DDT was first used as an insecticide in 1942. Resistance genes existed before this time in houseflies and other insects. By 1970, no farmer would bother using this chemical. Why?
What will be an ideal response?
As DDT was used, the susceptible animals died, and only those with the natural ability to detoxify the poison were left to reproduce. Thus, the only insects left to reproduce were those with the successful trait. Farmers soon learned that the chemical was a waste of money.
You might also like to view...
The first affected family member who seeks medical attention for a genetic disorder is called the ____________________
Fill in the blank(s) with correct word
The region of South China emerged as China's core manufacturing region due to all of the following except
A) its harbors and ports. B) the established trade and manufacturing networks of Macau and Hong Kong. C) capital investment from Hong Kong, Taiwan and the Chinese Diaspora. D) its rich energy and natural resources base. E) its harbor and ports and its rich energy and natural resources base.
What caused the greatest mass extinction, in terms of species lost, at the end of the Permian?
a. global cooling b. sea level decline c. asteroid impact d. overhunting by humans e. increased volcanic activity
The moon lacks life and varies dramatically in temperature. If we could keep a layer of water spread on the surface of the moon, what effect would it have?
A) Physical conditions would remain the same. B) Because water has a high heat of vaporization, the temperatures would rise to the upper extremes. C) The temperatures would drop to the lower extremes. D) Water would absorb and hold heat and moderate the temperature extremes. E) Life would be possible, but it would have to withstand these extremes in temperature.