Question

Joanna and Stephanie are researching the effects of global warming. They notice that several types of organisms, such as armadillos, gnats, and alligators, are found much further north than they were found twenty years ago. They conclude that the change of location for these species is directly related to global warming.

What would you tell them about the validity of their conclusion?
Responses
A They have made a valid conclusion.They have made a valid conclusion.
B They should test their hypothesis before coming to that conclusion.They should test their hypothesis before coming to that conclusion.
C Global warming could not cause a species to move to different locations.Global warming could not cause a species to move to different locations.
D They should research more species to see if others have moved further north over the last twenty years.They should research more species to see if others have moved further north over the last twenty years.

Answer 1

B

They've observed a correlation (range shifts) but haven't tested causation. To validly conclude that global warming caused the shifts they need to collect data, control for other factors (land use, human introductions, habitat changes), and test the hypothesis.