RBSE Class - 10 Science Lesson - 19 Biodiversity And Its Conservation Notes

Biodiversity and Its Conservation 

Biodiversity:-

• Biodiversity is composed of two words:- Bio - which means life and diversity - which means variation. 
• Accordingly the meaning of biodiversity is - the diversity found among the living beings found on the earth. 
• Biodiversity is a comprehensive term because the word living organisms includes the entire flora and fauna present on the earth. Its expanse ranges from microscopic plant algae to giant Banyan tree and Redwood, from microscopic water plankton to Mammoth, Whales and from bacteria to voluminous Elephants. 
• According to the "Technology Assessment Report" published by the United States of America in 1987, biodiversity has been defined as follows: "The diversity, asymmetry and ecological complexity found among the biological organisms is called biodiversity." 
• Presently, the biodiversity found on our planet is the result of the continuous evolutionary and developmental process of life continuing from billions of years. In fact, biodiversity is very essential to maintain the balance our ecosystem.

Levels of biodiversity:- 

Species diversity Species: - 

• The total number of different species of organisms (plants and animals) found in any specified area is called species diversity of that region.
• The general meaning of biodiversity is better understood by species diversity.
• It acts as a scale to measure the balance of an ecosystem.
• A group of organisms whose members are identical in appearance and have the ability to produce their offspring's by reproduction in natural conditions is called a species. 
• The microbial density and diversity is many folds higher than the other organisms found on earth. It is noteworthy here that only one gram of soil contains about more than 10 million bacteria and 50 thousand fungi. 

Genetic Diversity:- 

• The variation found in different members of the same species due to the genes (hereditary unit) is called genetic diversity. 
• This diversity is found between different population groups of one species or between different members of a population. 
• The different characters found in the members of same species (like varieties of Rice, Deer or Frog) inhabiting in different ecosystems of the world are example of genetic diversity. 
• The higher the genetic variation in the members of a species, the lesser will be the risk of its extinction, because it will have greater ability to adapt as per the environment. 
• This variation is also responsible for the genesis of new members (varieties) of a species. 

Ecosystem Diversity:- 

• These ecological systems have their own geographical and environmental characteristics due to which they differ in the flora and fauna. Such variation is called as the diversity of the ecosystem. 
• The system established by mutual interactions among all the living organisms and the prevailing abiotic components in a specified area is called Ecosystem. 
• Many types of ecosystem such as grasslands, mountains, desert, moist land, sea, river-valley, tropical forest etc are found on the earth. 

Global biodiversity:- 

• There is lack of complete information about the biodiversity present throughout the World.
•  According to the Millennium Ecosystem Assessment, about 50 to 300 million species of organisms are found on our planet out of which scientists could identify 17 to 20 million species only. 
• Biodiversity distribution on Earth is uneven. The equator has the richest biodiversity but as we go away from the equator biodiversity decreases. The middle and south-east America and south-east Asia, where the maximum tropical forests on the Earth are found, has very rich floral biodiversity. 
• These regions accounts for only 7 percent of the total area of the Earth, but hosts two-thirds of the world's floral diversity, 30 percent of invertebrates and 90 percent of pests. 
• According to the report of Ministry of Environment and Forests, Government of India (year 1999) the world wide distribution of different species of plants and animals found at different levels can be understood from the following illustrations:  

Floral Diversity of the World:- 

1. Viruses  - 4000 
2. Bacteria - 4000 
3. Algae - 40000 
4. Angiosperms Plant - 250000 
5. Fungi - 72000 
6. Gymnosperms - 750 
7. Pteridophytes - 13000 
8. Bryophytes - 16000  
9. Lichens - 17000. 

The Animal diversity of the World:- 

1. Mollusca – 66535 
2. Arthropoda – 987949 
3. vertebrate – 4629 
4. Avian – 9026 
5. Protista – 31529 
6. reptiles – 5817 
7. Amphibians – 5150 
8. fishes – 21723 
9. invertebrates – 87121 
10. prototherian – 2106.  

Biodiversity of India:- 

• India, due to its geographical location, has very rich biodiversity. 
• India occupies only 2.4 percent of the total land of the world but it accounts for 7 to 8 percent of the total biodiversity found throughout the world. 
• Almost all types of ecosystems that exist in the world such as grasslands, tropical rain forests, mangroves, coral reefs, river-valleys, islands, marshes etc. are found in India. Because of this reason, India has been included in 17 Mega biodiversity rich countries. 
• According to the report of the Ministry of Environment and Forest (2009) Government of India, 45968 plant species and 91364 animal species have been identified in India. 
• The plant species comprises of 16,000 Fruit-Flowering plants, 12,500 Fungi, 2,500 Bryophytes, 2,300 Algae, 1,600 Lichens and 1,000 Ferns species. 
• Similarly, 397 species of Mammals, 1232 of Birds, 460 of Reptiles, 240 of Amphibians, 2546 of Fish and 59300 Pests and Insect species are found here. 
• On account of its agricultural diversity, India has a prominent place in the world. In terms of its agriculture input, India has been placed on seventh place in the world. 
• About 167 species of food crops are grown in India. About 50,000 varieties of rice and 1,000 varieties of mango are found in our country.

(3) Indo-Burma Biodiversity Hotspot 

This hotspot spans about 23,73,000 sq. Km area and extends in tropical East Asia covering parts of China, India, Myanmar, Vietnam, Thailand, Cambodia and Malaysia. 

This extensively large hotspot houses 13500 plant species, 433 types of mammalian species, 1266 types of amphibians and 1262 fish species. 

*In the year 2009, the Gangetic Dolphin was declared as India's National Aquatic Animal. The dolphin has the same significance in the river ecological system, which the tiger has in the forest. 

Endemic Species:-

Species which are found in a particular area, i.e., whose distribution or extension is limited to a specific area, are called Endemic Species. 

For example, the Lemur is limited to Madagascar Island only. 

Similarly, Lion tailed Macaque Monkey, Met sequoia plant is found only in a specific valley of China. 

The Nilgiri Tahr and Lion tailed Macaque Monkey are found only in the Western Ghats of India. 

The "Dodo" bird, which was firstly discovered in the year 1658, was an endemic species of an island of Mauritius. Due to the increased human activities and hunting on that island, this bird became extinct in just 23 years. It was last seen in the year 1681. 

India is a nation which is rich in endemic species. Most endemic species of India are found in the Western Ghats, the north-eastern Himalayas and Andaman and Nicobar islands. In India, 17612 species of the wild animals, 44 species of the mammals, 57 species of the birds, 187 species of the reptiles and 110 species of amphibians are endemic. In addition, 5150 endemic species of plants are also found in India. 

The main reasons for the endemic nature of a species are :- 

the interaction between the region's climatic and geographical conditions and mutual interaction with other species. Due to the limited expansion of the endemic species, they are likely to get extinct or threatened. Therefore, there is a need to give special attention to their protection. 

Importance of biodiversity:- 

Biodiversity is a natural resource which can fulfill the natural and organic requirements needed for the life of organisms. 

This fulfills the basic necessities of human beings. 

The importance or value of biodiversity can be understood as per the following: 

(1) Economic significance 

1. Biodiversity directly provides us diversified food, paddy, cereals, fruits and vegetables, fuel, animal feed, building wood, industrial raw materials etc. 
2. To meet the requirements of increasing population, biodiversity is being used to increase the agricultural yields as well as in the development of varieties of disease resistant and insect resistant crops. 
3. For example, the development of the dwarf varieties of wheat, which were responsible for the green revolution, was done from the Naren-10 variety of wheat found in Japan and the development of dwarf species of paddy was done from the Dee-Geo-woo-gen variety found in Taiwan. 
4. In Asia, in the decade of year 1970, paddy crop in 1,60,000 hectare area was destroyed by the Grassy Stunt Virus. At that time, paddy species resistant to the above disease was developed by using the wild paddy species "Oryza Nivara" which was collected in Eastern Uttar Pradesh in 1963.In this way, biodiversity of food grains acts as a boon for the humans. 
5. Today, the entire world is worried for limited resources of petroleum and its uncontrolled exploitation. In such a condition, plants such as Jatropa and Karanja have shown a ray of new hope because the seeds of these plants can be used to develop organic fuels. These plants are also known as biodiesel trees. 

(2) Medicinal value 

1. Since ancient times, many herbaceous plants are being used for the treatment of many types of diseases. According to an estimate, approximately 40 percent of the medicines available today are obtained from the plants. 
2. Treatment of many incurable diseases, which were reported from time to time on earth, has always been sought through the biodiversity. 
3. The treatment of incurable malaria fever was found in the bark of Cinchona plant. 
4. Similarly Vincristine and Vinblastine are used in the treatment of incurable blood cancer (Leukemia). 
5. Bark of tree Taxus baccata is used in the treatment of cancer. 
6. Rauvolfia serpentina is used in the treatment of hypertension. 
7. Treatment of AIDS which has become an epidemic disease in today's world, is also possible with biodiversity. AIDS resistant properties have been found in plants like Tulsi, Brahmi, Ashvagandha, Shatavari, Gilgo, Giloya etc. 

(3) Environmental value 

(a) Protection of food chain 

We know that in a food chain one organism consumes another, that is, one species depends on another species. Therefore, the extinction of any one species may result in a danger of the termination of the food chain. A rich biodiversity ensures multiple food chains (the food web) operating in an ecosystem. On extinction of any species in a food chain, another species operating in the food web can conserve the food chain by compensating its deficiency. 

(b) Regulation of Nutrient cycle 

Biodiversity is helpful in maintaining the nutrient cycle. The micro-organisms of soil break down the dead parts of plants and animals resulting in the replenishment of the nutrients back to the plants. This is how this cycle continues. 

(c) Disposal of environmental pollutants 

Biodiversity also plays an important role in the disposal of environmental pollutants. Some plants have the property of degrading and absorption of the pollutants. 

For example, a plant called Catharanthus roseus has the ability to disintegrate the deadly explosive chemicals like trinitrotoluene. 

Micro-organisms like Pseudomonas putida, Arthobacter viscosus and Citrobacter spp. have the ability to remove heavy metals from the industrial effluents. 

In the same way fungi Rhizopus oryzae has the ability to remove Uranium and Thorium and Penicillium chrysogenium has the ability to eliminate harmful elements such as Radium. 

(d) Social, cultural and spiritual significance 

The human culture and environment has developed simultaneously. Before the today's modem and consumerist approach, a harmony existed between the humans and nature. Even today, some tribal societies are completely dependent on the nature to fulfill their needs. 

Some plants like , Banyan tree, Mango, Basil (Tulsi), Amla, Banana etc. still have very special place in our society and we worship them on some festivals. 

Similarly, some animals like cow, peacock, goose, rat, elephant etc. are also very special in our culture. 

Our country still has some reserve forest areas called Dev vans and people voluntarily conserve these places. 

*Considering the economic, environmental, social and cultural significance of biodiversity on a global scale, the year 2010 was celebrated as International Biodiversity Year by the United Nations, so that the world community should fly to maintain and understand the importance of biodiversity. 

22 May has been declared as the International Biodiversity Day by the United Nations. 

In fact, biodiversity is an outstanding gift of nature which plays an important role in maintaining life on the Earth. 

Therefore, we all have the duty to protect the biodiversity so that life on earth could smile in its various forms. 

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