Ch 1 PPT NOTES.notebook
2
September 05, 2014
Question Mosquitoes carry malaria and other diseases. In order to control mosquito populations, a powerful pesticide called DDT was used for many years. DDT entered lakes, ponds, and rivers and accumulated in the tissues of fish. When birds, such as eagles, consumed the fish, they produced eggs with very thin shells. The thinshelled eggs broke when the parents sat on them and the populations of eagles and other birds suffered. The U.S. government banned the use of DDT in 1972.
How did the banning of DDT most likely affect the population of bald eagles in the United States?
A. The eagle population rapidly declined after the banning of DDT.If a student chooses A, he or she may not understand that DDT originally caused a decrease in the eagle population. Therefore, removing DDT from the ecosystem allowed the eagle population to recover.
B. The eagle population was not affected by the banning of DDT.If a student chooses B, he or she may not understand that the eagle population was already affected by DDT, so banning it removes the original effect.
C. The eagle population slowly increased after the banning of DDT.This is the correct answer.Although DDT was at one time effective in controlling mosquito populations, it inadvertently caused the decline of an important predator in the ecosystem.
D. The eagle population increased and then rapidly decreased after the banning of DDT.If a student chooses D, he or she may not understand that the eagle population would increase upon the removal of DDT.
Ch 1 PPT NOTES.notebook
30
September 05, 2014
Journal Entry
1. What is VALID data and how can experiments be biased?
2. Why must scientists remain unbiased?
3. How could this statement be "true" but still not be valid data?
"Only 5% of Asian babies were born with low birth weight due to smoking and 70% of African babies were born with low birth weight due to smoking."
***This data is ONLY an example for this journal entry.***