Assignment Task: Read the following case study from Understanding Environment (Jain, 2004, p. 25).
The Real Story: The Day the Cats were Parachuted In
Some years ago, the ABC Health Services sent supplies of DDT to Gyanpur to control the mosquitoes that were spreading malaria among the people. As the DDT was sprayed, the mosquitoes were quickly wiped out. But there were thousands of lizards in the village that ate these mosquitoes (which had absorbed the sprayed DDT) and they, in turn, kept accumulating the DDT in their bodies. When these lizards ate mosquitoes, they also absorbed a lot of the DDT. Due to the accumulation of so much DDT in their bodies, the lizards became very inactive and slow. This made it easier for cats to catch the lizards, one of their favorite foods. At about the same time, people also found that hordes of caterpillars had moved in to feed on the roofing materials of their homes. They realized that the lizards, which had previously kept the caterpillar population under control, were now being eaten by the cats. And now, all over Gyanpur, the cats that ate the lizards died from DDT poisoning. Then rats moved in because there were no cats to control their population. With the rats came a new danger: plague. Officials sent out emergency calls for cats, which were sent in by airplane and dropped by parachute (p.3).
Respond to the following:
1. Choose an ecosystem that interests you. Describe the ecosystem you selected and the inhabitants of the ecosystem.
2. Think about the balance between the inhabitants of that ecosystem. What might happen if one small thing was changed? Choose an example of one change, describe it, and then discuss what the impacts that change might have on the ecosystem.
3. Considering the change you discussed, what action would need to be taken to reverse the change and restore the ecosystem? Would all impacts be reversible? Why or why not?