Many people may not imagine that the origin of human life began with a fish 300 million years ago. Recently, Chinese scientific researchers found the world's oldest jaw-like tooth fossils based on a batch of fish fossil specimens found in Chongqing's special buried fossil library and Guizhou's Shiqian fossil library. They discovered a batch of ancient fish fossils, including the oldest jaw-like miracle Xiushan fish, revealing the rise of jaw-like vertebrates. The discovery of this batch of fossils gives key evidence "from fish to humans". Chinese scientists published four articles in the journal Nature and appeared on the cover of Nature, which shows the value of this research. What is the "jaw"? The jaw is the mouth that can be opened and closed up. The jaw is the upper jaw and chin, pairs. Yes, among our common vertebrates, 99.8% of them belong to this category, which is the jaw . Evolution of jaw and teeth is a milestone in biological evolution. The earliest teeth fossils discovered in the past were born about 425 million years ago. This new discovery advances the date of the appearance of jaw teeth to about 439 million years ago, 1,004 earlier than before. Million years.
We will sort out this process based on the research of scientists.
From fish to jawed
Wenchang fish is the ancestor of vertebrates. It is a transitional animal between invertebrates and vertebrates. It is the most primitive chordates. At the same time, Wenchang fish is also the ancestor of primitive fish. Wenchang fish is an model organism that studies the evolution of vertebrates. It has dorsal nerve tubes, notochords and pharyngeal gill slits throughout its life. The head is called the ventricle, because the neural cord is compared in the part of the head neural cord . Large, but not real brain. Wenchang fish obviously contains collagen -based bone elements similar to vertebrates. Its histology , gene expression pattern and gene regulation network (differentiation pathway) of bone formation are all very similar to vertebrate cartilage.
https://www.brosoft.com/ It is to suck water containing tiny animals and sediments into the mouth. Most of them live in water. Because the body is like a fish-shaped animal, it is called jawless fish.
jedites evolved into jawless creatures, and then continued to evolve many kinds of fish. Among them, Ostracoderms (Ostracoderms, no jaw, gills have been completely used for breathing, no longer used for feeding, and were later classified into jawless general class) and Shield-Skinned Fish (Placodermi, the lowest jawed vertebrates) have been in the Devonian period. Extinct,
Armored Fish Class
During the Silurian-Devonian period, the fish living in the water were the only vertebrates, so this period is also called the "Era of Fish". Fish are generally divided into cartilage fish and bone fish and shielded fish. Among the bone fish, they are divided into two categories: radial fin fish and fermented fish. Now, the cartilage fish in fish that is believed to be in zoology , and a branch of bone fish has evolved into tetrapods.
From the evolution of humans in the Meatfin Fish Island
Bonefish evolved into tetrapod animals, and the radiated fin fish still lives in the ocean and has reproduced a huge race. About 380 million years ago, at that time (Dyvonian) fish had already controlled the ocean, so the fin fish was looking for another living space. A fin fish landed on land, and a small step for the fin fish landed on land was a big step for the biological evolution . The difference between them and our common fish (radial fin fish) is the difference between them and the fins.
meat fin fish has a central axis bone in its fin and has obvious muscle tissue. The endoskeleton of the flesh fin is very important. In the absence of the buoyancy of the water, the fin of this type of fish can support its own body. Without them, the fish cannot support its own body, and it will be difficult to land. They are tetrapod vertebrates, and their limbs evolved from their flesh fins. They are divided into humerus, radius, ulnar, , carpal bone, , metacarpal bone and phalanx.It can be said that the morphology of the meat-finned fish is directly related to the evolution of tetrapods, laying the foundation for the formation of today's ecosystems.
All mammals, amphibians , and reptiles on land, their ancestors were all fin fish. 80 million years ago, an even hoof-sighted branch decided to return to the ocean, and eventually evolved into whale , becoming the master of the ocean.
At this time, we can come up with a complete evolution path, primitive amphibians → primitive reptiles → birds and mammals, and dinosaurs belong to reptiles . This is actually a change that occurs due to adapting to the land environment. (Hinalis is the earliest amphibian, which just evolved from a meat-finned fish, and then amphibians slowly developed. The earliest reptile, Lago Rock Dragon, appeared, and finally appeared like the mammal canine dentist .)
. After the dinosaurs became extinct , mammals made a cruel choice to survive the fittest. viviparous and breastfeeding became their evolutionary direction. Marsupials and egg species in mammals were quickly eliminated.
It is in this evolution process that humans stand out again and again, evolved into a developed brain, and the digestive system, excretion system, and reproductive system are separated from each other, learned to work, and understand to think.
From fin fish to amphibians to reptiles and then to the ancient apes we are familiar with, and then to Homo sapiens. It took humanity 400 million years of evolution to gain wisdom.
finfish originated from China
Here we want to say that finfish originated from China. In 1993, Professor Zhang Miman and Dr. Zhu Min discovered Ken's fish in this area. After research, it was revealed that southern China is the center of origin of finfish. In 1999 and 2001, related papers were published in the British journal Nature. In 2012, Zhu Min, a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, and others, discovered the earliest snout stalker fossil to date - Yunnan pore bone fish in the Prague strata of the Early Devons, Zhaotong, Yunnan. It once again proves that the fin fish originated in southern China, and the British magazine Nature once again reported this latest discovery by Zhu Min and others. All these prove that the origin of meat-finned fish in China.
The fossil materials of the earliest fin fish were almost all discovered in China. Zhu et al. (2009) Why did the fin fish go ashore? Scientists have proposed two hypotheses. The first is, at the end of the Devonian period, although the oceans still occupy a large part of the earth, as the land area increases, the environment in which fish live becomes drought, and they need to find other suitable water environments to climb up to the land to evolve limbs. Another hypothesis is even more interesting: in the ecological environment at that time, plants and invertebrates had already appeared on land, providing a new predation environment for meat-finned fish, which could not only occupy the blank ecological niche on land, but also avoid competition in the water. This is also a hypothesis of the origin of tetrapods.
The value of this scientist research
What is the main significance of this scientist research? We just said that the fin fish developed in the Devonian period (.405 billion years ago-350 million years ago) .
. From the Devonian period, we call it Silurian . But in this era, about 420 million to 440 million years ago, the fossil record was very sporadic. Basically, jaw-like materials are spines and scales like this, and there is still a 35 million-year fossil record gap in early jaw-like organisms (that is, the transition type between jaw-like and jaw-free). So basically the understanding of our ancestors who have jaws is that they are a bit blind and touch elephants. Only when we have mastered sufficient fossil data can we completely piece together the evolutionary process of Wenchang-Jiangless-Jiang-Jiang-Flexible-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-Terminal-
This time, scientists not only found a considerable number of jaw-free fossils, but also found a transition type between jaw-free and jaw-free. This discovery that fills the gap in evolutionary history is naturally worth 4 Nature and also worth a cover.
The latest three-dimensional artistic restoration of the five new species of Silurian ancient fish found in the top to bottom are Shenacanthus vermiformis, Fanjingshania renovata, Qiannodus duplicas, Tujiaaspis vividus and Xiushanosteus mirabilis
It can be said that the Chongqing specific buried fossil library discovered this time is another world-class special buried fossil library discovered in my country after the Chengjiang Biota and the Rehe Biota, which provides a large amount of key evidence for the exploration of the evolution of the Tree of Life. It confirmed that as of 440 million years ago, various major groups of jaws had already flourished in the , South China region of my country. By the late Silurian period, more diverse and larger jaw species appeared and began to spread around the world, starting the process of fish landing and eventually evolving into humans.
