  Deformations of minimal surfaces lying in constant time slices in static
space-times are studied. An exact and universal formula for a change of the
area of a minimal surface under shifts of nearby point-like particles is found.
It allows one to introduce a local temperature on the surface and represent
variations of its area in a thermodynamical form by assuming that the entropy
in the Planck units equals the quarter of the area. These results provide a
strong support to a recent hypothesis that gravity has an entropic origin, the
minimal surfaces being a sort of holographic screens. The gravitational entropy
also acquires a definite physical meaning related to quantum entanglement of
fundamental degrees of freedom across the screen.
