Historical study: The dinosaurs were at their prime when the asteroid hit the Earth

A new study provides the strongest evidence yet that dinosaurs were injured in their infancy and were not in decline at the time the asteroid struck.

A Landmark study revealed that dinosaurs dominated the world until a deadly asteroid hit the Earth, which led to its mass extinction about 66 million years ago.

The results have been published in the journal Science advances On December 7th, he provided the strongest evidence yet that dinosaurs were snapped in their prime. At the time the Chicxulub asteroid struck, the dinosaurs weren’t in decline.

Scientists have long debated why non-avian dinosaurs, including Tyrannosaurus rex and Triceratops, went extinct — while other mammals and species such as turtles and crocodiles survived.

“Dinosaurs were strong, with stable ecosystems, until suddenly an asteroid killed them..” – Professor Steve Brusatte

Led by an international team of paleontologists and ecologists, the study analyzed 1,600 fossil records from North America. The researchers modeled the food chains and ecological habitats of land-dwelling and freshwater animals over the past several million years

chalky
The Cretaceous period is a geological period that lasted from about 145 to 66 million years ago. It is the third and final period of the Mesozoic Era. It ended with the Cretaceous-Paleogene extinction event.

“data-gt-translate-attributes=”[{” attribute=””>Cretaceous, and the first few million years of the Paleogene period, after the asteroid hit.

For some time paleontologists have known that many small mammals lived alongside the dinosaurs. However, this research reveals that these mammals were diversifying their diets, adapting to their environments, and becoming more important components of ecosystems as the Cretaceous unfolded. Meanwhile, the dinosaurs were entrenched in stable niches to which they were supremely well adapted.

Mammals didn’t just take advantage of the dinosaurs dying, experts say. They were creating their own advantages through diversifying – by occupying new ecological niches, evolving more varied diets and behaviors, and enduring small shifts in climate, by rapidly adapting. These behaviors probably helped them to survive, as they were better able than the dinosaurs to cope with the radical and abrupt destruction caused by the asteroid.

Triceratops prorsus Munching on Cycads

Triceratops prorsus munching on cycads disturbs primitive cousins of placental (left) and marsupial (right) mammals in the underbrush- while a softshell turtle climbs up on a log, unaware that its freshwater ecology will shelter it from the impending doom from space. Credit: Henry Sharpe

First author, Jorge García-Girón, Geography Research Unit, University of Oulu, Finland and Department of Biodiversity and Environmental Management, University of León, Spain, said: “Our study provides a compelling picture of the ecological structure, food webs, and niches of the last dinosaur-dominated ecosystems of the Cretaceous period and the first mammal-dominated ecosystems after the asteroid hit. This helps us to understand one of the age-old mysteries of paleontology: why all the non-bird dinosaurs died, but birds and mammals endured.”

Co-lead author, Alfio Alessandro Chiarenza, Department of Ecology and Animal Biology, University of Vigo, Spain, said: “It seems that the stable ecology of the last dinosaurs actually hindered their survival in the wake of the asteroid impact, which abruptly changed the ecological rules of the time. Conversely, some birds, mammals, crocodilians, and turtles had previously been better adapted to unstable and rapid shifts in their environments, which might have made them better able to survive when things suddenly went bad when the asteroid hit.”

Senior author, Professor Steve Brusatte, Personal Chair of Palaeontology and Evolution, School of GeoSciences, University of Edinburgh, said: “Dinosaurs were going strong, with stable ecosystems, right until the asteroid suddenly killed them off. Meanwhile, mammals were diversifying their diets, ecologies, and behaviors while dinosaurs were still alive. So it wasn’t simply that mammals took advantage of the dinosaurs dying, but they were making their own advantages, which ecologically preadapted them to survive the extinction and move into niches left vacant by the dead dinosaurs.”

Reference: “Shifts in food webs and niche stability shaped survivorship and extinction at the end-Cretaceous” by Jorge García-Girón, Alfio Alessandro Chiarenza, Janne Alahuhta, David G. DeMar, Jani Heino, Philip D. Mannion, Thomas E. Williamson, Gregory P. Wilson Mantilla and Stephen L. Brusatte, 7 December 2022, Science Advances.
DOI: 10.1126/sciadv.add5040

The research is published in the journal Science Advances. It was funded by National Science Foundation (USA), Academy of Finland, European Union Next Generation European Research Council (ERC) Starting Grant, European Union’s Horizon 2020 Research and Innovation Programme, Juan de la Cierva Formación 2020 Fellowship funded by the Ministry of Science and Innovation from the European Union Next Generation.


#Historical #study #dinosaurs #prime #asteroid #hit #Earth

Leave a Reply

Your email address will not be published. Required fields are marked *