On October 27, Nature published an article with information that was a bombshell! Zhang Zhiliang, a doctoral student under the guidance of Professor Zhang Zhifei of Northwest University's early life research team, actually found what can be said to be the earliest batch of fossils on the earth, from the earliest known bryozoan on the earth - bryozoan.
The research team is investigating
According to the article titled "Fossil Evidence Reveals the Origin of Bryozoan Fabus in the Early Cambrian Period", the team found millimeter-sized microenvironmental limestone in the biological clastic limestone of the Xi artemisia section of the Xiaoyangba Section of the Xiaoyangba Formation in Zhenba County, Shaanxi Province, through acid etching experiments.
Authorities in the relevant academic circles inside and outside the United Nations believe that these millimeter fossils come from the earliest bryozoan fossils on Earth, bryozoans are the basal group of bryozoans, and this fossil extends the origin of bryozoans to an even older 50 million years.
Fossils of bryozoans found this time
Most people are hearing about bryozoans and mosses for the first time, right? With the results of the study going to go further, let's first understand this mysterious animal group.
Bryozoans, also known as exoanals, because their anus is located outside the crown of the tentacles. However, in the past, the bryophyte phylum was actually a combination of internal animals and external animals, and it is not clear when specifically referring to external animals.
The moss phylum sounds extremely old, but there are about 5,000 extant species left within it. About 15,000 other species are known from fossils. Like brachiopods and broomsticks, mosses possess a special cilia tentacle ring, called a tentacle ring, that collects food particles suspended in water.
Bryophytes are a widely distributed group of aquatic invertebrates whose members form communities made up of many connected units, somewhat similar to polyps. Their individual size is usually no more than one millimeter long, and the largest group of mosses is only 0.5 meters in diameter. Until the middle of the 18th century, bryozoans were treated like corals as plants; hence the name "bryozoans". It was not until the middle of the 19th century that bryozoans were distinguished from spiny animals and were first described as characteristic of animal structures.
The reason why they used to be confused with corals was because they were also gathered by many individual animals, but their shape was very irregular, but to some extent very coordinated, and they had a comprehensive physiology and behavior of the entire organism.
This biological settlement is very advanced and even has a neural response. The nervous system of the lichen worm consists of small ganglia located between the mouth and the anus. In some bryozoan settlements, bryozoans unite all mosses through holes between individual animal bodies. But after being stimulated, these animal bodies will react, and almost immediately the nearby mosses will cause the same reaction, at which point a neural response will occur and contract.
Bryozoans have a life cycle that contains both asexual and sexual reproduction stages. Asexual reproduction in which sex cells are involved produce genetically identical offspring, a process that is essentially cloning oneself, also known as "sprouting." However, asexual reproduction alone may lead to a decrease in genetic diversity, so it is accompanied by sexual reproduction.
In sexual reproduction, bryozoans directly discharge eggs and sperm into the water, and when the eggs and sperm come into contact, they fuse and fertilize, and sexual reproduction produces the genetic variability necessary for the species to adapt to changing conditions.
They can even reproduce in an entire community. Flocks of animals at the edge of the community separate in special fault zones and grow into new communities, which is also a form of asexual reproduction.
These different forms of reproduction are all a means of perpetuating and disseminating successful genetic structures.
The history of the moss is quite long. Beginning in the Lower Ordovician season (488 million to 472 million years ago), most limestone formations, especially alternating shale limestone formations, are rich in bryozoan fossils because the bones of calcified lichen mosses are easily preserved.
Between the Early Paleozoic Era (542 million and 251 million years ago), bryophytes dominated the population and evolved rapidly in the Ordovician and peaked in homotopy. From that time on, the moss body became longer and longer, the diaphragm was deposited, and slowly lived as a community unit. After the Ordovicians, probably due to the competition of cryptocephalus, the importance of bryophytes began to decline, and the number declined rapidly at the end of the Permian.
But they have survived strongly to this day.