The unified whole formed by the interaction between biological community and its inorganic environment is called ecosystem.
The ecosystem on the earth can be divided into terrestrial ecosystem and water ecosystem.
In terrestrial ecosystem, it can be divided into forest ecosystem, grassland ecosystem and farmland ecosystem.
In aquatic ecosystem, it can be divided into marine ecosystem and fresh water ecosystem.
Forest ecosystem {Forest ecosystem is distributed in humid or relatively humid areas, and its main characteristics are various kinds of animals and plants, complex community structure, and long-term stable population density and community structure. Plants in the forest are mainly trees, but there are also shrubs and herbs. Because animals in the forest can easily find rich food and habitats in the trees, there are many kinds of climbing creatures on the trees, such as rats, raccoons, tarsiers, gibbons, refugees, tree frogs and so on. Adapted to the life of climbing trees, these animals have a series of characteristics in shape and structure. For example, squirrels and other animals have curved and sharp claws and developed foot pads on their palms; The fingers (toes) of animals such as tarsiers have special suction cups; The toes that escaped from the camp were crouching in pairs; Animals such as capuchin monkeys have long curved tails that can be wrapped around branches to hang their bodies. Because there are many obstacles in the forest, carnivores often ambush and hunt, and the hunted animals often hide to avoid the enemy. Because of the dense underground roots and moist soil in the forest, it is not conducive to animals to dig holes, so there are very few animals digging holes in the forest. Most birds in the forest build their nests in branches or tree holes, which is obviously much safer than building nests on the ground.
Features: There are many kinds of animals and plants, the population structure is complex, and the population density and community structure can be in a relatively stable state for a long time.
Function: 1. Economic benefit: Forest ecosystem is a treasure house of human resources. In addition to providing a lot of wood, forests can also produce products with great economic value, such as rosin, camphor, tung oil and rubber. There are not only a large number of edible plants in the forest, such as jujube, persimmon, chestnut, kiwi fruit, litchi, etc., but also many oil plants, such as camellia oleifera, tung oil tree and Xanthoceras sorbifolia Bunge, as well as rich medicinal resources. 2. Ecological benefits: it can adjust the balance of oxygen and carbon dioxide in the biosphere and improve the ecological environment; Water conservation and soil and water conservation are known as "green reservoirs"; Wind and sand fixation, climate regulation, air purification, pollution elimination, etc.
Grassland ecosystem
Grassland ecosystem is distributed in arid areas with little annual rainfall. Compared with forest ecosystem, the species of animals and plants in grassland ecosystem are much less, and the community structure is not as complicated as the former. In different seasons or years, the rainfall is very uneven, so the population density and community structure often change dramatically. The plants on the grassland are mainly herbs, but there are also some shrubs. Due to the low rainfall, trees are very scarce. Adapted to the life on the grassland, most animals there have the behavior characteristics of digging holes or running fast. There are many rodents on the grassland, almost all of which live underground. There are many kinds of insects that dig holes, such as ants and crickets. Animals that can't dig holes (such as reptiles and birds) often use rodent caves. Caves are of great significance for animal defense, avoiding enemies and storing food. There are many animals with strong running ability on the grassland, such as gazelle, antelope, rhinoceros, jerboa, hare, wolf, fox, leopard, lion and so on. Gazelle can run at a speed of 60 kilometers per hour, and cheetah can run at a speed of 90 kilometers per hour. This is related to the flat and open terrain and few obstacles on the grassland. Amphibians and aquatic animals are very scarce in grassland ecosystem due to water shortage.
Features: Grassland ecosystem is distributed in arid areas, with few species of animals and plants. In different seasons or years, the rainfall is very uneven, and the population density and community structure often change dramatically.
Function: 1. Economic benefit: Grassland ecosystem is an important production base of animal husbandry. There are many herbages with high nutritional value and strong palatability in grassland ecosystem, which are used to graze important livestock. It can produce meat, milk, skin and wool, and provide a large number of livestock products with unique economic functions. 2. Ecological effect: Grassland ecosystem is an important ecological barrier to regulate climate; Prevent the land from being eroded by wind and sand. In 2000, sandstorms exceeding 10 hit Beijing, the western development, the Yangtze River flood and many other major problems made many of us realize that the ecological function of grassland is actually more important and prominent.
marine eco-system
The ocean accounts for 70% of the earth's surface area. The oceans on the whole earth are connected as a whole, and the seawater is mobile, so it can be said that all the oceans on the earth are a huge ecosystem. There are a lot of creatures living in this ecosystem, which are very different from those on land. Most animals in the ocean can swim in the water. Can't run or fly fast. Plants in the ocean can carry out photosynthesis in water. They have neither tall trunks nor developed roots. Abiotic factors affecting marine life are mainly sunlight, temperature, salinity and so on. This is also different from life on earth. Plants in the ocean are mainly phytoplankton, such as diatoms. Although there are few phytoplankton, they are abundant and are the main bait for herbivores. There are also many large algae in shallow waters, such as kelp and Undaria pinnatifida. There are many kinds of animals in the ocean. The water layer with water depth less than 200m has sufficient sunlight and a large number of phytoplankton. This water layer mainly concentrates a variety of marine animals, including zooplankton, shrimps, fish and so on. Plants and herbivores that can carry out photosynthesis cannot survive in the deep sea area with a water depth of more than 200m, but there are still many carnivores. These animals have special adaptability to the deep-sea environment. Some fish have degenerated eyes and rely on long tentacles at the front of their bodies to explore food. Some fish have special luminous organs, which are good for finding food and enemies.
Features: There are many kinds of animals and plants, and the structure is stable. All the oceans on the earth are a huge ecosystem.
Function: 1. Economic effect: It contains extremely rich biological resources and is also a treasure house of human resources. Many marine organisms can be used as industrial raw materials, and some of them have high medicinal value. 2. Ecological effect: providing 70% oxygen in the biosphere and maintaining the balance of carbon dioxide and oxygen in the atmosphere; The ocean can maintain the water cycle and regulate the climate; The water vapor evaporated from the ocean is converted into precipitation, which can supplement a lot of fresh water for terrestrial ecosystems.
Wetland ecosystem
According to the definition of "wetlands international Convention Especially as Waterfowl Habitat", swamps, peatlands, rivers, lakes, mangroves, coastal beaches and even shallow waters with a water depth of less than 6 meters at low tide belong to wetlands. There are many types of wetlands in China, including winding beaches and rivers. Lakes are dotted with marshes. In addition, there are a large number of constructed wetlands, such as reservoirs, ponds and rice fields. These numerous wetlands not only have obvious economic benefits, but also have great ecological benefits. Wetlands are often directly used as water sources for domestic water and industrial and agricultural water. Wetlands can also replenish groundwater. In rainy season or flood season, wetland becomes a huge reservoir, which plays the role of regulating flow and controlling flood. In dry season, the water stored in wetlands can supplement surface runoff and groundwater, thus alleviating drought. Wetlands are rich in animal and plant resources. For example, reed growing in marshland is an important raw material for paper industry and has high economic value. This swamp is suitable for many waterfowl. Marshes on both sides of rivers and lakes are places where fish breed and fatten.
Function: 1. Economic function: Wetland is rich in animal and plant resources. Wetlands are often used as water sources for domestic water and industrial and agricultural water. 2. Ecological function: Wetlands have powerful water regulation function (not only regulating water flow and controlling flood, but also replenishing surface runoff and groundwater, thus alleviating drought); Wetlands have a powerful function of purifying the environment.
Present situation: In the freshwater ecosystem, the main body is freshwater, and all other aquatic animals and plants belong to the object. As long as it doesn't destroy the fresh water environment of the subject, the object generally won't have much problem. Then, this ecosystem can basically maintain balance.
Farmland ecosystem
Farmland ecosystem is an artificial ecosystem, and its main feature is that people play a very prominent role, and various crops planted by people are the main members of this ecosystem. There are few species of animals and plants in farmland, and the community structure is single. People must constantly engage in activities such as sowing, fertilization, irrigation, weeding and pest control, so that the farmland ecosystem can develop in a beneficial way. Therefore, it can be said that the farmland ecosystem is artificially controlled to some extent. Once the role of human beings disappears, the farmland ecosystem will be rapidly degraded, and the dominant crops will be replaced by weeds and other plants.
Features: few species, simple food web structure, poor stability and many human factors.
Function: provide food, vegetables, etc. For humanity.
Present situation: At present, a large number of chemical fertilizers and pesticides are used in farmland in China, while organic fertilizers beneficial to soil are rarely used, and the content of soil organic matter in China is declining. At the same time, grain production is increasingly dependent on chemical fertilizers. Once there is no chemical fertilizer, the grain output will definitely decline, and even new and excellent varieties will generally consume water and fertilizer. In addition, due to industrial development, farmland ecosystem has been seriously polluted, threatening all living things in the system. For example, the pollution of the Huaihe River and the Yangtze River, the main grain producing areas in China, has caused great damage to the surrounding ecosystems and will definitely affect the quality and output of grain in the future. The recycling of waste in the system has not yet been realized. Although "returning straw to field" has been advocated for many years, it is rarely implemented in various places.
Urban ecosystem
It is a unified whole formed by the interaction between urban residents and their environment, and also a special artificial ecosystem established by human beings on the basis of transforming and adapting to the natural environment. All the facilities in the city are made by people, who play an important leading role, and most of the food needed by urban residents depends on the artificial input of other ecosystems; Industry, construction, transportation, etc. A lot of materials and energy are needed in cities, which must also be imported from outside and quickly transformed into various products. At the same time, a large number of wastes produced by human beings in production activities and daily life in cities must be transported to other ecosystems because they cannot be completely decomposed and reused in this system. It can be seen that the urban ecosystem is very dependent on other ecosystems, and it will also have strong interference with other ecosystems. Urbanization is the inevitable trend of the development of human society. In the process of urbanization, human beings confine most wild animals to smaller and smaller areas, and at the same time, they enclose themselves in the artificial environment composed of reinforced concrete and various kinds of pollution, resulting in various diseases of modern civilization. Therefore, improving and protecting the urban ecological environment is a subject that human beings should attach great importance to in the process of urban construction and development.
Features: The city is a special artificial ecosystem with people as the center, which has great dependence on other ecosystems and will have strong interference with other ecosystems.
Function: production function: providing rich material and information products for the society; Life function: to provide convenient living conditions and comfortable living environment for citizens. }
Ecological balance is a dynamic balance.
Once disturbed by natural and man-made factors, it exceeds the self-regulation ability of the ecosystem, and cannot be restored to its original stable state, the structure and function of the ecosystem are destroyed, and the input and output of matter and energy are unbalanced, resulting in system component defects (such as the reduction of biodiversity, etc.). ), structural changes (such as sudden increase or decrease of animal population, changes in food chain, etc. ), the energy flow is blocked and the material circulation is interrupted, which is generally called ecological imbalance and serious ecological disaster.
Ecological disaster: the ecological disaster on the earth is getting more and more serious, and there is no silence. The scale of space spans land, sea and air, and the scale of time affects dozens of generations. The earth itself is an identical life, the causal relationship is unimaginable, and the scale of ecological disasters is difficult to measure. According to the statistics of World Watch, the number of ecological refugees caused by various ecological disasters is as high as 1 10 million every year.
One of the most striking global ecological disasters is the hole in the ozone layer in the sky. Due to the destruction of human activities, the ozone layer is getting thinner and thinner. The ozone layer prevents radiation from reaching the surface. If the ozone layer continues to disappear, life on earth will disappear. Scientists point out that as long as the ozone layer changes to 1%, 10 years, tens of millions of people may develop skin cancer. In 2000, there were 2000 ozone holes in Antarctica. 8.3 million square kilometers, larger than three United States, extending to the southernmost tip of South America. There is also a hole in the ozone layer over the Arctic, which will affect densely populated areas such as Western Europe, Northeast Asia and North America.
Let's look at a regional ecological disaster in Europe-the terrorist pollution of the Rhine River. German national television station ZDF exposed the chief culprit of the ecological disaster in the Rhine in recent years, that is, the terrorist activities of former Soviet agents.
During the period of 1986, large chemical plants, pharmaceutical factories and their warehouses in Europe exploded one after another, and highly toxic chemicals flowed into the Rhine River, which brought devastating disasters to the Rhine River flowing through many countries. Even today, more than ten years later, the incidence of various strange diseases among residents nearby is much higher than that in other areas.
An accidental local ecological disaster in Taiwan Province Province -- Amas oil spill pollution incident. Amas ran aground on the rocks in the eastern sea area of Hengchun Eguanbi, and about 1, 100 tons of heavy oil and diesel oil leaked from the ship, polluting the sea area and coast of Eguanbi. Under the northeast monsoon, the Longkeng Ecological Reserve in Kenting National Park bears the brunt of coral reefs.
Creating ecological disasters is not only the patent of modern people. In history, even in prehistoric times, we can see many man-made ecological disasters. The ancient Loulan country, which was once prosperous in Han Dynasty in China, died of desertification due to over-exploitation, which is a man-made ecological disaster recorded in history. According to a recent article in Science magazine, human beings killed a large number of wild animals, which led to the mass extinction of prehistoric animals on all continents. This was a man-made ecological disaster in prehistoric times.
Ecological disasters can be said to be the most common disasters in this century. So, what are the ecological disasters? Ecological disaster refers to the destruction and loss of ecological structure and function caused by special interference events, which in turn causes harm, influence and extinction to related lives. The magnitude of disasters varies greatly, and large-scale ecological disasters cover a large time and space scale, with a wide range of damage and a long recovery time. How did these early ecological disasters come about? Despite these man-made ecological disasters,
People who enjoy the benefits are always different from those who suffer the damage, and so are those who destroy and those who save. The scapegoat always repeats itself in history. Imperfect economic system always sacrifices ecology, which not only shifts the environmental cost to the people, but also uses the people's tax subsidies for governance, resulting in a greater disparity between the rich and the poor. Many developing countries have suffered many serious ecological disasters, such as droughts, floods, mudslides and sandstorms. With so many cases and lessons,
Therefore, ecological disasters need careful management, not only to recover afterwards, but also to prevent beforehand. First, the country needs the protection of ecological security, because many ecological disasters are gradually formed and need the monitoring and response of the country. Second, individuals need to adjust their lifestyles. Too many ecological disasters are caused by ignorance and need personal vigilance and cognition. Faced with so many ecological crises, there is not much time left, and mankind must make a choice between saving and destroying as soon as possible.