You may not know, it but decisions you make every
day can have an impact on the rest of the world. We can see this
by looking at a National Park in Michigan: Isle Royale.
Isle Royale is one of several National Parks in Michigan.
It lies in northern Lake Superior, closer to Canada and Minnesota
than to Michigan. The island is very isolated due to the fact
that it is separated from the rest of the world by the icy waters
of Lake Superior. Because of the island's distance from industrial
centers and its general isolation, scientists studying water pollution
in the region expected to find little or no pollution in the lakes
on the island. They were surprised to find that some Isle Royale
lakes were more polluted than mainland waters.