title: Probabilities of encounters between objects in biological systems: meta-observer view.
abstract: Encounters between objects play a crucial role in creating specific patterns of organization in many biological systems. This paper explores a general, quantitative principle of encounter probabilities, applicable over various levels of organization, as a fundamental step toward a comprehensive theory of biological probability ranging from cells through organisms to ecological communities. Based on the cognizers-system model, a general description of encounter probabilities in a finite position space is derived as a function of the number, or density, of objects with cognitive, selectivity properties incorporated as parameters. There is a prevailing wisdom, as supposed in many scientific thoughts, that the per-unit-time number of encounters between focal and target objects is given as a linear function of the density of target objects. One result shows that this idea does not describe the real nature of encounter probabilities or rates, but only a special case or approximation of a fundamental description. The analysis also explicates conditions for ignoring the presence of non-target objects, and those for the aggregation of two or more different objects into the same type sharing the same cognitive properties in the description of the probabilities.
authors.affiliation: Department of Biology and Earth Sciences, Faculty of Science, Ehime University, 2-5 Bunkyo-Cho, Matsuyama, Ehime, 790-8577, Japan. nakajima@sci.ehime-u.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
mesh_terms: D000818:Animals; D003071:Cognition; D003142:Communication; D017753:Ecosystem; D008954:Models, Biological; D011336:Probability