The bubonic plague pandemic in the middle of the 14th century in Europe alone killed about 30 million people. People unwittingly began to think about sanitation. In some German duchies orders were issued for the production of exclusively closed vessels. Thus the classic beer mugs with hinged lids appeared. Seventy million years before the plague, the bivalve mollusks rudists evolved in the same direction.
As a rule, members of their class have two parts of the shell commensurate with each other. In this case, a series of genetic mutations resulted in transformation of one of the shells into a cone-shaped, thick-walled vessel up to a meter in size, the narrow end clinging to the bottom. The other became a lid with a muscular attachment. It looks like a container for a foamy drink, only alive and living in water. More precisely, on the shelf.
Rudiments spread to the shallow waters within the tropics and subtropics. The water there was much brackier and warmer than today, 6 to 14 degrees Celsius. In this favorable strip, they began to evolve unusually intensively. The number of genera exceeded a hundred and all of them differed strikingly from other representatives of bivalves. Scientists are still unable to unequivocally answer the question: why exactly rudists, and not oysters, for example, were capable of such a rapid evolution.
The French paleontologist Collette Deschazo wrote that at the beginning of the Paleogene period, some 66-60 million years ago, the range of rudiments corresponded to the maximum possible expansion for such creatures. Like corals, they formed vast reefs, up to hundreds of meters or more in height, clustering together, something not seen in their ancestors or congeners.
However, oysters survived to this day, while rudiments no longer existed in nature by the mid-Paleogene. The reasons for the extinction are just as unclear as there is no scientific justification for the explosive evolution of these marine animals. Researchers have proposed several hypotheses, but none of them is definitely confirmed.
It has been proven that climatic changes could not have had a fatal effect on the population. The vulnerability of rudivores in this sense is no higher than that of other bivalves or gastropods, sponges or corals. The emergence of new species of bony fish, more adept at eating mollusk larvae than their predecessors, is also unlikely to claim the role of a fatal factor. The assumptions about a lack of oxygen or lime for shell construction are not conclusive either.
According to Deschazo, rudists are the model illustration of the concept of the "drying up of the creative power" of a biological community. This is what she saw as the main cause of extinction. Variability slows down, new genera and families "sprout" less and less frequently, and at some point evolutionary development comes to a halt. The researcher compared this process to the life of a tree: first the leaves wither, then the trunk dries up.
Such an interpretation rather accurately corresponds to the movements of society as well. In particular, with the theory of the development of ethnic groups under the influence of passionarity factor, that is, the spread in a particular human population of people whose interests go beyond purely personal and tribal. According to the concept of the creator of the theory, Lev Gumilev, ethnic groups pass through several regular stages in their history. As the specific weight of passionaries in the society increases, it changes from a predominantly "quiet" philistine way of life to a situation where it is impossible to maintain the status quo. At such moments, empires emerged and carried out their expansion. Each of them, according to Gumilev, necessarily reaches a "critical mass" of passionarity. Then inevitably follows a decline. Public energy begins to fade, and new hegemons take the place of the decrepit hegemons.
The total duration of the cycle the scientist estimated at 1200-1500 years. The rise of the Moscow state falls at the end of the 15th century - liberation from the Mongol yoke. Then the passionarity of the Russian ethnos was growing, and reached its peak at the end of the 18th century, i.e. under Catherine II. In the 19th century, the empire went to the stage of fracture, and to date, almost entered the inertial period of development. In another 250 years or so, as Gumilev believed, should begin the dark ages and finally a "rebirth."
Peter I carved his famous cup with a lid from Karelian birch and ivory somewhere between 1710 and 1720. The tsar, who carried his personal lathe with him on foreign trips so as not to be distracted from his work, could only appear at the time of the most intense outburst of passionarity in society. The skillful work adorned Peter's workroom. Today it is on display in the State Hermitage Museum as a reminder that even the highest social achievements are inevitably followed by a fading of creative energy. It's just like the rudists.