At dawn, the dawn of dawn, just wait for this moment, life begins to explode Cambrian origin Cambrian biometrics 01 Odd shrimp 02 Obabin Sea Scorpion 03 A wide variety of trilobites 04 Grotesque worms 05 Waivaa worms 06 Pickax worms, Haikou fish and Kunming fish 07 Cheering worms Crazy life evolution path Biological explosion causes 01 days 02 Dili 03 People and the end of madness

For the past

Human beings always have an innate curiosity and awe

For life

There are still many unknowns for human beings to be explored

Written by | Redlichia

| Small pounds

Proofreading | Qin Huaqing

After a long night in the Cambrian period more than 4 billion years ago, the earth ushered in a new era - cambrian. Earth's biological world has undergone earth-shaking changes, and the "Cambrian explosion of life" that occurred in the Cambrian period has also become a well-known hot topic, and it is still listed as one of the "ten major scientific problems" by the international academic community. Even Darwin, who was first discovered, was confused by this, and it became a powerful weapon for his academic opponents to frequently attack him. This problem continues to this day. Among the many epochs of the Phanerozoic, the Cambrian at the head of the era is so hot that even domestic chips and domestic dramas are named "Cambrian", because the Cambrian represents the beginning of a new era, represents the beginning of a revolution, and also refers to a mysterious era of waves and outbreaks, short and beautiful. Let's take you into the mysterious and spectacular Cambrian era to explore the origin of the explosion of life.

At dawn, the dawn of dawn, just wait for this moment, life begins to explode Cambrian origin Cambrian biometrics 01 Odd shrimp 02 Obabin Sea Scorpion 03 A wide variety of trilobites 04 Grotesque worms 05 Waivaa worms 06 Pickax worms, Haikou fish and Kunming fish 07 Cheering worms Crazy life evolution path Biological explosion causes 01 days 02 Dili 03 People and the end of madness

<h1 class="pgc-h-arrow-right" data-track="12" > cambrian origin</h1>

Cambrian (Є) refers to a period of 541 million to 485.4 million years ago, spanning only more than 50 million years, but produced biological mutations in the biological world that were larger than the previous 4 billion years. The cambrian name is also deeply literary, and its origins are worth investigating. In 1835, this limestone formation was first discovered in the Welsh Mountains in western England, known as cambrian mountain in the roman era, so he named this period after the old name of the mountain, and then Japanese scholars transliterated it as "Cambrian" (transliteration: カンブキ, Roman: kanbuki), which was accepted by early Chinese geologists and continues to this day. The abbreviation Є is derived from Cyrillic, and the pronunciation of le is similar to that in English, but because scholars are accustomed to reading Cambrian, they often misread this abbreviation as "kan". Cambrian does not mean that this period is in a cold period, on the contrary, cambrian is a period of "not cold but still martial", the average surface temperature is more than 25 degrees, far more than the surface temperature of the current earth, Shangwu refers to the creatures of this time are engaged in a crazy arms race, armed with sharp weapons and hard shells.

British geologist Adam Sedgwick

The Second Cambrian period is divided into four epochs, namely the Newfoundland (541-521 million years), the Second (521-509 million years), the Miaoling (509-497 million years), the Furong (497-4854 million years), and there are 6 golden nails in the Cambrian strata, of which 4 are determined in China. (Gold nails refer to the points used to determine the stratigraphic profile of the global age stratigraphic unit boundary, and China has 11 golden nails, ranking first in the world.) ）

Cambrian stratigraphic year representation

Satellite imagery of the Burgess region of Canada

Burgis Shale - a paradise for fossil lovers

Yunnan Chengjiang Hat Tianshan Mountain

Chengjiang biota discovery point

Qingjiang biota - another important fossil source of the Cambrian explosion

Cambrian biota restoration map

<h1 class="pgc-h-arrow-right" data-track="31" > Cambrian biometrics</h1>

The cambrian period left us with the most important impression is the complex biological composition and strange biological species, biological evolution seems to be like trial and error in different directions at will, the strange appearance of living things even grotesque painters are amazed. These various evolutionary routes eventually retained only a few useful features, gradually evolving into the current biological appearance, so cambrian is the first epoch of the Ezoogen, a new milestone in the development of the earth. First of all, let's take a look at a few star seafood products that have exploded in life.

Cambrian oceans, ancient cup creatures are the most common low-level animals on the seabed

A summary of Cambrian creatures

Comparison of various Cambrian creatures and human sizes

<h1 class="pgc-h-arrow-right" data-track="39" >01 odd shrimp</h1>

Before the explosion, the shape of the organism was still relatively small, the largest would not exceed 10 centimeters, but the odd shrimp did not follow the common sense in many organisms super-evolved. It went straight from a centimeter-sized creature to a 1-meter-long behemoth, so much so that when paleontologists first discovered it, they treated different parts of it as different creatures. It was not until the 1990s, when scientists at the Institute of Southern Antiquity in China discovered a complete fossil of a strange shrimp in the MaotianShan Mountains, that the secret of the first marine overlord 500 million years ago was revealed to the world.

Odd shrimp restoration diagram

The odd shrimp had a pair of huge specialized predatory appendages in its mouth, a pair of large kazilan eyes, and paddle-like limbs suitable for swimming, which completely lost its resistance to creatures that did not even have eyes and swimming ability at that time, which made all animals at that time afraid. A large number of animals have evolved hard shells to support the last stubbornness in order to resist, but in order to prevent these fish from slipping through the net, their predatory limbs also have dense spines for opening the shell, and the mouthparts of the odd shrimp also have 32 sharp teeth, which makes the hard shell thin. This organism is widely distributed in the Burgess Shale and chengjiang biota.

The predatory limbs of the odd shrimp

Giant mouthpiece of odd shrimp

Canadian odd shrimp

Image

Other species of prawns

Odd shrimp restoration morphology diagram

Kirin shrimp - a close relative of the newly discovered odd shrimp in Chengjiang

<h1 class="pgc-h-arrow-right" data-track="54" >02 Obabin Sea Scorpion</h1>

Strangely shaped creatures were not uncommon in the Cambrian Period, but the Obabin sea scorpion was unique. Although this sea scorpion is called a sea scorpion, it has nothing to do with the sea scorpion that dominated the Silurian period. It is a moderate size, but the relatively odd shrimp can only be said to be tiny, with a total length of up to 7 cm. Its paddle-like appendages for swimming are similar to those of the odd shrimp, and the unique thing is that it has a predatory limb in its mouth, similar to a robotic arm that can rummage on the seabed and clip small creatures to feed into the mouth. The head also has a full 5 Kazilan eyes, and the ability to prey and escape is full. The Obavin sea scorpion and the odd shrimp belong to the same order of shrimp, and there are many strange Cambrian predators in this order.

Map of the Obabin Sea Scorpion Restoration

Swarms of Obabin sea scorpions

The Obapien sea scorpion is preying on the Amisk hairy jaw

The Obavin sea scorpion preys on undersea animals

<h1 class="pgc-h-arrow-right" data-track="64" >03 A wide variety of trilobites</h1>

Trilobites are the most ancient creatures in the Cambrian ocean, just like the fish in the modern ocean, the Cambrian ocean is also known as the "trilobite era". As the most elementary consumer, although the trilobite has also evolved the strongest organ such as the eye, it can only wear heavy armor to prevent the attack of strange shrimp, just like the relationship between sharks and ordinary sea fish. There are many kinds of trilobites, so their appearance is strange and forgivable, Lederliki is the most typical trilobite, the other 9 orders of trilobites have different looks, some have spikes, some have rabbit ears, and even to the later Devonian trilobite form is more diverse. They live by benthic, swimming or plankton, and have evolved different morphological structures according to different living environments and living characteristics.

Trilobite restoration diagram

Different Lederliki worms

Ear-shaped Fantasia (painted by Huo Xiuquan of nangusuo)

<h1 class="pgc-h-arrow-right" data-track="73" >04 Grotesque</h1>

The first monster of the Cambrian Period, the grotesque worm, has stumped paleontologists with its unique appearance from the beginning of its discovery. The slender body has several pairs of hard spines on one side, soft limbs on one side, and an unknown orb at the tail. Scientists initially thought that the long spines were legs, the soft limbs were feeding appendages, and the spheres were the heads. But the truth is all the opposite, after research and a large number of fossils found that the soft limbs are the real legs, the long thorns on the back for defense, the real head on the other side of the slender body, the development of a pair of single eyes and mouth organs, the spherical object is actually a fossil formed by the squeezed internal organs. Grotesque insects and shrimp are both leaf-legged animals.

Wrong grotesque worm recovery diagram (abdomen and back opposite, head and tail error)

Get close to the correct grotesque worm restoration diagram

Correct grotesque worm (there are ten feet in total, two fingers on the front 6, one finger on the back 4, and three pairs of predatory limbs on the neck)

<h1 class="pgc-h-arrow-right" data-track="80" >05 Vevoya worm</h1>

It is about 5 cm long and resembles a thorny turtle shell. Covered with carapace-like scales and rows of spines, the Vevaria resembles a slug, but it has no clear relationship with any of the surviving animal phylums. Vevariae lived in the early Cambrian and Middle Cambrian periods and is known to have a range of larvae, the smallest being 2 mm.

Fossil and restoration of Vevaria insects

Vevaa worm recovery diagram

<h1 class="pgc-h-arrow-right" data-track="85" >06 pickups, haikou and Kunming fish</h1>

Found in the Burgess shale 505 million years ago, and haikou fish and Kunming fish found in the Chengjiang biota 520 million years ago, Pikalars are the earliest vertebrates produced by biological explosions and are also recognized as the common ancestor of humans and other vertebrates. They were small, the most primitive fish, at the lowest level of animals in the Cambrian biological world, but after 100 million years they became the masters of the world and still ruled the entire planet today.

Pika worm recovery diagram (pickup worm may not be a vertebrate)

Restoration of haikou fish

Kunming fish restoration map

<h1 class="pgc-h-arrow-right" data-track="93" >07 cheering bugs</h1>

The cheering insect is characterized by several pairs of soft limbs, consisting of as many as 20 to 30 limbs, but unlike the animals with hard shells at that time, it was naked in its entirety, without any shell protection, and scientists believed that it might have special venom and camouflage as a defense and predation.

Cheering bug restoration diagram

Ecological restoration map of cheering insects, with mimeticism

Cambrian morphologically diverse creatures

Maltaceae

Micronet worms

Evolved the mimetic Herpetogaster

Odaira worm

<h1 class="pgc-h-arrow-right" data-track="109" > crazy way of life evolution </h1>

</h1>

Cambrian explosions gave rise to almost all of today's phyla, which evolved rapidly in a short period of time, turning the pre-Cambrian silent ocean into a lively zoo in an instant. Cambrian explosions are not simply evolved completely in one dynasty, according to paleontologists, Cambrian explosions are multi-stage curtain mushroom cloud-like eruptions. Below, we briefly describe the crazy evolution path of these creatures.

Cambrian Memorabilia (Wikipedia)

The Curtain Pattern of the Cambrian Explosion of Life (Zhu Maoyan, 2019)

Prologue (570-539 million years): Cambrian immediately followed by the Neoproterozoic Edicaran period, after the end of the "Snowball Earth" event that froze the entire earth, the Ediacaran period had already germinated the seeds of complex life, giving birth to the Ediacaran biota, and when the boring single shell fauna wiped out the Ediacaran soft organisms without any resistance, the evolution of the organisms fell into a dead end in an instant. But this 30 million-year scuffle also kicked off the Cambrian explosion.

Act I (539-521 million years): After that, in the First Newfoundland of the Cambrian Period, the small shell fauna continued to enrich species, with porous, spiny and bilateral symmetrical animals, especially crowned chakra, radiating rapidly, and the appearance of brachiopods marked the peak of the first act. The increased content of phosphate and calcium ions in the oceans makes it possible to have hard shells and exoskeletons. The Meishu Village Fauna in Southern China and the Tomot Fauna in Siberia are representative of the small shell fauna.

Act II (521-515 million years): At the peak of the Cambrian explosion, a large number of animal superphytes and phylum first-class animal crowns and stem group branches appeared on Earth, especially the large outbreak of hind-mouthed animals, with pan-arthropods as the dominant group. The Chengjiang biota is the pioneer biota of this stage. After the evolution of the second act, a complex and complete ecosystem was laid for the Cambrian.

<h1 class="pgc-h-arrow-right" data-track="120" > cause of the biological explosion</h1>

The real cause of the Cambrian explosion has not yet been conclusively determined, but after more than a century, researchers' efforts have gradually brought everyone closer to the truth. Different inferences about the causes of the explosion have their own advantages and disadvantages, but it is certain that the explosion of life must have been created by many reasons. It can be summed up in three points: time, location, and people.

Opportunities are given to those who are prepared. What life needs most is a suitable environment, and the most important thing in the environment is the oxygen on which to survive. Oxygen is the source of life, through the Precambrian period since the birth of cyanobacteria since the continuous transformation of the earth's toxic gases, after more than 3 billion years of unremitting efforts, the earth's oxygen content has reached a height of 16.4%. As a result, two important "great oxidation events" occurred between 2.5 billion and 600 million years, so soon after the fission of the Rhodinia supercontinent, the Ediacaran biota was born, but at that time, most of the jellyfish-like molluscs were born, and there was not a high diversity. The temperature also reached pleasant conditions in the Cambrian Period, with an average temperature of 10 °C higher than before, and the warm temperature was more suitable for a holiday in the shallow sea. At this time, seawater provided another important condition for life, that is, organic matter, in the late Precambrian period to the early Cambrian, the concentration of phosphate in seawater increased sharply, and marine sediments also changed from dolomite to calcareous, providing the calcium ions needed, calcium and phosphorus are important conditions for the composition of the shell and exoskeleton, these organic matter and high concentrations of oxygen, making biodiversity outbreaks called possible. In fact, in the distribution of species in most Cambrian biota, arthropods with hard shells always make up the vast majority. Frequent changes in the marine environment from neohozoic to cambrian periods were recorded by negative anomalous changes in δ13C. At this time, the earth provided sufficient environmental conditions for the outbreak of biodiversity.

Temperature changes over periods of geological history

Changes in oxygen concentrations over geological history

Species abundance of the Chengjiang biota, with arthropods accounting for the vast majority (Zhu Maoyan, 2019)

<h1 class="pgc-h-arrow-right" data-track="131" >02 location</h1>

The most suitable environment for biological survival is the warm shallow sea, and the shallow sea environment is distributed around the continent. Supercontinents are massive masses that appear periodically on Earth and tend to undergo regular cracking and aggregation. The cracking of the Rodinia supercontinent may have contributed to the birth of the Precambrian Edia biota, just as before the Cambrian period scholars speculated that there was a Pannotia continent in the southern hemisphere of the Earth for 600-540 million years, which split into gondwana and three smaller continents: Lauren, Polo and Siberia with 540 million years of fission. A large number of cracking events gave the Earth an extremely long coastline at that time. Coupled with rising temperatures, sea levels rise, greatly increasing the area of shallow seas and providing sufficient hotbeds for biological eruptions. Combined with the abundant oxygen content and nutrients at that time, it was a perfect time for organisms to multiply.

Formation of the continent of Gondwana

The Panosian supercontinent disintegrated to form an extremely long coastline and vast shallow seas

<h1 class="pgc-h-arrow-right" data-track="137" >03 people and</h1>

The term man and man is far-fetched to use, but it is the organism itself that drives the hyperevolution of life. Originally, it was thought that the establishment of ecosystem predatory nets was the main condition, and the emergence of the strongest predator, the odd shrimp, promoted the divergence of stratigraphic organisms and constantly evolved to protect themselves. But the obvious flaw in this theory lies in how the high-ranking predators appear. In the past two decades, there has been an explanation for genetic mutations, the HOX gene (homologous genes) is a class of genes that specifically regulate the shape of an organism, and once a mutation occurs, the biological body will undergo partial deformation. A series of experiments on fruit flies have found that when the HOX gene is mutated, the flies sometimes have antennae that become legs, or grow several more pairs of wings, resulting in large-scale shape mutations. So some biologists believe that simultaneous mutations in certain genes contributed to the emergence of a large number of exotic organisms in the early Cambrian period, and after the great explosion these genes were locked and no new organisms were produced. This theory has even been written into middle school biology textbooks. Living things began to change from themselves, and at the same time, they were both favorable to the time and place, and the same conditions were achieved to form the living world that is now prosperous.

Cambrian biota restoration map (painted by Yang Dinghua)

Perhaps it is too coincidental or even illogical for these conditions to appear at the same time, but in fact, the earth has accumulated 4 billion years of luck for this event, and finally waited for this great moment in the middle age of the earth. The Cambrian explosion of life brought infinite vitality and vitality to the silent earth.

Until now, much of the evidence is still untenable, and there are many deficiencies. It is still waiting for you to explore further.

<h1 class="pgc-h-arrow-right" data-track="143" > the epilogue after the madness </h1>

The Cambrian explosion gave birth to many strange creatures, and the explosive increase in species diversity made the ocean stage an imposing drama. But this drama will eventually end, and the biological explosion will end in the form of mass extinction.

More than 50 million years after the explosion, the first mass extinction event in the history of the earth ushered in, and a great purge of strange creatures occurred, and about 49% of the genus on the earth disappeared in this event. The reason may be due to a large-scale hypoxia event, and some researchers believe that cosmic radiation destroyed the Earth's ozone layer and led to the mass extinction of life on the sea surface.

At this point, the vigorous Cambrian explosion came to a temporary end, and this event gave birth to the primitive ancestors of almost all modern creatures, igniting the flame of hope for the Earth biota. Although it ended in an extinction event, the seeds of civilization are still there, and another generation of glorious worlds will follow. Next:Ordovician – Molluscs dominate the oceans.

Ordovician oceans

Resources

1. Wikipedia - Cambrian

2. Zhihu - Cambrian Life Explosion Problem Discussion

3.Bowring, S. A., et al. "Calibrating rates of early Cambrian evolution. " Science 261.5126(1993):1293-1298.

4.He T , Zhu M , Mills B J W , et al. Possible links between extreme oxygen perturbations and the Cambrian radiation of animals[J]. Nature Geoscience, 2019.

5. Chen Junyuan et al. "Chengjiang Biota: A Witness to the Cambrian Explosion," National Museum of Natural Science (1996).

6. Shu degan, etc. "On the Cambrian Explosion and the Formation of Animal Trees," Paleontology Journal 48.3 (2009):414-427.

7.ZHU Maoyan, ZHAO Fangchen, YIN Zongjun, et al. Research on the Cambrian outbreak in China: Progress and prospects[J]. SCIENCE CHINA EARTH SCIENCES, 2019(10).

8. Zhu Maoyan. "The Origin of Animals and the Cambrian Explosion: Fossil Evidence from China," Acta Paleontology 49.3(2010):269-287.

This article is reprinted with permission from the WeChat public account "Institute of Geology and Geotaology, Chinese Academy of Sciences". The pictures are all from the Network, the original title is "Breaking Dawn, Dawn - Cambrian".

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