This paper presents a tracking algorithm for the adaptive control of nonlinear dynamic systems represented in Strict Feedback Form with parametric uncertainty. The construction of the stabilizing algorithm is given using Passivity-based arguments that result in an Adaptive Passivity-Based Controller (APBC). This paper also shows a comparison with a controller designed via Adaptive Backstepping with tuning functions. The Adaptive Backstepping Controller (ABC) has many additional coupling terms that make its design and implementation more complex and may also result in unwanted transients. On the other hand, the APBC has a convenient decoupling property that provides a diagnostic tool for detection of non-parametric model error.