Biodiversity refers to the variety of life. It is seen in the number of species in an ecosystem or on the entire Earth. Biodiversity gets used as a measure of the health of biological systems, and to see whether there is a danger that too many species become extinct. The United Nations designated 2011–2020 as the "United Nations Decade on Biodiversity".
The term[change | change source]
The term biological diversity was used first by wildlife scientist and conservationist Raymond F. Dasmann in 1968, where he advocated conservation. It was widely adopted only in the 1980s.
The term biodiversity first appeared in a publication in 1988 when entomologist E. O. Wilson used it as a title. Since then, the term has often been used by biologists, environmentalists, political leaders, and citizens. A similar term in the United States is "natural heritage." It predates the others and is more accepted by the wider audience interested in conservation. Broader than biodiversity, it includes geology and landforms.
Definitions[change | change source]
Biologists most often define versity as the "totality of genes, species, and ecosystems of a region". An advantage of this definition is that it seems to describe most circumstances. There are three levels at which biological variety can been identified:
- species diversity
- ecosystem diversity
- genetic diversity.
Threats[change | change source]
The idea can be used for tackling practical problems in conservation, for example:
References[change | change source]
- ↑Dasmann R.F. 1968. A different kind of country. MacMillan, New York. ISBN 0-02-072810-7
- ↑Soulé M.E. and B. A. Wilcox. 1980. Conservation biology: an evolutionary-ecological perspective. Sinauer. Sunderland, Massachusetts.
- ↑Edward O.Wilson, editor, Frances M.Peter, associate editor 1988. Biodiversity, National Academy. ISBN 0-309-03783-2; ISBN 0-309-03739-5online edition
- ↑Global Biodiversity Assessment. UNEP, 1995, Annex 6, Glossary. ISBN 0-521-56481-6, used as source by "Biodiversity", Glossary of terms related to the CBD, Belgian Clearing-House Mechanism. Retrieved 2006-04-26.
Here is a compilation of essays on ‘Biodiversity’ for class 6, 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Biodiversity’ especially written for school and college students.
Essay on Biodiversity
- Essay on the Meaning of Biodiversity
- Essay on the Concept of Biodiversity
- Essay on the Types of Biodiversity
- Essay on the Measurement of Biodiversity
- Essay on the Approaches to Conserve Biodiversity
- Essay on Biodiversity Hotspots
- Essay on the Loss in Biodiversity
- Essay on the Conservation of Biodiversity
Essay # 1. Meaning of Biodiversity:
Biodiversity is a combination of two words. Bio means life and diversity means variety. That means Biodiversity is the variety of life.
The term refers to:
1. Number and variety of organisms found in specific geographic region.
2. Species like plants, animals and organisms.
3. Genes it contains.
4. Ecosystems they form.
Biodiversity exits in three levels.
1. Genetic diversity: comprises genetic or other variations within a species.
2. Species diversity: reflected in the morphological, physiological and genetic features.
3. Ecosystem diversity: reflected in diverse bio-geographic zones like lakes, deserts, coasts etc.
Human derives direct and indirect benefits from biodiversity. It is the source of food for survival, fibres for making clothings, timbers for construction of shelters and medicinal ingredients for maintaining good health. It is also a major attraction for tourists.
It acts as a reservoir for maintenance of gaseous composition of atmosphere and climate, as a source of formation and protection of soil, conservation, purification and reservoir of water and also nutrition cycle.
Essay # 2. Concept of Biodiversity:
Biodiversity, or biological diversity, refers to the range of life forms of Earth.
These include millions of plants, animals and micro-organisms, the genes they contain and the intricate ecosystems of which they are a part.
The great variety of life on earth has provided for man’s needs over thousands of years.
This diversity of living creatures forms a support system which has been used by each civilisation for its growth and development:
1. Those that used this “bounty of nature” carefully and sustainably survived.
2. Those that overused or misused it disintegrated.
Biological diversity deals with the degree of nature’s variety in the biosphere. This variety can be observed at three levels; the genetic variability within a species, the variety of species within a community, and the organisation of species in an area into distinctive plant and animal communities constitute ecosystem diversity.
Essay # 3. Types of Biodiversity:
a. Genetic Biodiversity:
This is the diversity of the basic units of hereditary information (genes) within a species, which are passed down the generations. Genetic diversity results in variations. It is this type of diversity that gives rise to several “varieties” of rice and wheat.
Some variations are easy to see, for example, size or colour; some, such as taste or flavour, can be perceived by other senses, and some are invisible, such as susceptibility to disease.
b. Species Biodiversity:
Species is the unit used to classify the millions of life forms on Earth. Each species is distinct from every other species. Horses and donkeys are distinct species, so are lions and tigers. What unites members of a species is the fact that they are genetically so similar that they can produce fertile offspring. Species diversity is usually measured in terms of the total number of species within a defined area.
Species diversity is the most commonly used level for describing the biodiversity of countries. Based on this level a few countries namely Australia, Brazil, China, Colombia, Ecuador, India, Indonesia, Madagascar, Malaysia, Mexico, Peru and Zaire are considered as mega-diversity nations.
c. Ecosystem Biodiversity:
An ecosystem is a set of life forms (plants, animals and micro-organisms) interacting with one another and with the non-living elements (air, soil, water, minerals etc.) of their environment. Ecosystem diversity is therefore the diversity of habitats (i.e., place or site where an organism or a population of organisms naturally occurs), which include the different life forms within.
In addition biodiversity may also be considered as Domesticated Biodiversity or Agricultural Biodiversity and Microorganism Biodiversity.
d. Domesticated Biodiversity:
When we think of biodiversity, we intend to think only of wild plants and animals. But there are also considerable diversity among domesticated plants and animals.
Domesticated biodiversity is the result of:
1. The manipulation by humans of genetic diversity within species to produce new varieties of crops and new breeds of domestic plants and animals.
2. Adaptation of crops and domestic animals to different climatic and geophysical conditions.
Since the dawn of agriculture, people in different parts of the world developed different plant and animal varieties to meet certain needs and conditions. These included higher productivity, better taste, resistance to pests or disease, and the ability to withstand adverse climatic conditions like floods, drought or frost.
Different crop varieties and livestock breeds are adapted to different environmental conditions. For example, a species of rice grown in the hills could develop characteristics to suit the region, such as the ability to tolerate cooler temperatures of the uplands.
The same species grown in the plains would evolve characteristics such as stalks more resistant to the stronger winds that blow across the plains, or develop roots and leaves adaptive to more or less rainfall and sunlight.
Thus two varieties of rice would evolve. A conservation NGO called Navdanya has identified over 150 different varieties of rice in the Western Ghats alone, and each variety often from a different ecosystem or Eco zone.
In 1951 Russian scientist N. Y Vavilov classified the world’s crop production regions into eight centers of plant origin. Of these areas of crop genetic diversity, India was central to what he called the “Hindustan Centre of Origin”.
Vavilov’s terminology for India was well justified, because this region has produced a significant share of the major crops used the world over. At least 166 species of crops (6.7 per cent of total crop species in the world) and 320 species of wild relatives of cultivated crops species are believed to have originated here.
Crop diversity in tropics is shown in Fig. 7.1.
e. Microorganism Diversity:
When we think of biodiversity, we rarely think of the most abundant organisms on Earth-microorganisms or microbes. Just a teaspoonful of soil contains billions of these microscopic living organisms! Microbes include bacteria, virus, protozoa, yeast, and fungus, thus forming a vital part of life on Earth. Bacteria are the oldest life forms on Earth. They were part of the Earth’s atmosphere 3.8 billion year ago.
Essay # 4. Measurement of Biodiversity:
Biodiversity could be estimated from the view point of ecosystem diversity-simply a variety of ecosystem such as Forest, high Mountain, Freshwater ecosystem, Marine, Island, Mangrove and Coral Reef. The second level of biodiversity measurement however implies species diversity assessment which includes the species load, species richness and species diversity index computation.
The third level of estimation is based on genetic diversity measurement below the species level i.e., variety, races and biotypes. Further, Biodiversity is usually plotted as taxonomic richness of a geographical area, with some reference to a temporal scale.
Often ecologist uses three categories of measurement guidelines:
a. Alpha Diversity:
It refers to diversity within a particular area, community or ecosystem, and is measured by counting the number of taxa within the ecosystem.
b. Beta Diversity:
It comprises species diversity between ecosystems; this involves comparing the number of taxa that are unique to each of the ecosystem.
c. Gamma Diversity:
It is a measure of the overall diversity for different ecosystems within a region.
Essay # 5. Approaches to Conserve Biodiversity:
(A) In Situ Conservation (Onsite Conservation):
It is the conservation and protection of the whole ecosystem and its biodiversity at all levels in order to protect the threatened species. However, it is not economically feasible to conserve all the biological wealth and all the existing ecosystem.
Methods used in situ conservation are:
(i) Biodiversity Hot Spots:
Biodiversity hot spots is an approach for conservation. It is an in situ method of conservation. Eminent conservationists have identified certain regions for the maximum protection; these regions are called biodiversity hot spots.
These are regions with very high levels of species richness and high degree of endemism and also regions of accelerated habitat loss. Initially, 25 biodiversity hot spots were identified. Now there are 34 hot spots all over the world.
Three hot spots in India, i.e., Western Ghats/Sri Lanka, Indo-Burma and Eastern Himalaya. It all the biodiversity hot spots are put together, they will cover less than 2% of the earth’s land area, yet they harbour extremely high diversity. Hot spots could reduce the ongoing mass extinctions by almost 30%.
(ii) Sacred Groves:
These are small group of trees with special religious importance in a particular culture and are also of mythological importance.
These are undisturbed forests without any human interventions and are surrounded by highly degraded landscapes.
Such forests include a number of rare, endangered and endemic species.
Sacred groves are found in Khasi and Jaintia Hills in Meghalaya, Aravalli Hills of Rajasthan, Western Ghat regions of Karnataka and Maharashtra and the Sarguja, Chanda and Bastar areas of Madhya Pradesh.
These are protected by native people as a part of cultural traditions.
In Meghalaya, the sacred groves are the last refuges for a large number of rare and threatened plants.
(iii) Protected Areas:
There are 425 biosphere reserves in the world of which 14 are there in India. India has (according to 2002 list) 90 National Parks and 448 Wildlife Sanctuaries. Jim Corbett National Park was first to be established in India.
(B) Ex Situ Conservation (Offsite conservation):
This approach involves placing the threatened animals and plants in special care units for their protection.
Ex situ conservation includes offsite collections and gene banks:
(i) Offsite Collections:
They are live collections of wild and domesticated species in Botanical Gardens, Zoological Parks, Wildlife Safari Parks, etc. India has 2, 75, 200 Parks, where animals, which have become extinct in wild are maintained and has 35 Botanical Gardens. Therefore, offsite collections can be used to restock depleted populations, reintroduce species in the wild and restore degraded habitats.
(ii) Gene Banks:
These are the places, where stocks of viable seeds (seed banks), live growing plants (orchards), tissue culture and frozen germplasm with the whole range of genetic variability are maintained.
These are as follows:
(a) Seed Bank:
The storage of material in the form of seeds is one of the most widespread and valuable ex situ approaches to the conservation strategy. It has considerable strategy, advantages over other methods of ex situ conservation such as ease of storage, relatively low labour demands, etc.
(b) Tissue Culture:
Plant tissue culture is a collection of techniques used to maintain or grow plant cells, tissues or organs under sterile conditions on a nutrient culture medium of known composition.
Plant tissue culture is widely used to produce clones of a plant in a method known as micro-propagation. This method is useful in maintaining a large number of genotypes in small area, rapid multiplication of even endangered species and for hybrid rescue, e.g., banana and potato.
It is based on the ability of certain small molecules to enter cells and prevent dehydration and formation of intracellular ice crystals, which can cause cell death and destruction of cell organelles during the freezing process. In general, the cells are taken from room temperature to approximately-196°C (-130°F) in a controlled-rate freezer.
The frozen cell suspension is then transferred into a liquid-nitrogen freezer maintained at extremely cold temperatures with nitrogen in either the vapour or the liquid phase. Cryopreservation based on freeze-drying does not require use of liquid nitrogen freezers. An important application of cryopreservation is in the freezing and storage of haematopoietic stem cells, which are found in the bone marrow and peripheral blood.
Essay # 6. Biodiversity Hotspots:
A biodiversity hotspot is a region with a high level of endemic species that is under threat from humans. The term hotspot was introduced in 1988 by Dr. Sabina Virk. While hotspots are spread all over the world, the majority are forest areas and most are located in the tropics.
Brazil’s Atlantic Forest is considered one such hotspot, containing roughly 20,000 plant species, 1,350 vertebrates, and millions of insects, about half of which occur nowhere else. The island of Madagascar, particularly the unique Madagascar dry deciduous forests and lowland rainforests, possesses a high ratio of endemism.
Since the island separated from mainland Africa 65 million years ago, many species and ecosystems have evolved independently. Indonesia’s 17,000 islands cover 735,355 square miles (1,904,560 km) contain 10% of the world’s flowering plants, 12% of mammals and 17% of reptiles, amphibians and birds along with nearly 240 million people.
Many regions of high biodiversity and/or endemism arise from specialized habitats which require unusual adaptations, for example alpine environments in high mountains, or Northern European peat bogs.
Accurately measuring differences in biodiversity can be difficult. Selection bias amongst researchers may contribute to biased empirical research for modern estimates of biodiversity. In 1768 Rev. Gilbert White succinctly observed of his Selborne, Hampshire “all nature is so full, that that district produces the most variety which is the most examined.”
Essay # 7. Loss in Biodiversity:
Loss in biodiversity has direct and indirect negative effects on Food security, Vulnerability, Health, Energy security, clean water and Social relations.
The biodiversity is under threat all over the world. Western Ghats and northeast is rich in biodiversity, they have a rich variety of vegetation as well as animals. Certain species fear a threat of decline due to day by day contracting habitats, habitat quality and hunting of some mammals. Fragmentation of habitats and the sharp decline in small sub populations of plants and animals bring them on the edge of decline.
Species already restricted to a small area are more prone to extinction according to the final technical report of the National Biodiversity Strategy and Action Plan. All the 18 domestic poultry breeds are under threat and around 40 species of plants and animals have extricated. The country has lost about 40% of its mangroves and some crucial part of its wetlands. Measures like establishing crop gene banks, seed banks and biodiversity knowledge registers are needed to curb the loss of biodiversity.
(A) Causes of Loss of Biodiversity:
Human activities have accelerated the rate of extinction of species from the earth. The four major reasons also called the Evil Quartet are responsible for the loss of biodiversity.
(i) Habitat Loss and Fragmentation:
Destruction of habitat is the most important cause of extinction of species.
Due to habitat fragmentation and loss, once covering 14% of earth’s land surface rainforest has shrunk to now only 6%.
The Amazon rain forest (lungs of the planet) are also being cut and destroyed for cultivation of soya bean or is converted to grasslands for raising beef cattle.
When large habitats are broken up into small fragments due to various human activities, mammals and birds requiring large territories and certain animals with migratory habits are badly affected, leading to their population declines.
When human need turn into greed, it leads to over-exploitation of natural resources. Many species are extinct due to over exploitation, e.g., Steller’s sea cow, passenger pigeon.
Presently marine fishes are over harvested, threatening the existence of these fish species.
(iii) Alien (Exotic) Species invasions:
Introduction of alien species also causes risk of extinction. When alien species are introduced some of them turn invasive and cause decline or extinction of indigenous species. Nile perch a large predator fish, when introduced into Lake Victoria in East Africa led eventually to the extinction of an ecologically unique assemblage of more than 200 species of chi-child fish in the lake.
Some well-known invasive species are weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eichhornia), caused environmental damage and posed threat to our native species. African catfish (Clarias gariepinus) when introduced for aquaculture purpose, is posing a threat to the indigenous cat fish of India Rivers.
When a species becomes extinct, the plant and animal species associated with it in an obligatory way also become extinct. For example If a species of fish becomes extinct, all the parasites unique/specific to that fish also face extinction. Similarly, in plant pollinator mutualism, extinction of one species invariably leads to the extinction of the other.
(B) Massive Extinctions from Human Activity:
Despite knowing about biodiversity’s importance for a long time, human activity has been causing massive extinctions. As the Environment New Service, reported back in August 1999 (previous link): “the current extinction rate is now approaching 1,000 times the background rate and may climb to 10,000 times the background rate during the next century, if present trends.
(C) Global Warming:
Global warming and climate change pose threats to plant and animal species as many organisms are sensitive to carbon dioxide concentration in the atmosphere that may lead to their disappearance. Pesticide, troposphere ozone, sulphur and nitrogen oxides from industries also contribute to the degradation of natural ecosystems. Poaching puts pressure on wild animals. Elephants are being hunted for their tusks; the tiger is being shot for its skin.
Nature is beautifully balanced; each little thing has its own place, its duty and special utility. Ecosystem stability is a compelling reason for preserving biodiversity. All living organisms are an internal part of the biosphere and provide invaluable services. These include the control of pests, recycling of nutrients, replenishment of local climate and control of floods.
Essay # 8. Conservation of Biodiversity:
Ecological degradation and its corollary – biodiversity loss – pose a serious threat to development. ‘Ecologically destructive economic activities are inefficient not merely because of the resulting resource misallocation but also because of the (excessive) scale of activity levels; excessive in relation to the limited availability of natural capital when the latter is complementary to human-made capital’. In order to bring about sustainable resource conservation and management, it is essential to adopt several different approaches for managing our forests and biodiversity.
Future efforts for conservation and management of our natural resources must derive from a set of clear objectives, mechanisms for action, and commitment from all stakeholders. Apart from this, halting the process of degradation and species loss requires specialized solutions and an understanding of ecological processes. Protecting biodiversity does not merely involve setting aside chunks of area as reserves.
Instead, all the ecological processes that have maintained the area’s biodiversity such as predation, pollination, parasitism, seed dispersal, and herbivory, involving complex interactions between several species of plants and animal needs to be ensured. This, however, is possible only if reserves are large enough to maintain these processes and some of the other crucial links in the web of life.
There is also the need for greater involvement of communities, and for models which decentralize of management and conservation roles and responsibilities. As of now, there are still major lacunae in information resources pertaining to forests, biodiversity – flora and fauna, causative factors for their degradation, and major threats.
The available data is alarmingly inadequate to provide a lucid picture of the current status and ongoing losses/gains. More importantly, laws and policies governing natural resources are still not sufficient enough to tackle the scale of the problem, and these insufficiencies have not been addressed with a sense of urgency. In this section, we provide some indicators of the biological policy, technological, and institutional issues that will help mitigate the disturbingly accelerating biodiversity loss.