With my 2nd graders, we watched this video showing the rich wildlife of the African landscape:
Next, I introduced them to the concept of silhouettes. This is a tough one for little ones because you have to explain light direction and shadowing. Even though they may not totally understand the abstract concept, they can gain an understanding of why the images are all in black. I emphasized painting their sunsets from light to dark, starting with yellow and ending with red, or the darkest color on their palette. Here are a few examples:
by Aaryn J.
by Brian T.
by Aaliyah B.
by anonymous 2nd grader