This preview shows page 1. Sign up to view the full content.
Unformatted text preview: no; would have been largely synchronous globally, and is not. also, cooling occurred in
early Pleistocene with no extinction of large mammals
no; extinctions occurred without replacement by new taxa; many vacant niches
Competitive exclusion? remain unfilled still
Human hunting (Martin, 1984)? most plausible; can explain high selective, asynchronous,and patchy
patterns The 6th mass extinction
Are we causing a mass extinction? W hat’s the evidence?
1 in 8 birds, 1 in 4 mammals, 1 in 5 invertebrates, 1 in 3 amphibians and half of all turtles face extinction
Paleoclimate - study with stratigraphic record or isotopic record
Stratigraphic —> desert —> tropical —> glacial
Cross-bedded sandstone, coal beds, glacial till
Isotopic —> oxygen isotope data in ice cores warming .7C over 20th century
Atmosphere: increase shown from Mauna Loa records
Increase of green house gases
Effects of Climate Change - glacial retreat; sea-level rise; extreme weather events (flood, drought, etc.);
changes in agricultural yield; species extinction; increases in range of disease vectors
Coral Reef Bleaching
2/3 of polar bears will disappear by 2050 due to loss of habitat and pray
Major loss 50-90% of penguins over last 50 years due to loss of habitat and pray...
View Full Document
- Spring '08