Over a hundred years ago, the prairies of South Dakota were home to dozens of kinds of grasses and hundreds of kinds of insects. This supported many populations of small mammals and birds. Today the prairies are dominated by domesticated wheat crops that humans can harvest and use for food. Pesticides used in growing the crops have killed off many kinds of insects that once lived there. In addition, the pesticides have poisoned populations of native mammals, such as prairie dogs. Which of these is most likely an additional change that has occurred in this ecosystem?
A.
There has been an increase in the amount of space available to mammal populations.
B.
There has been an increase in the variety of food sources available to bird populations.
C.
Native grasses have adapted to become more edible to humans.
D.
Pesticides have been washed into local sources of drinking water.
1 answer
D. Pesticides have been washed into local sources of drinking water.