Biodiversity is the variety and differences among living organisms from all sources, including terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are a part. 

It is virtually synonymous with “Life on earth”. Biologists most often define "biological diversity" or

"biodiversity" as the "totality of genes, species, and ecosystems of a region".

The biodiversity found on Earth today consists of many millions of distinct biological species, which is the product of nearly 3.5 billion years of evolution.

Levels of Biodiversity:

1) Genetic diversity: It is a level of biodiversity that refers to the total number

of genetic characteristics in the genetic makeup of a species.

Biodiversity:

It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary.

E.g. rice Varieties and teak wood varieties2) Species diversity:

Species: A discrete group of organisms of the same kind. It refers to the variety of species within a region. Species diversity is an index that incorporates the

number of species in an area and also their relative abundance.

It is generally a much more useful value than species richness.

E.g. Plant species- apple, mango, grapes etc. Animal species- lion, tiger, elephant etc.

3) Community and Ecosystem diversity:

Ecosystem diversity refers to the diversity of a place at the level of ecosystems. This has 3 perspective:

Alpha Diversity: Within community diversity. Alpha diversity refers to the diversity of organisms sharing the same Community/Habitat.

Beta Diversity: Between community diversity. It refers to the diversity of organisms sharing two habitat.

Gamma Diversity : Diversity of the habitat over the total landscape or geographical area is called gamma diversity

E.g. River Ecosystem, land ecosystem etc.

Significance of Biodiversity• It is very important for human life. As we depend

on plants, animals for our food, medicine and industrial products.

• It protects the fresh air, clean water, and productive land.

• It is also important for forestry, fisheries and agriculture which depends on biological resources available in nature.

• Loss of biodiversity has a serious economic and social costs for any country.

Loss of biodiversity• The farmers prefer hybrid seeds as a result many

plant species became extinct or destroyed. • For the production of drugs the pharmaceutical

companies collect wild plants, so several medical plants become extinct.

• Tropical forest is the main sources of the worlds medicine. Every year these forest are disappearing due to agriculture, mining ,logging.

• E.g. Taxus baccate In sub-Himalayan region.

Values of Biodiversity: Biodiversity is vital for healthy biosphere. Biodiversity is

must for the stabilty and proper functioning of the biosphere. Food: About 80,000 edible plants and about 90% of

present day food crops have been domesticated from wild.

Drugs & Medicines: About 75% of world’s population depend on plants or plant extracts.

Fuel: Forests have been used since ages for fuel wood. Fossil fuels are also products of Biodiversity.

Social Value: Many of the plants like Tulsi, Lotus, Peepal etc are considered holy and sacred.

About 2.1 million species have been identified till date, while many more species are believed to exist.

According to UNEP estimate, approximately 9.0 – 52 million of species exist on Earth

India’s position is 10th in the world & 4th in Asia in terms of Plant diversity.

Classification and importance of values of biodiversity

Biodiversity

Consumptive Use value

Productive use Value

Social ValueEthical or

Existence valueAesthetic value

Productive use values• Biodiversity products have obtained a commercial value.• These products are marketed and sold. These products may

be derived from the animals and plants.• E.g. animals products- silk, wool, tusk, leather, fish and

animals .• Plant products- wood, cotton, fruits and vegetables.• Rice- 22% of the cropped area and cereals accounts for

39% of the cropped area.• Oil seed production also helped in saving large amount of

foreign exchange spent on importing edible oils.• SOCIAL VALUES:• It refers to the manner in which the bio-resources are used

to the society.• These values are associated with the social life, religion and

spiritual aspects of the people.

• E.g. Holy plants- tulsi, peepal, lotus.• Holy Animals- Cow, snake, bull, peacock.• Ethical Values (or) Existence Value:• It involves ethical issues like all life must be preserved.• Biodiversity is considered to have great value on religious and

cultural basis.• The ethical value means that a species may or may not be

used , but its existence in nature gives us pleasure.• E.g. river Ganga is considered as holy river.• Vembu, tulsi, are some of the trees worshipped by the tamilians.• AESTHETIC VALUE: • The beautiful nature of plants and animals insist us to protect

the biodiversity.• The most important aesthetic value of biodiversity is Eco-

tourism.

• E.g. the pleasant music of wild birds, colour of butterfly, colour of flowers, colour of peacocks are very important for aesthetic value.

• OPTION VALUES:• Options values are the potentials of biodiversity that are

presently unknown and need to be known.• The optional value of biodiversity suggests that any

species may be proved to be a valuable species after someday.

• E.g. Growing biotechnology field is searching a species for causing the diseases of cancer and AIDS.

• Medical plants and herbs play a very important role in our Indian economic growth.

Global Biodiversity

• Total number of living species in the world-20 million.• Tropical deforestation alone is reducing the biodiversity

by 0.5% every year.

Terrestrial biodiversity or Biomass:• It is the largest ecological units present in different

geographic areas and are named in different ways.

GLOBAL Biodiversity

TROPHICAL RAIN FORESTS

TEMPERATURE FORESTS

Tropical rain forests:• These are the earth's largest storehouse of biodiversity. • They are inhabited by millions of species of plants,

insects, birds, amphibians and mammals. • About 50 to 75% of global biodiversity lies in these

tropical rain forests. (a) Medicinal plants: More than 25% of the world's

prescription drugs are extracted from plants growing in tropical forest.

(b) Flowering plant: Nearly 1,30,000 flowering plant species are found available. Now we know only 1-3% of these plant species.

Temperate forests: These have much less biodiversity. Globally, they have

nearly, (a) 1,70,000 flowering plants. (b) 30,000 vertebrates. (c) 2,50,000 other group of species.

Marine Biodiversity• Marine diversity is much higher than terrestrial biodiversity.• Estuaries, coastal waters and oceans are biologically diverse, but the diversity is very low. Sea is the cradle of every known phylum. Out of the 35 existing phyla of multicellular animals, 34 are marine. • E.g. Protozoan (Single called animals), Bacteria and Cyanobacteria, Algae, Fungi (Mushrooms) Higher Plants, Jelly fish, Corals etc. • Biodiversity at national level (India): India is second largest nation containing 5% of world's biodiversity and 2% of the earth surface. Rank of India in biodiversity: It has been estimated that India gets. (i) 10th rank among the plant rich countries of the world. (ii) 11th rank among the endemic species of higher vertebrates. (iii) 6th rank among the centers of diversity and origin of agricultural crops.

• Medical Value:• More than 2000 medical plants are cultivated in India, which can cure many disease.• E.g. Tulsi and Neem is well known plant for its medicinal values. • Tunneric in lndia was proved to be an anti-carcinogen.• Commercial value:• Indian sandal wood has high commercial value, if it is sold

in abroad. • Indian tobacco has high nicotine content, when compared to

other tobacco. • Several species of non - wild edible mushrooms cultivated and exported to advanced countries.• More than 100 species of microorganisms were collected from Indian soils and cultured, developed and formulated in the abroad laboratories. E.g. flowering plants, insects, fishes, birds, reptiles, and mammals.

Biodiversity at local levels or Measurement of Biodiversity

BiodiversityAt local levels

Point Richness Alpha Diversity Beta Diversity Gamma Diversity

1. Point Richness: It refers to the number of species that can be found at a single point in a given space.

2. Alpha richness (or) Alpha diversity: It refers to the number of species found in a small homogeneous area. It is strongly correlated with physical variables.

3. Beta richness (or) Beta diversity: It refers to the rate of change in species composition across different habitats. It means that the number of species increases as more heterogeneous habitats are taken into consideration

4. Gamma richness (or) Gamma diversity: It refers to the rate

of change across large landscape. Biodiversity a Tamilnadu • The distribution of plants· and animals among different • districts of Tamil Nadu is uneven. • E.g. Western Ghats has 1500 species of plants, 50 • species of mammals and 90 reptiles. • Birds of several species is coming to Vedanthangal from • far off places. • The elephant sanctuaries at Anaimalai. MEGA· DIVERSITY • There are nearly 170 countries in the world and 12 of them contain 70% of our planet's biodiversity. • The following 12 countries, Australia, Brazil, China, • Colombia, Ecuador, the United States, India, Indonesia, Madagascar, Mexico, Peru and Democratic Republic of the Congo regions are known as mega diversity regions.

• Endemism (or) Endemic species • The species which are confined to a particular area are called endemic species. • Our country has a rich endemic flora and fauna. • About 33% of the flowering plants, 53% of fresh water fishes, 60% amphibians, 36% reptiles and 10% mammalian are endemic species. 1. Plant diversity • Nearly 5000 flowering plants and 166 crop plant species have their origin in India. 2. Marine diversity • More than 340 coral species of the world are found here. • Several species of mangrove plants and sea grasses are also found in our country. 3. Agro-biodiversity • There are 167 crop species and wild relatives.• India is considered to be the origin of 30,000 to 50,000 varieties of rice, mango, turmeric, ginger, sugarcane, etc.

• 4. Animal biodiversity • There are 75,000 animal species including 5,000 insects. • India is a home to about nearly 2,00,000 living organisms. • RED Data book (or) Red List:• Red book is a catalogue of taxa facing risk of extinction. The purpose of preparation of red list is to (i) provide awareness to the degree of threat to biodiversity. (ii) provide global index on already decline of biodiversity. (iii) identification of species at high risk of extinction. (iv) help in conservation action. (v) information about international agreements. India ranks 2nd in terms of the number of threatened mammals and 6th among the countries with the most threatened birds. E.g. Pitcher plant has become endemic in Eastern Himalayas. • Taxus wallichina has come under red dad category due to its over exploitation.

A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity that is threatened with destruction.

An area is designated as a hot spot when it contains at least 0.5% of plant species as endemic.

There are 25 such hot spots of biodiversity on a global level, out of which two are present in India.

These are:Indo- Burma (earlier The Eastern Himalayas) and The western Ghats & Sri Lanka.. 

These hot spots covering less than 2% of the world’s land area are found to have about 50% of the terrestrial biodiversity.

Hot- spots of Biodiversity:

Indo- Burma (Eastern Himalayas) Hotspot: The hotspot includes all of Cambodia, Vietnam & Laos, and

nearly the entire areas of Thailand, Myanmar & Bhutan as well as part of Nepal, far eastern India and extreme southern China.

In addition, it covers several offshore Island including Mainan Islands in the south China Sea and Andaman & Nicobar Islands in Indian Ocean.

Indo-Burma is one of the most threatened biodiversity hotspots, due to the rate of resource exploitation and habitat loss.

Criteria for determining hot-spots: No. of Endemic Species i.e. the species which are found no

where else. Degree of threat, which is measured in terms of Habitat

loss.

Western Ghats and Sri Lanka, also known as the “Sahyadri Hills” encompasses the montane forests in the southwestern parts of India and on the neighboring Islands of Sri Lanka.

The entire extent of hotspot was originally about 1,82,500 square kms, but due to tremendous population pressure, now only 12,445 square Km or 6.8% is in pristine condition.

The important populations include Asian elephant, Indian tigers and the endangered lion tailed macaque.

Reasons for Rich biodiversity in the tropics: The tropics have a more stable climate. Warm temperature and high humidity in the tropical areas

provide favorable conditions. No single species can dominate and thus there is an opportunity

for many species to coexist. Among plants, rate of out- crossing appear to be higher in tropics.

Western Ghats and Sri Lanka:

Extinction is a natural event and, from a geological perspective, routine.

In last century, human impact has been so severe that thousands of species and varieties are becoming extinct annually.

Some of the main causes are: Habitat loss, degradation, fragmentation: Habitat loss & degradation are major causes of species

extinction, affecting 89% of all threatened birds, 83% of mammals & 91% of all threatened plants assessed globally (IUCN, 2000)

The main causes of habitat are agriculture activities, Mining, development of human settlement, industry etc.

According to ICUN,UNEP report, more than 50% of wildlife habitat has been destroyed in 49 out of 61 old world tropical countries.

Threats to Biodiversity:

Factors influencing Habitat loss• 1. Deforestation: The loss of habitat is mainly caused by

deforestation activities.• The forest and grasslands are the natural homes of

thousands of species, which disintegrate due to loss of their natural habitat.

• 2. Destruction of wetlands: The wetlands, estuaries and mangroves are destroyed due to draining, filling and pollution, which causes huge biodiversity loss.

• 3. Habitat fragmentation: Sometimes the habitat is divided into small and scattered patches. This phenomenon is known as habitat fragmentation.

• 4. Raw material: For the production of hybrid seeds, the wild plants are used as raw materials. As a result, many plant species become extinct.

• 5. Production of drugs: Many pharmaceutical companies collect wild plant for the production of drugs.

• Therefore several medicinal plant species are on the verge of extinction.

• 6. Illegal trade: Illegal trade on wild life also reduces the bio-diversity and leads to habitat loss.

• 7. Developmental activities: Construction of massive dams in the forest areas, discharge industrial effluents which kills the birds and other aquatic organisms.

Poaching of Wildlife: Poaching is another threat that has emerged in

recent decades as one of the primary reason for decline in number of species.

Wildlife is sold and traded in many countries for live specimens, folk medicines, furs, Skin, and other products such as Ivory, horns etc amounting to millions of dollars.

Factors influencing poaching:1. Human population: Increased human population in our

country has led to pressure on forest resources, which ultimately causes degradation of wildlife habitats.

2. Commercial activities: Since the trading of such wildlife products is highly profit, poaching makes the poachers to just hunt these prohibital wildlife and smuggle it to other countries.

3. Wild life products: Furs, horns, tasks, live specimens, herbal products.

4. Wealth of wildlife: The developing nations in Asia, Latin America and Africa have richest source of biodiversity.

5. Importers of wild life: Japan, Taiwan, Hong Kong are the major importer of wildlife products (or) wildlife itself.

Man – wildlife conflicts: The conflict between man and wildlife started with the evolution

of man, but intensity increased due to the activities of modern man

Due to the lack of stable food and disruption of movement, wild animals came out of forest area and attack the agricultural field and humans and in turn got killed by the humans.

Factors influencing man - animal conflicts :• Shrinking of forest cover compels wildlife to move outside the

forest and attack the fields and humans• Human encroachment into the forest area induces a conflict

between man and the wildlife.• Injured animals have a tendency to attack man. • Earlier, forest departments used to cultivate sugarcane, paddy,

coconut trees in the sanctuaries. When the favourite food of elephants (i.e., bamboo leaves) were not available, they feed them to the elephants.

Remedial measures or conservation of biodiversity• Adequate crop and cattle compensation schemes must be

Started.

• Solar powered fencing must be provided along with electric

current proof trenches to prevent the animals from entering

into the fields.

• Cropping pattern should be changed near the forest borders.

• Adequate food, and water should be made available for the

wild animals within forest zones.

• The development and constructional work in and around

forest region must be stopped.

Introduction of Exotic species:Organisms introduced into habitats where

they are not native are termed as exotics.They can be thought of as Biological

Pollutants and are considered to be among the most damaging agents of habitat alteration and degradation the world.

Climate change:A changing global climate threatens species and ecosystems.

The distribution of species (biogeography) is largely determined by climate.

Climate change may simply shift these distributions but, for a number of reasons, plants and animals may not be able to adjust.

Endangered Species: According to The International Union of Conservation of

Nature and Natural Resources (IUCN), the species that considered in imminent danger of extinction and whose survival is unlikely, if factors causing their decline continue to operate.

Out of about 47,000 species of plants in our country, 7000 are endemic

India contains 172 species of animals considered globally threatened by IUCN, or 2.9% of the world’s total number of threatened species.

These include 53 species of mammals, 69 birds, 23 reptiles and 3 amphibians

As many as 3,000- 4,000 higher plants may be under high degree of threat in India

Thus Indian subcontinent has about 62% endemic flora, restricted mainly to Himalayas, khasi Hills & Western Ghats.

Sapria himalayana, Uvaria lurida, Napenthes khasians etc. are some endemic flora of our country.

A large number out of a total of 81,000 species of animals in our country is endemic. About 62% amphibians and 50% lizards are endemic to western Ghats.

Golden monkey, Niligiri Langur, Indian Wolf, Red Fox, Himalayan Brown Bear, Great Indian One Horned Rhinoceros are some examples of endemic animal species of India.

Factors affecting Endangered species1. Pollution:

Humans dispose their waste products on nature. So, the

land, river, and air get polluted severely.

These pollutants enter our environment and travel through the food chain and accumulate in the tissues of the living things, finally it leads to death.

 2. Over - exploitation: Over - exploitation of the natural resources and poaching of wild animals also leads to extinct of wild animals.

3. Climate change: Climate change is brought about by the accumulation of greenhouse gases in the atmosphere.

Climate change threatens organisms and ecosystems, which cannot accommodate the change of environmental conditions.

 

Endemic Species• The species which are found only in a particular region

are known as endemic species.• In India of 47,000 species- 7000 plants are endemic.• Flora: • Animals are present in a particular region.• E.g. sapria Himalayas, ovaria lurida.• Fauna:

• Plants present in a 'particular region or period.

• E.g. Monitor lizards (varanus), reticulated python, Indian.

salamander and viviparous toad .

Factors affecting Endemic species

• Habitat loss and fragmentation, because of the draining and filling of inland wetlands.

• Pollution also play an important role. • E.g. Frog eggs, tadpoles and adults are very

sensitive to many pollutants especially pesticides. • Populations of same can also be reduced by

introduction of non-active predators and competitors (like fish) and disease producing organism.

The convention on Biological Diversity held in June, 1992 stressed the need of the conservation of Biodiversity for sustainable development and perpetuation of human beings on earth.

Conservation is defined as “ the management of human use of the biosphere so that it may yield the greatest sustainable benefit to the present generation while maintaining its potential to meet the needs and aspirations of the future generations”.

The two basic approaches to wildlife conservation in protected habitats are:

1) In- situ conservation and 2) Ex- situ conservation.

Conservation of Biodiversity:

In- situ conservation: It simply means conservation of species in its natural

ecosystem or even in man made ecosystems. This strategy emphasizes protection of total ecosystem

through a network of “protected area”. Protected Areas: an area of land and/or sea specially

dedicated to the protection and maintenance of biological diversity and managed through legal effective means.

There are different categories of protected areas which are managed with different objectives. These include; Biosphere reserves, National parks, Wild Life Sanctuaries etc.

At present we have 11 major biosphere reserves, 80 National parks, 420 wildlife sanctuaries in our country covering 4% of the geographic area.

The JIM CORBETT National Park was 1st national park established in India.

What is Difference among Biosphere reserves, National parks, Wild Life Sanctuaries ?

Examples of Biosphere reserves of India:

1.Nilgiri- 5,520 sq.km2.Nanda Devi- 5,860.69 sq. km3.Manas – 2837 sq. km4.Gulf of Mannar – 10,500 sq. km5.Great Nicobar – 885 sq. km6.Panchmarhi – 4,926.28 Sq Km

Examples of some National park in India1.Kaziranga- Assam, Gir National Park- Gujarat, Periyar – Kerala, Sariska – Rajasthan

Examples of some Wild Life Sanctuaries of India:1.Ghana Bird sanctuaries2.Hazaribagh sanctuaries3.Abohar wild life sanctuaries4.Jaldapara wild life sanctuaries5.Mudamalai wild life sanctuaries

Ex- situ conservation: It is defined as “the conservation of component of

biological diversity (Sample of genetic diversity, particularly of endangered species) outside their natural habitats”.

It involves maintenance and breeding of endangered plant and animal species under partially or wholly controlled conditions. E.g. Zoos, Botanical Gardens, Aquaria, Nurseries, DNA bank, Seed bank, Gene bank etc.

There are more than 1500 Botanical gardens in the world containing more than 80,000 species.

There are more than 800 zoos around the world with about 3,000 species of mammals, birds, reptiles and amphibians.

In India, we have many gene bank. The important ones are: National Bureau of Plant genetic Resources (NBPGR),

New Delhi: Agricultural and horticultural crops and their wild varieties

are preserved by cryo-preservation of seeds (at -196º C in Liquid Nitrogen), pollen etc.

National Facility for Plant Tissue Culture Repository (NFPTCR) at NBPGR Campus New Delhi:

It has been set up for the development of a facility of conservation of varieties of crop plants/ trees by tissue culture.

Factors affecting Biodiversity:

• Biodiversity is generally disturbed by human activities such as construction of dams in forest areas, release of industrial wastes, using pesticides and insecticides in the crop fields, urbanization, etc..

• Poaching of wild animals, over exploitation of natural resources, degradation of habitats, affect biodiversity.

• The marine ecosystems are also disturbed due to oil spills and discharge of effluents.

• The climatic factors like global warming, ozone depletion, acid rain also affect the biodiversity.

• Advantages (or) need of biodiversity conservation • It provides immediate benefits to the society such as recreation

and tourism. • Drugs, herbs, food and other important raw materials can be

derived from plants and animals. • It also preserves the genetic diversity of plants and animals. • Ensures the sustainable utilization life supporting systems on

earth. • It leads to conservation of essential ecological diversity and life

supporting systems. • Since the biodiversity loss results in ecological and

environmental deterioration, it is essential to conserve the biodiversity.

END OF THE CHAPTER