How do the finches of the Galapagos Islands demonstrate evolution?

The finches adapted over time to better suit their environment that they were in -- the size and shape of their beaks changed as a result of natural selection.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands