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AECC on Environment Studies

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IGNOU BEVAE 181 Solved Free Assignment

BEVAE 181 Solved Free Assignment July 2023 & January 2024

Q 1. Why ecological significance of forest is more important in present day context? Explain.

Ans: A Forest provides an environment for diverse plants and animals. They help in cleaning the environment, maintains micro-climate and water cycle of an area.

The world’s forests hold significance for all of their inhabitants as well as for the general health of the planet.

They help to avert soil attrition and decompose of plants or its parts replenish the soil with nutrients. They preserve an appropriate equilibrium of oxygen and carbon dioxide in the atmosphere.

They also present a variety of raw materials such as timber, wood etc and provides food inhabitants and nearby peoples.

Forests have a significant ecological utility in fixing and storing carbon from the atmosphere.

The benefits of forests to society and to the mixture of life make it essential that they are sheltered from deforestation and other possible harmful impacts of civilization.

Plants, animals, water, light, air temperature and soil etc. are the components of Natural Environment. These Factors collectively form the natural environment of a particular region.

From the beginning, the Almighty Creator has established a balance in these elements.

Any single notable change in any element of nature of any particular area affects the established balance among the total elements.

Ultimately it causes the adverse reaction to the environment as a whole. As a result, the natural environment is destroyed and gradually it becomes inhabitable.

The flora, particularly the forest of a region or of a country plays a direct role in maintaining the natural environment and protecting a balance because the plants are the Primary Producer.

For example, if there is no plant in any water reservoir (or marshy land), then no fish will survive there and in absence of fish, the fish-dependent cranes, other birds and snakes will not be able to live there.

If the forests of an area are destroyed, the water holding capacity of soil will be decreased rainfall will be less, degradation of land will increase, rivers will be silted up, and in the rainy season, the area will be flooded easily.

And due to the lowering of the water level in the dry season draught will appear.

The yield of crops will decrease and deficiency will increase. Again all the inhabiting animals, birds, frogs, snakes will perish or they will come to the cropland or locality in search of food.

If the number of plants is decreased the amount of CO2 will increase in the atmosphere and the natural balance will be destroyed.

So for leading a normal healthy life for ourselves and our next generation, we shall have to give adequate protection to our present forest resources and raise more and more forests and fruit trees to increase the plant resources according to the additional demand of the growing population.

In statics, approximately fifty countries have more than half of their total land area under forests, and 11 of these have more than 75 percent of their total land area under forests, on the other end sixty-four countries have less than 10 percent of their total land area enclosed by forests.

Seven countries of these have no forest land at all, and additional 57 have forests on less than 10 percent of their total land area.

Q 2. Answer the following questions in about 125 words each.

a) Explain the characteristics of Western Ghats for inclusion as Biodiversity hotspots.

Ans: As one of the world’s “hottest biodiversity hotspots” and a UNESCO World Heritage Site, the Western Ghats is on the conservation watch-list for being a rich but highly vulnerable region in urgent need of biodiversity conservation efforts.

Despite the negative effects of human activity and climate change, new species continue to be added to the endemic list of species that are recorded here including 16 birds, 124 reptiles, 159 amphibians, 16 mammals, 189 fishes, 69 odonates, 36 butterflies, and 1,600 flowering plants.

The climate of the Westem Ghats varies greatly with altitude and the area’s distance from the Equator. The lower reaches of the Ghats experience a tropical humid climate which is moderated by the area’s proximity to the sea.

During the monsoons, the Western Ghats act as a barrier to the rain-bearing clouds. Therefore, the windward side receives comparatively higher rainfall than the eastem part of the Ghats which is located in the rain-shadow area.

As a general observation in the world, endemic species are more common on the islands than on the mainland, having been forced to isolate upon the separation of landmasses.

But, being located on a large subcontinent, the Western Ghats makes an exception, as a mainland region containing one of the highest levels of endemism in the world.

About 54% of the 650 tree species, 65% of the amphibians, 62% of the reptiles, and 53% of the fishes are endemic. Of the known invertebrates, 80% of the tiger beetles are endemic.

The Westem Ghats is also home to at least 325 globally threatened species. Of these 325 globally threatened species, there are about 229 plant species, 32 mammal species, 15 avian species, 43 amphibian species, 5 reptilian species, and I fish species.

b) Why hydropower is regarded as the best source of energy? Explain it in detail.

Ans: Hydro is a Greek word, which means water. Hydro electricity is the conversion of the mechanical energy in flowing water into electricity.

Hydro electricity is generated when the force of falling water from dams, rivers or waterfalls is used to turn turbines, which then drives generators that produce electricity.

The energy produced is directed to a substation, where transformers “step up” the voltage before its transmission to the electricity grid.

Hydro is a Greek word, which means water. Hydro electricity is the conversion of the mechanical energy in flowing water into electricity.

Hydro electricity is generated when the force of falling water from dams, rivers or waterfalls is used to turn turbines, which then drives generators that produce electricity.

The energy produced is directed to a substation, where transformers “step up” the voltage before its transmission to the electricity grid.

c) The importance of Biomass has been increasing day by day in our surroundings among renewable resources.Explain it with suitable examples.

Ans: Biomass energy has rapidly become a vital part of the global renewable energy mix and account for an ever-growing share of electric capacity added worldwide.

Renewable energy supplies around one-fifth of the final energy consumption worldwide, counting traditional biomass, large hydropower, and “new” renewables (small hydro, modern biomass, wind, solar, geothermal, and biofuels).

Traditional biomass, primarily for cooking and heating, represents about 13 percent and is growing slowly or even declining in some regions as biomass is used more efficiently or replaced by alternative energy forms.

Some of the recent predictions suggest that biomass energy is likely to make up one third of the total world energy mix by 2050. Infact, biofuel provides around 3% of the world’s fuel for transport.

Biomass energy resources are readily available in rural and urban areas of all countries.

Biomass- based industries can foster rural development, provide employment opportunities and promote biomass re-growth through sustainable land management practices.

The negative aspects of traditional biomass utilization in developing countries can be mitigated by promotion of modem waste-to-energy technologies which provide solid, liquid and gaseous fuels as well as electricity.

Biomass wastes encompass a wide array of materials derived from agricultural, agro-industrial, and timber residues, as well as municipal and industrial wastes.

The most common technique for producing both heat and electrical energy from biomass wastes is direct combustion.

Thermal efficiencies as high as 80-90% can be achieved by advanced gasification technology with greatly reduced atmospheric emissions.

d) How does air pollution affect the atmospheric processes?

Ans: Global warming: There is an imbalance in the gaseous composition of the atmosphere as a result of greenhouse gas emissions. The Earth’s temperature has risen as a result of this.

Global warming refers to an increase in the Earth’s temperature. The melting of glaciers and rising sea levels have resulted as a result of this.

Many parts of the island are completely submerged. Acid rain: Acid rain occur when atmosphere is heavily polluted with nitrogen oxides and sulphur oxides.

The combustion of fossil fuels emits hazardous gases into the atmosphere. When water droplets come into contact with these contaminants, they become acidic and cause acid rain, hamming people, animals, and plants.

Disease: Humans have been detected with various respiratory and cardiovascular diseases as a result of air pollution. Lung cancer has been more common during the previous few decades.

Pneumonia and asthma are common in children who live near polluted environments. Every year, a large number of people die as a result of the direct or indirect impacts of air pollution.

Harmful effect on Animals: Pollutants in the air settle in the water, affecting aquatic life. Pollution also causes animals to leave their natural habitat and relocate.

This causes them to become stray and has resulted in the extinction of several animal species.

Ozone layer Depletion: The main source of ozone layer depletion is the emission of chlorofluorocarbons, halons, and hydrochlorofluorocarbons into the atmosphere.

The ozone layer’s depletion does not protect people from the harmful UV rays of the sun, which cause skin diseases and eye problems.

Harmful effects on plants: A high concentration of pollutants in the atmosphere harms the plants, causing leaf drop, reduced leaf size, and premature ageing, damaging plants, causing leaf spotting, photosynthetic activity to be slowed, and vegetative development to be stifled.

e) What is Disposal of waste? Why segregation of waste is needed?

Ans: Sometimes, wastes are illegally dumped into rivers and canals or used to fill land depressions without proper consultations. These practices cause a lot of problems in the long run.

These can range from the degradation of the soil quality to leaching toxic chemicals into underground water sources.

Therefore, to prevent such scenarios, proper waste disposal methods should be adopted.

Waste disposal means removing, discarding, recycling or destroying unwanted materials called waste that is produced from agriculture, domestic usage or industrial products.

Following the correct methods for waste disposal will ensure lesser pollution and hazards for the environment.

Proper waste management is necessary with steps involving the proper collection of waste and scientific treatments that may contribute less to water pollution, soil pollution and air pollution.

Wastes can be of numerous types and much of the waste generated today is non-biodegradable waste. Globalization and industrialization have contributed to this hugely.

The dumps with harmful substances in the waste can release toxic fumes and smoke.

Therefore, the correct disposal for the particular kind of waste is necessary, for example burning all kinds of wastes may lead to the above problem and cause harm to bodies.

Also, dumping into rivers and filling land depressions without proper administration is not encouraged.

Wastes including plastics, batteries, sanitary and oil products should be properly disposed of. Doing so may result in a hazardous environment and a polluted atmosphere.

Q 3. Explain the human-environment relationship by taking examples of biotic and abiotic components?

Ans: In general, abiotic factors like rock, soil, and water interact with biotic factors in the form of providing nutrients.

The water, phosphorus, nitrogen, and carbon cycles are examples of this. Another way biotic and abiotic factors interact is that biotic factors often change the geology and geography of an area.

The linkages between humans and the entire ecological unit are referred to as human-environment interaction.

Human social systems and their surroundings are complex adaptive systems. They’re complicated because environmental units and human social systems contain many elements and connections.

The feedback systems that support survival in a constantly changing environment are responsible for adaptiveness.

Types of Human Interaction

Depending on the environment : Every living thing in this world is reliant on the environment in which it exists. Living organisms cannot survive without interaction, whether for air, water, food, or shelter.

On the other hand, humans have expanded to the point where someone living in Boston may be reliant on the environment in Central America for particular foods or on minerals mined in China for electronics.

Essentially, everything you see is entirely reliant on environmental resources that originate thousands of miles away.

Modification of the environment : Human actions frequently cause environmental change, which can have beneficial and harmful consequences.

Even the most environmentally friendly farming methods and renewable energy projects require natural resources.

Humans consume a growing quantity of land to construct homes, shopping malls, and schools. When it gets colder, we bum coal, wood, and oil that we all acquire from our environment.

Adaptation to the environment : People live in the oddest areas, partly due to evolutionary achievements. The better a species adapts to changes in its environment, the more likely it is to survive.

You can see how much we’ve adapted to our natural habitat by looking for individuals living above the arctic circle, in dense wildernesses, and dry savannahs.


Natural resource utilization : People use various natural resources in their daily lives, including lumber, metals, and oil.

There is also a reliance on food and water to survive. People use energy for various reasons, including domestic cooking and industrial purposes.

Clothing, transportation services, building, technological devices, and other commonly used things all require different resources to be manufactured.

Natural resource demand continues to rise as the world’s population grows, and per capita consumption increases with socio-economic progress natural resource depletion due to extraction and exploitation, particularly concems for nonrenewable resources.

Deforestation : Deforestation is a problematic situation that arises due to the overuse of natural resources and represents human-environmental interaction. When forests are cleared, the trees are not restored or regrown.

Ethiopia, Mexico, Brazil, America, Congo, and India have removed a large portion of their forests for economic and agricultural objectives to meet food, fuel, and construction material demands.

These operations have resulted in a continuous loss of forestland, which is currently occurring. Deforestation has a slew of negative consequences.

For starters, they are home to a diverse range of trees, plants, and creatures, ranging from tiny insects to birds, mammals, and reptiles.

Converting forests to agricultural lands reduces biodiversity, which is essential for humans because they rely on other living organisms to provide a variety of needs, including:

Food: It is obtained from plants such as wheat, rice, maize, and animals like fish, poultry, and Cows.

Water Resources : The utilization of water resources is a strong indicator of human interaction with the environment. Water is used for various purposes, including home, agricultural, and industrial processes.

In different places of the cosmos, the relative quantities of the three groupings differ. On the other hand, agriculture consumes the most significant amount of water.

Water demand is increasing, resulting in unsustainable usage of water resources.
Water is refilled when it is recycled; however, extracting large amounts of water from water bodies for home, agricultural, or industrial purposes reduces the amount of water available for current and future generations.

Q 4. “As humans civilisation progressed, man started altering the environment in the pursuit of creating an economic, social and cultural environment of his own choice. This slowly resulted in the depletion of natural resources and degradation of environment.” Explain it in context of national legislations of water acts?

Ans: The Parliament recognizing the importance of water free from pollution enacted the Water (Prevention and Control) of Pollution Act in 1974 (Water Act, 1974).

This Act was enacted to ensure the wholesomeness of water and to ensure that with industrialization and growth of cities domestic and industrial effluents and waste waters are not thrown into the streams and rivers without being treated first.

For these purposes the act also envisages the creation of a Central Pollution Control Board and the State Pollution Control Boards in the States.

Although the main legislation dealing with water pollution is the Water Act, 1974, most of the litigations have been filed under the general criminal law or under Articles 32 and 226 of Constitution of India.

In the period between 1980 to 1990, there has been a massive increase in pollution related litigations.

In fact, just from 1990 to 1993, upto thirteen judgements have been delivered by different courts on this issue.

And a number of prosecutions against polluting industries have been launched under Section 33 of the Water Act.

The awareness and consideration for environment covers several environmental issues such as pollution of water, air and soil, land degradation, industrialization, urbanization, depletion of natural resources etc.

Environmental Law plays a very crucial and important role in regulating the use of natural resources and in protecting the environment.

The success of environmental legislations mainly depends on the way they are enforced. Legislation also serves as a valuable tool for educating masses about their responsibility in maintaining healthy environment.

Numerous legislations have already been put forth at national and international levels.

In this lesson, you will learn about some important environmental legislations. Indian legislations are called Acts where as the international legislations are in the form of conventions, protocols and treaties.

The genesis of various legislations in the country lies in the environmental problems. There should be effective legislations to protect the environment or else the need for resources by the growing population will create havoc on the environment.

The other important aspect At national level serious efforts have been made for the improvement and protection of environment by incorporating changes the constitution of India.

Our constitution, originally, did not contain any direct provision regarding the protection of natural environment.

However, after the United Nations Conference on Human Environment, held in Stockholm in 1972. Indian constitution was amended to include protection of the environment as a constitutional mandate.

Although India had an Elephant’s Preservation Act of 1879 and a Forest Act of 1927, environment related legislation came very late in 1972 with Wild Life Protection Act 1971.

As we all know, India is one of the twelve mega diversity countries. There are innumerable species, whose potential is not even known till date.

Biodiversity has direct consumption value in agriculture, medicine and industry apart from it being a nations’ wealth. There is constitutional provision in India for biodiversity conservation.

The forty second amendment Clause (g) to Article 51A of the Indian constitution made it a fundamental duty to protect and improve the natural environment.

“It shall to be duty of every citizen of India to protect and improve the natural environment including forests, lakes, rivers and wild life and have compassion for living creatures.”

There is a directive, given to the State as one of the Directive Principles of State Policy regarding the protection and improvement of the environment.

Article 48A states “The State shall endeavour to protect and improve the environment and to safeguard the forests and wildlife of the country”.

The department of Environment was established in India in 1980 to ensure a healthy environment for the country.

This later became the Ministry of Environment and Forests in 1985. This Ministry has overall responsibility for administering and enforcing environmental legislations and policies.

The constitutional provisions are backed by a number of legislations – Acts and rules. Most of our environmental legislations are Acts of the Parliament or the State Legislatures.

These Acts generally delegate powers to regulating agencies, to make rules for the purpose of their implementation.

The Environment Protection Act of 1986 (EPA) came into force soon after the Bhopal Gas Tragedy and is considered umbrella legislation as it fills many lacunae in the existing legislations.

Thereafter, a large number of environmental legislations have been passed to deal with specific environmental problems.

For example in the recent past the use of CNG for public transport vehicles has been made mandatory in Delhi. This has reduced air pollution in Delhi.

Q 5. “Biosphere reserves are internationally recognised areas established to promote and demonstrate a balanced relationship between Humans and the Biosphere.” Elaborate this statement in the context of conservation of nature?

Ans: Biosphere Reserves (BRS) are representative parts of natural and cultural landscapes extending over large area of terrestrial or coastal/marine ecosystems or a combination thereof and representative examples of bio-geographic zones/provinces.

Criteria for designation of BR

A site that must contain an effectively protected and minimally disturbed core area of value of nature conservation.

The core area should be typical of a bio-geographical unit and large enough to sustain viable populations representing all trophic levels in the ecosystem.

The management authority to ensure the involvement/cooperation of local communities to bring variety of knowledge and experiences to link biodiversity conservation and socio-economic development while managing and containing the conflicts.

Areas potential for preservation of traditional tribal or rural modes of living for harmonious use of environment.

International Status of Biosphere Reserves (BR)

The UNESCO has introduced the designation Biosphere Reserve for natural areas to minimize conflict between development and conservation.

BRS are nominated by national government which meet a minimal set of criteria and adhere to minimal set of conditions for inclusion in the world network of Biosphere reserves under the Man and Biosphere Reserve Programme of UNESCO.

Globally 621 BRS representing from 117 countries included in the network so far. Structure and functions of BR:

Biosphere reserves are demarcated into following 3 inter-related zones:

Core Zone

Core zone must contain suitable habitat for numerous plant and animal species, including higher order predators and may contain centres of endemism.

Core areas often conserve the wild relatives of economic species and also represent important genetic reservoirs having exceptional scientific interest.

A core zone being National Park or Sanctuary/protected regulated mostly under the Wildlife (Protection) Act, 1972.

Whilst realizing that perturbation is an ingredient of ecosystem functioning, the core zone is to be kept free from 1 human pressures external to the system. Buffer Zone

The buffer zone, adjoins or surrounds core zone, uses and activities are managed in this area in the ways that help in protection of core zone in its natural condition.

These uses and activities include restoration, demonstration sites for enhancing value addition to the resources, limited recreation, tourism, fishing, grazing, etc; which are permitted to reduce its effect on core zone. Research and educational activities are to be encouraged.

Human activities, if natural within BR, are likely to continue if these do not adversely affect the ecological diversity.

Transition Zone

The transition area is the outermost part of a biosphere reserve. This is usually not delimited one and is a zone of cooperation where conservation knowledge and management skills are applied and uses are managed in harmony with the purpose of the biosphere reserve.

This includes settlements, crop lands, managed forests and area for intensive recreation and other economic uses characteristics of the region.

Importance of Biosphere Reserves

The importance of biosphere reserves is mentioned below:
Conservation Biosphere reserves conserve the species, ecosystems, genetic diversities, and landscapes without affecting the inhabitants.

Development It ensures sustainable developments including economic, cultural, social and economic developments.

Restoration The biosphere reserves restore any damage caused to the ecosystems and habitats.

Education and Research

These areas provide a lot of information on how to restore, conserve, and develop the ecosystem.

The researches provide ways to recreate landscapes that have been affected by human activities.

Land Use Planning

All the landowners, public institutions, farmers, scientists, industry, and conservation groups found in these areas can work together to look for comprehensive land management.

Healthy Ecosystems They help in maintaining healthy ecosystems by preventing soil erosion, protecting water springs, and maintaining the decomposers to maintain the soil quality.

Thus, we know that biosphere reserves are a great source for biodiversity conservation


Q 6. Explain the following terms in about 60 words each:

(a) Seed Bank

Ans: A seed bank is a place where seeds are stored to preserve genetic diversity for the future. They are usually flood, bomb and radiation-proof vaults holding jars of seeds from different plant species.

The seeds are typically kept at low humidity and in cold conditions – around -20°C. This helps to preserve the seeds, ensuring they can still grow when they are needed later.

More than 1,000 seed banks exist around the world, varying in type, size and focus. The largest in the world is the Millennium Seed Bank in Sussex, managed and coordinated by the Royal Botanic Gardens, Kew.

It opened in 2000 and holds seeds from almost 40,000 species around the world, including nearly all the UK’s native trees and plants.

(b) Incineration

Ans: Incineration is the destruction of something, especially waste material, by burning.

Incineration is a waste treatment process that involves the combustion of organic substances contained in waste materials.

Incineration of waste materials converts the waste into ash, flue gas and heat. Incineration is a method of waste disposal where trash is burned.

It is basically the destruction of waste. Trash is burned because it generates energy which is used for many different purposes.

Industrial plants for waste incineration are called waste-to-energy facilities. The energy is then burned and created into steam and then into electricity. This has a very similar process to coal and oil combustion.

(c) Biological Oxygen Demand

Ans: BOD, also called biological oxygen demand, is the amount of dissolved oxygen needed (i.e., demanded) by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.

The dissolved oxygen that microorganisms like bacteria need to oxidize, and organic substances in water, are referred to as BOD.

It is a metric for determining the quality of water.

Biological oxygen demand is significant for water quality.
Because it provides an index for determining the environmental impact of released effluent.

BOD is often used to remediate wastewater.

Because the breakdown of organic waste by microorganisms is a common treatment method. The amount of dissolved oxygen in streams and rivers is affected by biological oxygen demand.

Temperature, pH, microbes, organic, and inorganic elements all influence the rate of oxygen consumption.

Higher types of aquatic life consume less oxygen.
The effects of a high BOD are similar to those of a low dissolved oxygen level.

(d) Public Health

Ans: Public health is the science of protecting and improving the health of people and their communities.

This work is achieved by promoting healthy lifestyles, researching disease and injury prevention, and detecting, preventing and responding to infectious diseases.

Overall, public health is concerned with protecting the health of entire populations. These populations can be as small as a local neighborhood, or as big as an entire country or region of the world.

Public health professionals try to prevent problems from happening or recurring through implementing educational programs, recommending policies, administering services and conducting research- in contrast to clinical professionals like doctors and nurses, who focus primarily on treating individuals after they become sick or injured. Public health also works to limit health disparities.

A large part of public health is promoting health care equity, quality and accessibility.

Q 7. Answer the following questions in about 150 words each.

(a) What is lentic and lotic ecosystem? Explain these two with suitable examples.

Ans: Lentic systems, coming from the Latin term Lentus, means the aquatic system is moving very slowly, so slowly that the water appears to be motionless or nearly so.

If you’ve ever seen a pond, lake, or wetland, you’ve witnessed a lentic system! Typically, there is a lower species diversity here as well, but that doesn’t mean they aren’t present! You might see an aquatic sow bug (Isopoda, Asellidae) or a crane fly (Tipulidae).

Take a look in your local pond and see what critters are moving about! Lotic systems, coming from Lotus, are much faster flowing and you can visibly see the running water.

As mentioned before in one of our previous posts, fast moving waters which can be riffles can scour away at the surrounding landscape, much more as compared to lentic systems.

Lotic systems include rivers, streams and creeks and typically have a higher species diversity.

However, critters that like here must be able to hold on tight as the forces of the water is constantly acting upon them.

Some invertebrates have the ability to cement themselves onto a rock as to not be swept downriver, like black flies (Simuliidae), whereas others use it to their advantage by creating a net, catching any food which is swept up in the current like net-spinning caddisflies (Hydropsychidae).

A lentic aquatic body can be divided into four major zones, each of which has its own characteristics.

The zone around the margins of the aquatic body which consists of shallow waters is known as the Littoral zone.

Plenty of light is available and rooted plants grow in this zone only. Limnetic zone is the zone of open waters which are deeper as well.

1. There is a continuous uni-directional flow in a lotic system. The water usually flows in narrow channels which are not so deep as compared to lakes. It contains water derived from diverse sources.

The bottom of a lotic body continuously adds and receives materials from the mass of water above.

2) The volume of water keeps changing which in turn brings about changes in the velocity of water currents. The water levels in a lotic system also exhibit a wide range of fluctuations.

3) Water in a lotic system acts as an effective agent of transfer, transport and dilution. They keep eroding materials all along their channels and depositing them elsewhere.

Some examples of lotic ecosystems are any ecosystem that presents moving water, such as rivers, streams, springs, streams, and canals.

These are the different examples of lentic ecosystems that we find in nature:
Lakes and lagoons

They are the most representative lentic ecosystems and have a medium-large extension, as well as a depth that reaches 2,000 meters in some deep lakes.
Wetlands and swamps

Both are characterized by being very shallow, which is directly related to the large number of plant species they house, as well as amphibians and reptiles

(b) What is ecological succession? Explain the types of succession with suitable diagrams.

Ans: Ecological succession is the process by which the mix of species and habitat in an area changes over time.

Gradually, these communities replace one another until a “climax community”-like a mature forest is reached, or until a disturbance, like a fire, occurs.

Ecological succession is a fundamental concept in ecology. The ultimate aim of this process is to reach equilibrium in the ecosystem.

The community that achieves this aim is called a climax community. In an attempt to reach this equilibrium, some species increase in number while some others decrease.

In an area, the sequence of communities that undergo changes is called sere. Thus, each community that changes is called a seral stage or seral community.

All the communities that we observe today around us have undergone succession over a period of time since their existence.

Thus, we can say that evolution is a process that has taken place simultaneously with that of ecological succession. Also, the initiation of life on earth can be considered to be a result of this succession process.

If we consider an area where life starts from scratch through the process of succession, it is known as primary succession.

However, if life starts at a place after the area has lost all the life forms existing there, the process is called secondary succession.

It is obvious that primary succession is a rather slow process as life has to start from nothing whereas secondary succession is faster because it starts at a place which had already supported life before.

Moreover, the first species that comes into existence during primary succession is known as the pioneer species.


Primary succession happens when a new patch of land is created or exposed for the first time.

This can happen, for example, when lava cools and creates new rocks, or when a glacier retreats and exposes rocks without any soil.

During primary succession, organisms must start from scratch. First, lichens might attach themselves to rocks, and a few small plants able to live without much soil might appear. These are known as “pioneer species.”

Secondary succession happens when a climax community or intermediate community is impacted by a disturbance.

This restarts the cycle of succession, but not back to the beginning-soil and nutrients are still present.

For example, after a forest fire that kills all the mature trees on a particular landscape, grasses might grow, followed by shrubs and a variety of tree species, until eventually the community that existed before the fire is present again.

A climax community will persist in a given location until a disturbance occurs. However, in many ecosystems, disturbance occurs frequently enough that a matrix of community types may be consistently present on the landscape.

For example, in an area prone to wildfires like the western U.S., mature forests may exist near grassy meadows with fewer, scattered trees.

Consistent disturbance and variation in factors like water and nutrient availability over the course of decades thus allows many plant and animal communities to thrive within a particular climatic and geographic niche-not just those adapted to the absence of disturbance seen in climax communities.

(c) Explain the biocentrism and ecocentrism in context of human’s attitude towards nature?

Ans: Biocentrism is the environmental ethical belief that all living organisms must be allowed to pursue their own good, in the sense that each individual is pursuing a unique path for their own good in their own way.

This may mean a tree pursuing growth or a snake pursuing food or reproduction. Every life is equal, deserves to be valued equally, and should be treated with the same respect.

Ecocentrism can be defined as a philosophy that emphasizes the intrinsic value of all living organisms as well as their natural environment.

Ecocentrism seeks to deemphasize the importance of humans and promote the importance of plants, animals, microorganisms, water, soil, air, and more.

it stands in direct contrast with anthropocentrism, a philosophy that regards humans as the most important species.

It also stands in contrast with some more common environmental philosophies, including zoocentrism, which emphasizes animals, and biocentrism, which emphasizes living things but does not place as much value on non-living components of the environment.

The term “ecocentric” was coined by Aldo Leopold, dating back to his 1949 book, A Sand County Almanac: And Sketches Here and There.

The philosophy shares many similarities with the “deep ecology” movement begun in the 1980s by Arne Naess and George Sessions.

The main characteristics of the ecocentric ideology include placing value on the entire ecosphere, de- emphasizing the value of humans, and recognizing the importance of planet Earth as a whole.

Adopting an ecocentric worldview would mean many changes for society, including shrinking the human population, abandoning fossil fuels as a main energy source, adopting a more humane food system, and lowering the human standard of living.

Ecocentrism Examples
However, ecocentric policies do not need to be so grandiose. There are many examples of ecocentrism in the world today.

Typically, these are environmental policies that have the primary goal of protecting nature rather than serving humans.

The following are a few examples: Conservation Land &emdash; In the the United States, the first examples of conservation land can be traced back to the 19th century and the creation of Yellowstone National Park.

In order to meet the definition of “ecocentric,” conservation lands must be created to protect ecosystems, rather than simply to provide pretty hiking routes.

All over the world, many national parks and protected areas have begun to adopt this approach, limiting visitors and prioritizing environmental protection.

Protected Reefs The protection of coral reefs can be seen as an example of ecocentrism. Many protected reefs, and even man-made reefs, are lightly tread or entirely unvisited.

However, in order to be truly ecocentric, the reef’s protection must be driven by a desire to improve the ecosystem.

Protecting a reef to promote tourism or even to protect a coastline from storms would fall into the category of anthropocentrism.

Biocentrism examples:
Biocentrism does not value other living things for their usefulness to humans, but rather, believes that every living thing has an intrinsic, inherent value. This leads to an argument against harming other living things.

One example of biocentrism is vegetarianism or veganism. While an anthropocentric viewpoint (one in which humans are considered of higher moral value) considers it acceptable for humans to take the life of another animal in order to feed themselves, a biocentric one argues that because all living things are valued equally.

(d) Define natural calamities and its types with suitable examples.

Ans: Natural calamities are the calamities which are inflicted by God, or Nature, or man and his world. At these calamities, the unseen hand wreaks havoc in the part of the world it chooses to act upon.

On these natural activities of nature no scientific or technological developments can wield any control.

They can occur as and when and where ordains it. Natural calamities can be of many different kinds, but the similarly in all, is their massive destruction in the area of their occurrence.

The natural disasters are of many kinds, they are drought and famine, flood, earthquake, hailstrom and a cyclone.

Types of Natural Calamities:
Different natural, calamities can be distinguished from each other in terms of their nature and extent of their impact.

Calamities like: earthquakes, hailstorms, avalanches, landslides, etc., occur quite suddenly but they are restricted in their impact in terms of time and space.

Similarly, though floods and cyclones occur with some element of warning yet their occurrence is confined in duration.

Drought, on the other hand, spans over a much longer time-frame and its adverse impact on the economic activities and life of an area is of a more lasting nature.

The measures required to meet the threats posed by different calamities, therefore, differ considerably in terms of disaster preparedness and amelioration of the economic and social life of the affected people.

Major and Minor Calamities:

Natural calamities may be broadly grouped into major and minor types depending upon their potential to cause damage to human life and property.

While natural calamities like: earth quakes, droughts, floods and cyclones could be regarded as major, hailstorms, avalanches, landslides, fire accidents, etc.

Whose impact is localized and intensity of the damage is much less can be categorized as minor calamities.

Minor calamities like: hailstorms, avalanches, landslides and fires also occur without any appreciable degree of forewarning and cause damage to properties and lives.

However, areas prone to such disasters also could be identified and certain precautionary measures taken in the context of potential threat requiring general awareness and an ability to relate to a predefined system of appropriate responses on the part of the local administration.

Q 8. Explain the causes of ozone depletion? How do ultraviolet rays affects human health, animals, plants, micro-organisms, water and air quality.

Ans: Causes of Ozone Depletion
Depletion of the ozone layer is a serious worry that is linked to a variety of reasons. The following are the primary reasons for ozone layer depletion:

Natural Causes
Certain natural factors, such as sunspots and stratospheric winds, have been discovered to degrade the ozone layer. However, it only accounts for 1-2 percent of ozone layer loss. Volcanic eruptions are also contributing to the ozone layer’s depletion.

CFCs, or chlorofluorocarbons, are the primary cause of ozone layer loss. Solvents, spray aerosols, refrigerators, air conditioners, and other appliances emit these.

The UV radiations break down chlorofluorocarbon molecules in the stratosphere, releasing chlorine atoms. These atoms react with and destroy ozone.

Nitrogenous Compounds
Nitrogenous Compounds are compounds that contain nitrogen. Nitrogenous chemicals such as NO2, NO, and N20 are major contributors to ozone depletion.

Unregulated Rocket Launches According to studies, unregulated rocket launches deplete the ozone layer far more than CFCs do. If not regulated, this might lead to a significant depletion of the ozone layer by the year 2050.

ultraviolet rays affects human health, animals, plants, micro-organisms, water and air quality:

Reductions in the ozone layer due to human-created pollution increase the amount of UVA and UVB that reaches the surface.

This can impact human health, animals, marine organisms and plant life. In humans, increased UV exposure can cause skin cancers, cataracts and immune system damage.

Skin Cancer
Each year, more new cases of skin cancer are diagnosed in the U.S. than new cases of breast, prostate, lung, and colon cancer combined. One in five Americans will develop skin cancer in their lifetime.

One American dies from skin cancer every hour. Unprotected exposure to UV radiation is the most preventable risk factor for skin cancer.

Melanoma, the most serious form of skin cancer, is now one of the most common cancers among adolescents and young adults ages 15-29.

While melanoma accounts for about three percent of skin cancer cases, it causes more than 75 percent of skin cancer deaths. UV exposure and sunburns, particularly during childhood, are risk factors for the disease.

Not all melanomas are exclusively sun-related-other possible influences include genetic factors and immune system deficiencies.

Immune Suppression
Scientists have found that overexposure to UV radiation may suppress proper functioning of the body’s immune system and the skin’s natural defenses.

For example, the skin normally mounts a defense against foreign invaders such as cancers and infections.

But overexposure to UV radiation can weaken the immune system, reducing the skin’s ability to protect against these invaders. Effects on plants:

With regard to plants, UV-B impairs photosynthesis in many species. Overexposure to UV-B reduces size, productivity, and quality in many of the crop plant species that have been studied (among them, many varieties of rice, soybeans, winter wheat, cotton, and com).

Similarly, overexposure to UV-B impairs the productivity of phytoplankton in aquatic ecosystems. UV-B increases plants’ susceptibility to disease.

Scientists have found it affects enzyme reactions that conduct fundamental biological functions, it impairs cellular division in developing sea urchin eggs, and it changes the movements and orientation of tiny organisms as they move through ocean waters.

Since some species are more vulnerable to UV-B than others, an increase in UV-B exposure has the potential to cause a shift in species composition and diversity in various ecosystems.

Because UV-B affects organisms that move nutrients and energy through the biosphere, we can expect changes in their activities to alter biogeochemical cycles

Q 9. “Education for environmental awareness is essential for the younger generation as well as for the older generation.” Explain the statement with suitable examples.

Ans: Environmental Education imparts knowledge about the current situation and future prospects of nature. It teaches people to explore all the problems related to environment, and engage in wise ways of preserving it.

A number of schools have taken the initiative to provide practical as well as theoretical knowledge about the impact of human activities on Nature.

They take students out of the four walls of a classroom and make them do activities like gardening, watering plants, meditation in community parks etc. Education is the only way to make the best minds work productively.

In this era, the natural world is under threat. Different species of Flora and Fauna are on the verge of extinction, the air we breathe, the water we drink, the food we eat – everything is polluted or has contaminants.

By including Environmental studies as a subject in schools, as well as in higher education, we can make coming generations more sensitized and encourage them to find innovative solutions and methods for the way ahead, in order to protect nature.

Both physical and mental health get affected with a depletion of the environment. These can instead flourish if we come more in contact with Nature.

One of the best benefits of this type of education is that it takes place outside the confines of a classroom.

Students, who would not have otherwise spent this time outdoors, experience serenity and the healing powers of nature. In fact, treatment through natural means is called Eco-therapy.

It helps patients recover from depression, cures heart ailments, maintains Blood Pressure, sleep longevity, improves eyesight etc. It’s a no hidden fact that a person who remains closest to nature is likely to stay healthier.

Places with natural surroundings are best for artists to create their masterpieces. Poetry, painting, sculptures etc are all products of imagination, inspired by nature quote from the cult film Dead Poets Society says
“Medicine, law, engineering, these are the noble pursuits, necessary to sustain life but poetry, romance, love, beauty, these are what we stay alive for”.

Such creative work, more often than not, are the products of nature. Environmental education can make people recognize the hidden artist within them.

Environmental education makes people understand the importance of renewable energy. Non renewable sources of energy like petrol, diesel etc are the major sources of the world’s pollution.

Using renewable sources like solar energy, wind energy etc is encouraged Environment Education, and is imperative in our fight against global warming.

Q 10. “Water Harvesting is one of the effective measures to combat drought.” Explain this statement with suitable arguments.

Ans: Rainwater harvesting is the process of collecting rain when it falls for use when it doesn’t.

Used for centuries as a method of water conservation, rainwater harvesting involves setting out large barrels or cisterns that can collect rain for later use.

This fuels potable or non-potable water processes such as watering plants, washing cars, flushing toilets, cooking, or showering.

This can greatly help drought regions. Rainwater harvesting is an important source of local water supply in the context of global water and environmental challenge.

Nevertheless, the viability and safety of rainwater harvesting is often contested by water and health authorities.

Similar to all water supplies, rainwater harvesting systems should be appropriately designed and managed for their intended end uses.

While rain barrels are a good start in saving rainwater for future reuse, modem methodologies from the pond world have improved on the standard above-ground water tank by offering underground solutions.

The process of rainwater harvesting involves the collection and the storage of rainwater with the help of artificially designed systems that run off naturally or man- made catchment areas like- the rooftop, compounds, rock surface, hill slopes, artificially repaired impervious or semi-pervious land surface. The benefits of the rainwater harvesting system are listed below.

. Less cost.
. Helps in reducing the water bill.

  • Decreases the demand for water.
  • Reduces the need for imported water.
  • Promotes both water and energy conservation.
    . Improves the quality and quantity of groundwater.
    . Does not require a filtration system for landscape irrigation.

This technology is relatively simple, easy to install and operate.
It reduces soil erosion, stormwater runoff, flooding, and pollution of surface water with fertilizers, pesticides, metals and other sediments.

It is an excellent source of water for landscape irrigation with no chemicals, dissolved salts and free from all minerals.

Rainwater harvesting is a sustainable process that helps in preserving water for future needs. Water scarcity is a major concern in today’s scenario. The process of rainwater harvesting is a good way to conserve water.

Rainwater harvesting is the process of accumulation and storage of rainwater for reuse rather than allowing it to runoff.

The rainwater harvesting system is one of the best methods practised and followed to support the conservation of water.

Today, scarcity of good quality water has become a significant cause of concern. However, rainwater, which is pure and of good quality, can be used for inigation, washing, cleaning, bathing, cooking and also for other livestock requirements.


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