Dinosaurs became extinct many millions of years ago, but humanity is still trying to restore the picture of the world of ancient reptiles. Films are made about them, books are written, but in all the information in the mass media there are more hypotheses and fantasies than scientific facts. But what do we really know about them? SFU experts – a zoologist, geologist and paleontologist – talk about the life of ancient animals.

Last December, a group of scientists from different countries published a report on the study of a dinosaur egg that was found in China back in 2000. The peculiarity of the find lies in the almost perfect condition of the preserved embryo. The age of the remains is 72-76 million years. Who are the real dinosaurs and what descendants did they leave? What was the main reason for their extinction? And why do some remains survive while others do not?

Zoologist about the lifestyle of dinosaurs and the future man during their existence

Alexey Tikhonov , Associate Professor of the Department of Zoology, PhD, spoke about the structural features of dinosaurs, their life and what the future man was like when large reptiles occupied a dominant position on Earth.

Dinosaurs belong to the phylum of chordate vertebrates and belong to the class of reptiles. Reptiles are one of the oldest groups of vertebrate land animals. Reptiles existing today include turtles, crocodiles, scalybacks and two species of tuataria – representatives of the order Beakheads that have survived to this day.

The largest species of extinct reptiles include dinosaurs, ichthyosaurs, plesiosaurs and pterosaurs – flying lizards. The last three species, according to the speaker, lived in parallel with dinosaurs, but are not classified as them because they have a different origin. The subclass of cotylosaurs is the common ancestor of the largest ancient reptiles, and representatives of this class looked like modern lizards. Now cotylosaurs include two extant species of hatteria.

The expert also spoke about the place of dinosaurs in the food chain: when the species of dinosaurs was formed, they took a dominant position on the planet.

“The niches that mammals occupy now were then occupied by dinosaurs. Mammals had to adapt to the conditions of such a life and hide from them. Herbivorous dinosaurs were both small and large, and there were also carnivorous dinosaurs. Surely they had their own scavengers. There is even an opinion that the famous Tyrannosaurus Rex was more of a scavenger than an active predator,” Alexey Tikhonov.

Dinosaurs were primarily diurnal animals. They used sunlight to warm themselves to optimal temperatures. And mammals had to lead a nocturnal and secretive lifestyle. Therefore, their sound production was poorly developed; they did not know how to make complex sounds, as they still cannot do now. Dinosaurs, apparently, had a weak sense of smell, but their vision was well developed.

Dinosaurs lived all over the planet. Archosaurs, which included ichthyosaurs and plesiosaurs, also lived in water. There was no territorial isolation, since the continent was then united. The expert also told what the future man looked like in the era of dinosaurs:

“About 90 million years ago, the general group of primates split into primates and woolly winged animals. The group of primates then looked visually similar to modern rats. Around the same time, they ided into higher and lower primates. According to many anatomical and biological features, humans belong to the higher primates,” Alexey Tikhonov.

Geologist about ancient animal remains and the problems of their study

Alexey Lednev , geologist, senior lecturer at the Department of General and Engineering Geology, spoke about the features of preserving animal remains in general, their study and problems of paleontology and paleozoology.

The expert noted that paleontologists in their research work with fossilized remains – traces of ancient life that has survived to this day, preserved in the depths of the layers of the Earth. A dead animal, buried under sedimentary rocks, after time, under the influence of chemical reactions, acquires the properties of stone.

At the same time, the remains of organisms undergo changes. They may be destroyed, their structure may change, or the primary skeletal substance may be replaced by more stable minerals. According to the speaker, ferruginization, silicification, phosphatization, pyritization, etc. most often occur .

The scientist emphasized that Russian paleontology is a fundamental science that stands on the border of major branches of biology and geology. It has given a lot for understanding the evolutionary development of the Earth; it is the main tool for geological surveying, the basis for various directions in geology. According to the speaker, recently paleontology has been well illustrated by Kant’s theory of the “thing in itself . ”

A special branch of paleontology, paleozoology, studies the remains of dinosaurs. The problem of studying, according to the expert, is associated with the discovery, preparation, isolation of the remains of inidual iniduals from the accumulation and their classification.

“As for the causes of extinction, there have been several global extinctions throughout the history of the Earth. Some associate the most important geohistorical events with cosmic impacts of celestial bodies, others with the action of multiple environmental factors.

The first ones are simpler and more effective, which is why they are in the center of attention; the second ones are complex, uncertain, largely unfinished and cannot yet claim a leading role. Darwin wrote that to explain the extinction of dinosaurs, you need to know how they lived,” Alexey Lednev.

Paleontologist about the reasons for the extinction of dinosaurs and their modern “descendants”

Vadim Titov , paleontologist, candidate of biological sciences, associate professor of the Department of Zoology, ABiB SFU, leading researcher at the Southern Scientific Center of the Russian Academy of Sciences, spoke about the possible reasons for the extinction of dinosaurs and named their “descendants” living in our time.

The paleontologist noted that at the moment it is impossible to accurately answer why dinosaurs became extinct. There is a hypothesis, popular in North America, about the death of dinosaurs as a result of the impact of the Chicxulub asteroid in the Yucotan Peninsula . However, it cannot be considered the main reason for the extinction of this group of reptiles.

The specialist noted that the disappearance of dinosaurs was only an episode of one of the mass extinctions on our planet and it did not happen all at once – this process lasted several million years. At the end of the Cretaceous period (ended approximately 66 million years ago – Ed.) significant changes in vegetation cover, landscape and climate occurred: the continents changed their position and this affected ocean currents. This is how the climate changed: it became cooler. At the end of the Cretaceous, there was also a massive eruption of the Deccan Traps on the territory of modern Hindustan, which led to the release of large amounts of carbon dioxide and other gases into the atmosphere.

“The fall of the famous meteorite became, as it were, the final touch in the overall picture of the transformation of the animal and plant worlds – primarily in Central and North America. It is known that at the end of the Cretaceous period (about 66 million years ago), not only dinosaurs became extinct, but also a large number of other terrestrial and marine groups of organisms: both vertebrates and invertebrates. But at the same time, many relatives of dinosaurs survived, for example, crocodiles and birds. Moreover, birds are currently the most numerous group of terrestrial vertebrates. So the disappearance of dinosaurs, in the narrow sense, is rather a natural process,” Vadim Titov.

The scientist noted the presence of a genetic connection between modern chickens and dinosaurs. The very idea of ​​the closeness of the genes of chickens and dinosaurs came to us from a popular BBC film. However, this plot should not be taken literally. They are not direct relatives, and in addition to chickens, there are other “descendants” of dinosaurs in our modern world.

Some researchers who use the cladistic method of analyzing phylogeny (a branch of biology that studies the evolutionary development, or phylogeny, of the world of organisms. – Ed.), argue that birds are modern dinosaurs. Indeed, paleontological evidence strongly suggests that birds evolved from maniraptor dinosaurs in the Jurassic or even the late Triassic.

“The well-known representative of ancient lizard-tailed birds – Archeopteryx – is, in fact, one of the dinosaurs that began to master the air environment. All modern birds, representatives of another subclass of Fan-tailed birds, separated from the Lizard-tailed birds already in the Cretaceous period. Therefore, among the modern fauna, it is birds that are genetically closer to dinosaurs than crocodiles,” Vadim Titov.

Vadim Titov also spoke about the likelihood of humans recreating dinosaurs. According to the speaker, it will never be possible to do this in the form in which it is presented, for example, in the film “Jurassic Park”. The reason is that it is impossible to obtain and decipher the DNA of these ancient reptiles. The oldest DNA fragments, up to 1 million years old, are studied by paleogeneticists thanks to finds from permafrost. All the news about obtaining fragments of dinosaur DNA (including from amber) turned out to be the results of scientific errors as a result of the so-called. contamination of the objects being studied, when samples were contaminated with DNA fragments of modern organisms, including the researchers themselves.

Another question, according to the paleontologist, is the significance of such an achievement in science. This can be a very interesting scientific task and testing of techniques. However, such projects require significant funding. Just to recreate the dinosaur, there will be people willing to donate significant funds, the paleontologist noted. For example, work is currently underway to recreate the woolly mammoth, since there are wealthy people who want to immortalize themselves in this way.

By the way, the Museum of Mineralogy of the Institute of Geosciences of the Southern Federal University stores casts of dinosaur footprints. You can read more about them here.