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1.
Evolution takes place in an ecological setting that typically involves interactions with other organisms. To describe such
evolution, a structure is needed which incorporates the simultaneous evolution of interacting species. Here a formal framework
for this purpose is suggested, extending from the microscopic interactions between individuals – the immediate cause of natural
selection, through the mesoscopic population dynamics responsible for driving the replacement of one mutant phenotype by another,
to the macroscopic process of phenotypic evolution arising from many such substitutions. The process of coevolution that results
from this is illustrated in the context of predator–prey systems. With no more than qualitative information about the evolutionary
dynamics, some basic properties of predator–prey coevolution become evident. More detailed understanding requires specification
of an evolutionary dynamic; two models for this purpose are outlined, one from our own research on a stochastic process of
mutation and selection and the other from quantitative genetics. Much of the interest in coevolution has been to characterize
the properties of fixed points at which there is no further phenotypic evolution. Stability analysis of the fixed points of
evolutionary dynamical systems is reviewed and leads to conclusions about the asymptotic states of evolution rather different
from those of game-theoretic methods. These differences become especially important when evolution involves more than one
species.
Received 10 November 1993; received in revised form 25 July 1994 相似文献
2.
Jacques Gervet Alain Gallo Raphael Chalmeau Muriel Soleilhavoup 《Acta biotheoretica》1996,44(1):37-57
A distinction is made between two definitions of animal cognition: the one most frequently employed in cognitive sciences considers cognition as extracting and processing information; a more phenomenologically inspired model considers it as attributing to a form of the outside world a significance, linked to the state of the animal. The respective fields of validity of these two models are discussed along with the limitations they entail, and the questions they pose to evolutionary biologists are emphasized. This is followed by a presentation of a general overview of what might be the study of the evolution of knowledge in animals. 相似文献
3.
4.
Chaos in three species food chains 总被引:7,自引:0,他引:7
We study the dynamics of a three species food chain using bifurcation theory to demonstrate the existence of chaotic dynamics in the neighborhood of the equilibrium where the top species in the food chain is absent. The goal of our study is to demonstrate the presence of chaos in a class of ecological models, rather than just in a specific model. This work extends earlier numerical studies of a particular system by Hastings and Powell (1991) by showing that chaos occurs in a class of ecological models. The mathematical techniques we use are based on work by Guckenheimer and Holmes (1983) on co-dimension two bifurcations. However, restrictions on the equations we study imposed by ecological assumptions require a new and somewhat different analysis. 相似文献
5.
本文给出了方程dx/dt=f(x(t-1))出现4/(2n 1),4/(2n-1),4/(2n-3),…,4/7,4/5,4/3,4一周期解并蕴含浑沌的一个条件。 相似文献
6.
Marine nature reserves (MNRs) play an important role in biodiversity conservation and ecosystem restoration, which are valuable for marine resource protection in China. Many stakeholders are involved in MNRs. The interactions between MNR managers and other stakeholders affect the effectiveness of MNR management. This work divided MNR stakeholders into three categories and applied the analytical hierarchy process (AHP) to identify the key stakeholders. The game model was set up to analyze the strategies of MNR staff and stakeholders. The situation of key stakeholders and management was studied in two MNRs in Guangdong Province through field research and questionnaires. The results showed that fishermen were the main stakeholders in the two cases. The strategies adopted by MNR staff to improve the efficiency of law enforcement and decrease the probability of illegal activities of fishermen are to increase penalties, improve the arrest rate of illegal activities, and reduce the cost of law enforcement per patrol. We suggested that the fishermen’s negative impacts could be minimized by establishing a market management system to reduce illegal earnings, a record-keeping system to share additional benefits only with the fishermen who comply with the law, and an association mechanism in the coastal province to control illegal fishing across provincial boundaries. Identifying key stakeholders and analyzing their relationships could be helpful to find out the best strategy for different MNRs. Building a community of shared interests among various stakeholders could be a promising way to resolve conflicts and improve management effectiveness in MNRs. 相似文献
7.
A. P. Mller 《Journal of evolutionary biology》1996,9(6):677-694
Fluctuating asymmetry represents usually small, random deviations from symmetry in bilateral morphological characters. The ontogeny of asymmetry in morphological characters may reveal information about developmental processes in a general sense. I studied the development of fluctuating asymmetry in feather characters of the barn swallow Hirundo rustica, that are developed repeatedly during the single annual moult, with the following results. First, the side developing a larger feather was found to be partially biased, as demonstrated by one side consistently developing a larger feather under natural and experimentally induced growth episode events. Second, asymmetric feathers were found to consist of asymmetric daily growth increments, and the size of the increments developing under different environmental conditions were positively correlated. Third, fluctuating asymmetries of feathers developing under different environmental conditions were positively correlated, although the level of asymmetry was larger under adverse environmental conditions. Fourth, individual asymmetries in tail length and growth bar length were unrelated to the duration of the developmental period, although late growth increments were smaller and more symmetric than early increments. These observations suggest that fluctuating asymmetry partially arises as a consequence of a random bias in the feather follicles and differences in environmental conditions during ontogeny of feathers. 相似文献
8.
M. Heino V. Kaitala E. Ranta J. Lindstr?m 《Proceedings. Biological sciences / The Royal Society》1997,264(1381):481-486
We explore extinction rates using a spatially arranged set of subpopulations obeying Ricker dynamics. The population system is subjected to dispersal of individuals among the subpopulations as well as to local and global disturbances. We observe a tight positive correlation between global extinction rate and the level of synchrony in dynamics among thesubpopulations. Global disturbances and to a lesser extent, migration, are capable of synchronizing the temporal dynamics of the subpopulations over a rather wide span of the population growth rate r. Local noise decreases synchrony, as does increasing distance among the subpopulations. Synchrony also levels off with increasing r: in the chaotic region, subpopulations almost invariably behave asynchronously. We conclude that it is asynchrony that reduces the probability of global extinctions, not chaos as such: chaos is a special case only. The relationship between global extinction rate, synchronous dynamics and population growth rate is robust to changes in dispersal rates and ranges. 相似文献
9.
10.
Kathleen A. Hill Nicholas J. Schisler Shiva M. Singh 《Journal of molecular evolution》1992,35(3):261-269
Summary Chaos game representation (CGR) is a novel holistic approach that provides a visual image of a DNA sequence quite different from the traditional linear arrangement of nucleotides. Although it is known that CGR patterns depict base composition and sequentiality, the biological significance of the specific features of each pattern is not understood. To systematically examine these features, we have examined the coding sequences of 7 human globin genes and 29 relatively conserved alcohol dehydrogenase (Adh) genes from phylogenetically divergent species. The CGRs of human globin cDNAs were similar to one another and to the entire human globin gene complex. Interestingly, human globin CGRs were also strikingly similar to human Adh CGRs. Adh CGRs were similar for genes of the same or closely related species but were different for relatively conserved Adh genes from distantly related species. Dinucleotide frequencies may account for the self-similar pattern that is characteristic of vertebrate CGRs and the genome-specific features of CGR patterns. Mutational frequencies of dinucleotides may vary among genome types. The special features of CG dinucleotides of vertebrates represent such an example. The CGR patterns examined thus far suggest that the evolution of a gene and its coding sequence should not be examined in isolation. Consideration should be given to genome-specific differential mutation rates for different dinucleotides or specific oligonucleotides.
Offprint requests to: S. M. Singh 相似文献