Gaia hypothesis meaning can be understood by the Gaia hypothesis definition that can be stated as an interaction between living organisms on the Earth with their inorganic surroundings forming a complex, self-regulating and synergistic system that helps perpetuate and maintain optimum conditions for life on the planet.
It was hypothesized that by using the Gaia principle one can detect life in the atmosphere of other planets. The Gaia theory of James Lovelock was a relatively cheaper and reliable way to use such interactive combinations to find the possibility of life on planets other than the Earth.
The initial Gaia hypothesis states that the Earth has maintained its habitable state through a self-regulating feedback loop that is automatically carried out by the living organisms that are tightly coupled to their respective environments. The observations made in the James Lovelock Gaia Hypothesis were:
The Gaia theory named after the Greek Goddess Gaia, which represents the Earth was however heavily criticized initially against the natural selection principles proposed by Charles Darwin. The other criticism of the Gaia theory was its teleological nature of stating finality and not the cause of such occurrences in Lovelock Gaia. The refined Gaia hypothesis that aligned the Gaia model with the production of sulfur and iodine by sea creatures in quantities approximately required by the land creatures that supported and made the Gaia theory stating interactions stronger that bolster the hypothesis.
The theory and hypothesis were criticized due to the following reasons.
(b) Homeostatic Gaia stated that the stability of the natural environment is maintained by life and that stability enables life to exist disregarded stating it was not scientific because it was untestable.
(c) The Geophysical Gaia hypothesis stated new geophysical cycles that only aroused curiosity and piqued interest in researching the terrestrial geographical dynamics.
(d) The optimizing Gaia hypothesis was also disregarded because of its untestability and therefore unscientific nature that stated the planet shaped by Gaia made life for the environment as a whole.
The refined New Gaia hypothesis was a counter-argument by James Lovelock. Lovelock along with Andrew Watson developed a new model that is the Daisyworld Simulations which is a purely mathematical model. Daisyworld is to be considered a planet where only daisies grow and there are black daisies and white daisies. The conditions in the Daisyworld are in many respects similar to that of the Earth.
The Gaia hypothesis has had its fair share of criticism because of its need for more explicit formulation and consequently it being untestable and hence not scientifically proven. Even with this through the years various modifications have been done and via these two models of Gaia emerges the weak Gaia hypothesis that suggests the planetary processes are substantially influenced by the life on the planet which is widely supported. The other model is known as the strong Gaia hypothesis that states that life creates the earth’s systems in other words planetary processes are controlled by life which is not supported and widely accepted.
See: https://www.vedantu.com/geography/gaia-hypothesis
The math behind the Daisyworld model
This is simple account of the mathematical analysis behind the daisyworld model, as originally published in Andrew J. Watson and James E. Lovelock, "Biological homeostasis of the global environment: the parable of Daisyworld", Tellus (1983), 35B, 284-289. Refer to this article as "WL". The science behind the model is discussed in WL and elsewhere, see the bibliography.
As indicated in the title of WL, the heart of the model is a point attractor of a dynamical scheme. In this case, the main control parameter is
The state variables are:
But to find them individually, it is necessary to proceed with numerical integration. The results of these simulations occupy the bulk of tje WL paper.
See: http://www.vismath.org/research/gaia/WLpaper/daisymath.html
Daisyworld is an imaginary planet, similar to the Flatland model* of a two dimensional land, on which black and white daisies are the only things growing. The model explores the effect of a steadily increasing solar luminosity on the daisy populations and their effect on the resulting planetary temperature. The growth function for the daisies allows them to modulate the planet's temperature for many years, warming it early on as radiation absorbing black daisies grow, and cooling it later as reflective white daisies grow. Eventually, the solar luminosity increases beyond the daisies' capability to modulate the temperature and they die out, leading to a rapid rise in the planetary temperature. Daisyworld was conceived of by Andrew Watson and James Lovelock to illustrate how life might in part have been responsible for regulating Earth's temperature as the Sun's luminosity increased over time.
Hartmann352
* Flatland Model is derived from Flatland: A Romance of Many Dimensions, a satirical novella by the English schoolmaster Edwin Abbott Abbott, first published in 1884 by Seeley & Co. of London. Written pseudonymously by "A Square", the book used the fictional two-dimensional world of Flatland to comment on the hierarchy of Victorian culture, but the novella's more enduring contribution is its examination of dimensions.
Several films have been made from the story, including the feature film Flatland (2007). Other efforts have been short or experimental films, including one narrated by Dudley Moore and the short films Flatland: The Movie (2007) and Flatland 2: Sphereland (2012).
See: https://en.wikipedia.org/wiki/Flatland
It was hypothesized that by using the Gaia principle one can detect life in the atmosphere of other planets. The Gaia theory of James Lovelock was a relatively cheaper and reliable way to use such interactive combinations to find the possibility of life on planets other than the Earth.
The initial Gaia hypothesis states that the Earth has maintained its habitable state through a self-regulating feedback loop that is automatically carried out by the living organisms that are tightly coupled to their respective environments. The observations made in the James Lovelock Gaia Hypothesis were:
- Despite an increase in energy provided by the sun, the earth’s global surface temperature has been constant.
- Owing to the activities of life of the living organisms, the atmosphere is in an extreme state of disequilibrium of thermodynamics and yet the aspects of its composition are astoundingly stable. Even with so many atmospheric components of varying degrees like 20.7 percent of oxygen, 79 percent of nitrogen, traces of methane, and 0.03 percent of carbon dioxide, the atmospheric composition remains constant rather than unstable.
- Constant ocean salinity for a very long time can be contributed to the seawater circulation via the hot basaltic rocks that emerge on ocean spreading ridges as hot water vents.
- The earth system has consistently and continuously recovered from massive perturbations owing to its self-regulation complex process.
The Gaia theory named after the Greek Goddess Gaia, which represents the Earth was however heavily criticized initially against the natural selection principles proposed by Charles Darwin. The other criticism of the Gaia theory was its teleological nature of stating finality and not the cause of such occurrences in Lovelock Gaia. The refined Gaia hypothesis that aligned the Gaia model with the production of sulfur and iodine by sea creatures in quantities approximately required by the land creatures that supported and made the Gaia theory stating interactions stronger that bolster the hypothesis.
The theory and hypothesis were criticized due to the following reasons.
- The significant increase in global surface temperatures contradicts the observatory comment according to the theory.
- Salinity in the ocean is far from being at constant equilibrium as river salts have raised the salinity.
- The self-regulation theory is also disregarded as evidence against it was surfaced by reduced methane levels and oxygen shocks during the various ice ages that are during the Huronian, Sturtian, and Marinoan or Varanger Ice Ages.
- Dimethyl sulfide produced by the phytoplankton plays an important role in climate regulation and the process does not happen on its own as stated by James Lovelock.
- Another claim that stated the Gaia theory is contradictory to the Natural Selection theory and is far from the survival of the fittest theory that was the greatest diversion according to Lovelock’s theory.
- The other criticisms stated that Gaia had four hypotheses and not just one.
(b) Homeostatic Gaia stated that the stability of the natural environment is maintained by life and that stability enables life to exist disregarded stating it was not scientific because it was untestable.
(c) The Geophysical Gaia hypothesis stated new geophysical cycles that only aroused curiosity and piqued interest in researching the terrestrial geographical dynamics.
(d) The optimizing Gaia hypothesis was also disregarded because of its untestability and therefore unscientific nature that stated the planet shaped by Gaia made life for the environment as a whole.
The refined New Gaia hypothesis was a counter-argument by James Lovelock. Lovelock along with Andrew Watson developed a new model that is the Daisyworld Simulations which is a purely mathematical model. Daisyworld is to be considered a planet where only daisies grow and there are black daisies and white daisies. The conditions in the Daisyworld are in many respects similar to that of the Earth.
- Water and nutrients are abundant in Daisyworld for the daisies.
- The ability to grow and for the daisies to spread across this imaginary planet’s surface depends entirely on the temperature.
- The climate system in Daisyworld is simple with no greenhouse gases and clouds.
- The planetary incident light and radiation that affects the surface temperature depends on the aerial coverage of the grey soil by the white and black daisies.
- In this model, the planetary temperature regulation is underpinned by ecological competition by examining the energy budget which is the energy provided by the sun and with high energy temperature increases, and with low energy the temperature decreases.
- The albedo that is the reflection and the absorption of light is influenced by the colour of daisies.
- Light- The black daisies warm the Daisyworld by absorbing more light and white daisies cool the planet by reflecting more light.
- Growth- Black daisies grow and reproduce best at temperatures relatively lower than the white daisies that thrive at a higher temperature.
- When the temperature rises Daisyworld’s surface is filled with more white daisies that reduce heat input and consequently cooling the planet. For instance in figure 3 given below.
- With the decline in temperatures, the scenario in figure 2 takes place wherein the white daisies are outnumbered by the black daisies making the planet warmer by increasing absorption of the energy provided by the sunlight.
- Plant reproduction becomes equal when temperatures converge to the value of both their reproductive rates, both will thrive as shown in figure 1.
The Gaia hypothesis has had its fair share of criticism because of its need for more explicit formulation and consequently it being untestable and hence not scientifically proven. Even with this through the years various modifications have been done and via these two models of Gaia emerges the weak Gaia hypothesis that suggests the planetary processes are substantially influenced by the life on the planet which is widely supported. The other model is known as the strong Gaia hypothesis that states that life creates the earth’s systems in other words planetary processes are controlled by life which is not supported and widely accepted.
See: https://www.vedantu.com/geography/gaia-hypothesis
The math behind the Daisyworld model
This is simple account of the mathematical analysis behind the daisyworld model, as originally published in Andrew J. Watson and James E. Lovelock, "Biological homeostasis of the global environment: the parable of Daisyworld", Tellus (1983), 35B, 284-289. Refer to this article as "WL". The science behind the model is discussed in WL and elsewhere, see the bibliography.
As indicated in the title of WL, the heart of the model is a point attractor of a dynamical scheme. In this case, the main control parameter is
- L, the solar luminosity.
- AG, the albedo of bare ground,
- AB, the albedo of black daisies,
- AW, the albedo of white daisies.
The state variables are:
- alphaG, relative area of bare fertile ground,
- alphaB, relative area covered by black daisies,
- alphaW, relative area covered by white daisies,
- TG, average temperature over the bare ground,
- TB, average temperature over the black daisies,
- TW, average temperature over the white daisies.
Thus we have a two-dimensional dynamical system, given in equation (1) of WL, for the rates of change of alphaB and alphaW,A = alphaGAG + alphaBAB + alphaWAW
where x = alphaG, gamma is the death rate of all daisies, taken as 0.3 in the simulations, and beta is a quadratic function of the local temperature, equation (3) of WL,alphaW' = alphaW(x beta - gamma)
alphaB' = alphaB(x beta - gamma)
Now we look for the critical points. Assuming that both daisy areas are positive (a zero value means the game is over) we find the conditions for a critical point, as given in equations (14) of WL,beta(T) = max {0, 1 - 0.003265 (22.5 - T)^2}
which are constants independent of L, a surprising and hopeful result. From these equilibrium conditions, we find beta*, and from (1) we have (from the vanishing of the right hand sides) x beta* = gamma, so we may calculate the sum of the two daisy areas.T*B = 22.5 + (q'/2)+(AW - AB)
T*W = 22.5 - (q'/2)+(AW - AB)
But to find them individually, it is necessary to proceed with numerical integration. The results of these simulations occupy the bulk of tje WL paper.
See: http://www.vismath.org/research/gaia/WLpaper/daisymath.html
Daisyworld is an imaginary planet, similar to the Flatland model* of a two dimensional land, on which black and white daisies are the only things growing. The model explores the effect of a steadily increasing solar luminosity on the daisy populations and their effect on the resulting planetary temperature. The growth function for the daisies allows them to modulate the planet's temperature for many years, warming it early on as radiation absorbing black daisies grow, and cooling it later as reflective white daisies grow. Eventually, the solar luminosity increases beyond the daisies' capability to modulate the temperature and they die out, leading to a rapid rise in the planetary temperature. Daisyworld was conceived of by Andrew Watson and James Lovelock to illustrate how life might in part have been responsible for regulating Earth's temperature as the Sun's luminosity increased over time.
Hartmann352
* Flatland Model is derived from Flatland: A Romance of Many Dimensions, a satirical novella by the English schoolmaster Edwin Abbott Abbott, first published in 1884 by Seeley & Co. of London. Written pseudonymously by "A Square", the book used the fictional two-dimensional world of Flatland to comment on the hierarchy of Victorian culture, but the novella's more enduring contribution is its examination of dimensions.
Several films have been made from the story, including the feature film Flatland (2007). Other efforts have been short or experimental films, including one narrated by Dudley Moore and the short films Flatland: The Movie (2007) and Flatland 2: Sphereland (2012).
See: https://en.wikipedia.org/wiki/Flatland