Chapter Four (Sarah)

The theory that many species went extinct at one point in time due to a catastrophic event was brought to light by Walter and Luis Alvarez. They came to this conclusions due to the amount of missing fossils and since there were high levels of iridium in some of the rocks and clay that would have came from a asteroid. This theory was dismissed and ridiculed by many scientists and seen as a way to get attention. Something I noticed is that when scientists don't support a theory or idea they often see it as a joke and make fun of the theory and its supporters. Eventually, people started to believe and open up to the K-T theory which was interesting since they had believed Lyell's theory about a slow extinction for a long time.

At the end of the chapter, the author asks the question "How could a creature be adapted, either well or ill, for conditions it has never before encountered in its entire evolutionary history?"(page 90). I think it may mainly come down to luck. In many cases, the dinosaurs would have survived over most of the species that survived the asteroid if you go by natural selection, but dinosaurs died out by chance even though they seemed like they would have the highest chance of survival.