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The natural regulation of animal numbers

01 Jan 1954-
About: The article was published on 1954-01-01 and is currently open access. It has received 3086 citations till now. The article focuses on the topics: Animal ecology.
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Journal ArticleDOI
13 Dec 1968-Science
TL;DR: The population problem has no technical solution; it requires a fundamental extension in morality.
Abstract: The population problem has no technical solution; it requires a fundamental extension in morality.

22,421 citations

Journal ArticleDOI
TL;DR: The tragedy of the commons as a food basket is averted by private property, or something formally like it as mentioned in this paper, which is why the commons, if justifiable at all, is justifiable only under conditions of low-population density.
Abstract: The tragedy of the commons as a food basket is averted by private property, or something formally like it. The pollution problem is a consequence of population. Analysis of the pollution problem as a function of population density uncovers a not generally recognized principle of morality, namely: the morality of an act is a function of the state of the system at the time it is performed. Those who have more children will produce a larger fraction of the next generation than those with more susceptible consciences. Perhaps the simplest summary of the analysis of man’s population problems is this: the commons, if justifiable at all, is justifiable only under conditions of low-population density. As the human population has increased, the commons has had to be abandoned in one aspect after another. The man who takes money from a bank acts as if the bank were a commons.

7,119 citations

Journal ArticleDOI
TL;DR: In this article, the Dickcissel sex ratio is employed as an indirect index of suitability and a sex ratio index was found to be correlated positively with density, consistent with the hypothesis that territorial behavior in males of this species limits their density.
Abstract: This example is provided so that non-theorists may see actual applications of the theory previously described. The Dickcissel sex ratio is employed as an indirect index of suitability. A sex ratio index was found to be correlated positively with density. This is consistent with the hypothesis that territorial behavior in the males of this species limits their density. This study provides a valid example of how the problem can be approached and offers a first step in the eventual identification of the role of territorial behavior in the habitat distribution of a common species.

4,210 citations

Journal ArticleDOI
TL;DR: This review organizes ideas on the evolution of life histories into more comprehensive theory that makes more readily falsifiable predictions, and examination of different definitions of fitness.
Abstract: This review organizes ideas on the evolution of life histories. The key life-history traits are brood size, size of young, the age distribution of reproductive effort, the interaction of reproductive effort with adutl mortality, and the variation in these traits among an individual's progeny. The general theoretical problem is to predict which combinations of traits will evolve in organisms living in specified circumstances. First consider single traits. Theorists have made the following predictions: (1) Where adult exceeds juvenile mortality, the organism should reproduce only once in its lifetime. Where juvenile exceeds adult mortality, the organism should reproduce several times. (2) Brood size should maximize the number of young surviving to maturity, summed over the lifetime of the parent. But when optimum brood-size varies unpredictably in time, smaller broods should be favored because they decrease the chances of total failure on a given attempt. (3) In expanding populations, selection should minim...

3,422 citations

Journal ArticleDOI
TL;DR: The problem that is presented by the phytoplankton is essentially how it is possible for a number of species to coexist in a relatively isotropic or unstructured environment all competing for the same sorts of materials.
Abstract: The problem that I wish to discuss in the present contribution is raised by the very paradoxical situation of the plankton, particularly the phytoplankton, of relatively large bodies of water. We know from laboratory experiments conducted by many workers over a long period of time (summary in Provasoli and Pintner, 1960) that most members of the phytoplankton are phototrophs, able to reproduce and build up populations in inorganic media containing a source of CO2, inorganic nitrogen, sulphur, and phosphorus compounds and a considerable number of other elements (Na, K, Mg, Ca, Si, Fe, Mn, B, C1, Cu, Zn, Mo, Co and V) most of which are required in small concentrations and not all of which are known to be required by all groups. In addition, a number of species are known which require one or more vitamins, namely thiamin, the cobalamines (B or related compounds), or biotin. The problem that is presented by the phytoplankton is essentially how it is possible for a number of species to coexist in a relatively isotropic or unstructured environment all competing for the same sorts of materials. The problem is particularly acute because there is adequate evidence from enrichment experiments that natural waters, at least in the summer, present an environment of striking nutrient deficiency, so that competition is likely to be extremely severe. According to the principle of competitive exclusion (Hardin, 1960) known by many names and developed over a long period of time by many investigators (see Rand, 1952; Udvardy, 1959; and Hardin, 1960, for historic reviews), we should expect that one species alone would outcompete all the others so that in a final equilibrium situation the assemblage would reduce to a population of a single species. The principle of competitive exclusion has recently been under attack from a number of quarters. Since the principle can be deduced mathematically from a relatively simple series of postulates, which with the ordinary postulates of mathematics can be regarded as forming an axiom system, it follows that if the objections to the principle in any cases are valid, some or all the biological axioms introduced are in these cases incorrect. Most objections to the principle appear to imply the belief that equilibrium under a given set of environmental conditions is never in practice obtained. Since the deduction of the principle implies an equilibrium system, if such sys-

2,898 citations