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