November 18, 2009

Reading Ch. 13 YES, there is class on FRIDAY

How to Make Pumpkins Fly"It's a redneck thang. You wouldn't understood."

(Nov. 14) -- Start with one delightfully warped science project contest for grown-ups. Add a touch of county fair and a whole lot of tailgating. What do you get? Flying pumpkins. Every year on the first weekend after Halloween, competitors bring catapults, trebuchets, air cannons and all sorts of other pumpkin-launching contraptions to a vast cornfield near Bridgeville, Del. The World Championship Punkin Chunkin draws fans from all over the country to rural Sussex County, where a pumpkin is a "punkin" and "chunkin" rolls off the tongue so much easier than "chucking" after "punkin." This year, there were 109 machines in the competition, and 70,000 spectators.

Permian Mass

Extinction (251mya)

Devastated 90-95% all species• < 5% sea life survived• ~1/3 of large land

animals survived• Trees almost

obliterated

http://evolution-textbook.org/content/free/figures/ch10.htmlhttp://ngm.nationalgeographic.com/ngm/0009/feature4/index.html

Proposed Causes

Global cooling?• Caused other extinctions• Reduced marine habitats

Support• Pangaea formation

Glaciers at poles

• Siberian trapsFlood basalts

Likely cause?• Probably not

mid-Permian coolingClimate instability

http://www.emporia.edu/earthsci/student/kaczor1/rk.htmhttp://earthobservatory.nasa.gov/Features/SiberiaBlog2008/page9.php

Proposed Causes

Volcanic activity• Ash would block sunlight• Acid rain generation,

followed by greenhouse• Support

Siberian traps

Asteroid impact• Support

Possible impact crater– Anarctica

http://researchnews.osu.edu/archive/erthboom.htmhttp://science.nasa.gov/headlines/y2002/28jan_extinction.htmhttp://earthsci.org/fossils/space/craters/permian/permian.htmlhttp://www.scientificamerican.com/article.cfm?id=geologists-link-the-great

Proposed Causes Ocean anoxia

• Oxidation of organic matterCreated dead zones

• Bicarbonate burpCO2 upwelling

• Sulfide productionPhototroph blooms

– fed by nutrient input from eroding land– Chlorobium (GSB)

http://www.msnbc.msn.com/id/30563213/http://www.bio.ku.dk/nuf/projects/index.htmhttp://waterresearch.blogspot.com/2007/06/bule-green-algae-bloom-in-dianchi-lake.html