Question No. 1
- How does the biotic regulation concept relate to J. Lovelock's Gaia hypothesis?
- Answered 6 July 2003.
Question author: anonymous.
Asked 6 July 2003.
In the late 60s—early 70s of the twentieth century British scientist James Lovelock pointed to the fact that the gaseous composition of modern terrestrial atmosphere is far from the dynamic physico-chemical equilibrium that could be determined by the incoming solar radiation. Lovelock suggested that the contemporary non-equilibrium environmental conditions on Earth are maintained in a life-compatible state by life itself. According to the so-called Gaia hypothesis put forward by J. Lovelock (Lovelock, 1982; 1995), our planet can be viewed as a single superorganism. On a geological time scale this superorganism is able to compensate unfavourable environmental changes of geophysical and cosmic nature (e.g. filtration of matter from the Earth's core or long-term changes in solar luminosity).
1. Main Problem of Gaia Hypothesis
Gaia hypothesis ignores the fundamental fact that there are no types of living objects (from unicellular and multicellular organisms to social and ecological communities of organisms that might be called "superorganisms") that would exist in a single number like Gaia. Here lies the intrinsic flaw of the hypothesis.
The difference between living and non-living matter has to do with the unprecedented complexity of the former. The amount of information stored in the living matter per unit volume exceeds a similar characteristic of the inanimate world by twenty orders of magnitude (Gorshkov, Makar'eva, 2001; Gorshkov et al., 2002). To maintain such a fantastic level of order life uses a unique mechanism:
Any kind of living matter exists in the form of sets (populations) of similar objects (individuals). Within each set, the objects interact competitively with each other. Those objects that have lost the initial high level of order lose competitiveness and are forced from the population. The appearing vacancies are filled by the copies (offspring) of normal objects retaining the initial level of order.
Such a mechanism of order maintenance is unique for life and differentiates living matter from the inanimate world.
Environmental regulation is a complex information-consuming process. Information on proper structure and functioning of living organisms performing biotic regulation is written in molecular memory cells in the genomes of biological species. In the absence of a population and, consequently, competitive interaction the spontaneous decay of the genetic information of the biota goes unimpeded. Hence, regulation of the environment cannot be sustainably ensured by Gaia — a superorganism existing in a single number.
2. Gaia Hypothesis and Traditional Biological Science
Unexpectedly as it might seem from the first sight, propagation of the Gaia hypothesis has in several important ways contributed to discrediting the idea of biotic environmental control (Doolittle, 1981; Dawkins, 1982; Baerlocher, 1990; Saunders, 1994; Robertson, Robinson, 1998). The traditional biological science opposed Gaia by noting the following. As far as the global biota is not a single organism but represents a set of competing units (in the traditional biology these units are individual organisms, in the biotic regulation concept they are local ecological communities, see below), how can regulation of any global environmental parameter shared by all such objects emerge? In no way, seemingly.
Indeed, suppose that at the initial moment of time the planet is inhabited by living objects regulating the global environment. It means that as soon as the regulated environmental parameter (e.g. atmospheric gaseous composition) deviates from the optimum value, each living object spends some part of its metabolic energy compensating for the unfavourable change. On such a planet the air is always clean, the greenhouse effect is normal and so on.
Spontaneous decay of the genetic information of living objects continuously produces mutants, that is, objects with defective behaviour and morphology. Suppose that sooner or later there appears a mutant unable to perform work on stabilisation of the atmospheric gaseous composition. As a result, the global power of biotic regulation becomes lower and the global environmental conditions may start deteriorating (e.g. carbon dioxide concentration becomes either lower or higher than the optimum). Due to powerful atmospheric mixing, the environment becomes worse for all objects inhabiting the planet including both normal objects and mutants. All objects find themselves in equal environmental conditions. (An analogy from the human society: In centrally-planned economics both hard-workers and lazybones are practically equally paid and feature equal economic competitiveness.) Importantly, the non-regulating ("lazybones") mutant may spend all of its energy on competitive interaction and force out his normal ("hard-working") neighbours, who continue to contribute some part of their energy on regulation of the environmental conditions.
Nothing can prevent the ultimately ubiquitous spread of such non-regulation mutants. As soon as this happens, the genetic information needed for global environmental regulation will be irreversibly lost and the global mechanism of biotic regulation will be irreversibly destroyed. The uncontrolled global environmental conditions will then rapidly degrade to a state unfit for life.
The characteristic times of genetic decay (i.e. appearance of non-regulating mutants) are negligible on a geological time scale. Hence, according to the traditional biological science, a whatever prolonged existence of a biotic control of global environmental conditions is impossible.
If so, how should one treat the empirical evidence which provides a unambiguous testimony for existence of such a control? The traditional biological science simply ignores such evidence, thus remaining unable to explain the persistence of life-compatible environmental conditions on Earth during the last four billion years.
On the other hand, the Gaia hypothesis aims to explain the observed stability of life-compatible environmental conditions, but it cannot account for and comes in conflict with the major principle of life organisation — competitive interaction of living objects.
3. Contradiction Solved within Biotic Regulation Concept
No contradictions arise within the biotic regulation concept.
A fundamental new notion that is introduced within the biotic regulation concept is biotic sensitivity. Living objects that regulate the environment are only able to react to environmental changes if the latter exceed the value of biotic sensitivity.
Biotic sensitivity is likely to be a universal value of the order of 0.0001 (Gorshkov et al. 2000, pp. 70-73). For example, if the ambient concentration of carbon dioxide deviates from the optimum by, say, 1% (0.01 > 0.0001), the biota will notice such a change and will try to compensate for it. If the deviation constitutes one thousandths of a per cent (0.00001 < 0.0001), the biota will ignore such a change and will not react to it.
Using the notion of biotic sensitivity it becomes possible to explain how a set of competing objects can regulate globally shared environmental parameters (Gorshkov, 1986, 1995; Gorshkov et al., 2000). We dwell once again on the example of a biotic control of the gaseous composition of the atmosphere.
Due to the powerful processes of physical mixing of the atmosphere all living objects, whether they regulate the environment or not, find themselves — seemingly — in equal environmental conditions. As we discussed above, namely this fact prohibits effective elimination of the non-regulating mutants in the course of competitive interaction with normal objects performing environmental regulation.
Solution of the problem lies in the word "seemingly". Functioning of a living object may lead to a situation when its local environment appears to be slightly different from the global average. If such a slight difference is nevertheless significant, i.e. it exceeds biotic sensitivity, the living object is able to "feel" the advantage of environmental regulation. Normal objects will be able to drive their local environment to a state slightly, but appreciably, closer to the optimum than the non-regulating mutants. The latter will then have an appreciably lower competitiveness and can be forced out from the population. Despite the fact that local environments of normal objects and mutants may coincide to the high accuracy of biotic sensitivity (0.0001) and can significantly depart from the optimum.
We now illustrate this on a hypothetical example. Let us suppose that the living objects capable of environmental control are trees, while the regulated global environmental characteristic is atmospheric carbon dioxide concentration. Suppose further that in the course of a major atmospheric disturbance (volcanic eruption, anthropogenic activities) the global atmospheric carbon dioxide concentration becomes significantly higher than the biotic optimum. All trees on the tree-covered planet are thus faced with approximately equal unfavourable environmental conditions. Normal trees immediately begin to work on removing the excessive carbon from the atmosphere in order to restore the optimum concentration of carbon dioxide. This can be done, for example, by depositing the excessive atmospheric carbon in organic form in soil and sediments. Mutant trees incapable of biotic regulation do not react to the unfavourable environmental change.
Photosynthetic power of the biological productivity of trees is large enough for trees to be able to create internal atmospheres of the crowns, where carbon dioxide concentration can be several per cent lower than outside the crown. Thus, despite powerful mixing of the atmosphere (e.g. due to wind), the local carbon dioxide concentration of normal trees will be several per cent closer to the optimum than that of non-regulating mutant trees. Normal trees retaining the ability of environmental regulation will find themselves in a more favourable situation than mutants and will be able to outcompete the latter forcing them from the population.
As a result, the whole surface of the considered planet becomes covered by normal trees. There will appear a globally significant outflux of excessive carbon from the atmosphere. Normal trees will work in this direction until the global carbon dioxide concentration becomes indistinguishable from the initial optimum (within the accuracy of biotic sensitivity.)
4. Disturbed and Undisturbed Biota
In reality, objects capable of performing biotic regulation are not individual trees but local ecological communities of organisms functioning in a correlated manner. In forest ecosystems local ecological community is likely to be represented by an individual tree and the associated local biota (understory plants (mosses, shrubs), fungi, bacteria, insects etc.) As any other type of living order, the internal correlation and orderliness of local ecological communities is maintained in the course of their competitive interaction with each other. Unlike any individual biological species, local ecological communities are properly fitted for ensuring the huge variety of complex and interrelated environmental responses that are necessary for keeping their environment under control.
Hence, genetic decay (i.e. appearance of mutants, e.g. in the course of artificial selection and genetic modification of natural species) is not the only possible cause for degradation of the regulatory potential of the natural biota. The latter can be also destroyed by anthropogenic disturbance of the ecological community structure, i.e. by arbitrary changes imposed on population densities of species comprising the natural community. For example, in agricultural landscapes one exterminates natural vegetation and replaces it by monocultures used by man.
As ultra-complex ordered process, biotic regulation of the environment can be only performed by the undisturbed natural biota. (Similarly, any complex device can only function if it was assembled using a strictly specified number of strictly specified details.) Anthropogenically disturbed biota, provided its productivity is artificially maintained, can only facilitate environmental degradation.
The fundamental difference in structure and functioning of the disturbed and undisturbed biota is ignored in the Gaia hypothesis.
On the basis of analysis of global carbon cycle it is possible to quantify the global regulatory potential of the undisturbed biota. Within the framework of biotic regulation concept it was possible to estimate how the contemporary proportion of territories occupied by disturbed and undisturbed biota on a planetary scale should be changed in favour of the latter in order to stop the accumulation of carbon dioxide in the atmosphere leaving intact the current rate of fossil fuel burning (Gorshkov, Makarieva, 1998; Gorshkov et al., 2000, Chapter 6, p. 170).
5. The Time Scale Issue
Within the Gaia hypothesis one traditionally considers geophysical processes that are able to change the Earth's environment very slowly. For example, the rate of carbon dioxide filtration from the Earth's core is such that it could cause doubling of the modern carbon dioxide concentration over a time period of the order of several hundred thousand years. Solar luminosity (which determines the average amount of solar energy incoming per unit Earth's surface per unit time) changes much more slowly, increasing by about one per cent each hundred million years. Hence, one can conclude from the Gaia hypothesis that even if the whole of global biota were instantly destroyed, the humanity will face an unfavourable environmental outcome in the infinitely distant future (see, e.g., Schwartzman, 1999).
The biotic regulation concept shows that this conclusion is wrong. The destructive environmental impact of the anthropogenically disturbed biota is many orders of magnitude more powerful than that of related geophysical processes. In particular, the atmospheric concentration of carbon dioxide could double in about ten (instead of hundred thousand) years solely due to the respiration process of the living organisms of the Earth, were they not organised in natural ecological communities. In particular, through the process of respiration the living organisms of Earth are able to double the atmospheric carbon dioxide concentration in about ten (cf. hundred thousand) years.
In the natural biota such a dramatic change is never to occur, as far as any deviation from the optimum is immediately compensated by the natural biota (in particular, due to functioning of plants that are able to withdraw the excessive carbon from the atmosphere). The disturbed biota is incapable of environmental control. Hence, the processes of environmental degradation under biotic impact feature extraordinarily high rates. For example, the widely-discussed process of soil degradation is to a large degree due to the fact that on exploited (disturbed) territories the rate of synthesis of the soil organic matter is much lower than the rate of its decomposition performed by the local disturbed biota. The time scale of soil degradation is hundred years and less, so it may become pronounced during life time of one generation.
As shown in the biotic regulation concept (Gorshkov et al., 2000; Makar'eva, Gorshkov, 2001; Gorshkov, Makarieva, 2002) the modern climate of Earth is physically unstable. The unfavourable changes of the global mean surface temperature leading to irreversible degradation of the major food webs exploited by humans may also occur during several decades.
Unlike the Gaia hypothesis, the biotic regulation concept clearly proves that urgent conservation of undisturbed biota on globally significant areas of the planet's surface is an indispensable prerequisite for personal survival of contemporary people and their direct offspring.
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