James E. Lovelock and Lynn Margulis: is Gaia a living thing?
In this passage, British scientist James E. Lovelock defends the idea that Gaia is a living thing by comparing it to the trunk of a tree (which is alive, even though more than 90% of it consists of dead matter). Lovelock's basic argument--one not accepted by his detractors--is that the planetary environment on which contemporary life is based is a product of life itself. It was not the special planetary conditions on Earth that allowed the development of life, he claims, but life that caused the development and maintenance of conditions appropriate for life. The contributions of symbiologist Lynn Margulis to the symbiogenetic theory of the evolution of the eukaryotic cell by serial endosymbiosis on the primeval Earth have strengthened Lovelock's initial idea: that life and the environmental conditions in which it lives have coevolved.
"Living organisms are open systems in the sense that they take and excrete energy and matter. In theory, they are open as far as the bounds of the Universe; but they are also enclosed within a hierarchy of internal boundaries. As we move in towards the Earth from space, first we see the atmospheric boundary that encloses Gaia; then the borders of an ecosystem such as the forests; then the skin or bark of living animals and plants; further in are the cell membranes, and finally the nucleus of the cell and its DNA. If life is defined as a self-organizing system characterized by an actively sustained low entropy, then, viewed from outside each of these boundaries, what lies within is alive.
You may find it hard to swallow the notion that anything as large and apparently inanimate as the Earth is alive. Surely, you may say, the Earth is almost wholly rock and nearly all incandescent with heat. I am indebted to Jerome Rothstein, a physicist, for his enlightenment on this, and other things. In a thoughtful paper on the living Earth concept ..., he observed that the difficulty can be lessened if you let the image of a giant redwood tree enter your mind. The tree undoubtedly is alive, yet 99% [of it] is dead. The great tree is an ancient spire of dead wood, made of lignin and cellulose by the ancestors of the thin layer of living cells that go to constitute its bark. How like the Earth, and more so when we realize that many of the atoms of the rocks far down in the magma were once part of the ancestral life from which we all have come."
The Ages of Gaia
The Commonwealth Fund Book Program of Memorial Sloan-Kettering Cancer Center, New York (1988)
Reproduced with permission of Harold Ober Associates Incorporated
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|Publication:||Encyclopedia of the Biosphere|
|Date:||Nov 1, 2000|
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