Can you believe it? The ginkgo trees that can be seen everywhere on the streets are actually endangered species on the record!
There are even some plant experts who say that in fact the ginkgo tree is extinct!
What's going on behind this?
The same period as the dinosaurs
Back on Earth 200 million years ago, the boss was a dinosaur. Diplodocus must have eaten the leaves of the ginkgo tree, and the carnivorous Tyrannosaurus rex also tickled the bark of the ginkgo tree. There is no way, who made the ginkgo trees very widely distributed at that time.
At that time, the continental form was not what it is now, but in addition to the equatorial perimeter, ginkgo biloba grew from south to north and from east to west. There are also many members in the family, and there are five species in the family alone.
Compared with dinosaurs, ginkgo appeared nearly 100 million years earlier. From the domination of the earth by dinosaurs to their later demise, Ginkgo has seen and experienced it with her own eyes.
Fossilized ginkgo biloba found in Canada
Although it was not wiped out like the dinosaurs, the drastic changes in the environment on Earth still posed a serious threat to the survival of the entire family.
After the late Cretaceous, the formerly prominent families had withered away. As a gymnosperm ginkgo, it no longer has any advantages on the earth at that time, and the rising angiosperms have become a new type of "giant" in the plant world.
Since the Paleogene period, the distribution of ginkgo biloba on the earth has not had any advantages, it is like a declining aristocracy driven all the way by the climate and environment.
He was driven first out of North America, and then out of the high latitudes of Eurasia. During this period, it barely survived the Oligocene, and then to the end of the Miocene.
By the end of the Pliocene, the ginkgo biloba on the European continent had been completely wiped out, the living space was constantly compressed, and all members of the family were also extinct.
After that, the earth began to experience the Quaternary Ice Age, and the living space of Ginkgo shrank again. The temperature environment is strangling the last ginkgo species, and the last member of the family is about to say goodbye to the planet.
During this period, there was an area that was relatively uneroded by climate and glaciers, and the last remaining members of the Ginkgo family hid in this area, spending time past the period when the temperature was generally cold.
When the earth warmed up again, although the surroundings were completely unfamiliar plant species, the ginkgo biloba was still alive. In the face of new plant species, it is a true outlier. However, this area that allowed it to survive also became the last vein of the Ginkgo family to branch out later.
The land that "saved" its life was China, to be precise, in what is now East China, Central China and North China. Since then, the only remaining vein in the ginkgo family has become a unique tree species in the mainland.
After more than two million years of vicissitudes, the traces of Ginkgo's existence elsewhere on Earth have been erased. When human beings appeared, especially after the emergence of civilization, the rest of the world did not know what ginkgo was.
Even in China, ancient people only knew that the ginkgo tree was very old. It was not until modern times, with the discovery of fossils of ginkgo biloba, that people learned that it had a large family members more than 200 million years ago and spread all over the world.
As the so-called past is unbearable, the only remaining old man has become a "fossil" that has witnessed the great changes of the earth.
Fossil ginkgo biloba leaves from the Jurassic period
From China to go out again
In the field of biology, there are the terms relict species, which refers to the residues of the earth's great changes, and the latter refers to the habitat of the species during the earth's changes. Therefore, the relics can be simply understood as a refuge in the apocalypse.
There is no doubt that the mainland is a refuge for Ginkgo. After the earth's climate became mild again, it gradually began to spread from the area where it had taken refuge to a larger area. To this day, ginkgo biloba can be found everywhere in the world.
Biologists only know that ginkgo biloba gradually spread to the whole world later, but for a long time, it was not clear where on the continent it spread again.
Sampling points for gene analysis of Ginkgo biloba in China
According to the research of biologists, there are three main areas where ginkgo biloba can be established as "taking refuge" on the mainland. One area is located in East China, and Tianmu Mountain is the center of this area.
One area is located in West China, with Jinfo Mountain and Wuchuan in Guizhou as the distribution zone. There is also an area located in southern China, mainly in Xing'an, Guangxi, and Nanxiong, Guangdong.
There is still a great controversy in the academic circles about which branch of the ginkgo biloba in these areas has gradually spread from China to abroad. Because in addition to these main distribution areas, there are also mixed populations in China, such as Daba Mountain and Dahong Mountain.
And in addition to the fact that the source cannot be determined, there is currently controversy about the distribution of wild populations. Since a large number of ginkgo biloba is currently transplanted artificially, there is no dispute about the small number of wild populations, but what is controversial is its distribution area and quantity.
For example, on Tianmu Mountain, there were 254 ginkgo trees, and there has been no definite conclusion on whether they are wild or not. One view is that it is a wild species, because the Tianmu Mountain area is a former refuge for ginkgo.
There is also an opinion that it is not wild, because Tianmu Mountain has a long history of Buddhist activities, and it is highly likely that these ginkgo trees were planted by people in the past.
Whether it is wild or not, the botanical community should judge from the population level, in addition, the use of genetic information and genes, can also more accurately analyze the relevant situation.
Since 2014, relevant researchers have collected samples of 545 species of ginkgo biloba from all over the world, and finally established that these ginkgo trees that are currently distributed around the world are the first to go out from the mainland. As for the region from which they came from, there is still controversy.
Ginkgo biloba in the Shaolin Temple
However, the direction of transmission is that the ginkgo tree first spread from the mainland to the Korean Peninsula and Japan, and then to Europe and the Americas.
It is worth mentioning that Europeans first saw a ginkgo tree in Japan in 1691. For a long time, it was believed that the ginkgo trees in the West were transmitted from Japan.
However, according to the current genetic analysis, the genetic composition of European ginkgo biloba is closer to that of continental ginkgo, which can show that ginkgo biloba was spread from China in multiple routes in ancient times.
Gongsun Shuzhong speaks longevity
Previously, there was a view that the ginkgo tree population in Tianmu Mountain was artificially planted rather than wild, and the very important reason was that these trees were very old, hundreds or even thousands of years old, and it was difficult for future generations to distinguish whether it was wild or planted by someone.
Moreover, there is a continuity of Buddhist activities in Tianmu Mountain since ancient times, and there are indeed some ginkgo trees, which may have been planted by the ancients thousands of years ago. All of this illustrates the fact that ginkgo biloba has a lifespan that is not the same as that of other tree species.
In Pizhou, Jiangsu, there is a thousand-year-old ginkgo tree, which is planted during the Northern Wei Dynasty during the Northern and Southern Dynasties. If the conclusion is true, then the tree has lived for more than 1,500 years.
This is not counting the oldest ginkgo, the one at the foot of the floating mountain in Ju County, which is twice as old as the one in Pizhou. It is rumored that Zhou Gong Zeng Dong and Guimeng planted this ginkgo tree.
In mainland tradition, ginkgo biloba is known as the Gongsun tree, which means that the ginkgo tree grows extremely slowly. It takes at least 20 years for a tree to grow and bear fruit, and it is already half a century before the tree begins to bear fruit in large quantities.
Therefore, when the tree planter back then, by the time his grandchildren could pick ginkgo biloba, he had already become a white-haired old man, so he had the name Gongsun Tree.
Modern research has found that the age of ginkgo trees can generally reach more than 1,000 years. The reason for its longevity is that ginkgo biloba contains a variety of substances such as antioxidants and anti-bacteria.
In addition, there is no initiation instruction for aging in Ginkgo biloba's genes, which simply means that the genes do not trigger the aging program, and its genes will neither decline under the action of time, nor will its disease resistance decline.
In other words, in the natural environment, as long as it is not deliberately destroyed, ginkgo biloba can almost reach the state of eternal life. It is precisely because of this characteristic that the earth has been able to survive again and again in the several great changes it has experienced.
However, there are different views on the overall survival status of Ginkgo biloba.
A large number of endangered species
Since the early nineties of the last century, ginkgo biloba has been listed as an endangered plant. To this day, it remains a critically endangered and threatened species.
In the eyes of the public, the ginkgo tree seems to be everywhere, so how can it be associated with endangerment? There are two main reasons for this.
First of all, although there are many artificially cultivated ginkgo, there are not many wild ginkgo populations. For many years, there has been controversy surrounding the number of wild populations, which are small and no new distributions have been discovered. Even where there are wild populations, new wild tree species are rare or even non-existent.
Secondly, artificially planted ginkgo trees have the problem of inbreeding. Because there is no diversity in this model, in the process of planting, it is basically spread from the original single tree species, and the larger the population, the more there is a risk of inbreeding.
Therefore, some biologists are worried that if one day a disease against ginkgo suddenly appears in nature, due to the lack of this natural protective layer of diversity, all artificially planted ginkgo trees may be infected and die.
A similar situation has happened in the plant kingdom before. For example, the variety of Big Mack banana failed to resist yellow leaf disease because of its single gene, and eventually the variety of Big Mac disappeared, and what humans now eat is only a substitute for Chinese banana.
Because of this risk, there is an opinion that ginkgo, an ancient tree species, has been swept up in the vortex of extinction. The so-called extinction vortex is a biological concept.
To put it simply, a species of living thing is surrounded by risk factors, and the subsequent extinction is only a matter of time before it is irreversible.
epilogue
At present, there is also a view that the ginkgo tree is not in the vortex of extinction. The reason is that by studying the genome of ginkgo, it was found that the characteristics of its genetic variation are improving.
As long as there is genetic diversity in a species, then the species will not become extinct. There is an argument that ginkgo biloba has sufficient adaptation potential and therefore there is no risk of extinction.
From a practical point of view, there are various measures for the protection and cultivation of ginkgo biloba in various places. For example, the ginkgo breeding base in Tongjiang County is more than 1,000 acres, and the next step for botanists is to combine wild ginkgo biloba to cultivate more and better varieties.
It seems that there is still a lot more that humans have to do to make this tree, which was more than 200 million years old, continue to flourish.