A sampling of the range of animal and plant diversity can found by typing into your browser: animal diversity images or plant diversity images. The conclusion that animals are distinguished by feeding on other plant/animal material may be clued by showing videos of various animals feeding. For example:
earthworms feeding: https://www.youtube.com/watch?v=9ZHTerOJYMA ( Many kids will have the notion that earthworms feed on dirt. Emphasize, as noted in this video, that they are actually feeding on plant material within or on the surface of the soil. They get no energy or nutrients from soil particles.)
Many students will have the naive notions that plants likewise feed on soil. Use the logic described in the text to emphasize that this is not so. Plants gain their energy need directly from light (photosynthesis).