Researchers at the University of Bath and the Natural History Museum in London have carried out a new study that refutes claims that dinosaurs declined before a massive asteroid impact. The researchers believe that if the asteroid impact had not occurred, dinosaurs might have continued to dominate the planet. Dinosaurs survived and operated extensively around the world during the late Cretaceous asteroid impact.
Before the asteroid impact, dinosaurs occupied every continent on Earth and were the main animal form of most terrestrial ecosystems. Despite their widespread existence, paleontologists are still debating whether the diversity of dinosaurs declined when they benta. The researchers collected a different set of dinosaur family trees and used statistical models to assess whether each major dinosaur group could have produced a new species at the time.
The study found that dinosaurs did not decline before the asteroid hit, contradicting previous studies. The study also suggests that without impact, dinosaurs could continue to be the dominant group of land animals on Earth. Joe Bonso, a researcher who led the study, said other studies in the past have used a variety of methods to conclude that dinosaurs would have died even if the asteroid impact had not occurred.
New research suggests that as data sets expand, including a wider range of family trees and a wider dinosaur type in modern times, the results do not all point to this conclusion. Bonsall says only about half of the results suggest that dinosaurs were declining. Instead of simply calculating the number of species within a family, the researchers used statistical methods to overcome sampling bias and observe the rate of specimenization in the dinosaur family.
The main point of the paper is that it’s not as simple as looking at a few family trees to make a decision. Bonsall said there are large and inevitable deviations in the fossil record, and the lack of data tends to indicate a decline in species, but the decline may not reflect the actual situation at the time.