Tyranosaurus rex was really an oversized waddler, the ocean is blue because it is inefficient, and the first nuclear dart will probably be thrown for explicable ecological reasons. These are a few of the intriguing items Colinvaux takes on in eighteen thoughtful essays (the come-on title refers to just one) that rose to the surface when this eminent zoologist and textbook author spent a quiet year as a Guggenheim Fellow. The whole is a grabbag of his own research and ecological ponderings about plants, trees, air, climate, and humanity. He doesn't stop with life's pyramid as it was, he chases its future. There are Darwinian doubts about a surging world population that will be checked by natural selection. He shows the results of the most colossal of all experiments--doubling concentration in a short time of one of the planet's most important gases. And he sees hope for survival in our world's now-filthy waters. ""Scientists do not like their simple observations to be understood by others,"" notes Colinvaux. He's a ranking exception who begs understanding of the complex ecological links that make the Earth system tick. It is like sitting in on the lecture of a careful academic--occasionally crimped and professorial but highly educational.