britishcolumbia burgessshale cambrian cambriangeologicperiod canada contingence(philosophie) contingency(philosophy) evolución evolutie evolution extinction(biologie) extinction(biology) fossielen fossil fossiles fossils geology histoire history influence invertebratefossils invertebrates invertébrésfossiles life naturalhistory ongewerveldedieren paleontologie paleontology paléontologie philosophie philosophy schalies shale stratigraphic yohonationalpark évolution