Ah, okay.

As far as effects specifically, yeah, they also apply to objects on the
slides, depending on which set of effects you've chosen to use in your
presentation.

Open a new, blank presentation. This uses the "Office" theme. If you insert
a shape onto a slide and then on the Drawing Tools Format tab of the ribbon,
choose the "intense effect, accent 1" from the quick style gallery on the
Shape Styles group, you can see the change in effects when you apply
different themes or effects sets.

So, after you create this shape and apply the "intense effect" quick style,
go back to the Design tab and hover over the Apex theme. The object's
gradient fill will change to a diagonal one, and the shadow makes the object
look much further (farther?) from the slide than the shadow on the
Office-themed object.

Now hover over the Metro theme. It has kind of a "glowy" effect. Now Opulent
to see the "split" look in that object. And then Median to see its bevel
effect.

So now, just click the Effects button on the Themes group of the Design tab
and run your mouse over the effects sets. These are the effects the
different themes use by default. This way, you can see the effects applied
to your object on the slide, even though the colors and fonts remain
"Office-themed."