  A simple quark-diquark model for nucleon and $\Lambda$ structure is used to
calculate leading twist light-cone fragmentation functions for a quark to
inclusively decay into P or $\Lambda$. The parameters of the model are
determined by fitting to the known deep-inelastic structure functions of the
nucleon. When evolved from the initial to the final $Q^2$ scale, the calculated
fragmentation functions are in remarkable agreement (for $z>0.4 $) with those
extracted from partially inclusive $ep$ and $e^+ e^-$ experiments at high
energies. Predictions are made, using no additional parameters, for
longitudinally and transversely polarized quarks to fragment into p or
$\Lambda$.
