Yes, but you always have the option of setting ISO to automatic as well
But with the semi-auto modes there are always considerations to take depending on what you're shooting.
Aperture priority is *not* the de-facto best mode.
For stills photography yes, but as the name implies, Shutter Priority if you're doing wildlife.
If you're setting ISO manually then Aperture Priority is fine, but on my camera at least if I go as automatic as I can in Aperture with auto ISO enabled, it's much too conversative with shutter speed to freeze motion of moving animals. I don't know if it actually takes lens focal length into consideration, but when shooting on my 55-250mm Aperture priority with auto ISO seems to aim for shutter speeds in the area of 1/300