Talk:Extinction event

references

incorrect reference #52 Error--Page not Found —Preceding unsigned comment added by 86.177.109.86 (talk) 17:14, 13 March 2010 (UTC)

gnome work

the major and minor timescales go in opposite directions. Needs fixing Andrewjlockley (talk) 01:29, 11 August 2009 (UTC)

Volcanism

Is a major Impact event triggering the the volcainsm ? as both are often associated with a mass extinction ? Photnart 04:24, 20 November 2009 (UTC)

Sea-level falls - Clarification

The article mentions:

"But sea-level falls are very probably the result of other events, such as sustained global cooling or the sinking of the mid-ocean ridges."

When one discusses the mid-ocean ridges, the first question that pops into my mind is where is it going?

The way I'm thinking about it is a shift in mass from the ocean seabed to the continents, or processes that would make the continents smaller and taller would tend to cause the sea level to fall. This would include the sequestration of water in the form of ice

Processes that transfer mass from on the continents to the sea such as erosion or melting of ice would tend to make the sea level rise.

So, if a force such as subduction moved mass from under the seabed to depositing the material in with the Cascade Mountain Volcanoes, then that would be equivalent to removing the equivalent amount of mass displaced by the mountains from the ocean.

If, on the other hand, India collides with Asia, the Himalayan mountains are pushed up, and essentially the continental area is decreased and the oceans levels could fall.

Anyway, it seems as if the concept of transferring matter from the ocean to the continents needs clarification.--Keelec (talk) 19:05, 21 February 2010 (UTC)

Graphic Kvetching

It would be nice if the graph at the top of the page had its X/y axes labeled.

Basesurge (talk) —Preceding undated comment added 08:28, 7 April 2010 (UTC).

97% huh?

The intro overboldly states:

Over 97% of species that ever lived are now extinct

How the heavens can such a precise number be determined?? My questions are: 1. Do we know the current number of species by a precision better than 1:10? 2. Do we know the general life time of a species? 3. Do we actually know the extinction rates of former extinction events, counting all species (f.ex. archaean species)? 4. The sentence, in current form, also implies that a. all precambrian is accounted for, b. extraterrestial species are accounted for. 97% is overly absurd in the context of "species that ever lived". Rursus dixit. (^mbork³!) 11:17, 11 April 2010 (UTC)

If I understood it right, it is an estimate based on Mollusc/ Marine fossils. "Patterns of Phanerozoic extinction: a perspective from global data bases", Global Events and Event Stratigraphy, Berlin: Springer, 1996, pp. 35–51 {{citation}}: Unknown parameter |authors= ignored (help); Unknown parameter |editors= ignored (|editor= suggested) (help). Sepkoski's Global Genus Database of Marine Animals. Rohde, R.A. & Muller, R.A. (2005). "Cycles in fossil diversity". Nature. 434: 209–210.{{cite journal}}: CS1 maint: multiple names: authors list (link) Supplementary Material. --Chris.urs-o (talk) 11:42, 11 April 2010 (UTC)

Quote: "With kill rates for species estimated to have been as high as 77% and 96% for the largest extinctions." (Raup, David. M., 1979; Valentine et al., 1978). "Periodicity of extinctions in the geologic past" (PDF). Proc Natl Acad Sci U S A. 81 (3): 801–805. Feb. 1984. Retrieved 14-04-2010. {{cite journal}}: Check date values in: |accessdate= and |date= (help); Unknown parameter |authors= ignored (help), (Raup, D.M. 12 October 1979. Size of the Permo-Triassic Bottleneck and Its Evolutionary Implications. Science. 206 (4415), 217-218, DOI: 10.1126/science.206.4415.217.) (Quote: "Rarefaction analysis of extinctions in the Late Permian indicates that as many as 96 percent of all marine species may have died out, thus forcing the marine biosphere to pass through a small bottleneck." [1]), (J. W. Valentine, T. C. Foin, and D. Peart; January 1978; A provincial model of Phanerozoic marine diversity; Paleobiology; 4 (1); p. 55-66.). If I'm right: 4% survivors (96% kill rate) times 23% kill rate and others, equals less than 0.9% survivors (more than 99.1% kill rate) for the marine species, it seems ok for me... If the marine environment is bad, the terrestrial environment must be even worse. My personal opinion: species give a lil bit the wrong picture, genera would be better. Ok Philcha, I was just trying to prove that a kill rate of more than 97% is ok, although not in this formulation. --Chris.urs-o (talk) 08:28, 14 April 2010 (UTC)

Hi, Chris.urs-o, thanks for the refs. But I don't think there's a need for additional arithmetic - Raup's Size of the Permo-Triassic Bottleneck and Its Evolutionary Implications says marine 96% kill rate at P-Tr. The deaths of 96% of marine species at the P-Tr is often quoted, so I think it would be WP:OR to omit it. And I can see why a species figure could be significant (my OR :-D) - species reproduction. As for land: IMO fixing the P-Tr boundary on land was difficult (I've not looked at this for a while), but for a few Myr almost the only land vebretrate fossil was Lystrosaurus, which was cosmospolitan. --Philcha (talk) 13:05, 14 April 2010 (UTC)

Magnetic field

In Bill Bryson's "A Short History of Nearly Everything", he mentions that the changes in Earth's magnetic field can also lead to devastation. Such as when the field diminishes while in the process of flipping, cosmic rays would shred living beings' DNA to pieces. Is this a legitimate probability in any of the events? Rgrds. 64.85.221.35 (talk) 10:28, 13 May 2010 (UTC)

Earth's magnetic field#Magnetic field reversals occur all 300 ka, the last one occurred 780 ka. Regular events of a cycle are expected by nature and so the event alone do not cause an extinction event, but could worsen one. --Chris.urs-o (talk) 19:24, 13 May 2010 (UTC)

Automate archiving?

Does anyone object to me setting up automatic archiving for this page using MiszaBot? Unless otherwise agreed, I would set it to archive threads that have been inactive for 30 days and keep ten threads.--Oneiros (talk) 13:40, 14 May 2010 (UTC)

 Done--Oneiros (talk) 19:30, 18 May 2010 (UTC)

GeoGalactic Chronology

ICS data shows a repetition pattern on precise 417M-yr intervals. The Paleogene-Neogene -1Myr_ago, Ordovician-Siluran 416Mr-ago, Cretaceous 71Myr-ago Cambrian 488Myr-ago, Jurassic 146Myr-ago Vendian 563Myr-ago and Permian-Traissic 200Myr-ago Ediacaran 617Myr-ago. The Paleogene-Neogene (Oligoncene Notch) event 33-27Myr-ago and Odovician-Silurian event 443Myr-ago Myr_ago is suspiciously close (413Myr). The P-Tr event is 251Ma ago, and does not yet have a Phanerozoic pair. CB Events group Periods together, with the remaining terminus having GB (sixth interleaved sets) association. The Oligocene, Ordovician and P-Tr are classified as Central Bar (CB) alignment events because the other six are interleaved on sixth period offsets copying the Galactic (2+2+2) Six Arm structure. The inference is overlayed on the NASA Milky Way Galaxy [ref 3]. This galactic map also has sol orbital intercepts polar angles that match the Period intervals using a 0.863 degrees/Ma scaler (360/417).

Reference:

[1]Geologic-Galactic-Chronology.

[2] Paleoclimate: Oligocene epoch and p-tr boundary, cached

[3] Geologic Galactic Chronology NASA Overlay

NOTES: 1) I am intiating conference with NASA public affairs for the Galactic Map datum. 2) The Wilki extinction definition is loosely interpreted. Per professional references Period terminus causality are not exclusively extinction processes. Morbas (talk) 21:21, 6 June 2010 (UTC)

Mass Extinction Events - poor values for comparison

While the percentage of total families and total genera wiped out by each of the major five extinction events is given, the comparability falls short on the count of species as well as on dividing genera or species between land and sea. For the Late Devonian and Cretaceous-Tertiary events, the total percentage of species wiped out is given; however, for the Permian-Triassic event the percentages of land and marine species wiped out are given separately. Without knowing what percentage of the total species were marine-based and what percentage were land-based, it is not possible using this information to make an accurate comparison between the scale of the Permian-Triassic event and either of the other two aforementioned events in terms of species wiped out. Furthermore, the Triassic-Jurassic and Ordovician-Silurian events make no mention at all of the percentage of species wiped out, though I can understand if that data is simply not available (particularly for the latter event).

My point here is that tweaking the section to increase consistency in the stats given would be beneficial for people wishing to do a quick comparison of the various events. Granted they can still compare by genera or families; however, this strikes me as a less accurate and perhaps less useful comparison.

Thoughts on the matter? Celtic Minstrel (talk • contribs) 04:54, 9 June 2010 (UTC)