We would read the book The Very Hungry Caterpillar by Eric Carle. After reading the story we would each create our own caterpillar craft. Along with this craft the class would learn and discuss the life cycle of a caterpillar.
Life Science Worksheets: Life Cycle of a Frog. While I am against worksheets in the early learning classroom, I do, occasionally use them as a group activity. I love this visual for talking about the lifecycle of a frog.