Here's a bit of a crash course in poles: -
The upper pictures show a bode plot with frequency peaking in various amounts. The lower left picture attempts to show a 3D view of bode plot and poles and the lower right picture is the conventional pole zero diagram.
In other courses in which we deal with Bode plots, I notice that a
pole causes a -20dB/decade slope decrease? Why is there an incosistency?
There is no inconsistency; a single pole causes a peak in the spectrum and, due to the mathematical relationship (1/distance) between the pole centre and more distant positions on the jw axis there is a slope that results.
For a 2nd order low pass filter (example) there are two poles and the reciprocal-of-distance relationship leads directly to the ability calculate any point on the jw axis: -
Hope this helps. Related question and another related question and yet another related question. And another.