Biodiversity is the most popular word at home and abroad in recent years. Because the rational use of natural resources and the protection of ecological environment are the basis for human beings to achieve sustainable development, the research and protection of biodiversity has become a concern of all countries in the world. At present, both the United Nations and governments around the world invest a lot of manpower and funds in biodiversity research and protection every year, and some non-governmental organizations actively support and participate in global biodiversity protection. For example, the Global Environment Facility jointly established by the United Nations and the World Bank spends hundreds of millions of dollars each year to support biodiversity conservation. The MacArthur Foundation of the United States spent170,000 dollars in 1992 to support the protection of biodiversity.
From 65438 to 0992, the United Nations Conference on Environment and Development was held in Rio de Janeiro, Brazil, and many countries in the world sent delegations to attend. Our leaders also participated in this grand event. The Convention on Biological Diversity was adopted at this meeting, which marked a new stage of nature protection worldwide, from the protection of rare and endangered species to the protection of biodiversity.
1. What is biodiversity?
1. Put forward the concept of biodiversity.
Since the 20th century, with the continuous growth of the world population and the increasing scope and intensity of human activities, human society has encountered a series of unprecedented environmental problems, facing five major crises of population, resources, environment, food and energy. The solution of these problems is closely related to the protection of ecological environment and the rational utilization of natural resources.
After the Second World War, the international community paid more attention to the protection of biological resources while developing the economy, and did a lot of work in saving rare and endangered species and preventing excessive use of natural resources. 1948, the United Nations and the French government established the World Conservation Union (IUCN). The World Wildlife Fund was established in 196 1. 197 1 year, UNESCO put forward the famous "Man and Biosphere Plan". From 65438 to 0980, the Outline of World Nature Conservation, compiled by IUCN and other international nature conservation organizations, was officially promulgated, which put forward the idea of combining effective protection of natural resources with rational utilization of resources, which played a great role in promoting the protection of biological resources in all countries of the world.
After the 1980s, people gradually realized in the practice of nature conservation that there is a very close relationship between various species in nature and between living things and the surrounding environment. Therefore, it is far from enough to focus on the protection of the species itself, and it is often difficult to achieve ideal results. To save rare and endangered species, we should not only protect the wild populations of related species, but also protect their habitats. In other words, it is necessary to effectively protect the entire ecosystem where species live. In this context, the concept of biodiversity came into being.
2. Definition of biodiversity
Biodiversity (biodiversity or biological diversity in English) is a broad concept to describe the degree of diversity in nature. Different scholars have different definitions of biodiversity. For example, Onorsee et al. (1986) believe that biodiversity is embodied in multiple levels. Wilson and others believe that biodiversity is the diversity of life forms ("diversity of life") (Wilson &; Peter,1988; Wilson, 1992). Sun Ruyong (200 1) thinks that biodiversity generally refers to "all variations of life on earth".
In the Convention on Biological Diversity (1992), biodiversity is defined as "the variability of living organisms from all sources, including terrestrial, marine and other aquatic ecosystems and their ecological complexes; This includes the diversity within species, between species and ecosystems (biodiversity from all sources, including animals, land, sea and other aquatic ecosystems and their ecological complexes, including the diversity within species, between species and ecosystems) ".
In the book Conservation Biology, Jiang Zhigang et al. (1997) defined biodiversity as: "Biodiversity is an ecological complex formed by the synthesis of organisms, their environment and various related ecological processes, including animals, plants, microorganisms, their genes and complex ecosystems formed by their living environment."
Based on various viewpoints, we believe that "biodiversity refers to the diversity of all living things (animals, plants, microorganisms, etc.). On the earth, the genes they contain and the ecosystem formed by the interaction between these organisms and the environment. "
3. Major components of biodiversity
It usually includes genetic diversity, species diversity and ecosystem diversity.
(1) genetic diversity
Genetic diversity is an important part of biodiversity. Genetic diversity in a broad sense refers to the sum of all kinds of genetic information carried by organisms on earth. These genetic information are stored in the genes of individual organisms. So genetic diversity is also the genetic diversity of organisms. Any species or individual organism holds a large number of genetic genes, so it can be regarded as a gene pool. The more genes a species contains, the stronger its adaptability to the environment. Gene diversity is the basis of life evolution and species differentiation.
In a narrow sense, genetic diversity mainly refers to the changes of genes in organisms, including genetic variation between significantly different populations and within the same population (World Resources Institute, 1992). In addition, genetic diversity can be manifested in multiple levels, such as molecules, cells, individuals and so on. In nature, for most sexually reproductive species, individuals in the population often do not have exactly the same genotype, and the population is composed of these individuals with different genetic structures.
In the long-term evolution of organisms, the change (or mutation) of genetic material is the fundamental reason for genetic diversity. There are two main types of mutations in genetic material, namely, changes in the number and structure of chromosomes and changes in nucleotides in gene loci. The former is called chromosome aberration, and the latter is called gene mutation (or point mutation). In addition, gene recombination can also lead to genetic variation in organisms.
(2) Species diversity
Species are the basic unit of biological classification. What is a species has always been discussed by taxonomists and phylogenetic chemists. Meyer (1953) believes that species are groups that can (or may) reproduce with each other and have natural populations, and these groups are reproductive isolated from other groups. China scholar Chen (1978) defines a species as a reproductive unit, which consists of continuous population and discontinuous population. Species is the unit of evolution, the basic link of biological system line and the basic unit of classification. In taxonomy, morphological characteristics, geographical characteristics and genetic characteristics must be considered at the same time to determine a species. That is to say, as a species, it must meet the following conditions at the same time: ① it has relatively stable and consistent morphological characteristics to distinguish it from other species; ② As a population, it lives in a certain space, occupies a certain geographical distribution area, and lives and breeds in this area; (3) Each species has a specific genetic database, and different individuals of the same species can pair with each other to reproduce. Individuals of different species have reproductive isolation, and even if they cross, they cannot mate or produce different reproductive offspring.
Species diversity refers to the richness of biological species such as animals, plants and microorganisms on the earth. Species diversity includes two aspects: one is the species richness in a certain area, which can be called regional species diversity; Second, it refers to the uniformity of species distribution in ecology, which can be called ecological diversity or community species diversity (Jiang Zhigang et al., 1997). Species diversity is an objective index to measure the richness of biological resources in a certain area.
When describing the richness of biodiversity in a country or region, the most commonly used indicator is regional species diversity. There are three indicators to measure the regional species diversity: ① the total number of species, that is, the number of species in a specific region and a specific group; (2) Species density refers to the number of species in a specific group per unit area; ③ The proportion of endemic species refers to the proportion of endemic species of a certain group to the total number of species in a certain area.
(3) Ecosystem diversity.
Ecosystem is a natural synthesis of all kinds of living things and their surroundings. All species are part of the ecosystem. In the ecosystem, not only species depend on each other and restrict each other, but also organisms interact with various environmental factors around them. Structurally, the ecosystem is mainly composed of producers, consumers and decomposers. The function of ecosystem is to circulate various chemical elements on the earth and maintain the normal flow of energy among the components. The diversity of ecosystem mainly refers to the diversity of ecosystem composition, function and various ecological processes on the earth, including the diversity of habitats, biological communities and ecological processes. Among them, the diversity of habitats is the basis of the formation of ecosystem diversity, and the diversity of biological communities can reflect the diversity of ecosystem types.
In recent years, some scholars have proposed landscape diversity as the fourth level of biodiversity. Landscape is a large-scale space, which is a region with high spatial heterogeneity composed of some interactive landscape elements. Landscape element is the basic unit of landscape, which is equivalent to an ecosystem. Landscape diversity refers to the diversity of landscape composed of different types of landscape elements or ecosystems in spatial structure, action mechanism and time dynamics. Genetic diversity is the basis of species diversity and ecosystem diversity (Shi Liming et al. 1993 et al. 1994), or genetic diversity is the internal form of biodiversity. Species diversity is the basic unit of ecosystem diversity. Therefore, the diversity of ecosystem is inseparable from the diversity of species and the genetic diversity of different species.
4. Convention on Biological Diversity
The Convention on Biological Diversity is one of the most important nature conservation conventions reached by the international community. The Convention was formally adopted by the United Nations at the World Conference on Environment and Development held in Rio de Janeiro on June 5, 1992, and came into effect on February 29, 1993 (so 1993 is designated as the International Biodiversity Day every year). Up to now, more than 100 countries have joined the convention. The secretariat of the Convention is located in Geneva, Switzerland, and the highest governing body is the Conference of the Parties. The Conference of the Parties is composed of government representatives. Its responsibility is to adopt amendments, annexes and protocols to the Convention on Biological Diversity in accordance with the procedures stipulated in the Convention.
The objectives of the Convention on Biological Diversity are:
(1) Biodiversity protection and sustainable utilization of resources;
(2) Promote the fair and reasonable sharing of benefits generated by natural resources.
The main contents of the Convention on Biological Diversity are as follows:
(1) Each Party shall formulate national strategies, plans or programs for the protection and sustainable use of biodiversity, or modify existing strategies, plans or programs for this purpose.
(2) As far as possible and as appropriate, the protection and sustainable utilization of biodiversity should be incorporated into the plans, programs or policies of various departments.
(3) Take legislative, administrative or policy measures as appropriate, so that all parties providing genetic resources for biotechnology research, especially developing countries, can effectively participate in relevant research.
(4) Take all feasible measures to promote and urge the providers of genetic resources, especially developing countries, to give priority to the achievements and benefits of biotechnology based on the resources they provide on the basis of fairness.
(5) Developed country Parties shall provide new and additional funds to enable developing country Parties to meet the increased costs due to the implementation of the Convention.
(6) Developing countries should earnestly fulfill their obligations under the Convention and take measures to protect biodiversity.
Second, the origin and development of biodiversity
1. The history of biological evolution on earth
The radioactive age of the oldest rock found on the earth is 3.8 billion years. However, according to the dating of meteorites and moon rocks and other astronomical evidence, the formation of the earth and solar system was about 4.6 billion years ago (Peng Yixin and Huang, 1997).
(1) Precambrian (570 million years ago)
The study on the filamentous fossils unearthed in Western Australia in 1978- 1980 shows that prokaryotes appeared on the earth about 3.5 billion years ago. The earliest prokaryote was probably heterotrophs. Fossils found in rocks in South Africa show that cyanobacteria began to form 365,438+0-3.4 billion years ago. Cyanobacteria are prokaryotes capable of photosynthesis. About 2 billion years ago, oxygen released by photosynthesis began to contain oxygen in the atmosphere, which may lead to the extinction of many anaerobic organisms, but methanogens and related species still exist in anaerobic environment. The dominant era of cyanobacteria and other prokaryotes lasted about 2 billion years.
The earliest eukaryotes appeared about14-1500 million years ago. The origin of eukaryotes is an important event in the history of biological evolution, because with the formation of eukaryotes, chromosomes, meiosis and sexual reproduction began to appear. In Precambrian (800-670 million years ago), fungi, protozoa and algae in eukaryotes formed, and animals and plants began to differentiate. By the end of Precambrian, coelenterates, annelids or arthropods began to form.
(2) Paleozoic
CAMBRIAN (570-505 million years ago): About 590 million years ago, the appearance of various invertebrates marked the beginning of CAMBRIAN. During this period, many classes of arthropods, brachiopods, mollusks, polypods and echinoderms represented by trilobites began to form. These categories have been preserved until today, and some species still exist. In the marine sediments 5. 1 10,000 years ago, the earliest vertebrate remains-fragments of crustacean exoskeleton were found. In CAMBRIAN, all animal phyla have been formed.
Ordovician (505-438 million years ago): adaptive radiation appeared in the phylum of many animals, forming a large number of classes and orders. For example, echinoderms form 2 1 class, and corals in coelenterates begin to appear. During the Ordovician period, a large number of jaws and fins appeared and left complete fossils.
Silurian (438-408 million years ago): the biodiversity increased, and the jaw was diversified. At the same time, the jaw-like shield fish also began to appear. Vascular plants (ferns) and arthropods (scorpions, polypods) began to invade the land.
Devonian (408-360 million years ago): large-scale adaptive radiation occurred in corals and trilobites; Cephalopods appear. Jaw fish and shield fish reached the peak of diversity. Devonian is called "the age of fish", cartilaginous fish and bony fish originated one after another and then adapted to radiation. At the same time, amphibians, mosses, vascular plants (ferns, gymnosperms) and insects all originated in this period.
Carboniferous (360 million-286 million years ago): Terrestrial spore plants (ferns) flourished, forming a large area of forest, amphibians were diversified, and the earliest reptiles appeared. Insects adapt to radiation, and some primitive orders (Orthoptera, Cockroaches, Mayflies, Homoptera, etc. ) appear in large numbers.
(3) Mesozoic
Permian (286-248 million years ago): reptiles appeared adaptive radiation, and theropoda became the dominant group; Various insect groups are diversified, forming Odonata, Hemiptera, Neuroptera, Coleoptera, Diptera and other groups. Chrysanthemum stones multiply in large numbers.
Triassic (248-265,438+0.3 billion years ago): The second large-scale proliferation of ammonites increased the diversity of some groups of marine invertebrates (such as bivalves). Gymnosperms began to dominate. Reptiles adapted to radiation, forming turtles, ichthyosaurs, plesiosaurs and early dinosaurs (further forming plant dragons, crocodiles and dinosaurs). Early mammals appeared. The continent began to drift.
Jurassic (213-65438+44 million years ago): Dinosaurs were diversified, and pterosaurs, Lei Long, Liang Long, Stegosaurus and Triceratops appeared. Primitive birds (archaeopteryx, etc. ) appeared. Ancient mammals and gymnosperms dominated. This continent continues to drift.
Cretaceous (0.65-65438+44 million years ago): Most continents separated, dinosaurs continued to adapt to radiation and became extinct at the end of this period. The earliest snakes appeared and adapted to radiation. Yellow birds with the characteristics of modern birds appeared. Angiosperms and mammals began to diversify, marsupials and placental mammals began to differentiate.
(4) Cenozoic era
Tertiary (65-2 million years ago): angiosperms diversified on a large scale and became the dominant components in the forest. Insects adapt to radiation and form most modern families. Many modern vertebrate families have been formed.
Quaternary (2 million years ago): Glaciers appear repeatedly, and large mammals (such as saber-toothed tigers, mammoths, large bison, etc.). ) extinct, human beings appeared.
2. Basic forms of speciation
Forming a new species from the original species is called speciation. There are different hypotheses about the formation mechanism of new species, but gene mutation and natural selection are two basic processes. In the process of speciation, geographical isolation and reproductive isolation play a very key role. According to the planting area, it can be roughly divided into three types: exotic type, homologous type and neighboring type.
(1) Exotic speciation
Many populations of a species live in different spatial ranges. Because of geographical isolation, the gene communication between these populations is hindered, which leads to the accumulation of different genetic variations, gradually forming their own unique gene banks, and finally reproductive isolation from the original population, forming new species.
(2) Homologous speciation
Species living in the same area, due to resource constraints and fierce competition within the population, lead to niche differentiation. Groups occupying different niches have obstacles in gene communication and form new species through reproductive isolation.
(3) the formation of adjacent species
Some species are widely distributed, but their diffusion ability is poor. Some populations at the edge of their distribution area, due to the differences in habitat environment, form obstacles to gene exchange, gradually establish their own unique gene pool, and form reproductive isolation, and finally form new species.
Third, the significance of protecting biodiversity.
1. Natural and biological resources
Natural resources refer to the sum of all kinds of substances that human beings can directly obtain in nature and use for production or life. Natural resources generally refer to natural objects that exist naturally. Any part of nature, including soil, water, forest, grassland, minerals, wild animals and other substances, which people can use to improve their production or living conditions, belongs to natural resources. In 1972, the United Nations Environment Programme defines natural resources as "the general name of natural environmental factors that can generate economic value and improve the current and future welfare of human beings under certain time conditions".
With the development of productive forces and the progress of human society, the scope of natural resources will continue to expand. For example, air and natural scenery, which used to be considered as external factors, now belong to the category of natural resources.
A more accurate definition of natural resources is: natural substances and energy used to meet the needs of human production and life at the current level of productivity development and research (Jin Jianming et al., 199 1).
The natural resources on the earth generally include the following types:
(1) Climate resources: including air, heat, light, wind and precipitation.
(2) Water resources: including above-ground water (rivers, lakes and seas) and groundwater.
(3) Mineral resources: metallic minerals such as gold, silver, copper and iron, all kinds of precious stones and all kinds of rocks for building.
(4) Energy: including solar energy, coal, oil, natural gas and nuclear energy.
(5) Biological resources: Biological resources are an important part of natural resources. It is a living natural resource. Include animals, plants and microorganisms. The difference between biological resources and other abiotic resources is that it is a renewable natural resource, which can be used for a long time if it is developed reasonably.
2. The value of biodiversity:
Biological resources are biodiversity. Some organisms have been used as resources, while others are not regarded as potential biological resources. The value of biodiversity is often ignored by people. When people use biological resources, they directly consume them without market circulation, but only use them instead. Biodiversity has high development and utilization value and occupies a very important position in the economic activities of all countries in the world. The value of biodiversity is mainly reflected in the following aspects:
(1) Direct value: also called use value or commodity value. It is the value formed by people directly harvesting and utilizing biological resources. Including consumption value and production value.
Consumption and use value: refers to the value of some natural products that are directly consumed without market circulation. Biological resources are very important for people living in the areas where these biological resources are produced. People get daily necessities such as firewood, vegetables, fruits, meat, fur, medicines and building materials from nature. Especially in some economically underdeveloped areas, using biological resources is the main way for people to make a living.
For example:
A. About 80% of the world's population still mainly depends on various medicinal materials obtained from plants (Farnsworth, 1988). There are more than 2,000 species of animals and plants used as medicine in Amazon basin, and more than 5,000 species can be used as medicine in China.
B in Nepal, Tanzania and Malawi, wood and animal wastes provide 90% of the main energy demand, and 80% (80%) in other countries (Pearce, 1987).
Residents living in remote areas mainly come from hunting wild animals. In Africa, the meat products of wild animals account for a high proportion of people's food in protein; 20% in Nigeria and 40% in Botswana; Zaire is 75%; In Ghana, about 75% of protein's population comes from animals, including all kinds of fish, insects and snails; In some remote areas of Nigeria, protein provided by prey accounts for 20% of the total annual consumption.
D In Sarawak, eastern Malaysia, the value of wild boar captured and eaten by hunters every year can be converted into $4 billion in the market price. The world catches 654.38 billion tons of fish every year, mainly wild fish, and a large part of them are eaten by fishermen themselves.
Production and use value: refers to the value of products used for market circulation and sales at the time of commercial harvest. (once the products of biological resources are developed, they are often much more valuable than themselves. Common biological resources products are: wood, fish, animal fur, musk, velvet antler, medicinal animals and plants, honey, rubber, resin, fruits, dyes and so on. )
For example, in the western United States, a laxative product can be extracted from the bark of a drug Rhamnus rhamnoides. This drug is very popular, with an annual sales price of about $6,543,800+0,000 and a market sales price as high as $75 million per year. During the period of 1976- 1984, the profit of biological resources in the United States was as high as $87.6 billion per year.
Wood is an important export product of some developing countries, and the annual output value of wood in the world exceeds $75 billion. In Indonesia, wood is the second largest export product after oil. From 198 1- 1983, the annual value of wood products exported from Asia, Africa and South America is 8 1 billion dollars.
Some non-wood biological products also have a very important position. For example, Indonesia's foreign trade in non-wood products reached 200 million US dollars in 1982.
(2) Indirect value: The indirect value of biological resources is related to the ecosystem function, which is not reflected in the national economic accounting system, but their value may greatly exceed the direct value. Moreover, direct value often comes from indirect value, because the harvested animal and plant species must have their living environment, and they are part of the ecosystem. Species with no consumption, production and use value may play an important role in the ecosystem and support species with use and consumption value (Chen Lingzhi, 1994). The indirect value of biodiversity includes four values: non-consumption use value, selection value, existence value and scientific value.
① Non-expendable use value: the protection of biological resources can bring more and more benefits to human society, which varies from region to region and from species to species. It can be roughly summarized as follows:
* Photosynthesis fixes solar energy so that it can enter the food chain through green plants, thus providing a maintenance system for harvestable species.
* The functions of ecosystem include pollination, gene flow, cross fertilization and reproduction, maintaining the environment and species effectiveness that have an impact on economic species to obtain beneficial genetic quality, maintaining the evolution process and maintaining the eternal tension between competitors in the ecosystem.
* Absorb and decompose pollutants, including organic wastes, pesticides and air and water pollutants.
:: Recreation and ecotourism. Refers to people's recreational activities in different ways by using biological resources. Carrying out tourism activities without destroying the natural environment is called eco-tourism. For example, bird watching in the wild, flower viewing and forest bathing. The value of these activities is also called leisure value. Worldwide, ecotourism can earn $654.38+0.2 billion. For example, in Canada, about 84% of the population participate in recreational activities related to wildlife (such as hunting, visiting zoos, traveling in protected areas, etc.) every year. ), it can create about 800 million dollars of income for Canada every year (Fillon et al., 1985). Jiuzhaigou, Sichuan Province, China, is managed by the community. In addition, eco-tourism has certain ecological education function.
* Protect soil: High-quality soil protected by natural vegetation and litter can maintain fertility, prevent dangerous landslides, protect the coast and river banks, and prevent siltation from damaging coral reefs, fresh water and offshore fisheries.
:: Regulating climate: Ecosystems can regulate macro-climate and local climate, including the impact on temperature, precipitation and airflow.
* Hydrological stability: well-developed vegetation in the catchment can regulate runoff. The roots of plants go deep into the soil, making it easier for the soil to penetrate rainwater. Runoff in vegetation-covered areas is slower and more uniform than that in bare land. Generally, in forest-covered areas, floods can be reduced in rainy season, and rivers still have running water in dry season. For example, in the forest catchment area of Malaysia, the runoff per unit area is equivalent to about 50% of the peak runoff of rubber plantation and oil palm plantation. In the low peak period of runoff, it is about 1 times of plantation.
② Selection value: Protecting wild animal and plant resources and having as many genes as possible can provide more substitution opportunities for the breeding of crops, poultry and livestock. For example, a new lean pig is bred by crossing domestic pigs with wild boars. At present, there are hundreds of different breeds of domestic chickens, all of which are original chickens. Extraction of anticancer drugs from Taxus chinensis and Taxus chinensis. Now many wild animals and plants in nature may not be used by human beings for a long time, and their value is potential. Maybe our children and grandchildren can find their value and find ways to use them. Therefore, if we save one more species, we will leave an extra wealth for our descendants. )
③ Existence value: Although the direct value of some species is limited, their existence can bring some sense of honor or psychological satisfaction to the people in this area. Such as giant panda, golden monkey, brown eared pheasant, etc. There are many unique and rare animals in China, and people all over the country are proud of them. Panda has become a symbol of China.
④ Scientific value: Some animal and plant species are in a very important position in the history of biological evolution, and studying them is helpful to understand the process of biological evolution. For example, some remaining species (ginkgo biloba). 3. The importance of protecting biodiversity
Biodiversity is the foundation for the survival and development of human society. Many aspects of our clothing, food, housing, transportation and material and cultural life are closely related to maintaining biodiversity.
(1) First of all, biodiversity provides us with food, fiber, wood, medicinal materials and various industrial raw materials. All our food comes from nature. If we keep biodiversity, our food varieties will be enriched continuously. People's quality of life will continue to improve, from food and clothing to a well-off society.
(2) Biodiversity is still maintaining soil fertility, ensuring water quality and regulating climate.