According to some scientists, a massive asteroid plowed into the planet approximately 66 million years ago. It sent ash into the atmosphere and provoked a period of such severe climate change that 75 percent of all plant and animal species, including all non-avian dinosaurs, suddenly disappeared.
But were these species doing well or doing poorly in the period prior to their demise? In other words, were dinosaurs increasing or decreasing in diversity in the years ahead of the asteroid?
Recent research in PNAS attempts to answer these questions. Relying on fossilized dinosaur eggs and eggshells from China in the two million years leading up to the impact, this research reveals that dinosaur diversity did, in all likelihood, decline well before the dinosaurs' eventual extinction.
Past scholarship on dinosaur diversity sends some pretty mixed messages. Though some studies suggest that dinosaurs of all shapes, sizes and species thrived before their surprise ...
