Everyone loves the dinosaurs. A lot of people – if the Jurassic Park films are to be believed – would like to see them come back. But without their extinction, we wouldn’t be here today.
Even now, it’s still not clear what exactly caused the extinction event – but the best known hypothesis is that of Luis and Walter Alvarez, which states that a meteoric or cometary impact caused a nuclear winter-like effect that altered the climate drastically, wiping out something like 75% of all species alive at the time. It is believed that the Chicxulub meteor, which hit the Earth in what is now the Gulf of Mexico, near the coast of the Yucatan.
The effects were particularly felt by larger species – which included most dinosaurs – and the destruction was more severe on land than at sea. Many species of ocean animal were largely unaffected, notably including the sharks. In the wake of the event, some of the now open evolutionary niches were occupied by birds and the earlier mammals, the latter including our own ancestors.
