Before asteroid killed dinosaurs, they were getting extinct due to climate change
New Delhi : It is known that dinosaurs had extinct from planet Earth after a 12-km long asteroid crashed at the Yucatán peninsula in Mexico. The magnitude of the impact was so strong that it swept away many species of animals and plants.
A study by Nature Communications has found that the dinosaur species were already diminishing before the asteroid strike.
The study investigated the influence of ecological and physical factors, and found that decline of dinosaurs was driven by global climate cooling and herbivorous diversity drop. The latter is likely due to hadrosaurs outcompeting other herbivores.
"The most famous mass extinction was the disappearance of non-avian dinosaurs at the end of the Cretaceous, 66 million years ago (Mya), after ruling the Earth for 170 million years."
There is a debate on how environmental factors depleted the number of dinosaurs, and yet there are very few evidences to support the global decline across dinosaur groups prior to their extinction at the end of the Cretaceous.
The latest thorough analyses of fossil data found no evidence for a decline of non-avian dinosaurs before their extinction and little evidence of any decline in dinosaur species richness or ecological diversity during the last million years of the Cretaceous.
However, a phylogenetic study using dinosaur timetrees challenged the idea of a sudden extinction, but instead supported a diversity decline with extinction rates exceeding speciation rates well before the K/Pg event, which has been disputed recently. Thus, there is no consensus on whether dinosaurs were in decline or not prior to their extinction.