A custom-made Powerpoint may do wonders, I can even see species being animated properly and live-action to show movement, since comparative anatomy is so important in Zoology both in the past and present. As you go up the tree to higher forms, such as vertebrates, both live-action/animation and skeletal forms can be displayed (cross-sections under magnification could be used for lower forms). It might be too much, but at certain intervals differences in internal structure could be highlighted.