Evolution by Joan Slottow

This painting is built from 3 layers of canvas.  The lowest layer depicts the skulls of birds with the archaeopteryx, a toothed transitional form between dinosaurs and birds, on the bottom row and modern bird skulls above that.  Millions of years of evolution allowed birds to fill different environmental niches.  The diversification of the bill shape from straight to curved and from short to very long, as shown in this layer of the painting, allows different bird species to have vastly different diets.  The second layer consists of two evolutionary trees, representing the divergence of species over time.  The layer closest to the viewer compares the bones in bird and bat wings with the front legs of a grizzly bear and human arms.  Comparative anatomy shows that the front-appendage bones in different species are the same in number and form even though adapted for different tasks.