Non-perturbative Parton Distributions in the Proton

A model for the parton distributions in hadrons is derived from simple physical arguments leading to an analytical expression for the valence distributions. The sea parton distributions arise mainly from pions in hadronic fluctuations. Evolving from a low Q^2_0 scale with DGLAP gives the proton structure function F_2(x,Q^2) in good agreement with DIS data. An extension of the model to describe intrinsic charm quarks in the proton is discussed.