I use this unit for kindergarten every year. In their classrooms they get caterpillars and watch them hatch into butterflies then release them. So we talk about symmetry in butterflies, parts of a butterfly and the life cycle of a butterfly. The life cycle I use as the last page because it's the most fun. I get marshmallows for the egg, sour gummy worms for the caterpillar, tootsie rolls for the chrysalis (not the most prettiest of chrysalis' but they are yummy to eat!), and multi-colored pasta