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Cosmotheist
Thursday, December 30th, 2004, 05:59 AM
http://www.gaianet.fsbusiness.co.uk/gaiatheory.html
In the early 1960's, James Lovelock was invited by NASA to participate in the scientific research for evidence of life on Mars. His job was to design instruments, capable of detecting the presence of life, which could be sent on a spacecraft to Mars. This wasn't straightforward, since it was hard to know what to test for: any life forms on Mars may be radically different from those on Earth.
It was life processes, the cumulative actions of countless organisms, that were controlling the atmosphere. And viewed from outer space, the mass effect of these processes was that the Earth itself appeared as a living entity - especially in comparison with its dead neighbours. Lovelock had a sudden realisation that the Earth could best be described as a kind of super-organism:

"For me, the personal revelation of Gaia came quite suddenly - like a flash of enlightenment. I was in a small room on the top floor of a building at the Jet Propulsion Laboratory in Pasadena, California. It was the autumn of 1965 ... and I was talking with a colleague, Dian Hitchcock, about a paper we were preparing ... It was at that moment that I glimpsed Gaia. An awesome thought came to me. 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 favourable for organisms?" (1991)

PassionOfTheSerpent
Thursday, December 30th, 2004, 02:16 PM
Clearly the most interesting thing I've read today.

Sappho
Friday, December 31st, 2004, 05:19 AM
Gaia is obviously alive. People knew this many thousands of years past. I speak especially of the wise women and Goddess worshippers. What these men think they are "discovering" was obvious to those who worshipped Gaia long ago. Interesting article, I must say.

Dr. Solar Wolff
Monday, February 28th, 2005, 07:19 AM
Gaia approaches Truth more than most other scientific idea or religious idea. In fact, it really combines the two. My biggest criticism is the name he chose, Gaia. You know, we have a mother goddess in the Germanic tradition, of which Lovejoy was a part, since he is English, called Erde. Erde is the goddess of earth.

The Gaia hypothesis makes me somewhat suspicious of global warming as a long term threat.

PsycholgclMishap
Tuesday, September 6th, 2005, 07:31 AM
In 1965, J.E. Lovelock published the first scientific paper suggesting the Gaia hypothesis. The Gaia hypothesis states that the temperature and composition of the Earth's surface are actively controlled by life on the planet. It suggests that if changes in the gas composition, temperature or oxidation state of the Earth are caused by extraterrestial, biological, geological, or other disturbances, life responds to these changes by modifying the abiotic environment through growth and metabolism. In simplier terms, biological responses tend to regulate the state of the Earth's environment in their favor.

SOURCE: The Gaia Hypothesis (http://www.physicalgeography.net/fundamentals/5d.html)

Various links on the theory:
http://www.oceansonline.com/gaiaho.htm
http://www.gaianet.fsbusiness.co.uk/gaiatheory.html
http://www.ozi.com/ourplanet/gaia.html

I happened upon this theory some time ago but recent catastrophic news made me rehash my thoughts on the subject. The theory completely makes sense to me and may support not-so-PC arguments currently in discussion.

Supposing this theory is truth, Mother Earth is currently aware of her horrible state and is attempting to purify herself of the largest problems where they will "hurt" the most.

What are your thoughts on this subject?

Death and the Sun
Tuesday, September 6th, 2005, 09:58 AM
Some people who completely misunderstand the Gaia hypothesis have given it a bad reputation. You see, they suggest that the Earth is somehow is a conscious organism that actively regulates human activity, or that "Mother Earth" is an actual entity that is taking her revenge on us.

In addition to being silly, these theories are also empirically false: if the planet was somehow alive and wanted to take us out, it could, and would, have done so long ago.

What is true is that all ecopsystems are finely tuned systems, and you can't mess with them forever without some kind of repercussions. Rapid climate change will produce extreme weather, that is obvious.

PsycholgclMishap
Tuesday, September 6th, 2005, 04:12 PM
Some people who completely misunderstand the Gaia hypothesis have given it a bad reputation. You see, they suggest that the Earth is somehow is a conscious organism that actively regulates human activity, or that "Mother Earth" is an actual entity that is taking her revenge on us.

In addition to being silly, these theories are also empirically false: if the planet was somehow alive and wanted to take us out, it could, and would, have done so long ago.

What is true is that all ecopsystems are finely tuned systems, and you can't mess with them forever without some kind of repercussions. Rapid climate change will produce extreme weather, that is obvious.
Earth IS a living, breathing concious organism in more than one sense. What we do to our planet is directly effective to the deterioration of the Ozone layer, extinction of species and a number of other hindrances. Our Earth is reactive to our choices.

It is not a matter of Earth "want[ing] to take us out" -- it's a matter of Earth surviving the wrath of humankind.

Ethelwulf
Wednesday, September 7th, 2005, 12:02 AM
Isaac Asimov wrote on this, starting in "Foundation's Edge".

(Skip the next paragraph if you don't want any spoilers).

Now, I don't know if it was his intent to make the planet Gaia, a completely pansentient being (with all life on the planet sharing one consciousness and thus considering themselves each "Gaia"), the home from which the Mule came, and the cause of his amazing capabilites, the center of it all along from the very beginning, or if he decided to integrate this into the story along the way.

Anyway, my thoughts mirror Eldritch's. It is a primary rule in biology that all living organisms seek to live (iow, be living organisms). So, when something is threatening that existence, it does try to work to prevent that (just as we see, in man. A lot of social issues would be explained much clearer if they were brought back to this rudimentary level). However, sometimes the elements, the changes, are too much for the organism to live.

The earth is just like nature, it doesn't really have a will or a bias. We are killing ourselves, it isn't killing us. The stasis that humanity has been involved with, congruently with the other forms of life that keep us alive and that we have helped keep alive, has been dwindling. But the earth would still be around if we all died, as well as a number of other organisms. And there would most likely still be a number of humans still around, who would then have to undergo a number of hardships and transformations just to make it.

The living organisms in the arctic surely are trying as best they can, to deal with the depletion of the artic ice (55+ percent in 50 years gone, i believe is the figure), but not much that arctic life can do about making it colder. That is something that they aren't really able to make happen.

As an example, I've seen footage of Crocodiles in Asia, that die due to extreme heat and drought. The crocodile and other animals are aware of what is happening, but can't do much to prevent it. When drought comes, the rivers turn to mud, and a crocodile will go into the mud, cover himself in it as best he can to retain moisture, or hid in a hole somewhere, but sometimes the elements are simply too strong and prevail over that will.

So, there is definitely a desire for all life to keep living. However, some things can get so out of hand that it overwhelms that drive. In the case of earth, things undoubtedly attempt to thrive as best they can, but in the situation today, things can be occurring so fast that the natural evolution is no longer able to keep up with the social evolution that is ocurring.

PsycholgclMishap
Wednesday, September 7th, 2005, 12:23 AM
That is true but Earth IS a conglomeration of living organisms (more popularly referred to as Nature) and living organisms could not exist as they do on Earth without her.

Mammals, fish, plants and other living organisms come from Earth. Earth is a macrocosm of living things so in that is living itself. Existence as we know it would not be if it were not for Earth, the Gaia.

Ethelwulf
Wednesday, September 7th, 2005, 12:33 AM
I'm not disputing that.

Siegfried
Wednesday, September 7th, 2005, 11:32 AM
The Earth and its biosphere are an emergent, self-organizing system. To what degree the biosphere has a collective consciousness, is debatable, but I am absolutely convinced it is less concrete than the human mind.

PsycholgclMishap
Wednesday, September 7th, 2005, 03:09 PM
The Earth and its biosphere are an emergent, self-organizing system. To what degree the biosphere has a collective consciousness, is debatable, but I am absolutely convinced it is less concrete than the human mind.
That may be better way of phrasing it. ;)

Siegfried
Wednesday, September 7th, 2005, 04:02 PM
That may be better way of phrasing it. ;)

Thank you ;) Nice links, by the way.

Death and the Sun
Wednesday, September 7th, 2005, 05:42 PM
Earth IS a living, breathing concious organism in more than one sense. What we do to our planet is directly effective to the deterioration of the Ozone layer, extinction of species and a number of other hindrances. Our Earth is reactive to our choices.

It is not a matter of Earth "want[ing] to take us out" -- it's a matter of Earth surviving the wrath of humankind.

Please, the Earth is basically a ball of rock and dust. The thin biospehere on its surface is totally insignificant on the larger scheme of things. The Earth is not a living organism, any more than a stone with some lichen that dwell on its surface is an organism.


The Earth and its biosphere are an emergent, self-organizing system. To what degree the biosphere has a collective consciousness, is debatable, but I am absolutely convinced it is less concrete than the human mind.

A simple self-regulating system cannot be said to be alive without further evidence of consciousness.

Siegfried
Wednesday, September 7th, 2005, 06:17 PM
The Earth is not a living organism, any more than a stone with some lichen that dwell on its surface is an organism.

I disagree. The biosphere is a very complex web of interdependent species and races, it is far more than 'some lichen'. The interaction between the organisms that make up the biosphere gives rise to a higher level order, an emergent, self-organising system. It is obviously not at the same level of organisation as an ant (let alone a human), but it does bear similarity to an ant hill. In case you didn't know, an ant hill displays a collective life cycle and astonishing feats of internal self-organisation. Whether or not that's enough to consider the ant hill collectively as an organism is debatable. In any case it's a difference of degree, not of nature.

PsycholgclMishap
Wednesday, September 7th, 2005, 07:08 PM
Please, the Earth is basically a ball of rock and dust. The thin biospehere on its surface is totally insignificant on the larger scheme of things. The Earth is not a living organism, any more than a stone with some lichen that dwell on its surface is an organism.
Lava, plants, water, etc. are all part of Earth. Earth is a macrocosm of living organisms. Life does not exist without it. Earth sustains life.


A simple self-regulating system cannot be said to be alive without further evidence of consciousness.
False. A sea cucumber has no conciousness but it is alive and maintains itself, so do many microscopic organisms.

PsycholgclMishap
Wednesday, September 7th, 2005, 07:09 PM
I disagree. The biosphere is a very complex web of interdependent species and races, it is far more than 'some lichen'. The interaction between the organisms that make up the biosphere gives rise to a higher level order, an emergent, self-organising system. It is obviously not at the same level of organisation as an ant (let alone a human), but it does bear similarity to an ant hill. In case you didn't know, an ant hill displays a collective life cycle and astonishing feats of internal self-organisation. Whether or not that's enough to consider the ant hill collectively as an organism is debatable. In any case it's a difference of degree, not of nature.
Agreed! We would not exist without Earth, period!

Death and the Sun
Thursday, September 8th, 2005, 08:52 AM
I disagree. The biosphere is a very complex web of interdependent species and races, it is far more than 'some lichen'. The interaction between the organisms that make up the biosphere gives rise to a higher level order, an emergent, self-organising system.

Yes, but that does not make the planet Earth a living organism. The biospehere evolved around the earth and adapted to the conditions that exist here, the earth did not create it. Mind you I'm not debating that the earth's ecosystem is a self-regulating system.


It is obviously not at the same level of organisation as an ant (let alone a human), but it does bear similarity to an ant hill. In case you didn't know, an ant hill displays a collective life cycle and astonishing feats of internal self-organisation. Whether or not that's enough to consider the ant hill collectively as an organism is debatable. In any case it's a difference of degree, not of nature.

As a child I was fascinated with ants and would spend hours watching them, and later read quite a lot about them, so yes I am aware of all this. To be honest I'm not sure what the generally accepted definition of an "organism" is, but I suspect that an anthill would not qualify. What is obviously true is that a single ant would not survive without its mates, anymore than a single species would survive without all the other animal and plant species that inhabit its ecosystem.

False. A sea cucumber has no conciousness but it is alive and maintains itself, so do many microscopic organisms.

You are going about this ass-backwards.

I said a self-regulating system is not alive, unless there is other evidence of life or consciousness. I never said consciousness is a requisite of life. A sea cucumber may not have consciousness, but is unquestionable alive because it display other characteristics of living creatures.

Siegfried
Thursday, September 8th, 2005, 10:01 AM
As a child I was fascinated with ants and would spend hours watching them, and later read quite a lot about them, so yes I am aware of all this.

Then you probably know more about ants then I do. :)

To be honest I'm not sure what the generally accepted definition of an "organism"

This is what the American Heritage Dictionary says about 'organism':

An individual form of life, such as a plant, animal, bacterium, protist, or fungus; a body made up of organs, organelles, or other parts that work together to carry on the various processes of life.

In any case, an organism is a biological, self-organising system. That's what I meant when I said the difference between a 'regular' organism and an ant hill is one "of degree, not of nature".

Siegfried
Thursday, September 8th, 2005, 01:45 PM
There was a discussion on Blut und Boden about the Gaia hypothesis. PsycholgclMishap posted some links on the theory, which I shall reproduce here.

http://www.physicalgeography.net/fundamentals/5d.html
http://www.oceansonline.com/gaiaho.htm
http://www.gaianet.fsbusiness.co.uk/gaiatheory.html
http://www.ozi.com/ourplanet/gaia.html

I was wondering how the Skadites think about the Gaia concept. My comments from the BuB-thread;

The Earth and its biosphere are an emergent, self-organizing system. To what degree the biosphere has a collective consciousness, is debatable, but I am absolutely convinced it is less concrete than the human mind.
The biosphere is a very complex web of interdependent species and races [...] The interaction between the organisms that make up the biosphere gives rise to a higher level order, an emergent, self-organising system. It is obviously not at the same level of organisation as an ant (let alone a human), but it does bear similarity to an ant hill. In case you didn't know, an ant hill displays a collective life cycle and astonishing feats of internal self-organisation. Whether or not that's enough to consider the ant hill collectively as an organism is debatable. In any case it's a difference of degree, not of nature.

The first organic molecules (that would become the building blocks of the biosphere) were created from the inorganic materials of the planet, possibly through electric shocks. The biosphere emerged from the Earth, like consciousness is emerging from the biosphere. It's really not that much of a stretch to think of the biosphere as a result of telluric evolution. Of course, in man (and especially in the Europid race) biological organisation has reached the point where Life is able to take its first shaky steps into outer space.

Thoughts? :)

PsycholgclMishap
Thursday, September 8th, 2005, 04:22 PM
Yes, but that does not make the planet Earth a living organism. The biospehere evolved around the earth and adapted to the conditions that exist here, the earth did not create it. Mind you I'm not debating that the earth's ecosystem is a self-regulating system.
How can you say this? The biosphere evolved from within the Earth!!

PsycholgclMishap
Thursday, September 8th, 2005, 04:24 PM
In any case, an organism is a biological, self-organising system. That's what I meant when I said the difference between a 'regular' organism and an ant hill is one "of degree, not of nature".
Yes, sir!

http://dictionary.reference.com/search?q=organism

Siegfried
Thursday, September 8th, 2005, 06:04 PM
The biospehere evolved around the earth and adapted to the conditions that exist here, the earth did not create it.

The first organic molecules (that would become the building blocks of the biosphere) were created from the inorganic materials of the planet, possibly through electric shocks. The biosphere emerged from the Earth, like consciousness is emerging from the biosphere. It's really not that much of a stretch to think of the biosphere as a result of telluric evolution. Of course, in man (and especially in the Europid race) biological organisation has reached the point where Life is able to take its first shaky steps into outer space.

Siegfried
Monday, October 10th, 2005, 09:03 AM
What is Gaia? - by James Lovelock

In 1925 the American scientist Alfred Lotka published a small but important book, Physical Biology. In it he wrote: "It is not so much the organism or the species that evolves, but the entire system, species and environment. The two are inseparable." As a follower of Lotka, I want to consider extinction in the context of an evolutionary science that is as much about the rocks and oceans as about the living things that inhabit them. In this view what evolves is an ‘Earth system’ that can move gradually for long periods under an ever-warming sun. But as it evolves, sudden changes punctuate its gradual evolution: such as the appearance of oxygen, a glaciation, a species like humans, or the impact of tiny planets. Whether internally or externally driven, these events change the whole system.

Lotka’s view of evolution passed almost unnoticed in his time and it was not until the National Aeronautics and Space Administration (nasa) in the 1960s began exploring our planetary neighbourhood that this broader, transdisciplinary, view of the Earth was revisited. As part of nasa’s exploration team, it led me to propose, in a paper in Nature in 1965, that life and its environment are so closely coupled that the presence of life on a planet could be detected merely by analysing chemically the composition of its atmosphere. This proposal is now part of nasa’s astrobiology programme and they aim to use it in the search for life on extra-solar planets.

When we look at the Earth we see an atmosphere that, apart from the noble gases, has a composition almost wholly determined by the organisms at the surface. If some catastrophe removed all life from the Earth without changing anything else, the atmosphere and surface chemistry would rapidly — in geological terms — move to a state similar to those of Mars or Venus. These are dry planets with atmospheres dominated by carbon dioxide and close to the chemical equilibrium state. By contrast, we have a cool wet planet with an unstable atmosphere that stays constant and always fit for life. The odds against this are close to infinity.

Science is about probabilities, so we are forced to consider the difficult but more probable alternative: something regulates the atmosphere. What is it? It has to be something connected with life at the surface, because we know that the atmospheric gases, oxygen, methane and nitrous oxide, are almost wholly biological products, while others, nitrogen and carbon dioxide, have been massively changed in abundance by organisms. Moreover, the climate depends on atmospheric composition and there is evidence that the Earth has kept a fairly comfortable climate ever since life began, in spite of a 30% increase in solar luminosity. Together these facts led me to propose, in a 1969 paper in the jaas (Journal of the American Astronautical Society), that the biosphere was regulating the atmosphere in its own interests. Two years later I started collaborating with Lynn Margulis and we published a paper in Tellus where we stated: "The Gaia hypothesis views the biosphere as an active adaptive control system able to maintain the Earth in homeostasis."

This idea was so contradictory to the views of evolutionary biologists that it was not long before Ford Doolittle, Richard Dawkins and other biologists challenged it. They pointed out that global regulation by the organisms could never have evolved, because the organism itself was the unit of selection, not the Earth. In time I found myself agreeing with them. They were right: there was no way for organisms by themselves to evolve so that they could regulate the global environment. But, I wondered, could the whole system, organisms and environment together, evolve self-regulation? In 1981 I redrafted the hypothesis as an evolutionary model, ‘Daisyworld’, that was intended to show that self-regulation can take place on a planet where organisms evolve by natural selection in a responsive environment. Following the model, the Gaia hypothesis was restated as follows: "The evolution of organisms and their material environment proceeds as a single tight-coupled process from which self-regulation of the environment at a habitable state appears as an emergent phenomenon."

At about the same time, Andrew Watson, Mike Whitfield and I discovered the first mechanism for climate control by the Earth system, namely the biologically assisted reaction between atmospheric carbon dioxide (CO2) and calcium silicate in soil and on rocks. This process can regulate both climate and co2 at a level comfortable for plants. Soon other putative regulation mechanisms were discovered, such as the connection between ocean algae, dimethyl sulphide gas, clouds and climate. By the end of the 1980s there were sufficient evidence and models of the hypothetical system to justify calling it Gaia Theory.

Despite this, in the biological community Gaia Theory was almost wholly rejected, and Earth system science was ignored so far as evolution was concerned. Then in the mid-1990s William Hamilton became interested in Gaia theory. He accepted what was by then the strong evidence that the environment was regulated at a state comfortable for the biota. He saw it as a challenge to explain how this could be a consequence of evolution through natural selection. He published (with Tim Lenton) one paper on the cloud algal system, and his colleague Peter Henderson continues to model systems of biological evolution that include the material environment.

So what bearing does this new view of evolution have on the current mass extinction and what practical use is it?

1. It draws our attention to the biological infrastructure of the Earth, namely the micro-organisms. Lynn Margulis first pointed out their significance and that they still play an important, if not major part, in planetary regulation. Bacteria were the whole biosphere for 3 billion years before multi-cellular organisms such as humans and trees came on the scene.

2. In the real world, organisms grow in a material environment where growth is strongly constrained by the laws of physics and chemistry. When these constraints are included in evolutionary biology models, it becomes possible to build a wide range of stable model systems. These models offer insight into the nature of the Earth system and into the need for biodiversity. Biodiversity is usually valued for its aesthetic or human medicinal qualities; we think that biodiversity is an important part of planetary self-regulation.

3. We see the interglacial period that we are now in as a pathological state of the Earth system and see the ice ages as the normal state of the Earth system. In the present interglacial, all of the regulation systems we have so far discovered appear to be in positive feedback towards climate change. This means that any change, either to hotter or colder, is amplified not resisted. This is true of the mechanisms for pumping down co2 from the atmosphere, for cloud production by algae, and for the Daisyworld-like behaviour of the boreal and tropical forests. In addition, geophysical feedbacks, such as the effect of ice cover, are positive. An interglacial like now is a period when regulation has temporarily failed and is certainly no time to add more greenhouse gases or deplete biodiversity.

We are living in the midst of a great extinction, where the number of species is declining at a rate comparable in intensity with the extinctions that punctuate the geological record, such as that when the dinosaurs died out 65 million years ago. There is concern about the disappearance of plant and animal species from the equatorial regions, which are sometimes taken as representative of the natural state of the Earth. These tropical regions are indeed biodiverse, but I wonder if, instead of regarding this as a natural state, we should regard biodiversity as an indication that the Earth itself is continuously, but gently, perturbed. Even the single environmental variable, temperature, is perturbed on the short timescale of diurnal change, and through the yearly march of the seasons, to the alternation of glaciations with warm periods like now.

Models that Stephan Harding and I have made suggest that biodiversity is a symptom of perturbation during a state of comparative health. What seems important for sustenance is not so much biodiversity as such, but potential biodiversity, the capacity of a healthy system to respond through diversification when the need arises. In tropical forest and other regions under threat, destroying diversity will reduce the numbers of rare species. Among them may be those able to flourish and sustain the ecosystem when the next large environmental change takes place. It is the loss of diversity and the loss of the potential of the region to sustain biodiversity, that makes the large-scale replacement of natural ecosystems with farmland so dubious an act.

Gaia theory is not contrary to Darwin’s great vision; it is like neo-Darwinism, a new look at Darwin’s evolutionary theory. I suspect it will be some time before biologists and geologists collaborate closely enough for us to see the emergence of a truly unified Earth system science. William Hamilton, in a television interview, referred to the Gaian view of evolution as Copernican, but he added, "We await a Newton to explain how it works."

Siegfried
Monday, October 10th, 2005, 09:06 AM
What is Gaia? - by James Lovelock

In 1925 the American scientist Alfred Lotka published a small but important book, Physical Biology. In it he wrote: "It is not so much the organism or the species that evolves, but the entire system, species and environment. The two are inseparable." As a follower of Lotka, I want to consider extinction in the context of an evolutionary science that is as much about the rocks and oceans as about the living things that inhabit them. In this view what evolves is an ‘Earth system’ that can move gradually for long periods under an ever-warming sun. But as it evolves, sudden changes punctuate its gradual evolution: such as the appearance of oxygen, a glaciation, a species like humans, or the impact of tiny planets. Whether internally or externally driven, these events change the whole system.

Lotka’s view of evolution passed almost unnoticed in his time and it was not until the National Aeronautics and Space Administration (nasa) in the 1960s began exploring our planetary neighbourhood that this broader, transdisciplinary, view of the Earth was revisited. As part of nasa’s exploration team, it led me to propose, in a paper in Nature in 1965, that life and its environment are so closely coupled that the presence of life on a planet could be detected merely by analysing chemically the composition of its atmosphere. This proposal is now part of nasa’s astrobiology programme and they aim to use it in the search for life on extra-solar planets.

When we look at the Earth we see an atmosphere that, apart from the noble gases, has a composition almost wholly determined by the organisms at the surface. If some catastrophe removed all life from the Earth without changing anything else, the atmosphere and surface chemistry would rapidly — in geological terms — move to a state similar to those of Mars or Venus. These are dry planets with atmospheres dominated by carbon dioxide and close to the chemical equilibrium state. By contrast, we have a cool wet planet with an unstable atmosphere that stays constant and always fit for life. The odds against this are close to infinity.

Science is about probabilities, so we are forced to consider the difficult but more probable alternative: something regulates the atmosphere. What is it? It has to be something connected with life at the surface, because we know that the atmospheric gases, oxygen, methane and nitrous oxide, are almost wholly biological products, while others, nitrogen and carbon dioxide, have been massively changed in abundance by organisms. Moreover, the climate depends on atmospheric composition and there is evidence that the Earth has kept a fairly comfortable climate ever since life began, in spite of a 30% increase in solar luminosity. Together these facts led me to propose, in a 1969 paper in the jaas (Journal of the American Astronautical Society), that the biosphere was regulating the atmosphere in its own interests. Two years later I started collaborating with Lynn Margulis and we published a paper in Tellus where we stated: "The Gaia hypothesis views the biosphere as an active adaptive control system able to maintain the Earth in homeostasis."

This idea was so contradictory to the views of evolutionary biologists that it was not long before Ford Doolittle, Richard Dawkins and other biologists challenged it. They pointed out that global regulation by the organisms could never have evolved, because the organism itself was the unit of selection, not the Earth. In time I found myself agreeing with them. They were right: there was no way for organisms by themselves to evolve so that they could regulate the global environment. But, I wondered, could the whole system, organisms and environment together, evolve self-regulation? In 1981 I redrafted the hypothesis as an evolutionary model, ‘Daisyworld’, that was intended to show that self-regulation can take place on a planet where organisms evolve by natural selection in a responsive environment. Following the model, the Gaia hypothesis was restated as follows: "The evolution of organisms and their material environment proceeds as a single tight-coupled process from which self-regulation of the environment at a habitable state appears as an emergent phenomenon."

At about the same time, Andrew Watson, Mike Whitfield and I discovered the first mechanism for climate control by the Earth system, namely the biologically assisted reaction between atmospheric carbon dioxide (CO2) and calcium silicate in soil and on rocks. This process can regulate both climate and co2 at a level comfortable for plants. Soon other putative regulation mechanisms were discovered, such as the connection between ocean algae, dimethyl sulphide gas, clouds and climate. By the end of the 1980s there were sufficient evidence and models of the hypothetical system to justify calling it Gaia Theory.

Despite this, in the biological community Gaia Theory was almost wholly rejected, and Earth system science was ignored so far as evolution was concerned. Then in the mid-1990s William Hamilton became interested in Gaia theory. He accepted what was by then the strong evidence that the environment was regulated at a state comfortable for the biota. He saw it as a challenge to explain how this could be a consequence of evolution through natural selection. He published (with Tim Lenton) one paper on the cloud algal system, and his colleague Peter Henderson continues to model systems of biological evolution that include the material environment.

So what bearing does this new view of evolution have on the current mass extinction and what practical use is it?

1. It draws our attention to the biological infrastructure of the Earth, namely the micro-organisms. Lynn Margulis first pointed out their significance and that they still play an important, if not major part, in planetary regulation. Bacteria were the whole biosphere for 3 billion years before multi-cellular organisms such as humans and trees came on the scene.

2. In the real world, organisms grow in a material environment where growth is strongly constrained by the laws of physics and chemistry. When these constraints are included in evolutionary biology models, it becomes possible to build a wide range of stable model systems. These models offer insight into the nature of the Earth system and into the need for biodiversity. Biodiversity is usually valued for its aesthetic or human medicinal qualities; we think that biodiversity is an important part of planetary self-regulation.

3. We see the interglacial period that we are now in as a pathological state of the Earth system and see the ice ages as the normal state of the Earth system. In the present interglacial, all of the regulation systems we have so far discovered appear to be in positive feedback towards climate change. This means that any change, either to hotter or colder, is amplified not resisted. This is true of the mechanisms for pumping down co2 from the atmosphere, for cloud production by algae, and for the Daisyworld-like behaviour of the boreal and tropical forests. In addition, geophysical feedbacks, such as the effect of ice cover, are positive. An interglacial like now is a period when regulation has temporarily failed and is certainly no time to add more greenhouse gases or deplete biodiversity.

We are living in the midst of a great extinction, where the number of species is declining at a rate comparable in intensity with the extinctions that punctuate the geological record, such as that when the dinosaurs died out 65 million years ago. There is concern about the disappearance of plant and animal species from the equatorial regions, which are sometimes taken as representative of the natural state of the Earth. These tropical regions are indeed biodiverse, but I wonder if, instead of regarding this as a natural state, we should regard biodiversity as an indication that the Earth itself is continuously, but gently, perturbed. Even the single environmental variable, temperature, is perturbed on the short timescale of diurnal change, and through the yearly march of the seasons, to the alternation of glaciations with warm periods like now.

Models that Stephan Harding and I have made suggest that biodiversity is a symptom of perturbation during a state of comparative health. What seems important for sustenance is not so much biodiversity as such, but potential biodiversity, the capacity of a healthy system to respond through diversification when the need arises. In tropical forest and other regions under threat, destroying diversity will reduce the numbers of rare species. Among them may be those able to flourish and sustain the ecosystem when the next large environmental change takes place. It is the loss of diversity and the loss of the potential of the region to sustain biodiversity, that makes the large-scale replacement of natural ecosystems with farmland so dubious an act.

Gaia theory is not contrary to Darwin’s great vision; it is like neo-Darwinism, a new look at Darwin’s evolutionary theory. I suspect it will be some time before biologists and geologists collaborate closely enough for us to see the emergence of a truly unified Earth system science. William Hamilton, in a television interview, referred to the Gaian view of evolution as Copernican, but he added, "We await a Newton to explain how it works."

Siegmund
Monday, October 10th, 2005, 10:06 AM
It's interesting, but I always wonder to what extent such theories represent the anthropomorphization of an otherwise indifferent universe, just to make it feel more cozy and warm.

Take for example the fourth link, with the butterfly, simulated DNA strand, planets and repetitions of the word "imagine." Just how much of this is hard science? It appears, on the surface at least, to be less science and more New Age fantasy. Mysticism.

Nevertheless, the theory is tantalizing. The notion that the world and the creatures that inhabit it are an interconnected mechanism proceeds from common sense, and thus has a certain ring of truth to it. By extension, the conclusion that one should be extremely careful not to upset the (presumably) delicate balance of this system also carries an intuitive logic.

The question in my mind is twofold: how to apply the scientific method to this theory, and how to draw useful empirical conclusions from it.

Siegfried
Monday, October 10th, 2005, 10:27 AM
I agree, Siegmund. :) From what I have been able to gather, people like James Lovelock have put forth some very interesting insights, but their theories have been hijacked by the New Age crowd. That crowd is quick to seize a new scientific theory and then to present a simplified, stereotyped version of it to promote their own confused cults. It's not just the Gaia hypothesis; they did it with quantum physics as well.

Dr. Solar Wolff
Tuesday, October 11th, 2005, 12:33 AM
First, this should have been called the Erde Hypothesis since we have a Germanic goddess who fits the bill more closely than the Greek one and the inventor here was English.

I like it a great deal. I am not sure the earth is a thinking being but it certainly functions as a machine, bringing itself back into a state of balance after disaster or tampering. This is something to think about concerning global warming since the earth has been warmer in the past. But earth is also able to achieve a new balance. For instance, before the K-T meteor, 65 million years ago, the earth was warmer, wetter and had a highter oxygen content. After the firestorm, the climate was colder, dryer and had less oxygen which is like the mountain environment before the meteor. So, mountain species spread across the earth, earth achieved a new balance of temperature, moisture, soil, and oxygen, and what we call normal today are those same upland species of the Cretaceous--including mammels.