glacial stratigraphy of poolepynten and the natural …oi/lectures unis sept 2007/pdf...1 glacial...

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Glacial stratigraphy of Poolepynten and the natural history of the Polar Bear

Glacial Glacial stratigraphystratigraphy of of PoolepyntenPoolepynten and the natural and the natural history of the Polar Bearhistory of the Polar Bear

ÓÓlafur Inglafur IngóólfssonlfssonProfessor of geologyProfessor of geologyUniversity of IcelandUniversity of Iceland

(([email protected]@hi.is; www.hi.is/~oi); www.hi.is/~oi)

Project collaborator: Project collaborator: ØØystein Wiik, professor ystein Wiik, professor of zoology, University of Oslo, Norwayof zoology, University of Oslo, Norway

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Kapp Koburg, KongsKapp Koburg, Kongsøøyaya

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A huge male outside the Kapp Koburg hut, KongsA huge male outside the Kapp Koburg hut, Kongsøøya, 1991ya, 1991

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Natural history of the Polar BearNatural history of the Polar Bear

•• Rapid Quaternary environmental changes Rapid Quaternary environmental changes stimulated rapid evolution and the rise of stimulated rapid evolution and the rise of large mammals, or large mammals, or megafaunamegafauna. The Pleistocene . The Pleistocene megafaunamegafauna included the nowincluded the now--extinct woolly extinct woolly rhinoceros, woolly mammoths and large wolves rhinoceros, woolly mammoths and large wolves that were well adapted to cold climates. that were well adapted to cold climates.

Other mammals that evolved during the Other mammals that evolved during the PleistoPleisto--cenecene, like the caribou, the musk ox and the , like the caribou, the musk ox and the polar bear, continue to be an important part of polar bear, continue to be an important part of the arctic fauna. the arctic fauna.


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The polar bear (The polar bear (UrsusUrsus maritimusmaritimus) is the largest of the five ) is the largest of the five extant bear species of the genus extant bear species of the genus UrsusUrsus, the other four being , the other four being the brown bear (the brown bear (UrsusUrsus arctosarctos), the American black bear ), the American black bear ((UrsusUrsus americanusamericanus), the Asiatic black bear (), the Asiatic black bear (UrsusUrsus thibetanusthibetanus) ) and the sun bear (and the sun bear (UrsusUrsus malayanusmalayanus))

The polar bear is the only obligate carnivore among The polar bear is the only obligate carnivore among living bears, a highly specialized predator of seals. living bears, a highly specialized predator of seals.

Polar bears are circumpolar in Polar bears are circumpolar in distribution, and the southern distribution, and the southern limit of their range is deterlimit of their range is deter--mined by the distribution of mined by the distribution of pack ice and pack ice and landfastlandfast annual ice annual ice during winter.during winter.


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•• In a pioneer work on the In a pioneer work on the dental characteristics of the dental characteristics of the polar bear, polar bear, TheniusThenius (1953) (1953) concluded that a relatively concluded that a relatively late descent from the brown late descent from the brown bear was probable.bear was probable.


Close relationship between polar bears and Close relationship between polar bears and brown bears is corroborated by the observation brown bears is corroborated by the observation that the two species may produce fertile that the two species may produce fertile hybrids. Since the geographic ranges of polar hybrids. Since the geographic ranges of polar bears and brown bears rarely overlap, this bears and brown bears rarely overlap, this primarily happens when the bears meet in primarily happens when the bears meet in captivity. captivity.


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•• A male polar bear accidentally got into an enclosure with A male polar bear accidentally got into an enclosure with a female Kodiak (Alaskan Brown) bear at the US National a female Kodiak (Alaskan Brown) bear at the US National Zoo in 1936 resulting in three hybrid offspring. One Zoo in 1936 resulting in three hybrid offspring. One hybrid was named Willy and grew into an immense hybrid was named Willy and grew into an immense specimen. specimen.

•• The hybrid offspring were fertile and able to breed The hybrid offspring were fertile and able to breed successfully with each other (a male hybrid successfully successfully with each other (a male hybrid successfully bred with his 2 sisters). bred with his 2 sisters).

•• Polar bear/Brown bear hybrids are white at birth but Polar bear/Brown bear hybrids are white at birth but later turn bluelater turn blue--brown or yellowbrown or yellow--white. white.


Polar bearPolar bear--Brown bear hybrids known from Brown bear hybrids known from Zoological Gardens in Europe and USAZoological Gardens in Europe and USA

May 11, 2006—DNA analysis has confirmed that a bear shot in the Canadian Arctic last month is a half-polar bear, half-grizzly hybrid. While the two bear species have interbred in zoos, this is the first evidence of a wild polar bear-grizzly offspring.

http://news.nationalgeographic.com/news/2006/05/bear-hybrid-photo.html

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KurtKurtéénn (1964) concluded that polar bears (1964) concluded that polar bears probably branched off from brown bears probably branched off from brown bears which became isolated some time during which became isolated some time during Pleistocene, and with time became Pleistocene, and with time became increasingly specialized carnivores that increasingly specialized carnivores that hunt in the packhunt in the pack--ice.ice.

This conclusion has been supported by later This conclusion has been supported by later geneticalgenetical studies on the relationship between living studies on the relationship between living brown bears on the Alexander Archipelago, Alaska, brown bears on the Alexander Archipelago, Alaska, and polar bears (Heaton and polar bears (Heaton et alet al. 1996). . 1996).


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Phylogeny of the Phylogeny of the UrsidaeUrsidae

Modified from Waits Modified from Waits et alet al. (1999). (1999)

Summary of Summary of UrsidaeUrsidaedivergences and divergences and radiationsradiations

Sun BearSun Bear

Spectacled BearSpectacled Bear

Sloth BearSloth Bear

Giant PandaGiant Panda

Asiatic Black BearAsiatic Black Bear

Brown BearBrown Bear

American American Black BearBlack Bear

Polar BearPolar Bear12 MY12 MY

4 MY4 MY3.53.5--2 MY2 MY

??

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When did polar bears branch off from When did polar bears branch off from brown bears and head off into the packice?brown bears and head off into the packice?

•• KurtKurtéénn (1968) suggested, on basis of his studies of (1968) suggested, on basis of his studies of the fossil material, that perhaps the polar bear was as the fossil material, that perhaps the polar bear was as recent as 70recent as 70--100 ka BP. 100 ka BP.

•• Age models based on molecular studies of evolutionary Age models based on molecular studies of evolutionary relationships among extant species of bears differ relationships among extant species of bears differ considerably as to the divergence time of polar bears considerably as to the divergence time of polar bears from brown bears: Wayne from brown bears: Wayne et alet al. (1991) suggest this . (1991) suggest this happened 70happened 70--100 ka BP, Talbot & Shields (1996) 100 ka BP, Talbot & Shields (1996) suggested it happened 300suggested it happened 300--400 ka BP and Yu 400 ka BP and Yu et alet al. . (2004) concluded this might have happened 1000(2004) concluded this might have happened 1000--1500 1500 ka BP. ka BP.

The preservation potential on land The preservation potential on land for polar bear fossils is very low!for polar bear fossils is very low!

Photo: I.S.JPhoto: I.S.Jóónsdnsdóóttir, 2005ttir, 2005

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Polar bear fossils are very rarePolar bear fossils are very rare

•• Most polar bear fossils are subMost polar bear fossils are sub--recentrecent

•• A number of fossils from the last deglaciationA number of fossils from the last deglaciation

•• Two finds dated to around 70 ka BPTwo finds dated to around 70 ka BP

EemianEemianto Early to Early WeichselianWeichselian, , >45 ka; 150>45 ka; 150--80 ka80 kaPoolepynten, Prins Karls Forland, SvalbardPoolepynten, Prins Karls Forland, Svalbard

Early Early WeichselianWeichselian, 70, 70--100 ka100 kaKew Bridge, London, UKKew Bridge, London, UK

Early Early WeichselianWeichselian3939--42 ka; >7042 ka; >70±±8.5 ka8.5 kaNordcemgrottaNordcemgrotta, , KjKj ææpsvikpsvik, N Norway, N Norway

Middle Middle WeichselianWeichselian3636--28 ka28 kaHamnsundhellerenHamnsundhelleren, W Norway, W Norway

22 ka22 kaNordcemgrottaNordcemgrotta, , KjKj ææpsvikpsvik, N Norway, N Norway

12.32012.320±±125125KullabergKullaberg, , ScaniaScania, Sweden, Sweden

12.23012.230±±130130ÖÖstrastraKarupKarup, , ScaniaScania, Sweden, Sweden

11.24011.240±±180180AsdalAsdal, Denmark, Denmark

10.92510.925±±110110FinnFinnøøyy, Norway, Norway

10.17010.170±±125125KurKuröödd, , BohuslBohusläänn, Sweden, Sweden

50605060±±9595NuulliitNuulliit , Thule, Greenland, Thule, Greenland

34703470±±8585SSøønderlandnderland, Greenland, Greenland

33203320±±8585SSøønderlandnderland, Greenland, Greenland

21352135±±120120Prince of Wales Island, Nunavut, CanadaPrince of Wales Island, Nunavut, Canada

15201520±±110110BrBrøønlundnlundFjord, GreenlandFjord, Greenland

15601560±±6565Victoria Island, Nunavut, CanadaVictoria Island, Nunavut, Canada

15101510±±3030Arctic CanadaArctic Canada

14151415±±6060Washington Land, GreenlandWashington Land, Greenland

960960±±6060Washington Land, GreenlandWashington Land, Greenland

820820±±6060NortheasternNortheasternGreenlandGreenland

440440±±4545KolnKolnææss, Greenland, Greenland

Inferred ageInferred ageAge Age Fossil find, locationFossil find, location

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The The Poolepynten Poolepynten fossil site fossil site ––locationlocation

The Poolepynten fossil site The Poolepynten fossil site ––locationlocationBrucebukta

Coastal sections

Poolepynten

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The Poolepynten fossil site The Poolepynten fossil site ––locationlocation

The Poolepynten fossil site The Poolepynten fossil site ––stratigraphystratigraphy

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Unit A: Marine proUnit A: Marine pro--delta deposit. Contains fossil mollusk shells, kelp, delta deposit. Contains fossil mollusk shells, kelp, dropstones. Deposited under open marine conditions.dropstones. Deposited under open marine conditions.

Unit B1: Subglacial till, deposited by expanded local glacierUnit B1: Subglacial till, deposited by expanded local glacier

Unit B2: Glacigenic slump deposits, reworked till and marine Unit B2: Glacigenic slump deposits, reworked till and marine sediments.sediments.

Unit C: Shallow marine deposit. Contains fossil mollusk shells, Unit C: Shallow marine deposit. Contains fossil mollusk shells, kelp, kelp, dropstones. Deposited under open marine conditions.dropstones. Deposited under open marine conditions.

Unit D: Boulder lag and beach gravels.Unit D: Boulder lag and beach gravels.


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The Poolepynten fossil site The Poolepynten fossil site ––stratigraphy and glacial historystratigraphy and glacial history

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The Poolepynten fossil polar bear The Poolepynten fossil polar bear jawbone jawbone –– osteologyosteology

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300,00280,00260,00240,00220,00200,00180,00

Mandible length

120,00

110,00

100,00

90,00

80,00

70,00

60,00

Man

dib

le h

eig

ht

PoM

Fi

F

As

V2

The relationship between mandible length and mandible height in polar bears (○: females Svalbard, ●: males Svalbard, ■: PoolepyntenSvalbard, ▲: Asdal Denmark,▼: Finnøy Norway).

300,00280,00260,00240,00220,00200,00180,00

Mandible length

80,00

75,00

70,00

65,00

60,00

Mo

lar

too

thro

w le

ng

th

PoMFi

FAs

V2

Fig. 6. The relationship between mandible length and molar tooth-row length in polar bears (○: females Svalbard, ●: males Svalbard, ■: Poolepynten Svalbard, ▲: Asdal Denmark,▼: Finnøy Norway).

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18,0016,0014,0012,00

Length M3 alveoli

12,0

10,0

8,0

Bre

ath

M3

alve

oli

Po

M

FAs

V2

The relationship between length of M3 alveoli and breath of M3 alveoli in polar bears (○: females Svalbard, ●: males Svalbard, ■: Poolepynten Svalbard, ▲: Asdal Denmark,▼: Finnøy Norway).

The Poolepynten jawbone: from a The Poolepynten jawbone: from a fully grown female polar bearfully grown female polar bear

1414C AMS age determination of the C AMS age determination of the jawbone: >45.000 ka. jawbone: >45.000 ka.

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The Poolepynten fossil polar bear The Poolepynten fossil polar bear jawbone jawbone –– ageage

Glaciation curve for Glaciation curve for SvalbardSvalbard--Barents SeaBarents Sea

(from Mangerud (from Mangerud et al. 1998)et al. 1998)

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Conclusions and potentialsConclusions and potentials

•• The jawbone from the Poolepynten sections is The jawbone from the Poolepynten sections is probably the oldest hitherto known polar bear probably the oldest hitherto known polar bear fossil, >80 <150 ka old. Probably 100fossil, >80 <150 ka old. Probably 100±±10 ka.10 ka.

•• An attempt is being made to extract material An attempt is being made to extract material for DNAfor DNA--analysis to compare with presently analysis to compare with presently living animals and highlight polar bear evolution.living animals and highlight polar bear evolution.

Many elements of the late Many elements of the late PleistoPleisto--cenecene megafaunamegafauna did not survive the did not survive the earlyearly--mid Holocene climate optimum mid Holocene climate optimum at high Northern latitudes.at high Northern latitudes.

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The Polar BearThe Polar Bear’’s sister species, the large s sister species, the large Cave Bear, which appeared about 150 ka Cave Bear, which appeared about 150 ka BP, went extinct at the PleistoceneBP, went extinct at the Pleistocene--Holocene transition. Holocene transition.

One interesting aspect is that if the polar bear One interesting aspect is that if the polar bear developed from the brown bear during the early developed from the brown bear during the early part of the last (part of the last (WeichselianWeichselian) glacial cycle, as ) glacial cycle, as suggested by the fossil material, the present suggested by the fossil material, the present interglacial might be the first such that the interglacial might be the first such that the species has to endurespecies has to endure……

Interglacial survival of the Interglacial survival of the Polar BearPolar Bear

Photo: I.S. Jónsdóttir, 2006

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The polar bear main habitat, the sea ice, is rapidly diminishing due to warming at high latitudes. In these perspectives, there might be reason to fear for the future persistence of polar bears.

Photo: I.S. Jónsdóttir, 2006

AcknowledgementsAcknowledgementsThanks to the student partici-pants in AG-301/326 since 1998, in particular class of 2004!

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References and web-resourcesAaris-Sorensen, K. and Petersen, K.S. 1984. A Late Weichselian find of a polar bear (Ursus maritimus) from Denmark and reflections on the

paleoenvironment. Boreas 13: 29-33.Amstrup, S. C., and C. Gardner. 1994. Polar bear maternity denning in the Beaufort Sea. Journal of Wildlife Management 58: 1W10.Amstrup, S. C., G. Durner, I. Stirling, N. J. Lunn, and F. Messier. 2000. Movements and distribution of polar bears in the Beaufort Sea.

Canadian Journal of Zoology 78: 948W66.Andersson, Th, Forman, S., Ingólfsson, Ó. & Manley, W. 1999: Late Quaternary environmental history of central Prins Karls Forland,

Svalbard. Boreas 28, 292-307.Berglund, B. E., Håkansson, S. & Lepiksaar, J. 1992: Late Weichselian polar bear (Ursus maritimus Phipps) in southern Sweden. Sveriges

Geologiska Undersökning Ca 81: 31-42. Bergsten, H., Andersson, T. & Ingólfsson, Ó . 1998: Foraminiferal stratigraphy of raised marine deposits, representing isotope stage 5, Prins

Karls Forland, western Svalbard. Polar Research 17: 81–91.Demaster, D.P. and I. Stirling 1981 Ursus maritimus (Polar Bear). American Society of Mammalogists, Mammalian Species 145: 1-7.Ferguson, S. H., M. K. Taylor, E. W. Born, A. Rosing-Asvid, and F. Messier. 1999. Determinants of home range size for polar bears (Ursus

maritimus). Ecology Letters 2: 311W18.Flynn, J.J. et al. (2005): Molecular Phylogeny of the Carnivora (Mammalia): Assessing the Impact of Increased Sampling on Resolving

Enigmatic Relationships. Systematic Biology 54: 317–337.Kurtéen, B. 1964. The evolution of the polar bear, Ursus maritimus Phipps. Acta Zoologica Fennica 108: 1W30.Kurtén, B. & Anderson, E. 1980. Pleistocene Mammals of North America. New York, Columbia University Press, 442 p.Larsen, T., H. Tegelström, R. K. Juneja, and M. K. Taylor. 1983. Low protein variability and genetic similarity between populations of the polar

bear (Ursus maritimus). Polar Research 1: 97W105.Talbot, S. L., and G. F. Shields. 1996. Phylogeography of brown bears (Ursus arctos) of Alaska and paraphyly within the Ursidae. Molecular

Phylogenetics and Evolution 5: 477W94.Thenius, E. 1953. Concerning the analysis of the teeth of polar bears. Mammalogical Bulletin 1: 14W20.Waits, L.P. et al. (1999). Rapid Radiation Events in the Family Ursidae Indicated by Likelihood Phylogenetic Estimation from Multiple

Fragments of mtDNA. Molecular Phylogenetics and Evolution 13: 82–92,

http://www.messybeast.com/genetics/hybrid-mammals.html

http://www.polarbearsinternational.org/about-us/

http://www.bear.org/

http://www.albatrossnet.com/Zpbpointing.html

http://pbsg.npolar.no/Refs/refs.htm

http://www.mun.ca/biology/scarr/Phylogeny_of_Ursidae.htm

http://www.personal.psu.edu/users/w/x/wxk116/cavebears/

http://www.greatbear.org/index.htm

http://www.bear.org/SlideShows/SS_Home.html

My home page: www.hi.is/~oiMy home page: www.hi.is/~oi

Thank you!

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