The Geozoic Supereon

Geological time units are the lingua franca of earth sciences: they are a terminological convenience, a vernacular of any geological conversation, and a prerequisite of geo-scientific writing found throughout in earth science dictionaries and textbooks. Time units include terms formalized by stratigraphic committees as well as informal constructs erected ad hoc to communicate more efficiently. With these time terms we partition Earth’s history into utilitarian and intuitively understandable time segments that vary in length over seven orders of magnitude: from the 225-year-long Anthropocene (Crutzen and Stoermer, 2000) to the ,4-billion-year-long Precambrian (e.g., Hicks, 1885; Ball, 1906; formalized by De Villiers, 1969)

Sizes of the Largest Fossils in the Geological Record

This table contains taxonomic, size, and source information describing the largest known fossil plants, animals, protists, and prokaryotes in the fossil record. The prokaryote record covers only the Archaean and early Paleoproterozoic. The protist, animal, and vascular plant records cover all relevant geological periods from the Paleoproterozoic through the Neogene. See also http://bodysize.nescent.org