How to write your thoughts on biology and history?

One day in June 2007 +0 1.

The wild South China tiger from Shaanxi was discovered and photographed by a farmer in Shaanxi, which aroused widespread concern in society.

2007123 October

The cruise ship Explorer sank in the ecologically fragile Antarctic, and all the tourists survived. However, tens of thousands of gallons of heavy oil leaked from the ship, which led to ecological disaster in this area, and countless cherished species died and even became extinct.

Scene after scene, ecological events about wild animals happen around us.

Once, humans and wild animals lived in harmony in the arms of Mother Earth. Now, human beings dominate the earth, and the extinction rate of wild animals is 1000 times that of the past! 6.5438+million times faster than the formation speed! Almost every 1 hour, an animal goes extinct, huh? ! You didn't hear the sound! Yes 1 hour!

When people cheered for the discovery of the South China tiger, the number of wild tigers in China, the hometown of tigers in the world, was less than 200, and the number of wild tigers in the world was less than 1000, and most of them were concentrated in India, Indonesia and Thailand, which were developing rapidly and over-exploited. In the forest, you can rarely hear the once majestic tiger roar.

Let's take a look at the situation faced by wild animals!

In the sea.

Passing through one ship after another also poses a threat to marine life. There are several large-scale oil spills every year, and countless seabirds and fish die in the spill. When people are still calculating how much oil and dollars they have lost, how many people have thought about what the sea has lost? A few years later, the sea rich in species turned into a dead sea, with dead bodies of oil and fish floating everywhere? Can we just make a few tears in the corner of our eyes?

in the forest

Tree after tree fell. Forests are the lungs of the earth, which can purify the air. The forest is also a paradise for wild animals, with many strange animals. It is said that dozens of animals die every time a tree is cut down. Although there are few trees, they accumulate over time. What a shocking number! A few years later, when there are only yellow photos and computer hard drives left in the wildlife paradise, can we just laugh awkwardly?

in life

Air pollution, noise pollution, water pollution and biological invasion threaten wildlife. Just talk about biological invasion: rabbit disaster in Australia, "poisonous algae" in the Mediterranean, zebra mussels in the Great Lakes of the United States, "frogs" in Hawaii, Eupatorium adenophorum, Spartina, Bursaphelenchus xylophilus and Solidago canadensis, all of which have brought devastating blows to the survival of local wildlife. Let's take a look at water hyacinth, commonly known as water hyacinth. Dianchi Lake in Kunming, China, is called "ecological cancer" by experts because of the crazy spread of water hyacinth. Many endemic animals in Dianchi Lake quickly became extinct, and the bodies of fish often floated on the water. A few years later, when the beautiful scenery and endemic animals of Dianchi Lake become a page in history textbooks and a story among the old population, can we just bow our heads in shame?

There used to be hundreds of millions of North American passenger pigeons, which were extinct because of environmental changes and human culling.

Due to the environmental damage of the Yangtze River, the baiji, which has lived in the Yangtze River for 25 million years, is on the verge of extinction.

All things are similar, and all beings are born together.

The roar of the tiger is gradually leaving us, but the roar of nature is coming to us step by step.

This is not an alarmist, nor does joy bring sorrow. Nature's revenge is beyond our imagination.

What would you think if there were only humans left on the earth? What else can we do?

Finally, I leave you with a question: "Are you still waiting?"

On Neilingding Island, the southwest coast of Shenzhen, Mikania micrantha, a "plant killer", is spreading rapidly and has become an irresistible trend. In the past, this shady and leafy island was covered with Mikania micrantha. They are like huge nets, shrouded in the darkness of beautiful litchi trees, banana trees and acacia trees. Trees die silently because they can't get sunshine, flowers and green grass wither because they can't get fresh air, and the land on the island is becoming a wasteland. Neilingding Island, known as the "plant paradise", may be destroyed by Mikania micrantha.

This horrible "plant killer" originated in Central and South America. In 1980s, Mikania micrantha spread to Southeast Asia, causing immeasurable losses to farmers who planted cash crops such as bananas, tea, cocoa and rice. In the early 1990s, Mikania micrantha's magic feet set foot on Hainan Island in China. A few years later, I arrived in Shenzhen. In a 4000-mu plantation in Baoan, Shenzhen, almost 80% of the forest was ravaged by Mikania micrantha. Some fir forests have been blocked by Mikania micrantha and some hilltops have been completely covered by Mikania micrantha.

More than a hundred years ago, someone brought more than 20 English rabbits to Australia to breed. The rabbit house was destroyed by a fire, and the surviving rabbits fled to the wilderness. Because Australia's climate is suitable for rabbits to survive, and there are no natural enemies there, these survivors breed at an alarming rate and become rabbits. They compete with sheep for food, destroy grassland vegetation and cause huge losses to animal husbandry.

In recent years, in some coastal areas of southern China, a "plant killer" named Mikania micrantha landed quietly and spread rapidly under the conditions of warm climate and abundant rainfall. Before long, litchi trees with sparse flowers and trees, banana orchards, beautiful hills and Yuan Ye were soon covered with Mikania micrantha. The thick vines of these invaders entangled or covered local plants, took away the sunshine and nutrients that should belong to local plants, and caused serious damage to local vegetation.

For thousands of years, oceans, mountains, rivers and deserts have provided natural isolation barriers for the evolution of species and ecosystems. However, in recent hundreds of years, with the process of global integration, these barriers have gradually lost their due role. Alien species, with the help of human beings, cross the ocean, reach new habitats and thrive. Are they friends or enemies?

In early 2003, on a winter afternoon, we walked into the Beijing Aquarium and visited the processed piranha. Not long ago, piranha was once a popular pet that people rushed to visit. The sight of them tearing live fish makes many people tremble with fear, and they are called "the wolf clan in the water". But at the moment, they just lay motionless in the freezer, with hopeless eyes open. Reports about piranhas gradually decreased with their silence. However, although the initiator of the sensational event has remained silent, the thinking about alien invasive species will not stop. Why are people so afraid of them that they are not even allowed to live in small aquariums? Just because they are cruel by nature?

"Because there is no such fish in China," said the head of the aquarium, "piranha is native to the Amazon River basin in South America and has no natural enemies in China. Man-eating pomfret, with strong constitution and not strict requirements on water quality, can easily find water suitable for reproduction and growth in vast areas of southern China. Once it flows into natural waters, it will definitely break the existing biological chain and threaten the survival of indigenous fish. Just like the invasion of intruders, the damage to the ecology is unimaginable. "

I have read some reports about the invasion of alien species, but I always feel that the weaker names such as Mikania micrantha, Eupatorium adenophorum, Alternanthera philoxeroides and Maisui are related to "invasion". Man-eating pomfret has sharp teeth, but how can whitebait in Taihu Lake "cause a devastating blow to the ecosystem" without extra fingers? How far are alien invasive species from us?

Crayfish is an invasive species.

"Alien species have actually entered our lives, but we don't know it yet." Dr Wu Min from the Institute of Zoology, Chinese Academy of Sciences is an expert in shellfish research in China. He talked about invasive shellfish species. "For example, the crayfish that Beijingers love to eat, the scientific name is Procambarus clarkii, which originated in Mexico and later spread to North America, posing a great threat to fishery production and dams in the Great Lakes of the United States. In the 1920s and 1930s, it entered Nanjing area of China via Japan, and then spread rapidly in Jiangsu and Zhejiang provinces, posing a great threat to local fish, crustaceans and aquatic plants. They will dig holes in the dams of rice fields, and now the crayfish in Dongting Lake multiply in large numbers, threatening the dam facilities. " Dr. Wu Min also pointed out that Ampullaria gigantea and White Jade Snail, which were once active on people's dining tables, were introduced to China as high-protein foods in the early days and vigorously promoted. However, due to market reasons, they have been abandoned or escaped in large quantities, and now they have invaded farmland and natural systems and become pests of crops, vegetables and ecosystems.

It turns out that alien invasive species have reached our lips. The next interview became more and more scary. In addition to liriomyza sativae, Bursaphelenchus xylophilus and Hyphantria cunea, which have been treated as pests in agriculture, forestry and fishery, even in many bustling urban communities, roadsides, ditches, wasteland, gardens, playgrounds, lawns and other places that are easily overlooked by people, it has long been a paradise for invasive weeds. Veronica, abutilon, Datura stramonium, Amaranth retroflexus, and even ragweed, which makes Americans pale, can be seen everywhere.

Mr. Yang Chaofei from the State Environmental Protection Administration provided us with some figures: According to incomplete statistics, there are 0/07 species of exotic weeds and more than 40 species of exotic animals in China, ranging from vertebrates (mammals, birds, amphibians, reptiles and fish) to invertebrates (insects, crustaceans and mollusks), as well as bacteria, microorganisms and viruses. Dr. Xie Yan from the Institute of Zoology, Chinese Academy of Sciences, who was the first to conduct research on alien invasive organisms in China, told us: "At present, there are alien species in 34 provinces, municipalities, autonomous regions and special administrative regions in China, and almost all exotic weeds can be found except a few protected areas on the Qinghai-Tibet Plateau."

There are also preliminary statistical reports of direct economic losses caused by exotic species in China. It's boring to list the figures, but we should carefully read the following statistical reports: According to conservative estimates, the serious occurrence and damage area of forest invasive pests such as pine wood nematode, slash pine mealybug, pine cone scale, American white moth and pine cone scale in China has reached about 6.5438+0.5 million hectares every year. In recent years, serious agricultural invasive pests such as rice weevil, liriomyza sativae, potato beetle and African snail have reached 6.5438+0.4 million ~ 6.5438+0.6 million hectares every year. The economic loss of agriculture and forestry caused by alien species reaches 57.4 billion yuan every year, the cost of controlling Liriomyza sativae only needs 450 million yuan, and the cost of salvaging water hyacinth needs more than 565.438+0 billion yuan every year.

Biological invasion is a world problem. According to statistics, the losses caused by alien invasion in the United States, India and South Africa are as high as 654.38+05 billion US dollars, 654.38+03 billion US dollars and 80 billion US dollars respectively. Dr. Xie Yan believes that these are only conservative estimates, which are not enough to include those immeasurable hidden losses, such as the extinction of local biological species caused by exotic organisms, the reduction of biodiversity and the loss of aesthetic value caused by changing the environmental landscape.

Biological invasion leads to species endangerment and extinction.

Bai Chengshou, an expert from the Biosafety Office of the State Environmental Protection Agency, reminded me: "The concept of' foreign country' is not only defined by national boundaries." . People once had such a question, why the "four big fish" (green, grass, silver carp and bighead carp) have also become exotic species, but they are not native to China? The reason is that the "four big fish" are local indigenous species in many areas of China, but if they are introduced into the waters of high-altitude areas such as Yunnan, Qinghai and Xinjiang, they will become exotic species because these areas belong to completely different ecosystems. So is the whitebait in Taihu Lake.

Yunnan is the province with the richest fish species in China. However, since the 1960s, people have transplanted and introduced exotic fish twice for the purpose of industrial economy. For the first time, during the period of 1963- 1970, economic fish such as "four big fish" were introduced, and non-economic fish such as wheat ear fish and [[summer] tiger fish were introduced. The second large-scale introduction was in 1982- 1983, and the new whitebait and [[real] fish in Taihu Lake were introduced to Dianchi Lake, Xingyun Lake and other lakes. Among the original 432 indigenous fish species in Yunnan, about 130 species have not been collected in recent 5 years, accounting for about 30% of the total species; In addition, about 150 species of fish were common species in the 1960s, but now they are rare species, accounting for about 34.7% of the total species. The population of the remaining 152 species of fish is also significantly lower than that in the 1960s. Overfishing, water conservancy projects, reclamation around lakes and exotic fish are the four major factors that lead to the endangered fish in Yunnan, and exotic fish is the biggest factor that leads to the sharp decline of indigenous fish population. The extinction of salamanders in Dianchi Lake is also closely related to the introduction of exotic species in Dianchi Lake.

Spartina alterniflora, a terrible invasive organism ravaging Chongming Island in Shanghai, was introduced from the United States 20 years ago, which has the function of fixing sand and promoting siltation. Due to the lack of natural enemies, Spartina alterniflora has become the absolute overlord of Chongming beach, resulting in a large number of deaths of fish and shellfish due to lack of food, and fatal injuries to aquaculture. The break of the biological chain directly affects the survival of birds that feed on small fish on the island. "If it is not controlled, the biological chain of Chongming Island will be seriously broken." Spartina alterniflora is now spreading in Fujian coastal areas and other places, and the large-scale mangrove death in coastal beaches is the evil result caused by Spartina alterniflora.

At the end of Ming Dynasty, cactus was introduced to China, and now it can be seen all over the country. In the coastal areas of South China and the southwest dry-hot valley, cactus has defeated the local native plants and become the dominant community, where the original natural vegetation landscape may never be seen again.

In fact, some creatures in China have entered other areas and become invasive species in other places. Pueraria lobata, for example, was introduced into the United States as a medicinal material, but it multiplied in large numbers in the United States, which had a great impact on the local ecological environment. Another example is herring, which is just an ordinary carnivorous fish in China. However, when it accidentally spread to the United States, it has become a major fishery disaster in the United States. The local government even offered a reward of $65,438+000 for catching herring.

About 35% to 46% of the plants on the world endangered species list are caused by foreign invasion. The latest research shows that biological invasion has become the second largest factor leading to species endangerment and extinction, second only to habitat loss.

Invasive species will also directly threaten human health.

Measles, smallpox, bubonic plague and AIDS may all become invasive diseases. The cultivation of tropical rain forests by human beings has provided new opportunities for more viruses to invade, including viruses previously carried only in wild animals, such as Ebola virus that attacked Congo and other places many years ago. As mentioned above, the pollen of Ambrosia trifoliata is the main pathogen causing human pollen allergy, which can lead to hay fever. About 20% people in the United States are affected by pollen allergy. Although there are not many reports in China, many overseas Chinese will have hay fever symptoms within one or two years after coming to the United States. At present, ragweed has been distributed in Northeast China, North China, East China and Central China 15 provinces and cities. If a large-scale outbreak occurs, the consequences will be unimaginable.

All these are caused by "biological invasion", whether it is a formidable malignant infectious disease such as mad cow disease, foot-and-mouth disease, plague, or the notorious red ants in the United States, forest pests such as American white moth and pine wood nematode that ravage the northeast and north China, and water hyacinth that blocks the river course in Shanghai and covers the water surface of Dianchi Lake. Their harm has gone far beyond people's imagination, so that some people call it "cancer of the whole ecosystem"

You won't be surprised when you find one or two beetles you've never seen before on the roadside grass or in your yard. But in the eyes of biologists and ecologists, this may not be trivial. Experts call this kind of "immigrants" who originally lived in a foreign country and moved to a new ecological environment by unnatural means "biological invaders". They will not only destroy the original ecosystem in a certain area, but also cause immeasurable economic losses to human society.

In the early days of human civilization, land and navigation technologies were underdeveloped, and the ecological balance of nature was not greatly damaged. Under natural conditions, a dandelion seed may drift with the wind for dozens of kilometers before landing. If the conditions are suitable, it will take root, sprout and grow there. Fish and shrimp in mountain streams may swim with the water and settle down in rivers ... These are all carried out slowly without human intervention, and the time and space span are very limited, so it will not cause serious imbalance of the ecosystem.

If a species is not restricted by similar food competition, natural enemy destruction and many other factors in the new living environment, it is likely to multiply uncontrollably. 1988, several mussels (mollusks similar to mussels) originally living in the European continent were brought to the North American continent by a cargo ship. At that time, these "stowaways" mixed in the goods at the bottom of the warehouse did not attract the attention of the local people, and they were randomly abandoned in the waters near the Great Lakes. Unexpectedly, however, it has become a "paradise" for bamboo. Without the restriction of natural enemies, the number of scallops has increased dramatically, and almost all the drainage pipes in the Great Lakes have been "occupied" by them. So far, people have spent billions of dollars to clean and replace pipelines. Long-horned beetles from Asia and red ants from South America are two other "invaders" that plague Americans. The former madly destroys trees in Chicago and new york, while the latter specializes in biting people and animals and spreading diseases.

"Biological invaders" not only cause immeasurable economic losses to human beings, but also pose a great threat to other species and species diversity in the invaded areas. During World War II, palm tree snakes settled in Guam with a military cargo ship. This reptile living in trees specializes in preying on birds, attacking nests and devouring eggs. Since World War II, nine species of native birds in Guam 1 1 have been wiped out by brown snakes, and the number of the only two species is decreasing day by day, which is in danger of extinction at any time. Some biologists have seen palm snakes six times on the plane from Guam to Hawaii. They warned that there are no natural enemies on the island of Hawaii that can inhibit the reproduction of palm snakes. Once the palm tree snake settled in Hawaii, the birds on the island would be extinct.

Many biologists and ecologists blame the increasing number of "biological invaders" on the increasingly prosperous international trade. In fact, many "biological intruders" achieve the purpose of "smuggling" by hitchhiking in transnational trade. Take the current global fresh fruit and vegetable trade as an example. There are many insects and insect eggs attached to these goods, including extremely harmful pests, such as Mediterranean fruit flies. Although the animal and plant quarantine centers of customs in various countries strictly guard against these pests, it is difficult to ensure that there are no "bugs" that escape the net because of the huge volume of import and export goods. In addition, transnational pet trade also provides convenience for "biological invaders". In recent years, the news that the introduction of colorful ornamental fish has brought cholera to some areas is often seen in newspapers. Some foreign pets, such as snakes, lizards, bobcats, etc. Often escape from the fence due to the negligence or abandonment of the owner, and gather mountains to harm one side.

Some biologists point out that once a certain "biological invader" gains a foothold in the new environment and multiplies on a large scale, its number will be difficult to control. Even in today's highly developed science and technology, people will still be helpless in the face of plants and animals with strong adaptability and reproductive ability.

Some scholars in biology and ecology believe that human beings should not interfere too much in the migration process of biological species, because the imbalance is temporary and a species must follow the law of natural selection in the new environment. Not all "biological invaders" can survive, but the strong can survive. Even the strong in the ecosystem are restricted by various factors in the system and cannot do whatever they want. Therefore, the natural balance will eventually be achieved. However, more scholars are against it. They think that the process of natural adjustment is very long. If "biological invaders" are allowed to develop freely, many native species will be doomed to extinction and the species diversity in nature will be seriously damaged. In addition, the economic losses caused by "biological invaders" to human society are also amazing. In the United States alone, the economic losses caused by "biological invaders" are as high as more than 200 billion US dollars every year. How can people be indifferent to such astronomical figures?

At present, many countries in the world have begun to realize the seriousness of this problem and taken corresponding measures. For example, the US House of Representatives passed a bill in 1996, requiring relevant agencies to strengthen the monitoring of vehicles that may carry alien species. To this end, the US government is planning an inter-departmental monitoring plan.

So, let's do our part!