MATTHEW WATKINSON • WEB: http://www.fishsnorkel.com • TWITTER: http://twitter.com/fishsnorkel
WHAT ARE THE PRINCIPLES OF POPULATION? Matthew Watkinson
“...we are not here concerned with hopes or fears, only with the truth as far as our reason permits us to discover it...” Charles Darwin SUMMARY • • • •
Homo sapiens are animals until proven otherwise, rather than transcendent by default. The demographic transition (from r-strategy to K-strategy) may be a consequence of increasing population, rather than a solution to it. Escalating consumption may be driven by intraspecific competition (including sexual, exploitative and interference components), which is probably impossible to eliminate. “Solutions” involving universal human cooperation are built on quixotic hope, not science.
INTRODUCTION After the most thorough research of which I am capable, I am quite convinced that the behaviour of humanity, including such things as escalating consumption and the demographic transition, can be adequately explained by natural selection and, as a result, I would like to make sure the Royal Society considers the conclusions of those, like me, who are unable to accept the veracity of human transcendence and the existence of fairytale endings: “…periodical misery has existed ever since we have had any histories of mankind, does exist at present, and will for ever continue to exist, unless some decided change takes place in the physical constitution of our nature." Thomas Malthus, An Essay on the Principles of Population (1798). “…all organic beings, without exception, tend to increase at so high a ratio, that no district, no station, not even the whole surface of the land or the whole ocean, would hold the progeny of a single pair after a certain number of generations. The inevitable result is an ever-recurrent Struggle for Existence.” Charles Darwin, The Variation of Animals and Plants under Domestication (1868).
Indeed, I am hoping the Royal Society will decide once and for all whether Thomas Malthus and Charles Darwin were wrong to assume that humans are governed by the same principles of population that so obviously govern everything else, for that is, surely, the heart of the population debate. Will this particular population of competitive replicators (Homo sapiens), generated by more than three and a half thousand million years of competitive replication, successfully reject competitive replication in the absence of positive checks, or will it continue to behave in exactly the same way as everything else: blooming when conditions are favourable and unblooming when they are not? Crediting ourselves with the potential for harmonious “sustainability” is all very well, but we are nowhere near realising that potential, despite the escalating urgency of the situation (Earth Overshoot Day will fall on the 21st August in 2010, just a few decades after it did not exist at all: http://bit.ly/dj7X1n), and that is consistent with the hypothesis that it does not actually exist (the Humans Are Still Animals Hypothesis): “The germs of existence contained in this earth, if they could freely develop themselves, would fill millions of worlds in the course of a few thousand years. Necessity, that imperious, all-pervading law of nature, restrains them within the prescribed bounds. The race of plants and the race of animals shrink under this great restrictive law; and man cannot by any efforts of reason escape from it.” Thomas Malthus, An Essay on the Principles of Population (1798). “There is no exception to the rule that every organic being naturally increases at so high a rate, that, if not destroyed, the earth would soon be covered by the progeny of a single pair.” Charles Darwin, On the Origin of Species (1859).
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MATTHEW WATKINSON • WEB: http://www.fishsnorkel.com • TWITTER: http://twitter.com/fishsnorkel
THE DEMOGRAPHIC TRANSITION A lot of people currently regard the demographic transition as the solution to population growth and, thus, the saviour of humanity, but elsewhere in nature the transition from rstrategy to K-strategy is often the result of population growth, not the solution to it. Climax communities are often dominated by K strategists for example, as opposed to the r-strategists that dominate earlier successional communities. Indeed, it makes intuitive sense to me to prioritise quantity over quality while population densities and intraspecific competitive interactions are low (i.e. in virgin opportunities), and quality over quantity when population densities and intraspecific competitive interactions are high (i.e. in climax communities). This is the basis of Lars Witting’s Theory of Malthusian Relativity: “[The principle of density-dependent competitive interactions] recognises that self-replication generates population growth that results in increased densities of self-replicators generating increased interactive competition that selects for an increase in interactive quality.” Lars Witting, Inevitable evolution: back to The Origin and beyond the 20th Century paradigm of contingent evolution by historical natural selection (http://bit.ly/byQOBl).
And it has been empirically demonstrated in at least two populations of non-hominid animals. Firstly, in a population of side-blotched lizards (Uta stansburiana): “Our study shows that r-strategists, orange females, are favoured at low density because they produce large clutches of small eggs...Yellow females, the K-strategists, gain a rare advantage at high density through production of fewer but larger hatchlings.” Sinervo et al, Density cycles and an offspring quantity and quality game driven by natural selection (http://bit.ly/c8AMrP).
And secondly, in a population of bank voles (Myodes glareolus): “Females with low reproductive effort were especially favored in low densities. Moreover, females with high reproductive effort were most successful when they were rare in high density populations.” Mappes et al, Frequency and Density-Dependent Selection on Life-History Strategies – A Field Experiment (http://bit.ly/aCC3MG).
Both of these studies provide clear evidence of a demographic transition associated with increasing competition in other animals, and both lead to the following question: is the demographic transition in humans really the panacea some would like to believe, or is it a logical response to increasing competition for resources (both locally and globally) and actually linked to the natural tendency of all populations to grow until there are positive checks? That the human transition is traditionally associated with western affluence does not mean it cannot also explain fertility reductions elsewhere as well, as Virginia Deane Abernethy has attempted to explain in her papers on the Fertility Opportunity hypothesis, a Darwinian take on the human demographic transition that favours the existence of responses to positive checks over the biologically paradoxical “wisdom” of affluent humans: “Humans appear to be alert to environmental signs that indicate whether conditions for childbearing and nurture are more or less optimal, given the possibilities.” Virginia Deane Abernethy, A Darwinian Account of the Fertility Opportunity Hypothesis (http://bit.ly/cPj9A1). See also: Fertility decline; no mystery (http://bit.ly/dbGXBE).
The suggestion is that humans, like many other organic beings, restrict their fertility in response to negative environmental signals concerning the prospect of successfully raising children capable of competing in whatever circumstances happen to be relevant at the time, which, as it seems to me, is much easier to accept than a counter-intuitive and biologically nonsensical shift away from reproductive desire in response to expanding reproductive opportunity. “...population grows until stresses rise far enough to stop further increase.” Jay W. Forrester, World Dynamics (1973).
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MATTHEW WATKINSON • WEB: http://www.fishsnorkel.com • TWITTER: http://twitter.com/fishsnorkel
For example, if both parents have to work full-time in an industrialised society, there are obvious implications for the time and energy available for raising a large family, as discussed in the literature relating to the Maternal Role Incompatibility Hypothesis: “The association between fertility and women's labor force activity reflects the incompatibility between caring for children and participating in economically productive work that typifies industrialized societies. Prior to industrialization, work and child rearing tasks could be performed more or less simultaneously...As industrialization proceeded, however, childcare and economically productive work became increasingly incompatible.” Brewster and Rindfuss, Fertility and Women's Employment in Industrialized Nations (http://bit.ly/bwUHsK).
Essentially, K-strategist humans competing with other K-strategist humans may need to invest more in fewer offspring (and possibly none at all) than r-strategist humans competing with other r-strategist humans, which should come as no surprise to anyone. “The various theories which have sought to discover in wealth a cause of infertility, have missed the point that infertility is an important cause of wealth.” R. A. Fisher, The Genetical Theory of Natural Selection (1930).
Unfortunately however, if environmental signals about the availability of resources are important in determining human fertility rates, this has disturbing implications for the provision of humanitarian aid, because this may end up masking environmental signals, artificially altering fertility rates and, ultimately, leading to bigger problems in the future: “...if we make provision for rising population, population responds by rising.” Jay W. Forrester, World Dynamics (1973).
This obviously leads to some pretty distasteful conclusions about the role of charitable interference, but it is a logical consequence if we are animals like any other and one the Royal Society should probably consider if it really wants to deliver a “dispassionate assessment of the best available evidence”. “Nothing is easier than to admit in words the truth of the universal struggle for life, or more difficult—at least I have found it so—than constantly to bear this conclusion in mind.” Charles Darwin, On the Origin of Species (1859).
CONSPICUOUS CONSUMPTION Reducing consumption has also been championed as a solution to the impact of the human population, but escalating consumption may also be a function of our biology and thus not something we can ever hope to change on a significant scale. Here is a popular online encyclopaedia on intersexual selection for example, with obvious implications for those who have recognised the link between reproductive fitness and partner "quality" and the importance of female and male concession in the reproduction of Homo sapiens: “In species where the reproductive success of one sex depends heavily on winning the concession of the other, as with many polygamous birds [and humans], sexual selection will act by increasing the degree of preference to which it is due, with the consequence that both the trait preferred and the intensity of preference will be increased together. This process causes a fervent and rapid evolution of both the conspicuous ornamentation and the preference for such, until arrested directly or indirectly for ecological reasons. Thus, in many cases a positive feedback loop of sexual selection is created, resulting in exorbitant physical structures [and other resource-wasting traits] in the nonlimited sex, the most notorious example being the peacock [and the ostentatious human?].”
Being a social species, within which an individual’s reputation may be important, there may be exploitative drivers of what Thorstein Veblen called “conspicuous consumption” as well: “The basis on which good repute in any highly organized industrial community ultimately rests is
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MATTHEW WATKINSON • WEB: http://www.fishsnorkel.com • TWITTER: http://twitter.com/fishsnorkel
pecuniary strength; and the means of showing pecuniary strength, and so of gaining or retaining a good name, are leisure and a conspicuous consumption of goods.” Thorstein Veblen, The Theory of the Leisure Class (1899).
Essentially, ostentatious resource utilisation (culture?) may be an honest “handicap” signal that exists because of interspecific competition for status and reputation. A conclusion which is reinforced by work relating to the Rank Income Hypothesis: “The rank income hypothesis contrasts with traditional reference-income hypotheses, which suggest that utility from income depends on comparison to a social reference-group norm. We found that the ranked position of an individual’s income predicts general life satisfaction, whereas absolute income and reference income have no effect.” Boyce et al, Money and Happiness: Rank of Income, Not Income, Affects Life Satisfaction (http://bit.ly/dcaMSH).
It is also a conclusion that naturally emerges from the thermodynamic principle governing the investments required to succeed in a competitive environment (the Maximum Power Principle): “…the fundamental object of contention in the life-struggle, in the evolution of the organic world, is available energy. In accord with this observation is the principle that, in the struggle for existence, the advantage must go to those organisms whose energy-capturing devices are most efficient in directing available energy into channels favorable to the preservation of the species [race is probably a more appropriate term here, considering the relevance of competition within species as well as between].” A. J. Lotka, Contribution to the Energetics of Evolution (http://bit.ly/aEb4z0).
Unfortunately however, this means breaking the biological foundations of escalating resource consumption before the arrival of resource related positive checks (peak oil etc.) may actually involve eliminating all forms of intraspecific competition and, regardless of widespread belief to the contrary, including, quite remarkably, many who claim to represent the science of natural history, I can think of nothing more fanciful than a totally cooperative species: “…the struggle [for life] will almost invariably be most severe between the individuals of the same species, for they frequent the same districts, require the same food, and are exposed to the same dangers.” Charles Darwin, On the Origin of Species (1859).
(We have not even managed to eliminate crime, never mind a biological force that has been defining life for more than three and a half thousand million years.)
CONCLUSION Philosophers concerned with the sustainability of mankind can be divided into two basic categories: those that believe humanity’s escalating impact can be halted voluntarily in the absence of positive checks, and those that don’t. The latter are supported by the entire history of life on Earth (including mankind’s biologically predictable population bloom in response to its recent access to nearly half the planet’s accessible fossilised sunlight – see Appendix A for more on the relationship between energy supply and population size). The former are not, still: “It is, undoubtedly, a most disheartening reflection, that the great obstacle in the way to any extraordinary improvement in society, is of a nature that we can never hope to overcome.” Thomas Malthus, An Essay on the Principles of Population (1798). “...as man suffers from the same physical evils as the lower animals, he has no right to expect an immunity from the evils consequent on the struggle for existence.” Charles Darwin, The Descent of Man (1871).
So, when it comes to Homo sapiens, what are the principles of population?
“…but, alas! a scientific man ought to have no wishes, no affections a mere heart of stone.” Charles Darwin 4
MATTHEW WATKINSON • WEB: http://www.fishsnorkel.com • TWITTER: http://twitter.com/fishsnorkel
APPENDIX A: Fossilised Sunlight and the Human Population “...every surviving individual and species needs to do things that gain more energy than they cost, and those species that are successful in an evolutionary sense are those that generate a great deal of surplus energy that allows them to become abundant and to spread.” Hall et al, What is the Minimum EROI that a Sustainable Society Must Have? (http://bit.ly/b4NAEz).
Total carbon emissions from fossil-fuels (million tonnes of C)
It would be truly foolish just to put two graphs together and draw a conclusion, but these graphs would be consistent with a fairly robust link between the size of the primary energy supply and the size of the consumer population and, as such, they may be relevant to the human population debate. The first graph shows total carbon emissions from fossil fuels - as a proxy measurement for the total consumption of fossil fuels - in the context of a 10,000 year period centred on the year 2000. The second shows the size of the human population in the same period: 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 -3000
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Data source: Boden, T.A., G. Marland, and R.J. Andres. 2010. Global, Regional, and National Fossil-Fuel CO2 Emissions. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory (http://bit.ly/b92QUN).
Human population size (millions)
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Data Sources: US Census Bureau, Historical Estimates of World Population (http://bit.ly/bTYYnA). United Nations Population Division, World Population Prospects: The 2008 Revision (http://bit.ly/99bVVD).
Could the size of the human population be linked to the size of its primary energy supply? "Lighten any check, mitigate the destruction ever so little, and the number of the species will almost instantaneously increase to any amount." Charles Darwin, On the Origin of Species (1859).
And, if it is, what will happen when the supply of fossilised sunlight starts to decline (peak oil etc.)? 5