Dinosaurs may have died off from an asteroid that collided with the Earth at the wrong time for the once-dominant animals. A group of paleontologists believe if that space rock struck our planet earlier or later in history, many dinosaur species may have survived the event.
A "perfect storm" of conditions may have led to the demise of dinosaurs, according to a new study. Investigators examined recently-discovered fossils, most from North America, using the latest in analytical techniques.
University of Edinburgh researchers led an international team that found climatic changes were occurring all over the globe, starting a few million years before impact. These events included wide-spread vulcanism, that could have dramatically lowered global temperatures. Sea levels could have also been affected - with colder temperatures, much of the water in oceans would have frozen, leading to wide extinctions of marine species. This lack of biodiversity could have caused significant challenges to many types of dinosaurs, according to the study.
"The dinosaurs were victims of colossal bad luck. Not only did a giant asteroid strike, but it happened at the worst possible time, when their ecosystems were vulnerable. Our new findings help clarify one of the enduring mysteries of science," Steve Brusatte, a geologist with the University of Edinburgh, said.
After the asteroid, measuring six miles across, collided with Earth, the environmental damage caused the extinction of many species at the bottom of the food chain. This effect could have trickled up to dinosaurs, wiping out all of the animals, except those with the most bird-like characteristics.
Small mammals took advantage of a world without dinosaurs, quickly proliferating and become more advanced. Without the climatic changes from volcanism in the final few million years of the dinosaur's reign over Earth, it is possible humans may never have evolved in our present form.
In the study, researchers suggest that if the asteroid collided with Earth a few million years earlier, or later, more of the species could have survived the cataclysmic event. If the collision occurred more than a few million years ago, biodiversity at the bottom of the food chain would have been greater, lessening the damage done to top-level feeders. Additional species would have evolved following the series of eruptions, providing a greater degree of biodiversity when the Mount Everest-sized asteroid struck the Earth.
Additional studies taking place in China and Spain will provide additional insight into how climatic changes in the time leading up to the massive impact affect survivability of the animals.
An investigation into the role of vulcanism in the extinction of most dinosaurs was profiled in the journal Biological Reviews.