We picked up a big stack of books at the library which relate to caves, fossils, and prehistoric creatures. The visit to the cave has created many new fun conversations with A, who wants to repeatedly discuss how a living thing becomes a fossil. During our cave tour, the guide shone her flashlight to the ceiling of the cave, and jutting out was a large clear 2-3 foot long fossil of a squid like creature. I think that is what got him going. But the ideas of time, extinction, and just the history of life is a big subject.
One book we found was "Life On Earth: The Story of Evolution" by Steve Jenkins. It addresses in a pretty quick and fundamental way things like biodiversity, natural selection, and speciation. It has enough detail to interest my fact loving 4 year old, but not so much that he wanders off. The artwork is VERY cool too. The author creates amazing paper collages to illustrate his books. I think A could look at the one page of beetles for HOURS. We have read other books by Steve Jenkins - I am always inspired by his artwork.
We found a few other fun books - another favorite over the weekend was "Bugs Before Time: Prehistoric Insects and their Relatives". Very interesting!