The Cambrian explosion challenged the gradual change theory, but it was not proved. Even if it is true, it only shows that evolution can sometimes be carried out in a jumping way, and it cannot be denied that evolution is carried out in a gradual way at other times. The Cambrian explosion will not challenge the theory of evolution. Almost all animals' "doors" appeared in the early CAMBRIAN, which does not mean that their ancestors did not evolve, let alone that they did not evolve later. Creationists tried to give people the impression that almost all animals suddenly appeared at the same time and then only died out without evolution when introducing the Cambrian explosion. Actually, it's not like that at all. First of all, before the Cambrian, animals experienced a long evolutionary process. Since the 1950s, paleontologists have discovered a large number of Precambrian multicellular organisms and even animals in 30 places around the world, among which four places are the most numerous and famous: Mount Ediacara in Australia (so this period is called Ediacaran), the wrong spot in Newfoundland, Canada, the White Sea coast of Russia and Namibia. In addition, there is the Weng 'an fauna in China, which is said to be the oldest solid fossil fauna discovered so far. These Precambrian multicellular organisms include soft corals, jellyfish, worms and other strange creatures. Whether these multicellular organisms were the direct ancestors of CAMBRIAN animals was controversial in the past, because before 1995, there was still a geological gap between these multicellular organisms and CAMBRIAN animals, so some experts advocated that these early multicellular organisms were all extinct and evolved from single cells to multi-cells again in CAMBRIAN. 1995, a large number of Precambrian multicellular organisms appeared in the volcanic ash layer of Namibia, which just filled this gap. So few experts now suspect that Precambrian multicellular organisms are not related to CAMBRIAN animals.

Second, CAMBRIAN animals did not appear at the same time, but lasted for millions of years, which is of course a short time in evolutionary history, but it is incredible for creationism.

Third, the appearance of "almost all animal phyla" in Cambrian strata does not mean that "almost all animal species" appeared at that time. In fact, CAMBRIAN animals are generally only the primitive species of that phylum, and almost all of them became extinct in the future, and later species evolved. For example, there were only a few primitive chordates in Cambrian. After Cambrian, all groups of vertebrates, including fish, amphibians, reptiles, mammals and birds, were gradually evolved from primitive chordates. Modern vertebrate species have evolved for hundreds of millions of years.

Why are almost all animals in a very short time (millions of years! ), biologists have put forward many explanations. At present, Hox gene regulation theory is widely accepted. Hox gene is a "homologous alien" gene, which is the designer of animal shape blueprint and controls the formation position of various parts of the body during development. If the homeomorphism gene mutates, it will make the organs in one part of the animal become organs in other parts, which is the homeomorphism phenomenon. For example, mutating a homologous foreign gene can make Drosophila grow eyes, wings where eyes grow, or feet where tentacles grow. Hox gene exists in all vertebrates and most invertebrates, and its regulatory mechanism is similar, indicating that it may be one of the oldest genes and exists in the earliest animal ancestors. At first, the mutation of Hox had little effect on early embryos, but with the differentiation of tissues and organs, the influence of mutation gradually enlarged, leading to major changes in body structure. This can explain the CAMBRIAN species explosion. At that time, the gene structure and development process were simple, and the gene mutation of Hox was easy to preserve, which led to a colorful body structure.

Aoukel