Ecology
How could dinosaurs achieve such impressive growth? Some of them were up to 50 meters in height. Scientists have suggested that the effective functioning of the respiratory system helped dinosaurs be larger than other animals.
New research has rejected the popular theory that animals get bigger as they evolve. Although some dinosaurs grew larger over subsequent generations, this did not happen to all of their species.
“We looked at early archaeosaurs, including the first dinosaurs,” said Roger Benson, one of the authors of the research published in the journal Proceedings of the Royal Society B. — We noticed that some species reached gigantic sizes while others did not change, and some even shrank in size over the course of evolution.”
Benson, a vertebrate paleontologist at the University of Cambridge, also said that “pterosaurs, flying reptiles, are a good example of a species that has remained small in size for the period under study.” Many small herbivores have also been discovered, such as the Heterodontosaurus dinosaur and small predators such as the Coelophysis dinosaur.
Benson and his colleagues analyzed more than 400 animal species that lived from the late Permian period to the Middle Jurassic period.
Animal growth models over 100 million years support a theory called passive diffusion. This means that different evolutionary generations have a huge number of differences, including different growth patterns: some are getting bigger, others are smaller, and others don't change at all.
Research contradicts the existing theory that certain groups of animals (like dinosaurs) always get bigger as they evolve. Compared to existing terrestrial animals, many dinosaurs were just giants.
“Several aspects of dinosaur biology allowed them to reach the maximum size of other animals,” said Benson. “For example, parts of the skeleton contained air in many dinosaurs, and we think they had very effective lungs, like birds. This feature made it easier for them to maintain their weight on the ground and also made their breathing and heat exchange more efficient than other mammals.”
Benson added that since larger animals can lay more eggs and reproduce faster, being larger is more beneficial in terms of breeding.
Other researchers who study dinosaurs believe that the largest animals ate a lot and moved very little.
“Large herbivorous dinosaurs undoubtedly spent a lot of time eating,” the scientists said. “It has been observed that dinosaur heads are very small compared to the body, which can It meant that dinosaurs spent too little time chewing their food; most of the digestive processes took place in the intestines.”
Such models are very different from those of most herbivorous mammals, which had larger heads with more teeth. These animals took longer to chew their food.
Benson believes that any terrestrial animal alive today is unlikely to ever reach the size of dinosaurs. “Mammals, including humans, are warm-blooded creatures and produce a lot of internal heat,” he explains. “This is a problem for large body sizes because there is a risk overheating. It is possible that many extinct archaeosaurs, including dinosaurs, were between warm-blooded and cold-blooded living creatures.”
“If so, these creatures could have any body size,” he added. “It's impossible for people to become such giants.”