摘要:

This work is dedicated to Professor Kenneth Boulding, who, on so many delightful occasions has encouraged me to challenge even the most cherished of ideas.Adopting a comparative approach to the study of economic and ecological models of resource allocation behaviour it is evident that both fields have not only analogous theories but that these theories rest on similar but tenuous grounds. Application of optimality models to these areas now appears far too simplistic a reading of evolutionary and cultural history. There are strong reasons why such models, rather than offering new insight, lead to a dead end. First, it is difficult to justify the underlying assumptions and to find quantitative measures for the supposed objective function in decision making, for example, psychic satisfaction in economics; fitness in ecology. Second, given evolutionary and behavioural lags to changing environments, optimality arguments are difficult to test. Third, experimental work, while often elegant in its construction, has lacked sufficient realism to give confidence that its findings are applicable in nature. Finally, the results that have been obtained, even evaluated on their own grounds provide much in the way of counter‐examples to the principles of optimization in complex environments. It may be necessary to forego some of the elegance of the mathematical constructs to obtain descriptions of resource allocation behaviour that are better grounded in the real worl

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00616.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Juvenile Atlantic salmon (Salmo salar) meristic and morphometric characteristics were examined from 47 European and North American river populations. The relative importance of continental origin, stream gradient, overall temperature regime, and seasonal temperatures in explaining the phenotypic variation of these populations was evaluated using multi‐way ANOVA. Ecological factors explained a greater percentage of the variance than continental origin for both meristic and morphometric characters. Stream gradient was the most important factor explaining morphometric variation and April‐May mean temperature was the most important factor explaining meristic variat

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00617.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

The study of metabolism has traditionally focused upon factors that influence metabolic rate, at levels of both the metabolic pathway and the whole organism. This paper focuses on the cost, and thereby the efficiency, of metabolic processes. The genotype‐dependent cost of enzyme turnover is proposed as a biochemical genetic mechanism for relating genetic variation at single genes to phenotypic variation in quantitative traits of energy metabolism. Decreased costs of maintenance metabolism can accompany artificial selection for increased production (e.g. growth, reproduction, etc.) and lower maintenance is correlated with multiple locus heterozygosity in outbred populations. In both cases, high production has been associated with lower rates of protein turnover. Several factors influence the ATP‐equivalent cost of enzyme turnover. These factors are used to calculate the cost of turnover for a single enzyme. This cost can conservatively constitute up to several percent of the total daily mass‐specific energy demands of maintenance metabolism. Genetic variants of an enzyme can differ in the cost of turnover. These differences can constitute the basis for metabolic changes associated with artificial selection for production and the metabolic differences that are associated with individual levels of heterozygosity. The metabolic and evolutionary significance of genotype‐dependent turnover costs is a function of individual energy balance. The strength of selection against increases in cost will be an inverse function of individual energy balance and is therefore influenced by both environmental and genetic

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00618.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Advertisement calls of the cricket frog,Acris crepitans, show statistically significant variation among populations in all call variables measured. Call variables show strong clinal variation resulting in calls of lower frequency, longer duration and slower call rates produced byA. c. blanchardiin open habitat in the west of the range, and calls of higher frequency, shorter calls and faster call rates produced byA. c. crepitansin the pine forests in the eastern part of the range. This clinal variation does not result from pleiotropic effects of body size or any other morphological characters we measured.The two subspecies usually reside in different habitats, but someA. c. blanchardireside in an isolated pine forest in central Texas. By comparing the calls of this subspecies in open and forest habitat, and by statistically removing the effects of clinal variation for all populations, we determined that habitat explains some of the variation in call structure; this is not true of subspecies.Our data reject several hypotheses that purport to explain the evolution of mate recognition signals. (1) We reject the notion of Paterson and others that there is strong stabilizing selection on species‐specific mate recognition signals. (2) There is no support for the hypothesis that call variation is primarily due to pleiotropic effects of body size or other morphological characters over the geographic range we examined. (3) There is no evidence for reproductive character displacement. (4) Our data, as well as experimental studies of habitat acoustics, support the hypothesis that some differences in calls among habitats result from environmental selection on call structure to enhance call transmission. We suggest that the latter hypothesis does not explain the strong clinal component of call variation. This might result from the passive effects of gene flow between populations at the extremes of the range under selection generated by habitat acoustic

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00619.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Offspring derived from several single pair matings and a mass matingof Mytilus eduliswere cultured up to the juvenile stage in the laboratory. Samples were collected from the cultures at an early post‐ settlement (‘spat’) stage and again at the juvenile stage and were scored at up to nine enzyme loci using cellulose acetate and starch gel electrophoresis. An overall significant deficiency of heterozygotes was evident at the juvenile stage but not at the spat stage. Selection against heterozygotes (underdominance) is proposed as the cause.For each mating, shell lengths of juvenile mussels were measured and individuals were classed according to the number of loci at which they were heterozygous. No significant correlations were evident between heterozygosity class and either growth (shell length), or coefficient of variation of shell length. It is argued that these results provide support for the ‘associative overdominance’ rather than the ‘overdominance’ hypothesis as an explanation for heterozygosity/growth correlations in marine bivalves.These data also show that although heterozygosity and growth co‐occur in most data sets from natural populations, they may have distinctly d

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1991.tb00620.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY