a comparison of placental and marsupial evolution
DESCRIPTION
A Comparison of Placental and Marsupial Evolution. James Duke, Katie Mayer, & Stephen Ulrich. Placental-Marsupial Divergence. Sinodelphys szalayi. Eomaia scansoria. The oldest known ancestor to marsupials (125 million years old). - PowerPoint PPT PresentationTRANSCRIPT
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James Duke, Katie Mayer, & Stephen Ulrich
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The oldest known ancestor to marsupials (125 million years old)
The oldest known ancestor to placental mammals (125 million years old)
Eomaia scansoria
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Marsupial distribution in the late Cretaceous
http://www.scotese.com/images/094.jpg
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Current marsupial distribution
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Multiple reproductive organs
Short internal gestation period followed by long development in marsupium
Single reproductive organ
Long gestation period
PlacentaWider pelvic
openings
Placentals
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Survival association with death during pregnancy
Common birthing problems of placentalsAmniotic membraneAdvantages of shorter gestation period
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Brain structureSocialityDevelopmental focusOther, minor
differences
http://brainmind.com/images/CorpusCallosum222.jpg
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Australia•Habitat destruction•Introduction of predators by humans
Worldwide•Smaller average body size
Other•Stephen
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• Lessa, Enrique P. & Richard A. Farina. (1996). Reassessment of extinction patterns among the late Pleistocene mammals of South America. Palaeontology:Vol 39, part 3, 1996, pp 651-662. Retrieved from http://palaeontology.palass-pubs.org/pdf/Vol%2039/Pages%20651-662.pdf.
• Pickrell, John. (2003).Oldest Marsupial Fossil Found in China: National Geographic News. Retrieved from
• http://news.nationalgeographic.com/news/2003/12/1215_031215_oldestmarsupial.html
• Nowak, Ronald M. (1999). Walker's Book Of Mammals, Sixth Edition. Baltimore and London: Johns Hopkins University Press. p. 5.
• Springer, Mark S., John A.W. Kirsh, & Judd A. Case. The Chronicle of Marsupial Evolution: Molecular Evolution and Adaptive Radiation. Edited by Thomas J. Givnish & Kenneth J. Sytsma. 1997. Cambridge, United Kingdom: Cambridge University Press. Retrieved from http://books.google.com/books?hl=en&lr=&id=d06PgBvL5lIC&oi=fnd&pg=PA129&dq=marsupial+evolution&ots=rongh7ew3o&sig=7vNP_mvfqQhuef5HrtEtmuvSiF4#v=onepage&q=marsupial%20evolution&f=false.
• Tyndale-Biscoe, Hugh. (2005). Life of Marsupials. CSIRO publishing. Retrieved from http://www.publish.csiro.au/samples/LOMsample.pdf.