LECTURE  1                                                                  GAIA

In this lecture you will learn:

'The Gaia hypothesis is an ecological hypothesis proposing that the biosphere and the physical components of the Earth (atmosphere, cryosphere, hydrosphere and lithosphere) are closely integrated to form a complex interacting system that maintains the climatic and biogeochemical conditions on Earth in a preferred homeostasis. Originally proposed by James Lovelock as the earth feedback hypothesis,[1] it was named the Gaia Hypothesis after the Greek supreme goddess of Earth.[2] The hypothesis is frequently described as viewing the Earth as a single organism. Lovelock and other supporters of the idea now call it Gaia theory, regarding it as a scientific theory and not mere hypothesis, since they believe it has passed predictive tests.[3]" http://en.wikipedia.org/wiki/Gaia_hypothesis -an ecological hypothesis

-proposed by Dr. James Lovelock

-The hypothesis is frequently described as viewing the Earth as a single organism.

-A hypothesis becomes a theory by passing predictive tests

Supplemental readings: 

Formulation of the Gaia Hypothesis - it started with the idea of the search for evidence of extra-terrestrial life
- NASA targeted Mars as more likely
- Lovelock predicted the absence of life on Mars
-  Martian atmosphere was chemically dead, showed no change compared to earth's which is active and changing
Why was the Earth different? 

CO2, N                        CO2, N            N, O2
- Venus atmosphere is 95-96% carbon dioxide, 3-4% nitrogen, with traces of oxygen, argon and methane.
- Mars is 95.3% carbon dioxide, 2.7% nitrogen, 1.6% argon, only 0.15% oxygen and only 0.03% water.
- Earth's is 77% nitrogen,  21% oxygen with traces of carbon dioxide, methane and argon.
- the atmospheric gases which comprise the Earth's atmosphere is unique in our solar system.
Lovelock asked the question ... so what happened on Earth? - did it start with a different makeup?
- did something happen to change earths atmosphere? Especially so little CO2, so much oxygen and nitrogen?
- What complex processes are at work maybe for billions of years that would explain this uniqueness? What is the driving force to maintain such a unique combination?
In the late 1960's Lovelock considered the beginnings of life on Earth.

1. The earliest of life forms existed in the ancient oceans
2. They were the smallest and the simplest - bacteria and algae, there is fossil evidence for these now
3. almost 3 billion years ago, bacteria and photosynthetic algae began removing/using the carbon dioxide from the atmosphere. A lot went into energy molecules like glucose and other sugars, proteins, DNA etc... but huge quantities were permanently LOCKED UP in calcium carbonate.. better known as limestone.
4. AT THE SAME TIME, cyanobacteria and then algae photosynthesized and released oxygen.
5. over vast geological time spans - the atmosphere went from a typical high carbon dioxide or the other planets towards a mixture of nitrogen and oxygen. And oxygen based metabolism or aerobic combustion was REALLY the monolith in the 2001. It was the quantum leap of evolution.
6. This was the first time somebody put together the idea that LIFE could profoundly change the physical planet.
Why Gaia Hypothesis ? - Lovelock, began to formulate the explanation/ methods by which Earth was transfigured and transformed by a self evolving and self regulating living system.
- "Gaia" - after the Greek goddess who drew the living world forth from Chaos
The scientific community was not happy. 

Where's the proof?


- Up until this point, there was a very STATIC view of the Earth. The physical Earth simply was and life adapted to WHAT WAS ... but life did not CHANGE the physical Earth.

- By 1979 James Lovelock had published some of his ideas in a first book "Gaia: A New Look at Life on Earth" in which the statement of the specification of the Gaia Hypothesis had become somewhat better defined. 

"'...the physical and chemical condition of the surface of the Earth, of the atmosphere, and of the oceans has been and is actively made fit and comfortable by the presence of life itself. This is in contrast to the conventional wisdom which held that life adapted to the planetary conditions as it and they evolved their separate ways.'' - has been and is actively made fit and comfortable by the presence of life itself. The coevolution of physical and living
- in contrast to the prevailing idea that  life adapted to the planetary conditions as is and evolved to adapt
"The entire range of living matter on Earth from whales to viruses and from oaks to algae could be regarded as constituting a single living entity capable of maintaining the Earth's atmosphere to suit its overall needs and endowed with faculties and powers far beyond those of its constituent parts... [Gaia can be defined] as a complex entity involving the Earth's biosphere, atmosphere, oceans, and soil; the totality constituting a feedback of cybernetic systems which seeks an optimal physical and chemical environment for life on this planet." - this is a very important concept, that life itself on Earth regulates and moderates the physical Earth to make it habitable. An example is the response by plants to increased CO2 in the air which results in an increased growth of plants that lock up more CO2
* "To what extent is our collective intelligence also a part of Gaia? Do we as a species constitute a Gaian nervous system and a brain which can consciously anticipate environmental changes?" - of course, what this brings up is that intelligence is an evolutionary adaptation that can be used to moderate the physical world, to change it to make life more possible. Certainly the evolution of high level intelligence made it possible to handle and control fire, to build housing to keep us warm, to make clothing to keep us warm and let us spread out into very INHOSPITABLE parts of the globe. Irrigation allows us to grow food which wouldnt be able to grow there without human intervention. Humans as a species have been very successful terriformers, changing every aspect of the planet. 
* "The name of the living planet, Gaia, is not a synonym for the biosphere - that part of the Earth where living things are seen normally to exist. Still less is Gaia the same as the biota, which is simply the collection of all individual living organisms. The biota and the biosphere taken together form a part but not all of Gaia. Just as the shell is part of the snail, so the rocks, the air, and the oceans are part of Gaia. Gaia, as we shall see, has continuity with the past back to the origins of life, and in the future as long as life persists. Gaia, as a total planetary being, has properties that are not necessarily discernible by just knowing individual species or populations of organisms living together.  Specifically, the Gaia hypothesis says that the temperature, oxidation, state, acidity, and certain aspects of the rocks and waters are kept constant, and that this homeostasis is maintained by active feedback processes operated automatically and unconsciously by the biota." The Ages of Gaia: 1988] A Biography of Our Living Earth
- the interconnectedness of the all the natural terrestrial systems - not just the atmosphere - is beginning to emerge
Lovelock goes on to say ...
* "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. 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 which constitute its bark. How like the Earth, and more so when we realize that many of the atoms of the rocks far down into the magma were once part of the ancestral life of which we all have come."


- A MODEL system for GAIA
- a redwood tree is 99% dead, but the tree is alive. 

SCIENTIST WERE NOT HAPPY. For a start, it implied that studying the "parts" could never show the whole picture. Like saying we cant study birds without also studying the trees they live in, the food they eat .. but on a much larger scale. And that LARGE scale was extremely interdisciplinary.

"Theoretical ecology is enlarged. By taking the species and their physical environment together as a single system, we can, for the first time, build ecological models that are mathematically stable and yet include large numbers of competing species. In these models increased diversity among the species leads to better regulation."

- this theory of complexity is well illustrated by an examples of not seeing the WHOLE picture

1. killing pest with pesticides that also kill the prey species that ordinarily control the pests.

2. This leads to having to apply more and more pesticides as the pests adapt and become resistant. It is the kind of thinking where there is zero tolerance, rather than understanding there is an equilibrium and we can only push on it a bit by bringing in more predators.


The first great extinction occurred when photosynthetic and oxygen producing bacteria killed off all the bacteria that couldnt tolerate oxygen.  This was a CHEMICAL change in the Earths homeostasis.  The oxygen and nitrogen atmosphere is why our skies are blue.

Oxygen made it possible for the quantum leap forward in energy production called respiration.  It provided the energy for the evolution of multicellular organisms. 


 Blue green bacteria  Colonies of bacteria that form the rocks call Stromatolites.  They are "living fossils" and these rocks are found in the fossil record 3.5 billion years ago. 
CHALLENGE:  Given what you now know of the Gaia Hypothesis, discuss how at least 3 species have changed the ecosystem, the biota and/or abiota.
Review questions:
Describe  the atmospheres of Venus, Earth and Mars and how they triggered the basic question and then the Gaia hypothesis of Lovelock.
What evidence is there to support the Gaia hypothesis?
What is the "quantum leap" in the evolution of life on Earth.
Describe the homeostasis of Earth and give an example of how life moderates/modulates changes to bring Earth back to homeostasis.
Discuss how intelligence has been a very successful evolutionary adaptation.  Discuss how intelligence fits into the Gaia hypothesis.
In your own words describe how is a giant redwood tree a good model system/example for the Gaia hypothesis that both the biota and abiota are  participant in the active maintenance of homeostasis.
Give an example of the problems encountered when the WHOLE complexity of the inter-relatedness of life is not well understood before trying to change it.
Does the Gaia Hypothesis (as its detractors insist) support the concept of "directed evolution"?  How has/does the Gaia Hypothesis affect your view of movement to preserve the environment?  Does it support the environmental conservatives or the economic developmentalists?
Do you agree or disagree with the idea that human "intelligence" is simply another adaptive mechanism of evolution, much like sharp teeth and fast feet?  Given that we have quickly outstripped resources and caused the extinction of so many species without even understanding their role in the environment, is "intelligence" an evolutionary dead end like the Dodo (a ground laying, flightless bird)?  Are we destined to have a very short reign on Earth or is there any reason to believe that will we survive longer than the dinosaurs?