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KLI Brown Bag
Ecosystems as Self-Evolving Systems
Toshiyuki NAKAJIMA (Department of Biology, Ehime University, Japan)
2005-07-01 13:15 - 2005-07-01 13:15
KLI for Evolution and Cognition Research, Altenberg, Austria
Organized by KLI

Topic description:
The theory of natural selection explains that a population of organisms evolves by differential survival and reproduction of replicating entities such as organisms: If there is variation in phenotypic, heritable traits in the population of entities, and they differ in survivability and reproductivity in the shared environment, a type of entities with higher fitness than others will probabilistically increases in frequency in the population, and eventually replace others. This explanation of adaptive evolution has been widely accepted by biologists (e.g., Lewontin, 1970; Mayr, 1988). However, there are two black boxes involved. First, this explanation does not explain how and why variant types are created. Second, the causal mechanism of the replacement process is unclear. The first black box relates to the creation of new types of entities, the second to the causal-mechanistic or dynamic process of replacement of one type by another, or of coexistence of different types. I will argue that, first, the ecosystem works as a mechanical device that makes component species evolve through dynamic population processes operating in the ecosystem (Nakajima, 1998); second, the ecosystem involves the creation of new genetic types (variation) by dynamically sustaining many species (biodiversity) that provide genetic sources for creating new types of reproducing entities, such as organisms, through inter- or intra-specific transfer/recombination of genetic materials. This two-fold role of the ecosystem in evolution suggests to us a new view of the ecosystem: the ecosystem as an evolving system. The ecosystem evolves itself by providing genetic flow among component species and replacing one with another or making some of them coexist. In other words, the ecosystem is a self- evolving system. This kind of evolution is not Darwinian (i.e., variational evolution), but transformational evolution according to Mayr's definition. Therefore, the ecosystem is a non-Darwinian self-evolving system.

 

References:
Lewontin, R. C. 1970. The unit of selection. Annual Review of Ecology and Systematics 1: 1—18.
Mayr, E. 1988. Toward a New Philosophy of Biology. Harvard UP. Nakajima, T. 1998. Ecological mechanisms of evolution by natural selection. Journal of Theoretical Biology 190: 313—331.