Check revised lecture notes!

Time Line 1.8 MYBP Beginning of Pleistocene 1.7 MYBP Ancestral mammoth arrives in America ~ 0.2 MYBP Modern humans evolve in Africa ~ MYBP Modern humans arrive in America 0.01 MYBP 135 spp. extinct, last glacial retreat

Dispersal of Humans Nature 7 Dec p. 653.

Climate Change in Pleistocene Humans arrive in Australia Humans arrive in America

Australia Colonized ~ 50,000 years ago. No global warming at this time. Offers a natural experiment to compare human predation and climate change.

Gifford Miller, 1999 Genyornis

Genyornis (1999 Research!) Miller et al., Science 283:

Summary (but 8 years ago!) “From consideration of all of these stories for different continents there does not appear to any one factor responsible for the late Pleistocene extinctions... What is likely is that the primary lethal effect was the combination of these factors, acting in a synergistic manner on a fauna unaccustomed to so many disruptions at once.” Burney 1993.

My Opinion Human Hunting –Almost certainly –More work needed on early social structure Humans as Disease Vectors –Intriguing Predator-Prey Theory –Not an issue in America or Australia –Relevant to Africa Climate Change –Probably a factor in America

Are we on the verge of a MASS EXTINCTION?

Review: Deterministic Threats Change in physical environment –climate change –habitat destruction –pollution Change in biotic environment –Competition –Predation (including disease and human hunting) –Mutualism

Current Extinction Methods of Humans Overkill (Stellar’s sea cow) Introduced species –predators, disease, competitors Habitat destruction Global climate change Warfare

The Last Stellar’s Sea Cow, 1768

Whales Hunted to Near Extinction 1800’s - A record three year cruise killed < 100 whales ~30,000 whales killed, 2.5 million barrels of whale oil ~60,000 whales killed, 1.5 million barrels of oil

Brown tree snake (Guam rail) Tibbles eats all Stephan Island Wrens (1894) W.B. Espeut introduces mongooses onto Jamaica (1872) Domestic animals become feral predators Introduced Predators

Bird Extinctions in Eastern N.A.

The Heath Hen: Multiple Causes Nature Conservancy magazine July/August 1998 p. 8-9

Disease New Scientist 5 August 2000 p.35. Article by Debora MacKenzie

Humans and Disease

Lyme Disease

Deforestation 110,000 km 2 per year, 20 hectares per minute (A. Sommer, 1976) 55 km 2 per year (an area the size of WV), 10 hectares per minute (P. and A. Ehrlich 150,000 km 2 per year, 25 hectares per minute, one football field every second (N. Myers 1989).

Deforestation