And yet, why did megalodons, huge prehistoric sharks, disappear? ● The lower jaw of mammals was and remains an evolutionary mystery ● A life-sustaining molecule has been discovered in the Orion Nebula

And yet, why did megalodons, giant prehistoric sharks, disappear?

Considering the fact that at the beginning of August, a Hollywood production will be released, in which Jason Statham fights megalodons again, a production into which a lot of money was pumped, including for advertising, it was inevitable that some other scientific study would appear, which we also says something about giant prehistoric sharks, because that’s how things work.

On this occasion, we learn not only how serious some scientific publications, in this case PNAS, are, but also the reason why megalodons met their general evolutionary end. And the entire disclosure is signed by a group of American researchers, since, obviously, the premiere of the film takes place in their country.

Since megalodons, like all sharks, had cartilaginous bodies, the only parts that have stood the test of time are their teeth. The teeth, which with the help of simple mathematical calculations show us that these sharks, which lived between 23 and 3.6 million years ago, were also 15-20 meters long. More than twice the size of the largest modern sharks. At least that’s how it should be, because no one knows if megalodons were bondos or elongated.

In addition, starting with the teeth, the aforementioned researchers calculated the isotope ratios of oxygen and calcium phosphate present in the fossil remains. On the basis of this, they were able to determine, they say, that the body temperature of megalodons is higher than the temperature of the environment. In addition, it could change its average temperature up to seven degrees Celsius, depending on the needs.

In Romanian, the animal had warm blood. And that would have made it vulnerable to the climate changes it faced 3.6 million years ago. More precisely, due to global warming since then, the prey of megalodons, namely whales, would have decreased, and the former would have died of starvation. The same did not happen with the great white shark or with about five other species of sharks that have existed on Earth for about 33 million years and, like megalodons, are warm-blooded. But, being smaller in size, they have withstood global warming well.

The topic of climate change is also touched on here. So, good luck! Now, why Jason Statham kills the last megalodons, we don’t know how to explain it to you.

The lower jaw of mammals was and remains an evolutionary mystery

From whales to mice, all mammals that have ever existed have had one thing (one of them) in common: a solid, single-boned mandible. And this seems strange because no one has been able to explain why this trait is an evolutionary advantage.

If we look at reptiles, for example, we will see that their lower jaw consists of several bones. Snakes have four jaw bones that allow them to swallow prey that is much larger than their head. Hadrosaurs, duck-billed dinosaurs, had six lower jaw bones, and this gave them a much more complex chewing process than modern cows, by comparison. And examples can be continued. And then, why did this feature, namely the rigidity of the lower jaw, prevail in mammals?

The explanation was provided by a group of researchers, also American, in a study published in Philosophical Transactions of the Royal Society B: Biological Sciences. Paleontologists believe that this apparent involution has a great advantage. In particular, the bones of the lower jaw of mammalian ancestors evolved into what is now the inner ear. And this would give mammals an advantage over reptiles and other vertebrates.

However, it remains a mystery how the complex inner ear of mammals helped them occupy all the ecological niches vacated after the extinction of the dinosaurs, and this is a question that experts hope to answer in the near future.

A life-sustaining molecule has been identified in the Orion Nebula

It is methenium (CH3+), a carbocation (an ion containing a positively charged carbon atom) or, if you prefer the simpler version, a molecule believed to play an important role in what organic chemistry is all about. I mean life.

The information comes from the James Webb Telescope and was confirmed by an international team of at least 56 researchers in the journal Nature. As the authors of the study note, methenium is not one of the main ingredients for the existence of life, but its role is important because it can help in the formation of more complex carbon molecules.

Methenium was discovered in a disk of dust and gas orbiting a red dwarf star called d203-506. The record is not unprecedented. In fact, all stars have it around them when they are in the early stages of forming a star system. Methenium was unprecedented in that it was the first time it had been detected outside our solar system.

The paradox is that the protoplanetary disk of the mentioned star is bombarded by ultraviolet radiation from stars in the immediate vicinity. And this will mean that the molecules necessary for life, if they exist, will be destroyed. And yet it is ultraviolet radiation that would allow methenium to form.

The secret lies precisely in the fact that the UV radiation is short-lived (only a few million years), and the fact that it changes the chemistry of the protoplanetary disk may mean that they give rise to more complex molecules that, in theory, would give rise to organic chemistry .

It is assumed that our solar system also went through a similar stage in its origin. Obviously, the discovery of methenium does not prove the existence of life. But it is possible that it is there, in the Orion nebula, that we observe the formation of the prerequisites for the emergence of life.

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