sites: * Fortean Times * Mystic's Haven * TLCB * U.S. Message Text Formatting (USMTF) Program ------------ Member: Thailand-Laos-Cambodia Brotherhood (TLCB) Mailing List TLCB Web Site: < http://www.tlc-brotherhood.org >[Vietnam veterans, Allies, CIA/NSA, and "steenkeen" contractors are welcome.]
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