The Reproductive Imperative 2
..everything in a living thing is centred upon reproduction. A bacterium, an amoeba, a fern - what destiny can they dream of other than forming two bacteria, two amoeba, two ferns? If there are living beings on earth today, it is because other beings have reproduced with desperate eagerness for 2000 million years or more. Let us imagine ... the establishment of systems possessing certain properties of life, such as the ability to react to stimuli, to assimilate, to breathe, even to grow - but not to reproduce. Can they be called living systems? ..if on the other hand, there emerges a system capable of reproduction, ... that is a living system without any doubt. It will spread wherever conditions permit. The more it spreads, the greater its protection from catastrophe... In such a system, reproduction, which is the cause of existence, also becomes its purpose. It is doomed to reproduce or disappear.
It is death that brings about a requirement to 'reproduce or disappear'. It is only because the creatures die, by ageing, by accident, or through disease, that they must reproduce. If there was no death, there would be no reproduction. A population of creatures whose members age and die will dwindle to zero unless they are able to - at mininum - replace lost members with new ones. Where the creatures to be immortal, no members would be lost, and no new members would be needed to replace them. It is death, not reproduction, which is the primary characteristic of life - that the creatures grow, move, and reproduce for a brief period before dying. Some creatures grow, and some move, and some reproduce - but all of them ultimately die.
Far from it being that reproduction protects the creatures from the catastrophe of extinction, instead it is this reproduction which is the main threat to their continued existence. Reproduction, it could be said, is the mistake that the creatures make. The dream of the amoeba was its undoing. If the first primitive creatures that appeared in some primeval soup had desisted from reproduction, both they and the soup would still be here. Instead, as they multiplied they consumed the soup, and they died en masse when it was exhausted. If it is said that if there had been no such reproduction there would have been no evolution, then it must be asked: Why should there be any evolution?
It seems entirely plausible that there could be creatures which react to stimuli, assimilate, breathe, grow - but do not reproduce. Or at least reproduce at such a slow rate so as to simply replace those who succumb to death, maintaining a constant population. If such creatures lived for several millenia, and reproduced once in that interval, they would at least appear to human eyes to be non-reproducers, because it would require close observation for several millenia to determine that they actually did reproduce. Simply counting the numbers of such creatures would not show this reproduction, because the population would remain constant, with as many being born as died. Such creatures would be regarded, at least by those biologists for whom life is essentially reproduction, as not alive.
All reproduction involves division. A cell divides in two - mitosis - to produce two cells, or into four - meiosis - as a prelude to sexual reproduction. Now if a stone were to break in two, through the action of diurnal thermal expansion and fracture, and each daughter stone in turn divided in two, then the number of stones would increase first from one to two, and then from two to four, and so on. Here would be a form of mitosis. The population of stones would gradually increase. It is of no account that each generation of stones is smaller in size than the previous one: here is reproduction. The stones reproduce, therefore they are a form of life. If anyone complains that these stones evince no sign of metabolism or movement, it need only be pointed out that they swell in size as their temperature rises during the day, and shrink as it falls at night. They breathe, inducting and expending energy. Biologists would conclude that these stones were a form of life.
But if life is seen as primarily maintaining itself, not reproducing, these stones would not be seen as a form of life. For such stones do not act to maintain their integrity. When fractured, they do not heal themselves. Their division, or reproduction, demonstrates that they do not maintain themselves, but fall apart.
One reason, and probably the main reason, that Lovelock's Gaia hypothesis is unacceptable to biologists is that Gaia does not reproduce. The planet, this great stone, does not periodically divide into two daughters. Lovelock's propensity to refer to Gaia as 'she' may outrage them because for them this implies a reproductive capability, while Lovelock's Gaia instead shows maternal care, motherly love. Lovelock's Gaia acts to maintain a stable climate. In Lovelock's Daisyworld, heat-absorbing black daisies multiply to warm up the planet when solar radiation levels fall, and heat-reflecting white daisies become predominant when solar radiation rises, the two kinds of daisies acting to maintain, as far as is possible, a stable temperature. Lovelock's Gaia is non-reproducing, but self-maintaining. Lovelock's own definition of life, after failing to find any in biology, or adequate dictionary definitions, gives priority to self-maintenance:
Living things such as trees and horses and even bacteria can easily be perceived and recognized because they are bounded by walls, membranes, skin, or waxy coverings. Using energy directly from the Sun and indirectly from food, living systems incessantly act to maintain their identity, their integrity. Even as they grow and change, grow and reproduce, we do not lose track of them as visible, recognizable entities... When any individual fails to get energy and food, fails to act to maintain its identity, we recognize it as moribund or dead.
What a contrast this is with the quotation from Francois Jacob at the start of this essay. For Lovelock, life is essentially self-maintenance. It is powered, ultimately, by the energy of solar radiation. Without energy, unable to maintain itself, it dies. This is precisely the understanding of life that underpins Idle Theory. The only difference is that Idle life is always alternating between an inactive state and an active state during which it acquires the energy to maintain itself. For Lovelock, and in Idle Theory, reproduction is secondary.
There is a profound collision hidden here. Underlying this collision is the introduction of physics into biology. Lovelock is a physicist, familiar with concepts of energy and entropy. The biologists, by contrast, have historically been watching bacteria, and amoeba, and ferns multiplying. For Lovelock, and many others, life is all about energy. For biologists, it's all about reproduction.
I know that biologists insist that being alive implies the ability to reproduce and to correct errors of reproduction by natural selection. Should anything as significant as life be the sole property of a single discipline of science?
At present, the reproductive imperative of the biologists remains the orthodoxy. Selfish genes reproduce to produce more selfish genes, and Lovelock's recognizable entities are merely lumbering gene-carriers. Life remains the sole property of the discipline of biology. How much longer will this orthodoxy survive?
Author: Chris Davis
Last edited: 11 April 1998