468 research outputs found
Evolutionary ecology in-silico: Does mathematical modelling help in understanding the "generic" trends?
Motivated by the results of recent laboratory experiments (Yoshida et al.
Nature, 424, 303-306 (2003)) as well as many earlier field observations that
evolutionary changes can take place in ecosystems over relatively short
ecological time scales, several ``unified'' mathematical models of evolutionary
ecology have been developed over the last few years with the aim of describing
the statistical properties of data related to the evolution of ecosystems.
Moreover, because of the availability of sufficiently fast computers, it has
become possible to carry out detailed computer simulations of these models. For
the sake of completeness and to put these recent developments in the proper
perspective, we begin with a brief summary of some older models of ecological
phenomena and evolutionary processes. However, the main aim of this article is
to review critically these ``unified'' models, particularly those published in
the physics literature, in simple language that makes the new theories
accessible to wider audience.Comment: 28 pages, LATEX, 4 eps figure
Mass Extinctions vs. Uniformitarianism in Biological Evolution
It is usually believed that Darwin's theory leads to a smooth gradual
evolution, so that mass extinctions must be caused by external shocks. However,
it has recently been argued that mass extinctions arise from the intrinsic
dynamics of Darwinian evolution. Species become extinct when swept by
intermittent avalanches propagating through the global ecology. These ideas are
made concrete through studies of simple mathematical models of coevolving
species. The models exhibit self-organized criticality and describe some
general features of the extinction pattern in the fossil record.Comment: 17 pages uuencoded with style file lamuphys.sty. 9 figures not
included but can be obtained via [email protected]. to appear in ``Physics
of Biological Systems'' Lecture Notes in Physics (Springer-Verlag, Heidelberg
, 1996
Making the most of clade selection
Clade selection is unpopular with philosophers who otherwise accept multilevel selection theory. Clades cannot reproduce, and reproduction is widely thought necessary for evolution by natural selection, especially of complex adaptations. Using microbial evolutionary processes as heuristics, I argue contrariwise, that (1) clade growth (proliferation of contained species) substitutes for clade reproduction in the evolution of complex adaptation, (2) clade-level properties favoring persistence – species richness, dispersal, divergence, and possibly intraclade cooperation – are not collapsible into species-level traits, (3) such properties can be maintained by selection on clades, and (4) clade selection extends the explanatory power of the theory of evolution
Evolution models with extremal dynamics
AbstractThe random-neighbor version of the Bak-Sneppen biological evolution model is reproduced, along with an analogous model of random replicators, the latter eventually experiencing topology changes. In the absence of topology changes, both types of models self-organize to a critical state. Species extinctions in the replicator system degenerates the self-organization to a random walk, as does vanishing of species interaction for the BS-model. A replicator model with speciation is introduced, experiencing dramatic topology changes. It produces a variety of features, but self-organizes to a possibly critical state only in a few special cases. Speciation-extinction dynamics interfering with self-organization, biological macroevolution probably is not a self-organized critical system
Red Queen Coevolution on Fitness Landscapes
Species do not merely evolve, they also coevolve with other organisms.
Coevolution is a major force driving interacting species to continuously evolve
ex- ploring their fitness landscapes. Coevolution involves the coupling of
species fit- ness landscapes, linking species genetic changes with their
inter-specific ecological interactions. Here we first introduce the Red Queen
hypothesis of evolution com- menting on some theoretical aspects and empirical
evidences. As an introduction to the fitness landscape concept, we review key
issues on evolution on simple and rugged fitness landscapes. Then we present
key modeling examples of coevolution on different fitness landscapes at
different scales, from RNA viruses to complex ecosystems and macroevolution.Comment: 40 pages, 12 figures. To appear in "Recent Advances in the Theory and
Application of Fitness Landscapes" (H. Richter and A. Engelbrecht, eds.).
Springer Series in Emergence, Complexity, and Computation, 201
Mass Extinctions as Major Transitions
Both paleobiology and investigations of ‘major evolutionary transitions’ are intimately concerned with the macroevolutionary shape of life. It is surprising, then, how little paleontological perspectives and evidence inform studies of major transitions. I argue that this disconnect is partially justified because paleobiological investigation is typically ‘phenomena-led’, while investigations of major transitions (at least as commonly understood) are ‘theory-led’. The distinction turns on evidential relevance: in the former case, evidence is relevant in virtue of its relationship to some phenomena or hypotheses that concern those phenomena; in the latter, evidence is relevant in virtue of providing insights into, or tests of, an abstract body of theory. Because paleobiological data is by-and-large irrelevant to the theory which underwrites the traditional conception of major transitions, it is of limited use to that research program. I suggest that although the traditional conception of major transitions is neither ad-hoc or problematically incomplete, its promise of providing unificatory explanations of the transitions is unlikely to be kept. Further, examining paleobiological investigations of mass extinctions and organogenesis, I further argue that (1) whether or not transitions in paleobiology count as ‘major’ turns on how we conceive of major transitions (that is, the notion is sensitive to investigative context); (2) although major transitions potentially have a unified theoretical basis, recent developments suggest that investigations are becoming increasingly phenomena-led; (3) adopting phenomena-led investigations maximizes the evidence available to paleobiologists
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