For the anisotropic XY model in transverse magnetic field, we analyze the
ground state and its concurrence-free point for generic anisotropy,
and the time evolution of initial Bell states created in a fully polarized
background and on the ground state.
We find that the pairwise entanglement
propagates with a velocity proportional to the reduced interaction
for all the four Bell states.
A transmutation from singlet-like to triplet-like states is observed during the propagation.
Characteristic for the anisotropic models is the instantaneous
creation of pairwise entanglement from a fully polarized state;
furthermore, the propagation of pairwise entanglement is suppressed
in favor of a creation of different types of entanglement.
The "entanglement wave" evolving from a Bell state on the ground state
turns out to be very localized in space-time.
Our findings agree with a recently formulated conjecture on entanglement
sharing; some results are interpreted in terms of this conjecture.