A modified version of Image:Extinction Intensity.svg.

Changes:

1. Time runs from left to right (millions of years ago). Vertical axis is apparent percentage (not the absolute number) of marine animal genera becoming extinct.
2. Periods are coloured as per the Paris system - see w:Template:Period color for full explanation
3. Text removed so wikilinks can be floated over. See w:Template:Annotated image/Extinction for implementation.
4. Cubic polynomial removed as this doesn't convey any useful information and is mainly an artefact.
5. The caption on the original file is: Marine Genus Biodiversity: Extinction Intensity

Avètz la permission de copiar, distribuir e modificar aqueste document segon los tèrmes de la Licéncia de documentacion liura GNU, version 1.2 o mai recenta publicada per la Free Software Foundation; sens seccions inalterablas, sens tèxte de primièra pagina de tempa e sens tèxte de darrièra pagina de tempa. Un exemplar de la licéncia es inclús dins la seccion intitulada GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue

	Aqueste fichièr es jos licéncia Creative Commons licéncia generica atribucion-partiment a l'identic 3.0
	Sètz liure : de partejar – de copiar, distribuir e transmetre aquesta òbra d'adaptar – d'adaptar aquesta òbra Jos las condicions seguentas : atribucion – Vos cal atribuir aquesta òbra amb lo biais especificat per l'autor o lo concedent (mas pas dins un sens que suggerís que vos apròvan o qu'apròvan l'utilizacion d'aquesta òbra). partiment a l'identic – Se modificatz, transformatz, o vos basatz sus aquesta òbra, vos cal distribuir l'òbra resultanta jos la meteissa licéncia o una licéncia similara a aquesta.
	Aquest avís de llicència s'ha afegit a aquest fitxer d'acord amb l'actualització de la llicència GFDL.http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue

Descripcion

Adapted from Image:Extinction Intensity.svg

This figure shows the genus extinction intensity, i.e. the fraction of genera that are present in each interval of time but do not exist in the following interval. The data itself is taken from Rohde & Muller (2005, Supplementary Material), and are based on the Sepkoski's Compendium of Marine Fossil Animal Genera (2002). Note that these data do not represent all genera that have ever lived, but rather only a selection of marine genera whose qualities are such that they are easily preserved as fossils.

In the original version of this chart, the "Big Five" mass extinctions (Raup & Sepkoski 1982) are labeled in large font, and a variety of other features are labeled in smaller font. The two extinction events occurring in the Cambrian (i.e. Dresbachian and Botomian) are very large in percentage magnitude, but are not well known because of the relative scarcity of fossil producing life at that time (i.e. they are small in absolute numbers of known taxa). The Middle Permian extinction is now argued by many to constitute a distinct extinction horizon, though the actual extinction amounts are sometimes lumped together with the End Permian extinctions in reporting. As indicated, the "Late Devonian" extinction is actually resolvable into at least three distinct events spread over a period of ~40 million years. As these data are derived at the genus level, one can anticipate that the number of species extinctions is a higher percentage than shown here.

Many of the extinction events appear to be somewhat extended in time. In at least some cases this is the result of a paleontological artifact known as the Signor-Lipps effect (Signor & Lipps 1982). Briefly, this is the observation that inadequate sampling can cause a taxon to seem to disappear before its actual time of extinction. This has the effect of making an extinction event appear extended even if it occurred quite rapidly. Hence, when estimating the true magnitude of an extinction event it would be common to combine together the events occurring over several preceding bins as long as they also show excess extinctions. This explains why many estimates of the magnitude of an extinction event may be larger than the 20-30% shown as the largest single bin for most of the extinctions shown here.

References

• Raup, D. & Sepkoski, J. (1982). "Mass extinctions in the marine fossil record". Science 215: 1501–1503. DOI:10.1126/science.215.4539.1501.
• Rohde, R.A. & Muller, R.A. (2005). "Cycles in fossil diversity". Nature 434: 209-210. DOI:10.1038/nature03339.
• Sepkoski, J. (2002) A Compendium of Fossil Marine Animal Genera (eds. Jablonski, D. & Foote, M.) Bull. Am. Paleontol. no. 363 (Paleontological Research Institution, Ithaca, NY).
• Signor, P. and J. Lipps (1982) "Sampling bias, gradual extinction patterns and catastrophes in the fossil record", in Geologic Implications of Impacts of Large Asteroids and Comets on the Earth, I. Silver and P. Silver Eds, Geol. Soc. Amer. Special Paper 190, Boulder Colo. p. 291-296.

For comparison