Biodiversity: Introduction (Definition, Classification, Importance and Measurement of Biodiversity)


What is biodiversity?

Look deep into nature, and then you will understand everything better’
Albert Einstein


What is biodiversity?

@. Biodiversity- definition: “variability among living organisms”

@. Biodiversity is the variety and variability of genus, species and ecosystem between and within

@. It is the number of different organisms & their relative frequency in an ecosystem

@. The term Biodiversity is coined by Walter Rosen, 1985

@. About 50 million sps. of plants, animals & microbes are existing in the world

@. Among this only 2 million are identified so far

@. Biodiversity also includes: Variability of genus, Variability of varieties, Variability of species, Variability of populations in different ecosystems, Variability in relative abundance of species

@. Knowledge of biodiversity is essential for sustainable utilization of resources

@. Biological resources provide us: Nourishment, Clothing, House, Fuel, Medicine and Revenue

Levels of biodiversity:

@. Biodiversity can be considered in THREE levels

(1). Genetic diversity: Genetic variation within species, both among individuals within single population and among geographically separated populations

(2). Species diversity: Biodiversity covers the full range of species on earth. Includes all the species, microbes, viruses, bacteria to animals and plants

(3). Ecosystem / community diversity: Biodiversity also includes variations in the geographical communities. This includes: Variations in the community in which the species lives, The ecosystem in which the community exists, Interaction within and between biotic and abiotic components

Types of biodiversity:

There are different types of biodiversity can be observed in nature, they are

(1). Genetic diversity: diversity in the alleles of a single gene

(2). Organismal diversity: differences in morphology, anatomy, behaviour of organisms

(3). Population diversity: variations observed quantitative ecological parameters such as frequency, density, abundance etc.

(4). Species diversity: Measures the species number variations in different genera at a particular habitat

(5). Community diversity: variability among community composition of and ecosystem and variations in the ecological interactions

(6). Ecosystem diversity: deals with the variations of interdependence of biotic and abiotic factors in the ecosystem

(7). Landscape diversity: measures the species composition in different landscapes

(8). Biogeographic diversity: diversity observed in geological and geographic history over a large period of time

Measuring biodiversity:

Ø.  At simplest level: biodiversity is the species richness

Ø.  Various levels/parameters of measuring the biodiversity are:

(1). Alpha diversity

(2). Beta diversity

(3). Gamma diversity

How to measure biodiversity(1). Alpha diversity:

Ø  Alpha diversity refers to number of species in a single community at a particular time

Ø  Alpha diversity is better called as species richness

Ø  Alpha diversity is used to compare number of species in different communities

(2). Beta diversity:

Ø  It is the measure of degree of change in species composition along with an environmental gradient

Ø  Example: Beta diversity is high, if the species composition of moss communities changes successively at higher elevations on a mountain slope. Beta diversity is low if same species of moss occupy the whole mountain side

Beta diversity definition

(3). Gamma diversity:

Ø  Gamma diversity applies to large geographic scale

Ø  Gamma diversity is the rate at which additional species are encountered as geographical replacements within a habitat type in different localities

Ø  Gamma diversity is a species turnover rate with distance between sites of similar habitat or with expanding geographic areas”

Define Gamma Diversity

Uses of biodiversity:

Ø  Biodiversity, besides its ecological significance, provides a socio-economic asset to the nation

Ø  Uses related to biodiversity can be grouped into three categories:

(1). Productive use

(2). Consumptive use

(3). Indirect use

(1). Productive use:

Ø  Products commercially harvested from biodiversity for exchange in market

Ø  Productive value of biodiversity is concerned with national income

Ø  Biodiversity provides: fuel, timber, fish, fodder, fruits, honey, cereals, medicinal plants etc.

Ø  In India, income from biodiversity is nearly 30% (736.88 billion rupees, 1994-95)

(2). Consumptive use:

Ø  Consumptive use of biodiversity deals with natural products that are consumed directly

Ø  They are goods which do not come under normal circulation of trade

Ø  Example: non timber forest products, Honey collected from forests, Medicine collected from forests

(3). Indirect use:

Ø  Indict use is the most significant us of biodiversity

Ø  This value is related primarily with functions of ecosystem

Ø  Biodiversity is very essential for: Ecological balance, Constancy of climatic features and Soil maintenance

Importance/Significance of biodiversity:

Ø  Biodiversity indicates variations of life forms (species, ecosystem, biome)

Ø  Biodiversity indicate the health of ecosystem

Ø  Biodiversity is in part a functioning of climate

Ø  Biodiversity provides services like: Air quality and purity, Climate and seasons, Water purification, Pollination and seed dispersal, Prevention of erosion

Ø  Non material benefits of biodiversity are: Spiritual values, Aesthetic values, Education and knowledge systems

Ø  In agriculture biodiversity assist in the recovery of major cultivar when it is under sever attack of disease or pests

Ø  Biodiversity also act as a store house of germplasm of commercially important plants

Ø  About 80% of humans’ food supply comes from 20 kinds of plants, but human uses at least 40,000 species, all of them are the part of biodiversity

Ø  There are more plant products to be discovered from diversity, they are kept hidden in the depth of species richness

Ø  Biodiversity also support in drug discovery for modern diseases

Ø  Most of the drugs which are now in commercial trade are derived directly or  indirectly from biological resources

Ø  About 50% of drugs used in US are derived from biodiversity

Ø  According to WHO, 80% of world population depends on medicines from nature (biodiversity is the integral part of nature)

Ø  Many industrial materials are deriving from biological sources. These include building materials, fibbers, dyes, rubber and oil

Ø  Biodiversity provide security of resources such as water, timber, paper, fibre and food

Ø  Biodiversity support leisure activities such bird watching and trucking

Ø  Biodiversity also inspires musicians, painters and writers

Ø  Gardening, fishing & specimen collecting are depends on biodiversity

Ø  Biodiversity supports many ecosystem services that are not readily visible

Ø  Biodiversity has immense role in the regulation of the chemistry of our atmosphere and water supply

Ø  Biodiversity Helps in water purification, recycling nutrients and providing fertile soil


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