Some basic framework

Cambrian explosion: 543mya. Beginning of Phanerozoic EON, Paleozoic ERA, Cambrian PERIOD.

EPOCH: we live in the Holocene Epoch. Epoch is a subdivision of Period.

Phanerozoic EON: Paleozoic, Mesozoic, Cenozoic ERAS.
Permian extinction at end of Paleozoic, mass extinction at end of Cretaceous period (65mya), Mesozoic era.

LINNAEAN HIERARCHY
Domain, Kingdom, Phylum, Class, Cohort, Order, Family, Subfamily, Tribe, Genus, Species, Subspecies. (Mayr, WEI, p.23 (except for Domain [UCMP]).