Darwin, the founder of evolution, said that living things evolved gradually with changes in the environment, but he was wrong. Most creatures on Earth did not evolve gradually, but exploded over a period of time.
Go back 3.2 million years, when australopithecus walked upright on Earth for the first time; back 65 million years ago, the dinosaurs that flourished for 200 million years went extinct; and the Cambrian period predates these two eras by about 500 million years, when the "Cambrian explosion" occurred in the living world, and all kinds of wonderful creatures beyond our imagination appeared one after another in less than 10 million years and occupied the ocean.
<h2 class="pgc-h-arrow-right" > the most authentic record of "outbreaks" in Chengjiang, China</h2>
There are two places in the world with the best preserved Cambrian fossil record: one is the Rocky Mountains on the west coast of Canada, where Cambrian fossils appear in the Burgess Shale; the other is Chengjiang County, Yunnan Province, China. The fossils of the Burgess Shale were formed in the middle of the Cambrian Period, when the great explosion event had passed, while the fossil group of Chengjiang was formed at the beginning of the Cambrian Period, a true record of the process of various organisms from scratch.
Located more than 50 kilometers south of Kunming, the capital of Yunnan Province, Chengjiang is a typical pastoral area that has not been noticed by paleontologists before. However, the fossils discovered by Dr. Hou Xianguang in 1984 in the Area of Chengjiang MaotianShan Surprised scientists around the world and made Chengjiang a hot spot for studying the Cambrian explosion. Hou Xianguang's team continues to study the fossils of Chengjiang to this day. Although nearly 30 years have passed since its original discovery, fossils of high scientific value are still emerging, and Chengjiang has been included in the World Heritage Alternate List.
The first fossil Hou found in Chengjiang was the long-tailed Naraoia. This organism is no more than 6 centimeters long, but it has a very advanced body structure, and its body has black stripes shaped like ladders in the center of its body, and many feet are born from the "ladder" to the sides of the body. Like shrimp and crabs in the ocean today, its entire body is surrounded by chitinoskeletons. Before the Cambrian Period, there were very few types of organisms, and there were no long-legged, shelled creatures, but after entering the Cambrian Period, various evolved biological species suddenly appeared.
Hou Xianguang discovered the long-tailed Narrow worm during a field expedition on July 1, 1984. Recalling the scene, he said that due to excessive excitement, his hand holding the fossil was shaking uncontrollably. In the years that followed, Hou and other researchers found more than 200 fossils in the MaotianShan Mountains, all masterpieces of the Cambrian explosion.
Like the Chengjiang Hat Tianshan Mountains, it is rare that the formations of the early Cambrian can be deposited continuously across such a long period of time, and it provides us with a unique opportunity to interpret the whole process of the Cambrian explosion. In the Hat Tian Shan, a clear line between the precambrian (scientists call it "precambrian") and the Cambrian, two adjacent epoch strata, has also been found. Hou Xianguang said that from this boundary upwards, that is, in the Cambrian strata, a variety of fossils such as long-tailed nylons, trilobites, and so on have been found, all of which appear suddenly and are evidence of cambrian explosions; but below the boundary, that is, in the precambrian strata, no fossils with complex body structures have been found.
Hou Xianguang said that according to Darwin's theory of evolution, organisms evolved gradually, so fossils of evolved intermediate forms should be found in the precambrian strata, but it turns out that such intermediate types do not exist. Fossils from the Cambrian era suddenly appeared in the form of large explosions, which indicates that the creatures of the time completed their evolution in a very short time.
In precambrian times, the bodies of most creatures were flattened, with no eyes, no appendages, and no shells. A famous German paleontologist named Adolf Seilacher discovered in the 1980s that the various fossils of pre-Cambrian creatures have some common features: the body is flat, made up of many chambers connected, and the whole body is like an air cushion; there are no feeding organs, digestive organs and circulatory organs, which are spread through the epidermis to absorb nutrients and excrete waste. They are very different from the new creatures that emerged in the Cambrian era.
<h2 class="pgc-h-arrow-right" > "eating" and "being eaten" are the driving forces of evolution</h2>
Why did life evolve by leaps and bounds after the Cambrian Period? It turned out that carnivores in the ocean had emerged, and they specialized in hunting those that had no ability to resist. The vulnerable groups of animals, unwilling to be fish under the knife, have evolved protective shells. However, the road is one foot tall, and the devil is one foot tall, and the carnivores have evolved stronger teeth that can crush the hard shell of their prey.
More than 500 million years ago, the Chengjiang River was a shallow sea. The Gulaidliki, who lives on the seabed, deftly walks on the seabed with 36 feet and looks around warily with two crescent-shaped glasses.
The Chinese micronet worm belongs to the vulnerable group, and its food is mud on the seabed. This poor insect has no quarrel with the world, and the pieces of "shield" on its body are the only anti-enemy equipment.
Some animals burrow and dive into the mud and sand. Ancient leeches (Palaeoscolex) hide in the sand, spying on passers-by, waiting for an opportunity to attack their prey.
Wedge-shaped archaic insects swim in pairs in the sea. Strangely enough, their mouths never close, and they keep their mouths open while swimming.
The overlord of the Cambrian ocean is none other than the odd shrimp. The odd shrimp came and went alone, scanning the surroundings, looking for something to swallow. The odd shrimp swims in a graceful pose, and you can't see that it's a ferocious predator.
In Chengjiang, fossilized feces of invertebrates have also been found. From one of the fossil fecals, the researchers found a dense shell of a high-muscle worm (Kunmingella). The high muscle worm is a tiny marine animal with a body length of only about 5 mm. The discovery of a large number of high muscle worms from the feces further confirmed that there was a relationship between "eating" and "being eaten" between organisms at that time.
The Cambrian period was an era of explosive emergence of various organisms, and it was also the era of the formation of the relationship between the weak and the strong among organisms. The law of the jungle, which eats the weak and the strong, has actually become the driving force for the evolution of biological color. The colored creatures that Dr. Parker discovered with grating structures were created in such a sinister environment.