CONTENT STATEMENT
Human modifications of the physical environment in one place often lead to changes in other places (e.g., construction of a dam provides downstream flood control, construction of a city by-pass reduces commercial activity in the city center, implementation of dry farming techniques in a region leads to new transportation links and hubs).
CONTENT ELABORATION
The interaction of humans with the physical environment in one place can lead to expected (intended) as well as unexpected (unintended) consequences in other places due to the systemic and interdependent nature of the physical environment.
For example, the construction of the St. Lawrence Seaway had the intended consequence of facilitating transportation of goods by oceangoing vessels into the heartland of North America. It also had an unintended consequence of enabling invasive species of fish and mussels to penetrate throughout the Great Lakes drainage basin.
The use of strip mines had the expected effect of increasing ore extraction at lower cost, but also had an unintended effect of producing toxic runoff in neighboring lakes and streams.
EXPECTATIONS FOR LEARNING
Citing examples, explain how a human modification of the physical environment in one place can produce intended and unintended change in another place.