The Gaia hypothesis: A scienctific theory?

Gaia Hypothesis is a step to becoming a scientific theory

Author: Yih Shin, Ker (BEM)

The name Gaia is the name of an ancient Greek earth goddess. This goddess was at once gentle, feminine, and nurturing, but also ruthlessly cruel to any who failed to live in harmony with the planet. This name was then used appropriately for the new hypothesis, which appear in the late 1960s. What exactly is the Gaia hypothesis? As James Lovelock defined it “a complex entity involving the Earth's biosphere, atmosphere, oceans, and soil; the totality constituting a feedback or cybernetic system which seeks an optimal physical and chemical environment for life on this planet.” (Lovelock, J 1974) in simpler terms, biological responses tend to regulate the state of the Earth's environment in their favor. Many scientists criticize the Gaia hypothesis for being Teleology, a belief that all things have a predetermined purpose. We will discuss whether Gaia hypothesis qualifies as a scientific theory, the structure of a scientific theory and the brief history of the Gaia hypothesis.

In the early 1960’s James Lovelock was invited by NASA to participate in the scientific research for evidence of life in mars. This led him to think about what is life, how can life be detected. “The earth is bounded on the outside by space with which it exchanges energy and sunlight coming in and heat matter going out.” (Lovelock, 1991). He decided that the general characteristic of life was that it takes in energy and matter and discard waste products. All living things exhibit low entropy; therefore he could detect the atmosphere in Mars and show evidence that the planet is dead. Mars atmosphere like Venus consist of 95% carbon dioxide, with some oxygen and no methane. Comparing these planets, Earth was 77% nitrogen, 21%oxygen and methane. As a result Planet Mars was proven to be chemically dead. “The Earth's atmosphere was an extraordinary and unstable mixture of gases, yet I knew that it was constant in composition over quite long periods of time. Could it be that life on Earth not only made the atmosphere, but also regulated it - keeping it at a constant composition, and at a level favorable for organisms?" (Lovelock, J. 1991) Lovelock suggested that the life on earth interacts to regulate its internal environment to maintain a stable condition on earth, which the system is called the homeostatic feedback. This system operates unconsciously by the biota, controlling or stabilizing the earth global temperatures. James Lovelock explains the basic principles of control theory by using the iron in a thermostat that is used to act like a kind of thermometer “a metallic strip that is straight when cold, bends into a curve when heated, the sharpness of the curve increases as the temperature rises.” (Lovelock, J 1991) when the iron heats up, the strip bends with one end of it separates and pulls away the electrical contact until it cools down again. This is a simple example of self-regulating system that James Lovelock trying to explain. “A control system automatically regulates a condition such as temperature through a series of connected functions.” (Lovelock, J 1991) this also applies to living organism and the earth itself. The earth regulates itself to maintain favorable living conditions for living organism.

With ideas of the earth regulating its self, some took that idea to say the earth was acting with a sense of purpose, which is being a Teleology being. Teleology (from the Greek word teleos) declares that there is a purpose behind the mechanism of nature. However this was not what he meant. He stated that “Neither Lynn Margulis nor I have ever proposed that planetary self-regulation is purposeful ... Yet we have met persistent, almost dogmatic, criticism that our hypothesis is teleological.” (Lovelocks, J1991)

Criticism by Richard Dawkins and Ford Doolittle states that there is no way that the diverse living organisms of the earth could act in to their mutual advantages to regulate the whole planet. “There is no way that the diverse living organisms of the earth could act in symbiosis to regulate the planetary environment. Evolution by Natural Selection, they say, would always been in favour of the genes.” (Lovelock, J 1991). These criticisms made James Lovelock realized that he had been thinking intuitively instead of rationally about Gaia and the need of proper explanations to this hypothesis was lacking. In 1983 Lovelock created a scientific model that he calls it “daisy world”. Daisy world is a simple computer model planet, which grew only two species of organisms, dark and light coloured daisies. “Imagine that, just like the sun, Daisyworld ‘s star warms up as it evolves. Would the evolution of the Daisyworld ecosystem lead to the self-regulation of climate?” (Lovelock, J 1991). The Daisyworld model demonstrates the principle of self-regulation and also the answers to criticism by biologist. This simple experiment proves to scientist that Gaia can regulate without consciousness being involved. The science of Daisyworld planet is not difficult to comprehend, light daisies tend to reflect light, which cooling effect takes place, while dark ones absorb heat, and as a result the planet is warmed. Lovelock used real dynamics of real daisy growth in his model; therefore the growth of these daisies on the Daisyworld depends on the natural death rate of the daisies, space that is available, temperature that suits the growth of daisy and the present population. The planet revolves around a sun, from which it absorbs energy at a rate, which depends on the sun's shine and it also emit heat out to space. The redwood tree analogy where James Lovelock considers it one of the most helpful analogies used for explaining the Gaia hypothesis. In 1985 James Lovelock met American physicist, Jerome Rothstien at a meeting hosted by the Audubon Society. The meeting was called “Is the Earth a Living Organism?”. Rothstien proposed that the redwood tree is the closest to Gaia. Sequoia gigantea or else known as the redwood tree, they stand in groves on the west coast of America, the oldest tree that was calculated from it annular rings was 3000 years old. “Extraordinary thing about each of these trees is that more than 97per cent is dead. The wood that is the solid spire is dead, the thick bark around the tree is dead. The only live part is a thin circumferential layer of living cells that enfolds the wood and lies beneath the bark.” (Lovelock, J 1991) Another tiny fraction of life that is on the tree is the leaves, the flowers and the seeds. Gaia is made up of a massive amount of dead matter with a tiny fraction of living organisms beneath the thin layer of atmosphere, thus the red wood tree is similar to Gaia. The thin circumferential skin living cell also known as cambium keeps the tree alive and growing, earth act the similar way which is made up of living organisms. Living organisms on earth produces nitrogen, oxygen, carbon dioxide, methane and most of the gases in the air except for 1 per cent of xenon, neon argon, krypton and helium. “Like the bark, which is grown for the protection and sustenance of the living cells of the tree, the air has grown in composition so that it always sustain a favourable climate and a favourable chemical environment for life.” (Lovelock, J 1991)

“The difference between a scientific theory and an idea of philosophy or a religion is that a scientific theory can be tested”(Sherlock .R). A scientific theory is a generally accepted explanation of a scientific concept. It began as a hypothesis or an educated guess. Then experiments are carried out, failures, successes and breakthrough made the concepts developed, new understanding expand and the theory then is now a field of study. The term hypothesis is defined as a provisional theory that has not yet been tested. The Gaia Hypothesis based its concepts on science where Lovelock explains this theory by using the Daisyworld model experiment and not only that; it is used to prove to other scientist regarding the existence of feedback mechanisms. The experiment also shows that it was possible the control of the worldwide biomass could take place without awareness being involved. Using just that model experiment Lovelock still unable to declare that the Gaia Hypothesis is now a scientific theory but on its development on becoming a stronger set of theory. Does the Gaia hypothesis qualifies as a scientific theory? “Lovelock and Margulis's understanding of Gaia are considered valid scientific theories, and are now a part of biology proper.”(Wikipedia, 2004) the hypothesis they considered as a valid scientific theory from a different point of view. The hypothesis had led to the new science called biogeography or even geophysiology. This is a study of the interactions between the biota, the atmosphere and the oceans. Gaia hypothesis is appropriate to describe as a scientific theory in different point of view and different aspects of study.

The search for life in mars influenced James Lovelock to define life in a different point of view. The Gaia Hypothesis was born in the late 1960’s, Gaia a term that James Lovelock used to described planet earth, regulates itself to maintain suitable conditions for life unconsciously. Daisyworld planet mathematical model created by James Lovelock is used to refute criticism and explaining the hypothesis. Gaia Hypothesis based on the scientific concepts and is widely accepted by the scientific community. The Gaia hypothesis qualifies as a scientific theory in the study of geo-physiology and different point of aspect of study.