File:Phanerozoic Biodiversity.png

From Citizendium
Jump to navigation Jump to search

Phanerozoic_Biodiversity.png(627 × 371 pixels, file size: 21 KB, MIME type: image/png)

This file is from a shared repository and may be used by other projects. The description on its file description page there is shown below.

Summary

Extinction intensity during the Phanerozoic. As changes in biodiversity reflect both changes in origination and extinction, some events shown here are masked in the biodiversity curve by very rapid replacement with new species.

Following Rohde & Muller (2005), this figure shows the apparent changes in marine biodiversity throughout the last 542 million years (the Phanerozoic eon) based on the first and last appearance of the 36380 genera recorded in the Sepkoski Compendium (2002). The "Big Five" mass extinctions of Raup and Sepkoski (1982) are labeled as well as a number of additional, but less well-known extinction events. Conventional symbols for the periods of w:geologic time appear along the bottom. The distinctions for "all genera" and "well-resolved genera" follow Rohde & Muller (2005) and reflect either the inclusion of all of Sepkoski's taxa or only those where the first and last appearances were well-defined in time.

It is presently a matter of scientific debate whether the long-term trend appearing here is a genuine reflection of biological changes or is instead a reflection of the biases inherent to the process of paleontological investigation. Some have argued that most, or all, of the large rise going into the modern day is merely a reflection of the greater availability and preservation of recent geologic sections. Others dispute this, and argue that most of the long-term changes reflect genuine biological processes.

Rohde & Muller also argue that the fluctuations in biodiversity, especially occurring in the early part of the record, are too regularly spaced to have occurred by random chance. They conclude on the basis of a statistical argument that some unknown process influenced the waxing and waning of life with roughly a 62 million year periodicity. Periodic astronomical and geophysical processes are considered, but no particular process is definitively implicated.

This figure was originally prepared by Dragons flight from published data and is released under the GFDL.


GNU head Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.
w:en:Creative Commons
attribution share alike
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
You are free:
  • to share – to copy, distribute and transmit the work
  • to remix – to adapt the work
Under the following conditions:
  • attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
  • share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.
This licensing tag was added to this file as part of the GFDL licensing update.

References

  • Raup, D. & Sepkoski, J. (1982). "Mass extinctions in the marine fossil record". Science 215: 1501–1503.
  • Rohde, R.A. & Muller, R.A. (2005). "Cycles in fossil diversity". Nature 434: 209-210.
  • 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).


Derivative Works

Derivative works of this file:

[edit]

Captions

Apparent marine fossil diversity during the Phanerozoic

Items portrayed in this file

depicts

File history

Click on a date/time to view the file as it appeared at that time.

Date/TimeThumbnailDimensionsUserComment
current14:40, 26 February 2006Thumbnail for version as of 14:40, 26 February 2006627 × 371 (21 KB)imagescommonswiki>Merikanto~commonswikiClass Phanerozoic, Biodiversity curve.

The following file is a duplicate of this file (more details):

The following page uses this file: