humans and the pleistocene megafaunal extinction
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Humans and the Pleistocene Megafaunal Extinction. Kelsey T. Stilson. Cultural and Climate Revolution. Migrations change both humans and the ecosystem. Novel System. Stepped Global Extinction Events. - PowerPoint PPT PresentationTRANSCRIPT
Humans and the Pleistocene Megafaunal Extinction
Kelsey T. Stilson
Cultural and Climate Revolution
• Migrations change both humans and the ecosystem.
Shared Space
Humans
Ecosystem
Climate
Novel System
Stepped Global Extinction Events
Barnosky, AD; Koch, PL; Feranec, RS; Wing, SL; Shabel, AB. Assessing the causes of late Pleistocene extinctions on the continents. Science (New York, N.Y.) 2004 Oct 1; 306(5693): 70-5.
North America
• American Horse, Mammoths, Mastodons, Lions, Cheetahs, Giant Ground Sloths, Camels, Glyptodonts, Indricotheres, Saber-toothed cat, Dire wolves, Peccaries, Tapirs…
• Exceptions
Why do we look at Megafauna?• Megafauna = 44+ kg (100 lbs)• Early indicators of climate change!
=
Cenozoic
Paleocene Eocene Oligocene Miocene Pliocene Pleistocene Holocene
65 Ma 58 37 24 5 2 11,500 yrs
THERMAL MAXIMUM
MEGAFAUNAL EXTINCTION
ANTARCTIC GLACIATION
ANTARCTIC THAWING
ANTARCTIC REGLACIATION
Human Influence
• Overkill (Blitzkreig) Hypothesis: Paleoindians hunted the megafauna to extinction (Paul Martin)
• Timing is right, but the evidence is limited for complete human responsibility.
Too few taxa Few kill sites
• ‘Sitzkrieg’ Hypothesis: other ways humans alter the environment (Jared Diamond)
16 Ka
15 - 13 Ka
Other Predators
Non- human Predators
Prey population numbers controlled by Predators
Abundant resources and habitat space
Human Predation
Non-human predators forced to hunt less calorically efficient prey
Prey population controlled by predators
Abundant resources and habitat space
Hyperdisease• Brought over by humans or dogs with the migration over
beringia.• Extremely deadly• This would require the virus or bacteria to ‘jump’ between
different Orders, something that has never been observed in modern biology.
Bolide Impact
Guthrie, Dale R. New carbon dates link climatic change with human colonization and Pleistocene extinctions. Nature Vo. 441. Issue 7090 p.207
Implications for the Future
Overkill, Over-chill, Over-ill…• Humans today affect the ecosystem, how far
back does this go?• Depends on culture
• How will we change as we change our environment?
Thank You!
Special thanks to Professor Mark Carey, Professor Sam Hopkins,and Dr. Edward Davis