  The study of $ s-\bar s $ asymmetry is essential to better understand of the
structure of nucleon and also the perturbative and nonperturbative mechanisms
for sea quark generation. Actually, the nature and dynamical origins of this
asymmetry have always been an interesting subject to research both
experimentally and theoretically. One of the most powerful models can lead to $
s-\bar s $ asymmetry is the meson-baryon model (MBM). In this work, using a
simplified configuration of this model suggested by Pumplin, we calculate the $
s-\bar s $ asymmetry for different values of cutoff parameter $\Lambda$, to
study the dependence of model to this parameter and also to estimate the
theoretical uncertainty imposed on the results due to its uncertainty. Then, we
study the evolution of distributions obtained both at next-to-leading order
(NLO) and next-to-next-to-leading order (NNLO) using different evolution
schemes. It is shown that the evolution of the intrinsic quark distributions
from a low initial scale, as suggested by Chang and Pang, is not a good choice
at NNLO using variable flavor number scheme (VFNS).
