Abstract 127
Pavlíček, T., Pearlson, O., Cohen, T., Mısırlıoğlu, M., Yadav, S., Král, P. and Glasstetter, M., 2017: Evolution and Life of Oligochaetes. In Horton, C. G. (Ed.), Earthworms. Types, Roles and Research. Pp. 1-41. Nova Sci. Publ., Inc. New York. ISBN: 978-1-53612-176-6.

Symbiotic bacteria and other microorganisms are playing an important role in the adaptation of Oligochaeta to their environment.

An evolutionary unit upon which the natural selection operates might be a network-like extended phenotype encompassing worms and symbiotic microorganisms, and characterized by epigenetic regulation.

The extended phenotype plays a role in endozoochory. We propose endozoochory as a missing mechanism of Oligochaeta dispersal and in the put forward fusion-orthogonalization model for the diversification and speciation of the Oligochaeta populations. The endozoochory dispersal hypothesis suggests a passage of Oligochaeta cocoons and eggs through digestive tract of a vector, for example migrating birds.

The experimental validation of the endozoochory dispersal hypothesis might contribute to the dismissal of the plate tectonics hypothesis treating Oligochaeta species as passively ‘living fossiles’ whose evolution history is punctuated by tectonic/geologic events. The fusion-orthogonalization model of speciation considers error-prone macroevolutionary aneuploidy-polyploidy-like and microevolutionary mutation-recombination-like mechanisms generating clouds of quasispecies and ecological species, respectively. Since natural selection operates at the level of clouds and individuals at the population level, the criteria of the evolutionary success are, in a given environment, cloud stability and relative individual fitness. The loss of the most recent polarity layers during quasispeciation can reset the evolutionary process by re-wiring the exposed earlier polarity layers. Depending on the level of stress, the evolution of quasispecies continues via quasispeciation or via orthogonalization towards the establishment of ecological species.

Quasispeciation explains, among others, the appearance of morphologically and genotypically simplified parasitic worms and of lineages colonizing extreme environments, as well as the establishment of cyclicity in evolution.