Showing papers on "Selection (genetic algorithm) published in 1981"
TL;DR: Natural selection has now made its case, but similar delays in recognizing the role of selection in the other fields could deprive us of valuable help in solving the problems which confront us.
Abstract: Selection by consequences is a causal mode found only in living things, or in machines made by living things. It was first recognized in natural selection, but it also accounts for the shaping and maintenance of the behavior of the individual and the evolution of cultures. In al three of these fields, it replaces explanations based on the causal modes of classical mechanics. The replacement is strongly resisted. Natural selection has now made its case, but similar delays in recognizing the role of selection in the other fields could deprive us of valuable help in solving the problems which confront us.
1,309 citations
Journal Article•
1,156 citations
Journal Article•
566 citations
TL;DR: An experiment in which 150 proposals submitted to the National Science Foundation were evaluated independently by a new set of reviewers indicates that getting a research grant depends to a significant extent on chance.
Abstract: An experiment in which 150 proposals submitted to the National Science Foundation were evaluated independently by a new set of reviewers indicates that getting a research grant depends to a significant extent on chance. The degree of disagreement within the population of eligible reviewers is such that whether or not a proposal is funded depends in a large proportion of cases upon which reviewers happen to be selected for it. No evidence of systematic bias in the selection of NSF reviewers was found.
560 citations
TL;DR: In this article, an asymptotically optimal selection of regression variables is proposed, where the key assumption is that the number of control variables is infinite or increases with the sample size.
Abstract: SUMMARY An asymptotically optimal selection of regression variables is proposed. The key assumption is that the number of control variables is infinite or increases with the sample size. It is also shown that Mallows's Qp, Akaike's FPE -and AIC methods are all asymptotically equivalent to this method.
542 citations
TL;DR: Survival of Darwin's finches through a drought on Daphne Major Island was nonrandom and selection intensities are the highest yet recorded for a vertebrate population.
Abstract: Survival of Darwin's finches through a drought on Daphne Major Island was nonrandom. Large birds, especially males with large beaks, survived best because they were able to crack the large and hard seeds that predominated in the drought. Selection intensities, calculated by O'Donald's method, are the highest yet recorded for a vertebrate population.
540 citations
TL;DR: It is argued that parasite-host systems are ideal candidates for interdemic or "group" selection because of the potential for selection for avirulence based upon reduced host (hence group) survival.
Abstract: On theoretical grounds, we argue that parasite-host systems are ideal candidates for interdemic or "group" selection because of the potential for selection for avirulence based upon reduced host (hence group) survival. Such selection appears to have been an important ingredient in the stabilization of the myxomatosis-rabbit system in Australia, although clearly the evolution of resistance in the rabbit population also played a part. We present a simple mathematical model to demonstrate how easily group selection can (in theory) stabilize a parasite-host system. This model is not meant to be a literal translation of the myxomatosis-rabbit interaction, and in fact intentionally disregards host evolution; its purpose is to isolate the role of group selection in the parasite population. Fenner has established that both interdemic selection and host evolution were important in the stabilization of that system, although our model demonstrates that in theory interdemic selection alone could stabilize the interac...
509 citations
TL;DR: Natural selection for late-age fitness components increased late fecundity, female longevity, and the duration of female reproduction, while early fecundities and mean egg-laying rate decreased.
Abstract: Two types of small-scale selection experiments were performed. (1) Artificial selection experiments were performed on age-specific female fecundity. Selection for early fecundity over three generations produced a statistically detectable direct response. There was no detectable indirect response in other life-history characters. Selection for late fecundity over three generations did not produce any detectable direct response. Indirect responses were detected: early egg-laying decreased and longevity increased. (2) Natural selection for late-age fitness components increased late fecundity, female longevity, and the duration of female reproduction, while early fecundity and mean egg-laying rate decreased.
418 citations
TL;DR: This paper summarizes data on development rate for 54 species of insects and data on annual temperature regimes on an elevational and a latitudinal gradient and points out several new evolutionary consequences of the position and shape of the development rate curve in relation to season and location.
Abstract: The fact that development rate of insects changes with temperature implies that the rate at which time passes for a developing insect depends upon the temperature regime it experiences. Understanding this so-called physiological time is of the utmost importance in explaining adaptations of insect life histories to resources that vary seasonally. This paper summarizes data on development rate for 54 species of insects and data on annual temperature regimes on an elevational and a latitudinal gradient. It then treats the curve representing temperature-dependent development as a filter of the temperature regimes during various seasons. The analysis points out several new evolutionary consequences of the position and shape of the development rate curve in relation to season and location. (1) If the criterion for maximizing fitness is fastest development accumulation, the optimal development curve can be specified. (2) In locations with high midsummer temperatures selection could favor different development cu...
412 citations
331 citations
TL;DR: The segmentation algorithm proposed in this paper is a complex form of thresholding which utilizes multiple thresholds and not only works well for simple images but also produces reasonable segmentations for complex images.
TL;DR: Methods for the estimation of genetic correlations from inbred strain comparisons are presented and appear to be valid when compared to those derived from more demanding parent-offspring comparisons and to correlated responses to selection.
Abstract: Genetic correlations measure the extent of pleiotropic effects of polygenes on pairs of characters or the closeness of linkage between sets of loci influencing the traits and held in allelic (gametic) disequilibrium. Their importance for research lies primarily in predicting correlated responses of one trait to selection based on values for another, and secondarily in analyzing the complex organization of biological systems. Genetic correlations appear to limit the rate and set the direction of multivariate evolution. In view of this, efficient methods for estimating genetic correlations may be essential for understanding the role of behavior in adaptation and for predicting behavioral change in evolution. In this paper we present methods for the estimation of genetic correlations from inbred strain comparisons. Estimates from inbred strains are relatively easy to obtain and appear to be valid when compared to those derived from more demanding parent-offspring comparisons and to correlated responses to selection.
TL;DR: Laboratory experiments performed on a monogamous estrildid, the zebra finch, indicate that sex ratio of offspring is affected by non-genetic markers (colored plastic leg bands) that vary in attractiveness to birds.
Abstract: Laboratory experiments performed on a monogamous estrildid, the zebra finch (Poephila guttata), indicate that sex ratio of offspring is affected by non-genetic markers (colored plastic leg bands) that vary in attractiveness to birds. Results suggest that natural selection favors individuals that produce offspring of the sex of the more attractive parent within a breeding pair.
Book•
01 Jan 1981
TL;DR: Turbomachines : conception Reference Record created on 2005-11-18, modified on 2016-08-08.
Abstract: Keywords: turbomachines ; conception Reference Record created on 2005-11-18, modified on 2016-08-08
TL;DR: It is postulated that E. coli is composed of a relatively limited number of geographically widespread and genetically nearly isolated and monomorphic lineages, and the implications of these considerations of the genetic structure of E. bacteria populations on the interpretation of protein variation and the neutral gene hypothesis are discussed.
Abstract: As a consequence of sequential replacements by clones of higher fitness (periodic selection), bacterial populations would be continually purged of genetic variability, and the fate of selectively neutral alleles in very large populations of bacteria would be similar to that in demes of sexually reproducing organisms with small genetically effective population sizes. The significance of periodic selection in reducing genetic variability in these clonally reproducing species is dependent on the amount of genetic exchange between clones (recombination). In an effort to determine the relationship between the rates of periodic selection, recombination and the genetically effective sizes of bacterial populations, a model for periodic selection and infectious gene exchange has been developed and its properties analyzed. It shows that, for a given periodic selection regime, genetically effective population size increases exponentially with the rate of recombination.--With the parameters of this model in the range anticipated for natural populations of E. coli, the purging effects of periodic selection on genetic variability are significant; individual populations or lineages of this bacterial species would have very small genetically effective population sizes.--Based on this result, some other a priori considerations and a review of the results of epidemiological and genetic variability studies, it is postulated that E. coli is composed of a relatively limited number of geographically widespread and genetically nearly isolated and monomorphic lineages. The implications of these considerations of the genetic structure of E. coli populations on the interpretation of protein variation and the neutral gene hypothesis are discussed.
TL;DR: It is shown that the multilocus estimator provides a standard of reference that can be useful in analyzing the effects of factors such as population heterogeneity and post-mating zygotic selection on the transmission of genetic information at the population level.
Abstract: A multilocus method of estimating mating system parameters in populations is presented that recovers information from classification over multiple loci that single-locus estimators do not detect. It is shown that the multilocus estimator provides a standard of reference (null hypothesis) that can be useful in analyzing the effects of factors such as population heterogeneity and post-mating zygotic selection on the transmission of genetic information at the population level.
TL;DR: In this paper, a method, termed "bending", is proposed for the modification of the estimates of genetic (G) and phenotypic (P) covariance matrices, that are used in the construction of genetic selection indices for two or more traits.
Abstract: A method, termed 'bending', is proposed for the modification of the estimates of genetic (G) and phenotypic (P) covariance matrices, that are used in the construction of genetic selection indices for two or more traits. If P and G are estimated from the betweenand within-class covariance matrices, B and W respectively, in a one-way multivariate analysis of variance, then the method consists of contracting all the eigenvalues of the matrix product W-1B towards their mean but with the corresponding eigenvectors unchanged. The usefulness of the modification procedure is investigated by Monte Carlo simulation and Taylor series approximation methods. In general, the modification procedure improves the achieved response to selection, with the amount of improvement dependent on the (unknown) population parameters and the size of sample for estimation. In practice, there is some difficulty in selecting the value of the 'bending' factor; some very simple methods of doing this are proposed. If some of the parameter estimates are known to be defective (outside their valid limits), a simple and effective method for the selection of the 'bending' factor is to contract the eigenvalues so that they are all nonnegative.
TL;DR: It is demonstrated that current knowledge of the taxonomic distributions of dioecy and self-incompatibility systems provides good reasons for assuming that selection for outcrossing may frequently be a sine qua non for the evolution of dIOecy.
Abstract: The evolution of dioecy in plants has traditionally been explained as a result of selection for outcrossing (Baker 1959; Carlquist 1966, 1974; Darlington 1958; Darwin 1877; Gilmartin 1968; Ho and Ross 1974; Lewis 1942; Lloyd 1972, 1975; Mather 1940; Maynard Smith 1978; Ross 1970, 1978; Ross and Shaw 1971; Ross and Weir 1976; Stebbins 1951). Population genetical models, notably those of Charlesworth and Charlesworth (1978, 1979) have indicated that inbreeding depression is usually necessary for the evolution of dioecy from hermaphroditism. Recently, the importance of outcrossing has been questioned independently by several authors who, following Bateman (1948), propose that sexual selection acting on the male and female components of hermaphrodites (see Charnov 1979; Charnov et al. 1976; Janzen 1977) and selection for optimal resource allocation can also explain the evolution of dioecy. Willson (1979, p. 779) presents her version of this sexual selection hypothesis to counter \"the kneejerk response that the advantage of dioecy and other functional differentiations of sexual roles in plants lies solely in the advantage of outcrossing.\" Givnish (1980) and Bawa (1980) also question the causal role of selection for outcrossing in promoting dioecy and offer alternative models based on the ecological roles of pollination and dispersal. Although we applaud the development of new theory, we fear that this recent cohort of \"alternative\" explanations may obscure some important reasons for retaining the outcrossing hypothesis. Here we demonstrate that current knowledge of the taxonomic distributions of dioecy and self-incompatibility systems provides good reasons for assuming that selection for outcrossing may frequently be a sine qua non for the evolution of dioecy. Willson (1979), Bawa (1980), and Givnish (1980) provide variously detailed scenarios in which differential male and female costs and success rates can lead to dioecy independently of inbreeding/outbreeding considerations (see also Charnov 1979). Bawa and Givnish go on to document new ecological correlates of dioecy which, they believe, provide evidence for the sexual selection explanations. In general, the explanations cannot easily be refuted, because they make few explicit assumptions about genetic mechanisms and because they depend on certain relationships between costs and benefits that strongly resist quantitative study because of difficulties in selecting and measuring a fitness-based cost/benefit currency. For this reason we do not wish to debate the relative merits of specific details of these various proposals, except to state that all of them seem to depend on a rather high predictability of success for a particular genotype and on a high degree of heritability of phenotypic gender (see Williams 1975, p. 130). Such dependence may be unwarranted, given the plasticity of individual development in plants (see Gottlieb 1977) and the great importance of spatial location in mating success. Instead, we try to assess the overall importance of any mechanisms for evolving dioecy which are independent of outbreeding considerations. We also
Patent•
22 May 1981
TL;DR: In this paper, a cable television converter includes an oscillator and mixer for conversion of a selected input television channel to the specific output frequency of the converter, and a program selection device and a memory responsive to a user's preference.
Abstract: A cable television converter includes an oscillator and mixer for conversion of a selected input television channel to the specific output frequency of the converter. There is a program selection device, and a memory responsive thereto whereby a subscriber may designate certain channels for conversion to the output frequency. The program selection device provides for restricting access to only those designated channels in the memory whereby a subscriber may control access of members of the household to only certain permitted channels.
TL;DR: Density-dependent genetic evolution was tested in experimental populations of Drosophila melanogaster subject for eight generations to natural selection under high (K-selection) or low (r- selection) population density regimes, and results corroborate the predictions derived from formal models of density-dependent selection.
Abstract: Density-dependent genetic evolution was tested in experimental populations of Drosophila melanogaster subject for eight generations to natural selection under high (K-selection) or low (r-selection) population density regimes The test consisted of determining at high and at low densities the per capita rate of population growth of the selected populations At high densities, the K-selected populations showed a higher per capita rate of population growth than did r-selected populations, but the reverse was true at low densities These results corroborate the predictions derived from formal models of density-dependent selection However, no evidence of a trade-off in per capita rate of growth was observed in 25 populations of D melanogaster, each homozygous for a different second chromosome sampled from a natural population
TL;DR: The experimental evidence concerning the existence and importance of maternal effects in beef cattle, dairy cattle and swine is reviewed and some suggestions are given for altering management programs to increase production and selection efficiency.
TL;DR: The purpose of this paper is to provide a quantitative conceptual framework for understanding selection bias; this framework integrates both epidemiologic and statistical considerations.
Abstract: Consideration of factors involved in the selection of subjects is essential for evaluating the validity of a putative etiologic association. The purpose of this paper is to provide a quantitative conceptual framework for understanding selection bias; this framework integrates both epidemiologic and statistical considerations. Emphasis is given to specifying the conditions under which such bias is likely to occur, identifying the direction and magnitude of the bias, and illustrating how these features differ by type of study design.
TL;DR: This research returns to very basic scheduling models in search of fundamental insights and relationships that suggest guidelines for due-date selection in more complicated situations and exploits some fundamental results from scheduling theory involving the single-machine model in order to compare three basic strategies.
Abstract: In sequencing and scheduling models it is usually assumed that due dates represent exogeneous information. In many practical settings, however, due dates can be discretionary, or at least negotiable. Relatively few studies have incorporated discretionary due dates, and even then the rules proposed for due-date selection have seldom been developed from normative, analytic results. In this research we return to very basic scheduling models in search of fundamental insights and relationships that suggest guidelines for due-date selection in more complicated situations. We exploit some fundamental results from scheduling theory involving the single-machine model in order to compare three basic strategies for due-date selection.
01 Jan 1981
TL;DR: In this article, the authors explore the reasons for individual differences in animal behavior and points to various ways in which they deserve closer study, such as feeding, mating, or fighting behavior.
Abstract: This article explores reasons for individual differences in animal behavior and points to various ways in which they deserve closer study. Differences in feeding, mating, or fighting behavior may occur because selection favors the adoption of different strategies by different individuals. Variations in signals may arise through selection for animals to be identifiable as individuals or for their relatedness to others to be assessed. The variability of behavior itself varies between different patterns in which it has been measured. Variation may arise because the exact form of the behavior being measured makes little difference from the point of view of selection. It is also suggested that variability in other cases may come about because, in an unpredictable environment, the best course of action cannot be forecast.