Molecular Biodiversity Inventory of the Ichthyofauna of the Czech Republic

The degree of biodiversity was dynamically changing during the centuries and millennia, according to available resources it was gradually growing. In the course of evolution the periods of intensive speciation and relative “speciation rest“ were alternating, with five major episodes of mass extinction (Wilson, 1989; Raup, 1992). The worst extinction event took place at the end of the Permian period, 250 million years ago (Primack et al., 2001), the most recent and also the best known mass extinction event occurred in the late Cretaceous period, i. e. 65 million years ago (Freeland, 2005). From then on, the rate of speciation was in equilibrium with the rate of extinction, or was even higher. Currently, the rate of extinction is 100-1000 times higher, namely almost exclusively in consequence of human activity. Therefore a lot of experts call the present situation the sixth mass extinction (Primack et al., 2001). At present, only approximately 1.5 million species are described, of which the majority is represented by insects and plants (Wilson, 1992). According to various estimates the number of non-described species amounts to 10 million or even 30-150 million (Hammond, 1992).