IV.8.5.1 Gaia, the Earth’s biosphere, cannot experience biological evolution and therefore cannot be considered to be a living organism.

At this point, mention should be made of the Gaia hypothesis.In its “strong variant”, this hypothesis assumes that the entire biosphere of planet Earth consists of one enormous super-organism, encompassing various regulation mechanisms capable of maintaining conditions on the Earth’s surface, i.e. temperature, chemical composition of the atmosphere, etc. in the optimal range for living organisms (Lovelock & Margulis 1974; Lovelock 1995).However, the formation of such global homeostatic mechanisms useful from the standpoint of preservation of life is a very improbable phenomenon from the viewpoint of evolutionary biology.Gaia, the name of the hypothetical super-organism, is alone in our part of the universe, and does not have anything to compete with.There is no selection in the absence of competition and selection is the only natural mechanism that we know that is capable of forming similar adaptive regulation mechanisms.If a certain individual had to expend part of its resources to maintain the stability of its ecosystem, the other members of the population and members of other biological species would benefit from its activities.However, as was shown in the section dealing with group selection (see IV.8.2), this would be a highly unstable system in which individuals and species that would not submerge their resources in “generally beneficial activities”, but would only selfishly utilize the results of these activities of the rest, would rapidly predominate.

            The fact that a great many parameters of various systems, including the geological and geochemical parameters of our planet, are stable in the long term is caused quite prosaically by the fact that that there is a much greater chance of encountering a system and its subsystems in their stable states, in which they are maintained, e.g., by the existence of negative feedback, than in their transitory and thus, by definition, time-limited states (see also Chapter I.3.1).

             The Gaia hypothesis is extremely attractive but rather dangerous in its potential consequences.It is probably safer for the future of mankind and, unfortunately, closer to reality to see the global ecosystem as a chaotically acting time bomb where a tiny interference, such as destruction of the ozone layer, could lead through complicated, still unknown, positive feedbacks to irreversible drastic destruction of the entire biosphere, rather than as a concerned and purposefully arranged organism capable of sooner or later neutralizing our various foolish interferences in its structure.

            The weak version of the Gaia hypothesis simply assumes that the geological and biological cycles are very strong and closely interconnected on our planet and that the presence and activities of living organisms decide to a substantial degree which geological and geochemical processes take place on Earth and which properties the Earth exhibits.The large amount of exact data accumulated especially over the past 30 years shows that the Gaia hypothesis is probably correct in this variant.s 

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The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more
Draft translation from: Evoluční biologie, 2. vydání (Evolutionary biology, 2nd edition), J. Flegr, Academia Prague 2009. The translation was not done by biologist, therefore any suggestion concerning proper scientific terminology and language usage are highly welcomed. You can send your comments to flegratcesnet [dot] cz. Thank you.