VALUE OF BIODIVERSITY

Environmental services from species and ecosystems are essential at global, regional and local levels. Production of oxygen, reducing carbon dioxide, maintaining the water cycle, protecting soil is important services. The world now acknowledges that the loss of biodiversity contributes to global climatic changes. Forests are the main mechanism for the conversion of carbon dioxide into carbon and oxygen. The loss of forest cover, coupled with the increasing release of carbon dioxide and other gases through industrialization contributes to the ‘greenhouse effect’. Global warming is melting ice caps, resulting in a rise in the sea level which will submerge the low lying areas in the world. It is causing major atmospheric changes, leading to increased temperatures, serious droughts in some areas and unexpected floods in other areas. Biological diversity is also essential for preserving ecological processes, such as fixing and recycling of nutrients, soil formation, circulation and cleansing of air and water, global life support (plants absorb CO₂, give out O₂), maintaining the water balance within ecosystems, watershed protection, maintaining stream and river flows throughout the year, erosion control and local flood reduction. Food, clothing, housing, energy, medicines, are all resources that are directly or indirectly linked to the biological variety present in the biosphere. This is most obvious in the tribal communities who gather resources from the forest, or fisher folk who catch fish in marine or freshwater ecosystems. For others, such as agricultural communities, biodiversity is used to grow their crops to suit the environment. Urban communities generally use the greatest amount of goods and services, which are all indirectly drawn from natural ecosystems. It has become obvious that the preservation of biological resources is essential for the well-being and the long-term survival of mankind. This diversity of living organisms which is present in the wilderness, as well as in our crops and livestock, plays a major role in human ‘development’. The preservation of ‘biodiversity’ is therefore integral to any strategy that aims at improving the quality of human life.

Consumptive use value: The direct utilization of timber, food, fuel wood, fodder by local communities. The biodiversity held in the ecosystem provides forest dwellers with all their daily needs, food, building material, fodder, medicines and a variety of other products. They know the qualities and different uses of wood from different species of trees, and collect a large number of local fruits, roots and plant material that they use as food, construction material or medicines. Fisher folk are highly dependent on fish and know where and how to catch fish and other edible aquatic animals and plants.

Productive use value: The biotechnologist uses bio rich areas to ‘prospect’ and search for potential genetic properties in plants or animals that can be used to develop better varieties of crops that are used in farming and plantation programs or to develop better livestock. To the pharmacist, biological diversity is the raw material from which new drugs can be identified from plant or animal products. To industrialists; biodiversity is a rich store-house from which to develop new products. For the agricultural scientist the biodiversity in the wild relatives of crop plants is the basis for developing better crops. Genetic diversity enables scientists and farmers to develop better crops and domestic animals through careful breeding. Originally this was done by selecting or pollinating crops artificially to get a more productive or disease resistant strain. Today this is increasingly being done by genetic engineering, selecting genes from one plant and introducing them into another. New crop varieties (cultivars) are being developed using the genetic material found in wild relatives of crop plants through biotechnology. Even today, species of plants and animals are being constantly discovered in the wild. Thus these wild species are the building blocks for the betterment of human life and their loss is a great economic loss to mankind. Among the known species, only a tiny fraction has been investigated for their value in terms of food, or their medicinal or industrial potential. Preservation of biodiversity has now become essential for industrial growth and economic development. A variety of industries such as pharmaceuticals are highly dependent on identifying compounds of great economic value from the wide variety of wild species of plants located in undisturbed natural forests. This is called biological prospecting.

Social values: While traditional societies which had a small population and required less resources had preserved their biodiversity as a life supporting resource, modern man has rapidly depleted it even to the extent of leading to the irrecoverable loss due to extinction of several species. Thus apart from the local use or sale of products of biodiversity there is the social aspect in which more and more resources are used by affluent societies. The biodiversity has to a great extent been preserved by traditional societies that valued it as a resource and appreciated that its depletion would be a great loss to their society. The consumptive and productive value of biodiversity is closely linked to social concerns in traditional communities. ‘Ecosystem people’ value biodiversity as a part of their livelihood as well as through cultural and religious sentiments. A great variety of crops have been cultivated in traditional agricultural systems and this permitted a wide range of produce to be grown and marketed throughout the year and acted as an insurance against the failure of one crop. In recent years farmers have begun to receive economic incentives to grow cash crops for national or international markets, rather than to supply local needs. This has resulted in local food shortages, unemployment (cash crops are usually mechanized), landlessness and increased vulnerability to drought and floods.

Ethical and moral values: Ethical values related to biodiversity conservation are based on the importance of protecting all forms of life. All forms of life have the right to exist on earth. Man is only a small part of the Earth’s great family of species. Don’t plants and animals have an equal right to live and exist on our planet which is like an inhabited spaceship? We do not know if life as we know it exists elsewhere in the universe. Do we have the right to destroy life forms or do we have a duty to protect them? Apart from the economic importance of conserving biodiversity, there are several cultural, moral and ethical values which are associated with the sanctity of all forms of life. Indian civilization has over several generations preserved nature through local traditions. This has been an important part of the ancient philosophy of many of our cultures. We have in our country a large number of sacred groves or ‘deorais’ preserved by tribal people in several States. These sacred groves around ancient sacred sites and temples act as gene banks of wild plants.

Aesthetic value: Knowledge and an appreciation of the presence of biodiversity for its own sake is another reason to preserve it. Quite apart from killing wildlife for food, it is important as a tourist attraction. Biodiversity is a beautiful and wonderful aspect of nature. Sit in a forest and listen to the birds. Watch a spider weave its complex web. Observe a fish feeding. It is magnificent and fascinating.Symbols from wild species such as the lion of Hinduism, the elephant of Buddhism and deities such as Lord Ganesh, and the vehicles of several deities that are animals, have been venerated for thousands of years. Valmiki begins his epic story with a couplet on the unfortunate killing of a crane by a hunter. The ‘Tulsi’ has been placed at our doorsteps for centuries.

Option value: Keeping future possibilities open for their use is called option value. It is impossible to predict which of our species or traditional varieties of crops and domestic animals will be of great use in the future. To continue to improve cultivars and domestic livestock, we need to return to wild relatives of crop plants and animals. Thus the preservation of biodiversity must also include traditionally used strains already in existence in crops and domestic animals.

BIODIVERSITY

Biodiversity is the degree of variation of life forms within a given species, ecosystem, biome, or planet. Terrestrial biodiversity tends to be highest at low latitudes near the equator, which seems to be the result of the warm climate and high primary productivity. Marine biodiversity tends to be highest along coasts in the Western Pacific, where sea surface temperature is highest and in mid-latitudinal band in all oceans. Biodiversity generally tends to cluster in hotspots, and has been increasing through time but will be likely to slow in the future. 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 civilization for its growth and development. Those that used this “bounty of nature” carefully and sustainably survived. Those that overused or misused it disintegrated. Science has attempted to classify and categorize the variability in nature for over a century. This has led to an understanding of its organization into communities of plants and animals. This information has helped in utilizing the earth’s biological wealth for the benefit of humanity and has been integral to the process of ‘development’. This includes better health care, better crops and the use of these life forms as raw material for industrial growth which has led to a higher standard of living for the developed world. However this has also produced the modern consumerist society, which has had a negative effect on the diversity of biological resources upon which it is based. The diversity of life on earth is so great that if we use it sustainably we can go on developing new products from biodiversity for many generations. This can only happen if we manage biodiversity as a precious resource and prevent the extinction of species.

What is the actual definition=>>‘Biological diversity’ or biodiversity is that part of nature which includes the differences in genes among the individuals of a species, the variety and richness of all the plant and animal species at different scales in space, locally, in a region, in the country and the world, and various types of ecosystems, both terrestrial and aquatic, within a defined area. and its 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 organization of species in an area into distinctive plant and animal communities constitutes ecosystem diversity.

Genetic diversity: Each member of any animal or plant species differs widely from other individuals in its genetic makeup because of the large number of combinations possible in the genes that give every individual specific characteristic. Thus, for example, each human being is very different from all others. This genetic variability is essential for a healthy breeding population of a species. If the number of breeding individuals is reduced, the dissimilarity of genetic makeup is reduced and in-breeding occurs. Eventually this can lead to the extinction of the species. The diversity in wild species forms the ‘gene pool’ from which our crops and domestic animals have been developed over thousands of years. Today the variety of nature’s bounty is being further harnessed by using wild relatives of crop plants to create new varieties of more productive crops and to breed better domestic animals. Modern biotechnology manipulates genes for developing better types of medicines and a variety of industrial products.

Species diversity: The number of species of plants and animals that are present in a region constitutes its species diversity. This diversity is seen both in natural ecosystems and in agricultural ecosystems. Some areas are richer in species than others. Natural undisturbed tropical forests have much greater species richness than plantations developed by the Forest Department for timber production. A natural forest ecosystem provides a large number of non-wood products that local people depend on such as fruit, fuel wood, fodder, fiber, gum, resin and medicines. Timber plantations do not provide the large variety of goods that are essential for local consumption. In the long-term the economic sustainable returns from non-wood forest products is said to be greater than the returns from felling a forest for its timber. Thus the value of a natural forest, with all its species richness is much greater than a plantation. Modern intensive agricultural ecosystems have a relatively lower diversity of crops than traditional agro-pastoral farming systems where multiple crops were planted. At present conservation scientists have been able to identify and categorize about 1.8 million species on earth. However, many new species are being identified, especially in the flowering plants and insects. Areas that are rich in species diversity are called ‘hotspots’ of diversity. India is among the world’s 15 nations that are exceptionally rich in species diversity.

Ecosystem diversity: There are a large variety of different ecosystems on earth, which have their own complement of distinctive inter linked species based on the differences in the habitat. Ecosystem diversity can be described for a specific geographical region, or a political entity such as a country, a State or a taluka. Distinctive ecosystems include landscapes such as forests, grasslands, deserts, mountains, etc., as well as aquatic ecosystems such as rivers, lakes, and the sea. Each region also has man-modified areas such as farmland or grazing pastures.An ecosystem is referred to as ‘natural’ when it is relatively undisturbed by human activities or ‘modified’ when it is changed to other types of uses, such as farmland or urban areas. Ecosystems are most natural in wilderness areas. If natural ecosystems are overused or misused their productivity eventually decreases and they are then said to be degraded. India is exceptionally rich in its ecosystem diversity.

FUNCTION OF VARIOUS ECO-SYSTEMS

Forest ecosystems are dominated by trees that can mature to at least 2 m in height and provide a canopy of at least 20% cover, together with all the native wildlife, including birds, mammals, marsupials, amphibians, reptiles, insects, plants, as well as moss, fungi, micro-organisms and non-living things such as water, soil and air interacting within the same area.

Grassland ecosystem: A biological community that contains few trees or shrubs, is characterized by mixed herbaceous (non-woody) vegetation cover, and is dominated by grasses or grass like plants. Mixtures of trees and grasslands occur as savannas at transition zones with forests or where rainfall is marginal for trees. About 1.2 × 108 mi2 (4.6 × 107 km2) of the Earth's surface is covered with grasslands, which make up about 32% of the plant cover of the world. Grasslands occur in regions that are too dry for forests but that have sufficient soil water to support a closed herbaceous plant canopy that is lacking in deserts. Thus, temperate grasslands usually develop in areas with 10–40 in. (25–100 cm) of annual precipitation, although tropical grasslands may receive up to 60 in. (150 cm). Grasslands are found primarily on plains or rolling topography in the interiors of great land masses, and from sea level to elevations of nearly 16,400 ft (5000 m) in the Andes. Because of their continental location they experience large differences in seasonal climate and wide ranges in diurnal conditions. In general, there is at least one dry season during the year, and drought conditions occur periodically. Significant portions of the world's grasslands have been modified by grazing or tillage or have been converted to other uses. The most fertile and productive soils in the world have developed under grassland, and in many cases the natural species have been replaced by cultivated grasses (cereals).

Desert ecosystem: Deserts, like forests and grasslands, occur all around the world. Symmetrical clusters of deserts are found around the Tropic of Cancer and the Tropic of Capricorn - the two latitudes that define the area where the sun's angle at solar noon is closest to ninety degrees overhead at the Equinox. Deserts are formed in the driest of environment. The temperature of deserts may vary from very hot as in hot deserts, to a very cold as in cold deserts. The most important hot deserts of the world is the Sahara-Arabia-Gobi which extends from Africa to Central Asia. It has a highly irregular an insignificant rainfall and low humidity. Hot deserts also occurs in India such as Sindh-Rajasthan desert South America, North America and Australia, cold deserts occurs in Ladakh regions of Himalayas and Tibet. Desert plants which are adapted to drought conditions through reduced leaf size and the dropping of leaves in any conditions both reducing loss via evapotranspiration. The roots of most desert plants remain well developed and occur in the top of the soil in order to take maximum possible advantage of any rainfall. The animals present in the desert are reptiles, insects and rodents. All these animals have special morphological, physiological and etiological adaptations for desert. Some desert animals are newly adapted for high extremes of temperatures. In general large animals are very uncommon except male deer. Some desert plant closes their petals at night while many plants blossom only at night. There are some insects which remain active during the day while some insects are active at night. Some reptiles and insects are well adapted for their survival in deserts and excrete dry matter; kangaroo, rat and pocket mouse are able to live without drinking water. They do so by extracting the moisture from the seed they eat. The camel and the desert birds (ostrich) have an occasional drink of water but can go for long periods of time using the water stored in the body. Most insects of the deserts are herbivores. The species composition of desert ecosystem is much more varied and typical. The biotic components of deserts ecosystem are summarized as under:

(1) Producers: These are shrubs, bushes and some grasses and a few trees. The shrubs have widespread, branched root system. Some lower plants like xerophytes mosses may also be present.

(2) Consumers: The most common animals are reptiles and insects which are able to live under xeric conditions. These are also present some nocturnal rodents and birds. The camel feed on tender shoots of the plants.

(3) Decomposers: They are very few due to poor vegetation. The amount of dead organic matter is correspondingly less. There are also some fungi and bacteria most of which are hemophilic.

Aquatic ecosystems: An aquatic ecosystem is an ecosystem in a body of water. Communities of organisms that are dependent on each other and on their environment live in aquatic ecosystems. The two main types of aquatic ecosystems are Marine ecosystems & Freshwater ecosystems Aquatic ecosystems include oceans, lakes, rivers, streams, estuaries, and wetlands. Within these aquatic ecosystems are living things that depend on the water for survival (fish, plants & microorganisms). These ecosystems are very fragile and can be easily disturbed by pollution.

Marine Ecosystems: Marine ecosystems cover approximately 71% of the Earth's surface and contain approximately 97% of the planet's water. They generate 32% of the world's net primary production. They are distinguished from freshwater ecosystems by the presence of dissolved compounds, especially salts. Approximately 85% of the dissolved materials in seawater are sodium and chlorine. Seawater has an average salinity of 35 parts per thousand (ppt) of water. Actual salinity varies among different marine ecosystems. Marine ecosystems can be divided into many zones depending upon water depth and shoreline features. The oceanic zone is the vast open part of the ocean where animals such as whales, sharks, and tuna live. The benthic zone consists of substrates below water where many invertebrates live. The intertidal zone is the area between high and low tides; in this figure it is termed the littoral zone. Other near-shore (neritic) zones can include estuaries, salt marshes, coral reefs, lagoons and mangrove swamps. In the deep water, hydrothermal vents may occur where chemo synthetic sulfur bacteria form the base of the food web. Classes of organisms found in marine ecosystems include brown algae, dinoflagellates, corals, cephalopods, echinoderms, and sharks. Fish caught in marine ecosystems are the biggest source of commercial foods obtained from wild populations. Environmental problems concerning marine ecosystems include unsustainable exploitation of marine resources (for example overfishing of certain species), marine pollution, climate change, and building on coastal areas.

ECOLOGICAL SUCCESSION

The environment may be altered in substantial ways through the activities of humans, other living things, or when natural disasters occur, such as climate changes and volcanic eruptions.  Although these changes are sometimes occur very quickly, in most cases species replace others gradually, resulting in long-term changes in ecosystems. These gradual long term changes in altered ecosystems are called ecological successions.  Ecosystems tend to change with time until a stable system is formed. The type of succession which occurs in an ecosystem depends upon climatic and other limitations of a given geographical area. Pioneer organisms are the first organisms to reoccupy an area which has been disturbed by a disruption. Typical pioneers in a succession include grasses in a plowed field or lichens on rocks. These pioneer organisms modify their environment, ultimately creating conditions which are less favorable for themselves, but establishing conditions under which more advanced organisms can live.Over time, the succession occurs in a series of plant stages which leads to a stable final community which is very similar to the plant community which originally existed in the ecosystem. This final stable plant community is called a climax community. This community may reach a point of stability that can last for hundreds or thousands of years. It has been observed that when natural disasters occur, such as a floods or fires, the damaged ecosystem is likely to recover in a series of successional stages that eventually result in a stable system similar to the original one that occupied the area.

Primary Succession: Begins in new habitats, uninfluenced by pre-existing communities

Secondary Succession: Follows disruption of a pre-existing community (succession after forest fire, etc.)

Succession was among the first theories advanced in ecology and the study of succession remains at the core of ecological science.

FOOD CHAIN

Flow of energy in an ecosystem is one way process. The sequence of organism through which the energy flows, is known as food chain. Plants are eaten by insects, insects are eaten by frogs, the frogs are eaten by fish and fish are eaten by humans. The pattern of eating and being eaten forms a linear chain called food chain. Such a food chain can always be traced back to the producers. The primary producers trap radiant energy of the sun and transfers to chemical or potential energy of organic compounds like proteins, fats and carbohydrates. Formation of ATP (Adenosine triphosphate) during photo-synthesis is the first nutritional level. ATP is stored in food matter that is utilized by herbivores, the plant eaters. This process constitutes the second trophic level. When herbivores eat the plant, the organic compounds are re-oxidized and energy is liberated. Some energy is produced as heat which is not useful. Flow of energy is greatly reduced at each successive level of nutrition because of the energy utilization by the organisms and heat loses at each step in transformation of energy. This accounts for the decrease in biomass at each successive level. It should be noted that the number of steps in a food chain are always restricted to maximum four or five steps. Humans are at the end of a number of food chains.
TYPES OF FOOD CHAIN: 
There are three types of food chain in the nature

Grazing food chain:

The primary producers are the living green plants which are grazed on by grazing animals. It is found in aquatic and grassland ecosystem.

E.g. Phytoplankton →Zooplankton→ Fish→ Hawk

Detritus food chain:

This type of food chain starts from dead organic matter and so it is less dependent on solar energy. The dead organic matter is broken down into simple nutrients by microorganisms like fungi and bacteria. This type of food chain is found in forest ecosystem.

Dead organic matter→ Detritivores → Predators

Parasitic food chain: 

In this type of food chain either the producer or the consumer is parasitized and therefore the food passes to the smaller organism. The energy transfer through this kind of food chain is not significant.

Producer→ Herbivores→ Parasite→ Hyperparasites

SIGNIFICANCE OF FOOD CHAIN:

• They help in maintaining the ecological balance
• They help in understanding the feeding relations among organisms
• Energy flow and nutrient cycling take place through them
• helps in understanding interaction between organism and ecosystem
• Help in understanding the mechanism of energy flow and circulation of matter in ecosystem
• Helps to understand the movement of toxic substance and
• The problem associated with biological magnification in the ecosystem