Chengjiang fauna challenge Darwinian evolution?

Cambrian period began 570 million years ago, ending at 5.1 billion years ago, is the first Paleozoic geological record.Cambrian fossils before the lower strata, while in the Cambrian strata, found in a wide variety of animal fossils, and some paleontologists even believe that the ancestors of animals, the doors have been during this period, which is called Cambrian explosion of species.Most representative of the Cambrian fauna was discovered in 1909 in Canada, the Burgess Shale fauna.In 1984, Yunnan Chengjiang fauna found in the Cambrian, with the Burgess Shale fauna comparable to the growing importance of international academic circles.



Cambrian explosion of species has always been creationists against evolution for a reason.Since the Chengjiang fauna has been discovered and caused a sensation, after some media exaggeration of the preaching and the intentional distortion of some of the missionaries, the theory of evolution can not explain the Cambrian explosion of species of argument which is also quite popular in the Chinese.Recently, by the Nanjing Institute of Geology and Palaeontology by Chen Junyuan, Yunnan University and Northwestern University Hou Shu De Stem Chengjiang fauna and hosted by the Cambrian explosion won the National Natural Science Award first prize, has been found 20 years of the Chengjiang fauna moment has become the news.These reports similar, which Xinhua news agency said so: when life on Earth appeared in large numbers? Cambrian explosion produced what exactly? Chinese Academy of Sciences, Yunnan University and Northwestern University scientists are far from Chen, Hou and Shu De Stem lasted 20 years, have completed the Chengjiang fauna and the Cambrian explosion research projects, through the discovery of the Chengjiang fauna fossils and research in the world for the first time revealed the overall outline of the Cambrian explosion, confirmed that ancestors of almost all animals have the same starting line.



Chengjiang fauna due July 1, 1984 in Chengjiang County, Yunnan Province, named after the first discovery is the early Cambrian (about 5.3 billion years ago) and animal fossils more than one category, not only animal type more, and very rare to preserve the biological structure of software, the first life-like reproduction of the ancient landscape and marine life are spectacular animals of the original features.

three scientists said that the geological age of the Chengjiang fauna is in the period of the Cambrian explosion, it allows us to see 530 million years ago, truthfully fauna true face, a variety of animals in the Cambrian century period of rapid explosion of origin, now living on Earth have been almost all animal categories appear, not after a long period of evolution of slowly getting to the.



If, as the three scientists said, the various animal categories not change after a long period of evolution came slowly, then how did they come from? They implied that fast in a short period of time evolved (in biological evolution and evolution is synonymous with evolution are in English translation, following the general practice of using evolutionary basis), but did not elaborate, the press has not do add, so in some people listen to, even that is in the negative animals evolved.Reproduced a famous site in this story, the headline is used in the Chengjiang fauna confirms that almost all the animals are not evolved slowly removed the word, is no trivial matter, tantamount to a complete denial of the theory of evolution, so the speed of evolution speed of the dispute, the presence or absence of biological evolution into a dispute.

Science and Technology Daily reported on the subject simply called Cambrian Chengjiang fauna expose the mystery of Chinese scholars challenge the theory of evolution! Another common argument is the challenge of the Cambrian explosion of Darwin, not only the mass media, publicity materials say Christian, but the article has some experts say, for example, are far from the Cambrian explosion Chen and configuration of multi-cellular animal program originated in an article, the subject of a section called challenge Darwin, Darwin claimed that the various interpretations on the evolution of life, in fact, are in the stage of scientific hypotheses.

Darwinian evolution to the present scientific hypotheses are just? It faces the challenges of the new biology that it? We have to look at Darwinian evolution actually said what.Darwin's theory of evolution includes four sub:

a general theory of evolution: species is variable, the existing species to change from the other species, a species can become new species.This has long been biogeography, comparative anatomy, comparative embryology, paleontology and molecular biology and other disciplines, observation, experiments confirm that we are now even in the laboratory, field directly observed the generation of new species.So, this is a scientific fact, and its reliability with the earth is round, the same material made up of atoms.Today, in addition to an extremely biased individual while ignoring the fact that the religious beliefs of people, in fact, biologists no longer deny the fact of biological evolution.

Second, the common ancestor theory: all living things from a common ancestor.Molecular biology are found in all organisms use the same set of genetic code, biochemistry, molecular biology revealed that all have a high degree of consistency level, and ultimately confirmed by the vision of Darwin.So, this is a generally accepted scientific fact.

Third, choice selection theory: natural selection is the main mechanism of evolution.The existence of natural selection, is has been confirmed by numerous observations and experiments, so this is a scientific fact.But now academia is generally believed that the use of natural selection is not as extensive as Darwin envisaged.Natural selection is adaptive evolution (ie, organisms adapt to the environment) mechanism, for the non-adaptive evolution, there are other mechanisms of gene flow.In other words, natural selection can not be used to explain all evolutionary phenomena.Taking into account the adaptive evolution is the core of the phenomenon of biological evolution, that natural selection is the main mechanism of evolution is valid.

four, graded on: the pace of biological evolution yes tapered, and is a natural selection advantage of the accumulation of Wei Xiao's gradual improvement of the process variation, and not jump style.This is Darwin's theory of evolution in the more controversial parts.Darwin was alive and after death for a long time, most biologists, especially paleontologists believe that biological evolution is the transition can appear that the new forms and organs from a big jump, and not a tiny variation in the role of natural selection slowly and gradually accumulated.Including Huxley, including some of the fossils paleontologists are not the emphasis on continuity, and hold this view.In genetics for some time after the birth, early geneticists have not by stressing the continuity of genetic traits, and the general acceptance of jump.40 years in the 20th century, the modern synthesis theory of genetics and natural selection theory to successfully combine the advantages of the gradient of gradually accounted for.But in the last two or three years, paleontology and evolutionary developmental biology studies have shown that the process of biological evolution is likely to be gradual and the transition of two modes exist, and jump on the trend rise again.However, the theory of evolution says jump, except for some very special circumstances (such as the emergence of new plant species by hybridization), does not refer to generation or between generations of evolution, and may have experienced thousands of years, tens of thousands of years and even millions of years, but in a geological time seems very short to measure it.

Cambrian explosion is the gradient of the challenge, but not graded on whether the card.It even set up, it is sometimes, but that evolution is able to jump way, and at other times can not deny evolution is gradual manner.Cambrian explosion will not challenge the theory of evolution.Almost all animals in the Cambrian doors early stage, is not no way means that these animals evolved from ancestors, but does not mean that they did not occur after the evolution.Creationism in the introduction when the Cambrian explosion, trying to give this impression: almost all of the animals are also sudden, after the extinction of not only evolution.

In fact, simply not the case.First, before the Cambrian, animals have been a long process of evolution.Since the fifty years since, paleontologists have thirty places around the world found a lot of pre-Cambrian animals, and even multi-cellular organisms, the largest number, the most famous in four places: Australia's Ai Diya Gala Hill (Ediacara Hill) (so this period is known as Ai Diya Gala Ji (Ediacarian)), the error point of Newfoundland, Canada (Mistake Point), Russia's Baihai Hai shore and Namibia.Ciwai there Weng'an fauna of China, said to be the oldest ever found in the fossil fauna of the entity.These pre-Cambrian multicellular organisms, including soft corals, jellyfish, worms and other bizarre creatures.Whether these multi-cellular organisms is the direct ancestor of the Cambrian animals, previously controversial, because before 1995 to a multi-cellular organisms from the Cambrian period of geological gaps still exist in animals, so some experts have advocated all of these early multi-cellular organisms extinct in the Cambrian and again from a single cell to multicellular evolution.

In 1995, volcanic ash layers in Namibia appears a large number of multi-cellular organisms before the Cambrian, just fill out this blank, so few experts now suspect that the Precambrian multicellular Cambrian animal life and relationships without each other.Second, the Cambrian animals is not simultaneous, but lasted millions of years, which is of course a short time in evolutionary history, but creationism is, but it is much longer inconceivable.Third, almost all animals in the Cambrian strata there the door does not mean that almost all species of animals have been there at that time.In fact, the Cambrian animals in general is that the door of the original species, since almost all extinct, the species is the evolution later come.For example, the Cambrian there is only a few primitive chordates, and all kinds of colorful group of vertebrates, including fish, amphibians, reptiles, mammals and birds, are from the original spinal cord after the Cambrian the gradual evolution of animals come.The species is more modern vertebrates have evolved hundreds of millions of years of history.

why almost all the animals in a relatively short time the door (millions of years!) evolved within, biologists have put forward many explanations, are currently being more widely accepted theory is that Hox gene regulation.Hox gene is a homeotic gene, is the animal form the blueprint for designers, in the development process of the formation to control the position of body parts.If the homeotic gene mutation causes animals to become a part of other parts of the organ of organs, called homeotic.For example, let a homeotic gene mutation, enabling the body to the Director of the Drosophila eye, the eye in the place of the long wings, or in place of the long tentacles grow a foot.Hox genes in all vertebrates and most invertebrates are present, the mechanism of regulation is also similar, suggesting that it may be one of the most ancient genes, at the earliest ancestors of the animals existed.Hox mutations in the beginning caused little change in the early embryo, but with the tissues, organs, differentiation of stereotypes, the impact of mutation is amplified gradually, resulting in significant changes in body structure.This may explain the Cambrian explosion of species.At that time gene structure, developmental process is relatively simple, Hox gene mutations likely to be retained, resulting in a colorful body structure.




Darwin's theory of evolution after
amended to now is still the mainstream theory of biological evolution, with a very strong vitality.But why do we from time to time, you can hear the Darwin theory of evolution be challenged, questioned and even denied by this point? There are religious factors, but also ideological and cultural factors (many do not believe in the Christian humanists do not like Darwinian evolution, the mechanical color), it is worth noting that there are scientists psychological factors.Some scientists in order to emphasize the importance of their own research topics, consciously or unconsciously exaggerate the value of their results, and even some people clearly stand on the shoulders of giants, but giants kick kick anxious to show his greatness.This requires us, to be extra vigilant to say amazing, not to rely on.

Editor Zhang】 【