History, Humans &
the Price of Expansion
Tuesday Week 8
Announcements:
News Item: Annie Henderson
Mid-term grades posted - for most current grades, check Moodle
Advising week begins Mon. after spring break - sign up to meet with your advisor!!! Watch for emails from your advisor!! Please let me know if you're not sure how to do this...
Happy Spring Break! Be safe - have fun
Review:
What are the dangers of small population size?
Get a new bag of M&M's... & also a copy of the "Extinction Vortex" hand-out for each group member
Count - & note - your starting colors, then start eating them (but don't look! eat at random!);
How do the color distributions compare at 20 M&M's?
At 10 M&M's?
Has there been a loss of colors? What could this represent in an actual population of organisms?
Relate what you observed to the extinction vortex diagram & fill in the blanks...
Question of the Day: How long have humans been impacting biodiversity?
Objectives:
Know the main ways that humans impact/decrease biodiversity
"Centinelan" extinctions
Be able to explain when humans first started to impact diversity of other life forms
Recognize specific examples of extinctions linked to human expansion during pre-history
Polynesia
e.g. Hawaii
N. (& S.) America
New Zealand
Australia
Extinctions - "rifle shot" vs. "holocaust"
Return to moral question; spotted owl example
Powerpoint Slides for this topic
Question 1:
What evidence is there for human-caused extinctions in pre-history?
Example: North America, mega-fauna extinctions at the end of the Pleistocene
The Species:
Woolly Mammoth
Giant
Ground Sloth
Visit these websites for further insight into the theories used to explain N. American mega-fauna extinctions -
http://www.museum.state.il.us/exhibits/larson/lp_extinction.html (animated maps & introduction to 3 main arguments)
http://www.pbs.org/wgbh/nova/stoneage/megafauna.html (summary of 3 main arguments)
Question 1: Explanation
What evidence is there
for human-caused extinctions in pre-history?
This map shows how catastrophic large-animal extinctions occurred around the world not long after humans first arrived in a geographical region. Australia and New Guinea suffered their mass extinctions between 15,000 and 30,000 years ago, North and South America theirs between 10,000 and 12,000 years ago, and oceanic islands like the Greater Antilles, major Mediterranean islands, New Zealand, and Madagascar theirs between 1,000 and 6,000 years ago. All these occurred in the wake of initial human colonization. Numbers indicate percentages of extinct genera during the past 100,000 years. source: http://www.pbs.org/wgbh/nova/stoneage/megafauna.html |
Question 2:
What are the main mechanisms for human-caused extinctions?
Question 3:
Should we use heroic efforts to save rare species?
"rifle shot" vs. "holocaust" extinctions
Spotted Owl example