The problem with this graph is that before 500 years ago, extinction rates are approximated from studying fossils, which is a notoriously unreliable method of measuring extinction rates. As explained in the textbookBiodiversity and Environmental Philosophy, the “benchmark for assessing the severity of...
SMITH, R.M.H., AND BOTHA-BRINK, J., 2014, Anatomy of a mass extinction: sedimento- logical and taphonomic evidence for drought-induced die-offs at the Permo-Triassic boundary in the main Karoo Basin, South Africa: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 396, p. 99-118....