Researchers have previously shown that turtles use the Earth’s magnetic field for orientation. Researchers captured the turtles and artificially simulated the earth’s magnetic field as it would exist at different sites and then measured which direction the turtles tried to swim to. The original experiments and results were discussed in a pre-class video.
Imagine you are a researcher and hypothesize that the same brain region that is responsible for processing magnetic information in birds also functions like this in turtles. To test this you capture turtles at the same site and disable this same brain region in 10 of these turtles. You also have a control group of 10 turtles where you did NOT disable the brain region. Then you test both groups of turtles in the same way as the researchers did in their previous experiment: you measure their orientation while you artificially simulate the Earth’s magnetic field as it would exist at the northern site (red arrow). Remember that these turtles are in captivity so they cannot use other cues like ocean currents, smell, etc..
Draw what the results of this experiment should look like if your hypothesis is accurate and turtles use this brain region to interpret magnetic cues: You should draw two compass circles, one for each group (control and experimental) and indicate which direction(s) you would expect the turtles to try to swim into in each case. In your drawing, make sure you label clearly which results relate to the control group and which ones to the experimental group (whose brain region you disabled).
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