Paleontologists tell us how the world has changed and that change is the only constant

Fossils reveal 'missing links' in Earth's evolution after dinosaurs

What is now a dry, harsh mountain desert in south-west Wyoming was once a lush subtropical landscape with lakes, volcanoes and an abundance of wildlife.

In "The Lost World of Fossil Lake", Lance Grande takes us back more than 50 million years to reveal how North America developed in the period after the extinction of the dinosaurs.

He says that paleontologists always search for "missing links" in natural history, and in Fossil Lake, they find clues as to how today's world emerged all the time.

Researchers have collected prehistoric remnants from Fossil Butte, one of the world's richest fossil depots, since the so-called Bone Wars 150 years ago, when Edward Drinker Cope and Othniel Charles Marsh raced to become the top paleontologist of their time.

Mr Grande, a lecturer at the University of Chicago and adjunct professor at the University of Illinois, spoke to the BBC about his own decades-long work at the site.