A talk by Ludo Broothaers 

This is the story of how fish, amphibians, reptiles, dinosaurs, birds and mammals came to populate our planet. It spans the most recent 500 million years of earth's history. Comparison with present-day biology shows us how they evolved into what they are right now, all in accordance with what Charles Darwin taught us about natural selection. Moreover, recent developments in geology and paleontology (study of fossils) enabled us to know when, in earth's history, major steps in the evolution of those vertebrate animals occurred, and in some cases even why. Those living in the biosphere (the earth's surface and atmosphere) have not always enjoyed propitious circumstances. Climatic conditions have changed with apparently unpredictable whimsy, but the worst changes involved variations in the availability of oxygen in the air.