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A model predicting optimal timing of growth and reproduction in perennial species with indeterminate growth living in a seasonal environment, is presented. According to the model, the optimal fraction of growing season devoted to growth decreases with increasing individual age and size, which leads to S-shaped growth curves. Winter mortality seems to be a(More)
  • J Uchmański
  • 1985
The basic and simplest system that one can consider in ecology is a group of individuals of equal age and representing one species, that is, a cohort. This paper is an attempt to show that analysis of such a system may be of great importance to understanding basic ecological problems, such as, intraspecific competition and the dynamics of a single(More)
Is individual-based modelling really a new approach in ecology? A large part of the uncertainty surrounding this question is a consequence of imprecisely delimited boundaries between classical and individual-based modelling. Genuine 'individual-based' models describe a population made up of individuals that may differ from one another; they also describe(More)
Most models of theoretical population ecology consider population density as a state variable and thus ignore the fact that populations are composed not of identical average individuals but of individuals which are usually different. However, this individual variability may be important for population regulation. We therefore analysed an individual-based(More)
Although size at maturity and size and number of offspring are life-history traits widely studied in sexual and parthenogenetic reproduction, there is no such research on animals reproducing asexually without the involvement of gametes. Here we present an individual-based model in combination with experiments to study the clonal growth of Stylaria(More)
Although the abilities of prey to detect and respond to chemical substances associated with a predator have been widely reported, the factors promoting the evolution of responses to prey alarm cues vs. predator odours are still vague. In this article, we combined field research with laboratory experiments to explore which chemical substance associated with(More)
Although chemical alarm substances from damaged heterospecifics have been well documented to induce defense mechanisms in potential prey, data about antipredator responses to alarm cues from prey organisms of a distinct phylum are scarce. In this study, we analyze the response of an oligochaete to chemical alarm substances from distantly related(More)
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