No it isn't. In order to evolve, a species would have to add characteristics. That's the whole idea behind evolution theory. From a single cell to lungs and eyeballs, brains fingers, feet, toes, arms and legs. That's addition not subtraction.
your statement:
"Evolution theory also requires that the species improve, or add characteristics."
this is false. The theory of evolution does not *require* that species *improve* OR *add* characteristics.
The theory of evolution explains how some species, through mutation and selection, become better adapted to their changing environments as well as how other species, through mutation and selection, become MALADAPTED to their changing environments.
The theory of evolution explains how some species, through mutation and selection, add characteristics as well as how other species, through mutation and selection, LOSE chartacteristics.
for more detail, I now turn you over to Ichneumon's care.