Extinction hypotheses

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David Bressan

Nov 19, 2011, 1:22:30 PM11/19/11
to History of Paleontology
I’m trying to compile a list of extinction hypotheses – it would be
important to cite at least one representative reference or a short
history/author of the idea – glad for any help.

P.S: I found for the development of the Hyperdisease-hypothesis two
time-periods: 1950 or 1997, somebody has detailed info?

Following a list of hypotheses for Quaternary-extinction (the
sensational introduction were working-titles - please take them not to

-Death from Hell - Volcanoes:
Could a catastrophic eruption modify the climate and bring death to
the last survivors of a dying breed?

SAPELKO, T.V. & SHACKLEY, M.S. (2010): Significance of Ecological
Factors in the Middle to Upper Paleolithic Transition. Current
Anthropology 51 (5): 655-691 DOI: 10.1086/656185
RUBAN, D.A. (2009): A possible contribution of volcanism to the end-
Pleistocene megafaunal etinction. Natura Nascosta 39:26-32

-Collapse of the geomagnetic field:
Could the reversal of the geomagnetic field have deprived earth from
its shield against dangerous UV-rays? A new papers proposes the
increase of irridation as one of the factors contributing to the
demise of the Neanderthal-man.

VALET, J.-P. & VALLADAS, H. (2010): The Laschamp-Mono lake geomagnetic
events and the extinction of Neanderthal: a causal link or a
coincidence? Quaternary Science Reviews Vol.29 (27-28): 3887-3893

-Cosmic Impacts:
Was it a meteor or comet that devastated North America, and melted the
ice-shield of Greenland, bringing a little ice-age to the globe? This
hypothesis published in January 2009 raised a lot of media interest;
however the idea was not supported by the chronology of the extinction
of various species (ranging from various centuries to thousand of
years) and later research could not replicate the discovery of impact
evidence like nano-diamonds or microspheres in the sediments.

FIRESTONE et al. (2007): Evidence for an extraterrestrial impact
12,900 years ago that contributed to the megafaunal extinctions and
the Younger Dryas cooling. PNAS 105(52)

-Racial demise:
The Austrian palaeontologists Othenio Abel (1875-1946) propose that
the extinction of the cave bear was caused by the proliferation of a
race of inferior individuals by lack of natural selection. Abel was a
great palaeontologist, but with the establishment of the National
Socialism in Germany he begun to sympathize with the racial
pseudoscience promoted by the party, and this influenced also his
hypothesis in palaeontology.

ABEL, O. & KYRLE, G. (1931): Die Drachenhöhle bei Mixnitz. Speläol.
Monogr. VII - IX, Wien.
ABEL, O. (1932): La vie des animaux de l'epoque glaciare dans la
Caverne des Dragons a Mixnitz, en Styrie. Terre et Vie 2: 3-24

-Methane Massacre:
A research team of the University of New Mexico in Albuquerque adds a
something different approach to the problem of climate change as
extinction cause. SMITH et al. published a paper where they compared
the production of methane of modern farm animals to extinct
herbivores. Methane is a very effective green house gas. The research
team observed in the geological record strong variations of the
concentration of methane between the last glacial maximum, 18.000
years ago, and the Younger Dryas (13.000 years ago). Especially at the
beginning of the temperature drop of the Younger Dryas the
concentration of methane diminished considerable fast. The research
team speculates that with the beginning extinction of large herbivores
an important source of methane was removed from the climate system,
destabilizing climate and environment end enforcing the extinction
rate. The fast changes observed, faster than previously known
variations, maybe are also related to human activity, disproving
precedent research that excluded humans as triggers for the
Pleistocene extinction.

SMITH, F.A.; ELLIOTT, S.M.. & YONS, K. (2010): Methane emissions from
extinct megafauna. Nature Geoscience. Published online: 23. May 2010:

In 2006 a research on the pathological malformations of the American
Mastodon (Mammut americanum) and bison bones gave to the hypothesis
developed in the fifties of a disease-related large mammal extinction
new support. A large number of geographically and temporal separated
individuals showed signs attributed to an infection by tuberculosis.
A recent example how lethal pathogens can be for an isolated
population was observed on the Christmas Islands in the Indian Ocean.
Human colonization and introduced black rats (Rattus rattus) in 1899
brougth as pathogen an unicellular parasitic protist (Trypanosoma) on
the island. The endemic rat species (Rattus macleari) didn't possess a
natural resistance against the introduced parasite, and the population
suffered a rapid decline, in 1904 the species was considered extinct.

ROTHSCHILD, B.M. & LAUB, R. (2006): Hyperdisease in the late
Pleistocene: validation of an early 20th century hypothesis.
Naturwissenschaften 93:557-564
DOI 10.1007/s00114-006-0144-8
HYNES, W.H., et al. (2008): Historical Mammal Extinction on Christmas
Island (Indian Ocean) Correlates with Introduced Infectious Disease.
PLoS ONE 3(11): e3602. doi:10.1371/journal.pone.0003602

-The following environmental hypotheses identify climatic and
subsequent environment change , and intrinsic response of the
organisms, as the main causes of the mass extinction.

KOCH, P.L. & BARNOSKY, A.D. (2006): Late Quaternary Extinctions: State
of the Debate. Annu. Rev. Ecol. Evol. Syst. 37: 215-250.

--1. Habitat loss hypotheses
As climate changed, areas with adequate conditions to maintain
megafauna either disappeared or became too small/fragmented to support

--2. Mosaic-nutrient hypothesis
Climate change reduced growing season and plant diversity, and
increased plant defenses, reducing herbivore carrying capacity and
leading to extinction

--3. Co-evolutionary disequilibrium
Disruption of extensive Pleistocene networks of resource partitioning
by rapid glacial-interglacial transition led to extinction

--4. Self-organized instability
Extinction results from a slight perturbation amplified into a
catastrophe by dynamics intrinsic to complex, multicomponent
ecosystems with interacting subunits

-Human Overkill
The Overkill-hypotheses attribute the main extinction cause to human
activity, especially hunt and habitat destruction, but also
introduction of new animals and diseases.
In fact many animals got extinct when humans for the first time
arrived on the respective continent; However often a large period of
co-existence is observed, denying the idea of a direct "blitzkrieg"
against endemic species. Archeological evidence for active and
widespread hunting of large mammals like mammoths is rare, studied
remains show that the most common prey were smaller animals, as the
still existing bison or horse.

Jerrold Alpern

Nov 19, 2011, 4:22:23 PM11/19/11
to history-of-...@googlegroups.com, bressa...@gmail.com

Regarding the K-T extinction, you might be interested in these web sites:

http://www.ucmp.berkeley.edu/diapsids/extinction.html. - . U. Cal. Berkeley
extinction site

http://www.ucmp.berkeley.edu/education/events/cowen1b.html - U. Cal.
Berkeley, Dr. Richard Cowen�s K-T extinction lecture

http://ethomas.web.wesleyan.edu/ees123/mass_extinctions.htm - lecture on
mass extinctions from Wesleyan Univ.'s Dr. Ellen Thomas

http://www.geol.umd.edu/~tholtz/G104/lectures/104extinct.html - Dr. Thomas
Holtz�s extinction lecture at the Univ. of Md.

As for the Pleistocene extinctions, the most comprehensive, up-to-date
collection of papers available (at least for North America) is:
Haynes, Gary (ed.), 2009, American Megafaunal
Extinctions at the End of the Pleistocene, Springer

A similar collection for the Holocene is:

Turvey, Samuel T. (ed.), 2009, Holocene Extinctions,
Oxford Univ. Press

Still very relevant for extinctions in general is:

Ellis, Richard, 2004, No Turning Back: The Life and
Death of Animal Species, HarperCollins

All best,

Jerry Alpern

----- Original Message -----
From: "David Bressan" <bressa...@gmail.com>
To: "History of Paleontology" <history-of-...@googlegroups.com>
Sent: Saturday, November 19, 2011 1:22 PM
Subject: Extinction hypotheses

I�m trying to compile a list of extinction hypotheses � it would be

important to cite at least one representative reference or a short

history/author of the idea � glad for any help.

ABEL, O. & KYRLE, G. (1931): Die Drachenh�hle bei Mixnitz. Spel�ol.

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