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Biodiversity for Sustenance of Mankind: NBSE Class 12 Env
Get summaries, questions, answers, solutions, notes, extras, PDF and guides for Chapter 2 Biodiversity for Sustenance of Mankind: NBSE Class 12 Environment (Environmental Education) textbook, which is part of the syllabus of students studying under the Nagaland Board. These solutions, however, should only be treated as references and can be modified/changed.
If you notice any errors in the notes, please mention them in the comments
Summary
Nature maintains a balance. Living things are connected through food chains and food webs, where food and energy pass between them. As energy moves up each step, or trophic level, some is lost. This means higher levels support fewer individuals. Isaac Newton first explained this balance.
Energy and materials flow continuously. Plants, called producers, make food using sunlight, air, and water. Herbivores eat plants, and carnivores eat other animals; these are consumers. When organisms die, decomposers like bacteria and fungi break them down, returning nutrients to the soil for new plants. This cycle keeps nature balanced. Biodiversity, meaning many different kinds of life, is key to this balance. Human activities, however, can disrupt it. As human population and needs grow, nature faces pressure.
Biodiversity is vital for human survival and well-being. It provides basic needs like food, shelter, clothing, and medicines. Many traditional medicines come from plants and animals. For food security, having diverse crops is important. If only one crop type is grown and it gets a disease, much food can be lost. Wild plant relatives have helped save food supplies.
Biodiversity also gives us wood. Fisheries, rich in diverse water life, provide food globally. Nature offers unseen services too. Species depend on each other. A single tree can be a home, clean air, and hold soil. People enjoy nature’s beauty through parks and wildlife watching.
Cultural and religious values also help protect certain plants and animals. We can choose to save nature now for future use. Genetic variety within species is a resource for better crops and new medicines. Nature also helps control pollution, as some organisms clean air, water, and soil.
Using too many resources creates problems. Overpopulation and rising demands lead to resource limitations, meaning not enough for everyone or for nature to recover. Large projects, mining, and converting natural areas to farms or cities destroy biodiversity-rich places. Pollution also harms life. Forest destruction and habitat damage cause species to disappear. This loss of biodiversity can increase poverty and natural disasters. Taking steps to protect biodiversity is necessary.
Textbook solutions
Short Answer Questions
1. Define the term ‘Trophic Level’.
Answer: The term ‘Trophic Level’ refers to the position occupied by each species in a food chain. Trophic levels are also described as steps or divisions of a food chain and are characterised by the method of obtaining food. The number of trophic levels coincides with the number of species in a food chain.
2. Who has given the concept of balance in nature?
Answer: The concept of balance in nature was given for the first time by Issac Newton, who explained it in terms of thermodynamic laws.
3. What do you understand by interaction between living and non-living components?
Answer: I understand that the interaction between living and non-living components means there is a continuous interaction between the living and non-living matter of the environment. For example, green plants or producers make their own food with the help of the physical environment like sunlight, CO2, and water.
4. Why are herbivores and carnivores grouped under consumers?
Answer: Herbivores and carnivores are grouped under consumers because herbivores and other consumers take food from green plants. Higher-level consumers, in turn, take herbivores and other consumers as their food. This process of obtaining food from other organisms categorizes them as consumers.
5. What is option value?
Answer: Option value means that as biodiversity exists in nature, we always have the option of paying now for the future use of nature. For example, we can establish a national park so that we can use and enjoy it later.
Long Answer Questions
1. How is balance in nature maintained with the help of biotic factors? Explain.
Answer: Nature has its own way to keep balance in itself, and this balance is significantly maintained with the help of biotic factors. There is a link between different species in a community made by the pathway of food chains. In the living world, food and energy are passed between species through food chains and food webs. There is a continuous flow of energy and matter from one trophic level to another. Simultaneously, there is a continuous interaction between the living and non-living matter of the environment. For example, green plants or producers, which are biotic factors, make their own food with the help of the physical environment like sunlight, CO2, and water. Herbivores and other consumers, also biotic factors, take food from green plants. Higher-level consumers, in turn, take herbivores and other consumers as their food. After the death of animals and plants, these are decomposed by bacteria and fungi, which are biotic decomposers, thereby increasing soil fertility. Plants again use these minerals when they grow in soil. This continuous flow of food, minerals, and energy throughout nature, facilitated by these biotic interactions, keeps balance in it. In other words, it can be said that biodiversity itself, which encompasses all biotic factors, maintains a balance in nature.
2. How is aesthetic pleasure related with biodiversity?
Answer: Aesthetic pleasure is closely related to biodiversity. The number of people who visit a natural site is an indication of its aesthetic value. For example, lakhs of people visit Sanjay Gandhi National Park, on the outskirts of Mumbai every year, drawn by its natural beauty. Each species and ecosystem, which are components of biodiversity, provides richness and beauty to life on Earth. Millions of people derive aesthetic pleasure from enjoying activities such as camping, picnics, fishing, wildlife watching, and other recreational activities that are based on nature and its diverse life forms. Therefore, the diversity of life contributes significantly to the aesthetic experiences and enjoyment of people.
3. How is human survival related to biodiversity?
Answer: Human survival is related to biodiversity because biodiversity touches almost every aspect of our life, and its degeneration would mean a threat to the survival and sustenance of mankind. The most important value of biodiversity, particularly in developing countries like India, is that it meets basic survival needs of a vast number of people. Man cannot survive without biodiversity. Some traditional communities even today depend wholly or partially on the surrounding natural resources for their day-to-day needs of shelter, clothing, medicines, fertilisers, etc.
4. Describe the decomposition process in nature.
Answer: The decomposition process in nature occurs after the death of animals and plants. These are decomposed by bacteria and fungi, which increases soil fertility. Plants again use these minerals when they grow in soil. This continuous flow of food, minerals, and energy throughout nature, facilitated by decomposition, helps keep balance in it.
5. How is health and healing dependent on biodiversity?
Answer: Most of the people in developing countries depend on traditional methods for primary health care, most of which is derived from plants and some from animal and mineral sources. Nearly one-fourth of all prescription drugs used in the developed world are based on plants, some of which are indispensable like Aspirin from the plant Filipendula ulmaria and quinine from the bark of cinchona tree. Some medicinal plants and animals and their uses include Rauwolfia for hypertension, Cinchona bark for malaria treatment, Poppy plant as an analgesic, Rosy periwinkle plant as an anti-cancer drug, Penicillin as an antibiotic, and Foxglove plant as a heart stimulant. From animal sources, Bacterium provides antibiotics, Blowfly larva is a wound healer, and Sparge is used for leukaemia cure. Today, medical science is also progressing fast by utilising genetic resources, and vaccines and medicines are being produced by genetic engineering.
6. What do you know about resource limitation?
Answer: Major causes of biodiversity loss can be traced, directly or indirectly to the growing demands leading to resource limitations. A few of the factors responsible for this are overpopulation, growing demands, and unplanned development. The human overpopulation has put pressure on biodiversity. Greater demand for food and land, excessive consumption of minerals and other non-renewable resources, and high overuse and waste of energy have aggravated the problem which ultimately resulted in resource limitation.
Some of the main reasons behind resource limitations are:
- Large-scale development projects have contributed substantially to the loss of biodiversity-rich areas.
- The enormous demand for minerals in a rapidly industrialising economy has resulted in large-scale deforestation for mining purposes.
- Large areas rich in biodiversity have been reduced to small pockets due to their conversion to agricultural land or for construction of roads and housing.
- In the last few decades, changing market forces and the increase in demand for food have prompted farmers to change their traditional agricultural practices.
- Pollution of soil, water, and air affects the functioning of ecosystems and may reduce or eliminate sensitive species. For instance, in India, industrial effluents are destroying coral reefs and other marine life.
- Fresh water fish species are threatened because dams and water withdrawals have radically altered river systems.
Resource limitations can be broadly categorised as biological resource limitation, land resource limitation, water resource limitation, and mineral resource limitation. Biological resource limitation is generally associated with extinction of species, with the main reason behind it being the destruction of forests and degradation of habitat. These bring changes in the availability of food and space for normal growth, breeding habit, and movement in animals, thus posing a great threat to them. Land resource limitation is mostly associated with land use pattern; growing demand and modern agronomic practices along with industrialisation pose a great threat to land. Similarly, excessive use of water and minerals and pollution of water through human activities are also the reasons behind these resource limitations.
Think and Answer
Q. Is there any direct relationship between resource limitation and human activity?
Answer: Yes, there is a direct relationship between resource limitation and human activity. Major causes of biodiversity loss can be traced, directly or indirectly, to the growing demands of humans leading to resource limitations. Factors such as overpopulation, growing demands, and unplanned development are responsible for this. Human overpopulation has put pressure on biodiversity. Greater demand for food and land, excessive consumption of minerals and other non-renewable resources, and high overuse and waste of energy by humans have aggravated the problem, which ultimately resulted in resource limitation. Furthermore, excessive use of water and minerals and pollution of water through human activities are also reasons behind these resource limitations.
Project Work & Activity
Take potted plants and observe the effect of light, humidity and water on them for a month. Prepare a report of the conclusions relating them with ecosystem as a whole.
Answer: Do it yourself. Here are the instructions:
For this project, we need to see how light, humidity, and water affect plants over a month and then write a report about it, connecting our findings to the whole ecosystem. Here’s how you can do it:
1. Get Your Plants and Materials:
- Plants: Get 3 or 4 small potted plants. Try to get plants that are the same type and roughly the same size. This makes it easier to compare them.
- Pots: Make sure they all have drainage holes.
- Soil: Use the same type of soil if you’re repotting, or just use them as they are if already potted.
- Watering Can/Measuring Cup: To give specific amounts of water.
- Notebook & Pen: To write down all your observations.
- Ruler: To measure plant height.
- Camera (phone is fine): To take pictures of your plants.
- Locations: You’ll need places with different light conditions.
- (Optional for humidity): A clear plastic bag (large enough to cover a plant without touching it much) or a spray bottle for misting.
2. Set Up Your Experiment:
Label your plants (e.g., Plant 1, Plant 2, Plant 3, Plant 4). You want to change only one thing (variable) for some plants and keep everything else the same.
- Plant 1: The Control Plant
- Light: Place it in a spot with good, bright, indirect sunlight (like near a window but not scorching sun).
- Water: Water it regularly – when the top inch of soil feels dry. Don’t overwater.
- Humidity: Normal room humidity.
- This plant is your baseline to compare others against.
- Plant 2: Testing Low Light
- Light: Place it in a spot with low light (e.g., a shadier corner of a room, further from the window).
- Water: Water it the same way as Plant 1.
- Humidity: Normal room humidity.
- Plant 3: Testing Less Water
- Light: Place it in a spot with good light, similar to Plant 1.
- Water: Water it less often than Plant 1. For example, if you water Plant 1 twice a week, maybe water this one only once a week, or wait until the soil is very dry.
- Humidity: Normal room humidity.
- Plant 4: Testing Humidity (Optional, can be a bit tricky)
- Light: Place it in a spot with good light, similar to Plant 1.
- Water: Water it the same way as Plant 1.
- Humidity: Try to increase humidity. You can do this by:
- Lightly misting the leaves with water once a day.
- Or, placing the pot on a tray filled with pebbles and a little water (make sure the pot bottom isn’t sitting in the water).
- Or, you could try loosely covering it with a clear plastic bag for some part of the day, making sure there’s some air circulation.
3. Observe and Record (For One Month):
- Check your plants daily or every other day.
- In your notebook, for each plant, record:
- Date of observation.
- Height: Measure from the soil level to the top of the plant.
- Leaves: Count them if possible. Note their color (green, yellow, brown, spots?), are they firm or wilting? Any new leaves?
- Stem: Is it strong or weak?
- Overall appearance: Does it look healthy, droopy, vibrant?
- Soil: Note if it’s dry, moist, or wet before you water.
- Amount of water given (if you’re measuring).
- Take photos of each plant once a week from the same angle if possible. This will help show changes over time.
4. Prepare Your Report:
After one month, gather all your notes and photos. Your report should have these parts:
- Title: Something like “The Effect of Light, Water, and Humidity on Plant Growth and its Relation to Ecosystems.”
- Introduction:
- Briefly state the aim of your project (to observe how light, water, and humidity affect plants).
- Mention why plants are important (e.g., they produce food, oxygen).
- Materials Used:
- List everything you used (plants, pots, soil, ruler, etc.).
- Method/Procedure:
- Describe how you set up your experiment. Explain the conditions for each plant (Plant 1, Plant 2, etc.).
- Explain how often you observed and what you recorded.
- Observations and Results:
- Present your findings. You can use a table to show changes in height, leaf count, etc., for each plant over the month.
- Describe the changes you saw in each plant (e.g., “Plant 2 in low light grew taller but its leaves turned pale,” or “Plant 3 with less water started to wilt.”).
- Include your weekly photos, labeled.
- Discussion/Conclusions:
- Analyze your results: What effect did different light conditions have? What about different watering? And humidity (if you tested it)?
- Compare the growth of Plant 2, 3, (and 4) to Plant 1 (the control).
- Relate to the ecosystem as a whole: This is super important!
- Explain that plants need things like sunlight and water (non-living parts of the ecosystem) to make their food (photosynthesis) and grow.
- Discuss how healthy plants contribute to the balance in nature. For example, they provide food for herbivores, shelter for animals, produce oxygen we breathe, help keep soil in place, and even help clean the air.
- Think about what would happen in a real ecosystem if there was a big change in sunlight (e.g., a forest fire clearing trees, or new tall trees shading smaller ones), or water (e.g., a drought or a flood). How would it affect the plants, and then the animals and the whole environment?
- You can mention that biodiversity (lots of different types of plants and animals) helps keep ecosystems stable. If some plants are affected by a change, others might still survive.
- Difficulties/Limitations (Optional):
- Mention any problems you faced (e.g., it was hard to keep humidity constant).
Extras
Questions and Answers
1. What is the basic source of energy for an ecosystem?
Answer: The basic source of energy for an ecosystem is solar energy.
Q. How do bacteria and fungi aid soil fertility?
Answer: Bacteria and fungi aid soil fertility because after the death of animals and plants, these are decomposed by bacteria and fungi, which increases soil fertility.
Q. What is genetic diversity?
Answer: Genetic diversity is a form of biodiversity and is important in breeding crops and livestock; biodiversity is the main resource of genetic diversity, which in turn leads to a huge genetic resource.
Q. How many flowering plant species have been domesticated as food plants?
Answer: Among the few thousand of an estimated 2,50,000 species of flowering plants that have been treated directly as food resources, 200 species have been domesticated as food plants.
5. What percentage of the world’s food comes from twenty plant species?
Answer: About 90% of the world’s food comes from 20 plant species.
Q. Which wild plant supplied genes to rescue rice crops from grassy stunt virus?
Answer: Genes from a wild rice from India supplied genes to rescue rice crops from grassy stunt virus.
Q. What proportion of prescription drugs in developed countries are derived from plants?
Answer: Nearly one-fourth of all prescription drugs used in the developed world are based on plants.
Q. From which plant is aspirin obtained?
Answer: Aspirin is obtained from the plant Filipendula ulmaria.
Q. From which tree is quinine extracted?
Answer: Quinine is extracted from the bark of the cinchona tree.
Q. Give one example of an animal-derived source used in medicine.
Answer: One example of an animal-derived source used in medicine is bacterium, which is used as an antibiotic.
Q. What does ecotourism involve?
Answer: Ecotourism is a new concept at the global level that involves biodiversity. Ecotourism, as a part of tourism, includes enjoying landscapes, flora, and fauna—all at a time.
Q. Which flower is offered to the goddess Kali?
Answer: Among auspicious flowers offered in temples, Hibiscus is offered to Goddess Kali.
Q. Which animal is regarded as sacred because of its association with a deity?
Answer: The bull of Shiva is an animal regarded as sacred in our country on account of its association with a deity.
Q. Name two categories of resource limitation.
Answer: Two categories of resource limitation are biological resource limitation and land resource limitation.
Q. What does the term “sustenance” mean?
Answer: The term “sustenance” means nourishment; a means of support.
Q. What does “homeostasis” refer to in an ecosystem?
Answer: “Homeostasis,” or balance in nature, refers to how an ecosystem maintains a functional balance or a relatively stable state of equilibrium amongst its various components.
Q. What is meant by an ecosystem’s functional balance?
Answer: An ecosystem’s functional balance, or homeostasis, means that an ecosystem maintains a functional balance or a relatively stable state of equilibrium amongst its various components.
Q. What is the ten per cent rule in energy transfer between trophic levels?
Answer: The ten per cent rule in energy transfer between trophic levels states that only ten per cent of energy a trophic level receives is passed on to the next trophic level.
Q. Why do food chains normally contain no more than six species?
Answer: Food chains normally do not contain more than six species because the amount of energy transferred keeps on diminishing at each trophic level.
Q. How does biodiversity itself help maintain balance in nature?
Answer: Biodiversity itself helps maintain a balance in nature through the continuous flow of food, minerals, and energy throughout nature. Green plants or producers make their own food; herbivores and other consumers take food from green plants, and higher-level consumers take herbivores and other consumers as their food. After the death of animals and plants, these are decomposed by bacteria and fungi, increasing soil fertility, which plants again use. This continuous flow keeps balance in nature.
Q. Why is diversity in plant resources important for timber production?
Answer: Large diversity in plant resources is important for timber production because it is the source of different types of wood which are economically most important in national and international markets.
Q. What role do plants and certain micro-organisms play in pollution control?
Answer: Plants and some micro-organisms play a role in pollution control by helping in the removal of toxic substances from air, water, and soil.
Q. What is one ethical reason for preserving biodiversity?
Answer: One ethical reason for preserving biodiversity is that each species is unique and has a right to exist.
Q. Which human activity has threatened freshwater fish species?
Answer: Freshwater fish species are threatened because dams and water withdrawals, which are human activities, have radically altered river systems.
Q. How have industrial effluents affected marine ecosystems in India?
Answer: In India, industrial effluents are destroying coral reefs and other marine life, thereby affecting marine ecosystems.
Q. Explain the flow of energy and matter through different trophic levels in an ecosystem.
Answer: In an ecosystem, there is a continuous flow of energy and matter from one trophic level to another. Food and energy are passed between species through food chains and food webs. These chains normally do not contain more than six species because the amount of energy transferred keeps diminishing at each trophic level. Only ten per cent of the energy a trophic level receives is passed on to the next trophic level, meaning each level supports fewer individuals than the one before. For instance, green plants or producers make their own food. Herbivores and other consumers then take food from these green plants. Higher-level consumers, in turn, consume herbivores and other consumers. After the death of animals and plants, they are decomposed by bacteria and fungi, which increases soil fertility. Plants then use these minerals when they grow in soil. This continuous flow of food, minerals, and energy throughout nature maintains balance.
Q. Describe how producers, consumers and decomposers interact to maintain balance in nature.
Answer: Producers, consumers, and decomposers interact to maintain balance in nature through a continuous flow of energy and matter. Green plants, or producers, make their own food using elements from the physical environment like sunlight, CO2, and water. Herbivores and other consumers obtain food from these green plants, and higher-level consumers then feed on these herbivores and other consumers. When animals and plants die, they are decomposed by bacteria and fungi. This decomposition process increases soil fertility by returning minerals to the soil, which plants then use to grow. This entire cycle, involving the continuous flow of food, minerals, and energy, along with the continuous interaction between living and non-living matter of the environment, ensures that biodiversity itself maintains a balance in nature.
Q. Explain the consequences of replacing genetic diversity in crops with uniform varieties.
Answer: Replacing genetic diversity in crops and livestock with uniform varieties, a characteristic of modern agricultural practices, can lead to dangerous consequences. This loss of biodiversity in crop species has severe implications for global food security. Uniform crops are more susceptible to widespread destruction if a disease or pest to which they have no resistance emerges. For example, in the early 1970s, genes from a wild rice variety from India were crucial in saving rice crops from total destruction by the widespread grassy stunt virus in many parts of Asia, highlighting the importance of genetic diversity that is lost when uniform varieties are adopted.
Q. Describe the factors leading to biological resource limitation and its impact on species extinction.
Answer: Biological resource limitation is generally associated with the extinction of species. The main reasons behind this are the destruction of forests and the degradation of habitat. These factors bring changes in the availability of food and space for normal growth, breeding habits, and movement in animals, thus posing a great threat to them. More broadly, major causes of biodiversity loss, which lead to resource limitations, can be traced to growing demands due to factors like overpopulation, unplanned development, and increased consumption. Human overpopulation puts pressure on biodiversity through greater demand for food and land, excessive consumption of minerals and other non-renewable resources, and high overuse and waste of energy. Large-scale development projects, the enormous demand for minerals leading to large-scale deforestation for mining, and the conversion of biodiversity-rich areas to agricultural land or for construction of roads and housing also contribute. Furthermore, changing agricultural practices, pollution of soil, water, and air which affects ecosystem functioning and can eliminate sensitive species, and alterations to river systems due to dams and water withdrawals threaten species and lead to biological resource limitation.
Q. Explain the impact of land resource limitation on habitat availability and ecosystem functioning.
Answer: Land resource limitation, which is mostly associated with land use patterns, has a significant impact on habitat availability and ecosystem functioning. Growing demand for land, modern agronomic practices, and industrialisation pose a great threat to land. This leads to the destruction of forests and degradation of habitat, which in turn causes changes in the availability of food and space for animals, affecting their normal growth, breeding habits, and movement, and can ultimately lead to species extinction. Large areas rich in biodiversity are often reduced to small pockets when converted to agricultural land or used for the construction of roads and housing, thereby diminishing available habitats. Additionally, pollution of soil, water, and air, often linked to land use, affects the functioning of ecosystems and can reduce or eliminate sensitive species.
Q. Describe how water resource limitations threaten freshwater fish species and other aquatic life.
Answer: Freshwater fish species are threatened because dams and water withdrawals have radically altered river systems. Additionally, pollution of water affects the functioning of ecosystems and may reduce or eliminate sensitive species. For instance, in India, industrial effluents are destroying coral reefs and other marine life. Excessive use of water and pollution of water through human activities are also reasons behind these resource limitations.
Q. Describe mineral resource limitation and its effects on biodiversity.
Answer: Mineral resource limitation is a category of resource limitations. The enormous demand for minerals in a rapidly industrialising economy has resulted in large-scale deforestation for mining purposes, which in turn affects biodiversity. Excessive consumption of minerals and other non-renewable resources contributes to the problem of resource limitation, which ultimately puts pressure on biodiversity.
Q. Explain the role of ecotourism in promoting biodiversity conservation and recreation.
Answer: Ecotourism is a new concept at the global level that involves biodiversity. As a part of tourism, ecotourism includes enjoying landscapes, flora, and fauna—all at a time, thereby providing a means for recreation.
Q. Analyse how overpopulation and human demands contribute to resource limitations.
Answer: Major causes of biodiversity loss can be traced, directly or indirectly, to growing demands leading to resource limitations, with overpopulation and growing demands being a few of the factors responsible for this. Human overpopulation has put pressure on biodiversity. Greater demand for food and land, excessive consumption of minerals and other non-renewable resources, and high overuse and waste of energy have aggravated the problem, which ultimately resulted in resource limitation.
Q. Describe the impact of large-scale development projects and mining on biodiversity-rich areas.
Answer: Large-scale development projects have contributed substantially to the loss of biodiversity-rich areas. Furthermore, the enormous demand for minerals in a rapidly industrialising economy has resulted in large-scale deforestation for mining purposes. Large areas rich in biodiversity have also been reduced to small pockets due to their conversion to agricultural land or for the construction of roads and housing.
Q. Explain how changing market forces have led to unplanned agricultural practices affecting biodiversity.
Answer: In the last few decades, changing market forces and the increase in demand for food have prompted farmers to change their traditional agricultural practices, which in turn affects biodiversity.
Q. Analyse how pollution of soil, water and air disrupts ecosystem functioning and reduces sensitive species.
Answer: Pollution of soil, water, and air affects the functioning of ecosystems. Such pollution may reduce or eliminate sensitive species. For instance, in India, industrial effluents are destroying coral reefs and other marine life, thereby disrupting ecosystem functioning and reducing these sensitive species.
Q. Explain how traditional communities depend on biodiversity for their day-to-day needs of shelter, clothing, medicines and fertilisers.
Answer: The most important value of biodiversity, particularly in developing countries like India, is that it meets basic survival needs of a vast number of people. Man cannot survive without biodiversity. Some of the traditional communities even today depend wholly or partially on the surrounding natural resources for their day to day needs of shelter, clothing, medicines, fertilisers, etc.
Q. Describe the ecological services provided by biodiversity, giving examples where appropriate.
Answer: Biodiversity provides several important ecological services. Many species depend on each other for survival, and species evolve to fill particular habitats. The destruction of one species can lead to the extinction of other species, which underscores the importance of biodiversity in maintaining ecological stability. For example, a single tree provides not only its products of economic value but also offers the ecological service of providing a habitat for innumerable living things. In addition, such a tree also provides the services of conserving soil and purifying air.
Q. Explain how ethical and cultural values influence conservation of biodiversity.
Answer: Ethical and cultural values significantly influence the conservation of biodiversity.
From an ethical standpoint, ethics provides the basis for deciding what is good or bad, right or wrong. Each species is considered unique and possesses a right to exist. This ethical perspective leads to actions such as the boycott of fur, teak, ivory, and other valuable natural items at the international level, thereby contributing to conservation efforts.
From a religious and cultural perspective, various plants and animal species are considered sacred in our country due to their association with different deities. For instance, the bull is associated with Shiva, the rat with Ganesha, and the lion with Durga. Among auspicious flowers offered in temples, Hibiscus is offered to Goddess Kali and Dhatura flowers to Shiva. Furthermore, some forests are believed to be the abode of Gods, and such areas are preserved as pockets of rich biodiversity. Since ancient times, natural elements like forests and water have been worshipped by local and indigenous people, fostering a culture of conservation.
Q. Discuss the ways in which genetic engineering has utilised biodiversity resources in agriculture and medicine.
Answer: Biodiversity is the main resource of genetic diversity, which in turn leads to a huge genetic resource. With the advent of science, people are using this vast resource in hybridisation and genetic engineering techniques.
In agriculture, these techniques have led to developments such as the Green Revolution and White Revolution. Genetic diversity, as a form of biodiversity, is important in breeding crops and livestock. Many crops have been ‘rescued’ with genetic material from wild relatives or traditional varieties. For example, in the early 1970s, genes from a wild rice from India helped to save rice crops from total destruction by widespread grassy stunt virus in many parts of Asia.
In the field of medicine, medical science is also progressing fast by utilising genetic resources. Vaccines and medicines are being produced by genetic engineering.
42. Discuss the relationship between reduced biodiversity and increased poverty and frequency of natural disasters.
Answer: Reduction in biodiversity increases poverty in developing countries. Nowadays, the frequency of natural disasters is increasing due to the imbalance in nature. Thus, we must take concrete steps to save our biodiversity.
MCQs
1. What is the maximum number of species a food chain normally contains?
A. Four
B. Six
C. Eight
D. Ten
Answer: B. Six
2. What proportion of energy is passed from one trophic level to the next?
A. 1%
B. 10%
C. 50%
D. 90%
Answer: B. 10%
3. Why does each trophic level support fewer individuals than the one before?
A. Predation
B. Diminishing energy
C. Competition
D. Disease
Answer: B. Diminishing energy
4. Who first explained the concept of balance in nature?
A. Charles Darwin
B. Albert Einstein
C. Isaac Newton
D. James Watt
Answer: C. Isaac Newton
5. Which continuous flows maintain balance in nature?
A. Food, water and air
B. Food, minerals and energy
C. Minerals, sunlight and oxygen
D. Carbon, nitrogen and phosphorus
Answer: B. Food, minerals and energy
6. Which organisms make their own food using sunlight, CO₂ and water?
A. Fungi
B. Green plants
C. Herbivores
D. Decomposers
Answer: B. Green plants
7. Which category includes herbivores and carnivores?
A. Producers
B. Decomposers
C. Consumers
D. Autotrophs
Answer: C. Consumers
8. Which organisms decompose dead plants and animals to enrich the soil?
A. Bacteria and fungi
B. Earthworms
C. Insects
D. Algae
Answer: A. Bacteria and fungi
9. What term describes the position occupied by a species in a food chain?
A. Niche
B. Habitat
C. Trophic level
D. Ecosystem
Answer: C. Trophic level
10. Which percentage of the world’s food comes from 20 plant species?
A. 50%
B. 70%
C. 90%
D. 100%
Answer: C. 90%
11. Approximately how many species of flowering plants have been domesticated as food plants?
A. 50
B. 200
C. 500
D. 1 000
Answer: B. 200
12. What form of biodiversity is crucial for breeding crops and livestock?
A. Ecosystem diversity
B. Genetic diversity
C. Species diversity
D. Cultural diversity
Answer: B. Genetic diversity
13. In which decade did genes from wild rice help save rice crops from grassy stunt virus?
A. 1950s
B. 1960s
C. 1970s
D. 1980s
Answer: C. 1970s
14. Source of quinine is derived from which tree?
A. Willow
B. Cinchona
C. Oak
D. Pine
Answer: B. Cinchona
15. Which plant is the source of aspirin?
A. Filipendula ulmaria
B. Aloe vera
C. Chrysanthemum
D. Poppy
Answer: A. Filipendula ulmaria
16. Which of these plants is used to treat hypertension?
A. Rauwolfia
B. Cinchona
C. Foxglove
D. Rosy periwinkle
Answer: A. Rauwolfia
17. Which of these is used as an analgesic?
A. Poppy
B. Cinchona
C. Rauwolfia
D. Bacterium
Answer: A. Poppy
18. Which organism is the source of penicillin?
A. Fungus
B. Virus
C. Bacterium
D. Algae
Answer: C. Bacterium
19. Which plant is used as a heart stimulant?
A. Foxglove
B. Aloe vera
C. Rosy periwinkle
D. Cinchona
Answer: A. Foxglove
20. Which animal source is used for wound healing?
A. Maggot
B. Snail
C. Earthworm
D. Bee
Answer: A. Maggot
21. Fishery plays an important role in providing what?
A. Energy security
B. Food security
C. Water security
D. Health security
Answer: B. Food security
22. Which service involves habitat provision, soil conservation and air purification?
A. Cultural service
B. Recreational service
C. Ecological service
D. Economic service
Answer: C. Ecological service
23. Which term refers to the right of species to exist, leading to boycotts of fur and ivory?
A. Aesthetic value
B. Ethical reason
C. Option value
D. Cultural reason
Answer: B. Ethical reason
24. Which animal is associated with the deity Ganesha?
A. Cow
B. Rat
C. Elephant
D. Lion
Answer: B. Rat
25. Which flower is offered to the goddess Kali?
A. Marigold
B. Hibiscus
C. Lotus
D. Jasmine
Answer: B. Hibiscus
26. What does option value refer to?
A. Paying now for future use
B. Paying later for past use
C. No payment needed
D. Selling an option
Answer: A. Paying now for future use
27. Which revolutions were a result of genetic engineering techniques?
A. Industrial and digital
B. Green and White
C. Digital and Green
D. Green and Digital
Answer: B. Green and White
28. Which organisms help remove toxic substances from air, water and soil?
A. Plants and micro-organisms
B. Viruses and bacteria
C. Animals and fungi
D. Insects and worms
Answer: A. Plants and micro-organisms
29. What is ecotourism primarily concerned with?
A. Amusement parks
B. Industrial visits
C. Urban exploration
D. Enjoying landscapes, flora and fauna
Answer: D. Enjoying landscapes, flora and fauna
30. Which major factor leads to resource limitations?
A. Overpopulation
B. Telecommunications
C. Space travel
D. Internet use
Answer: A. Overpopulation
31. Which practice has resulted from changing market forces and increased food demand?
A. Traditional farming
B. Modern agronomic practices
C. Hunting
D. Fishing
Answer: B. Modern agronomic practices
32. What impacts coral reefs and other marine life in India?
A. Overfishing
B. Industrial effluents
C. Tourism
D. Aquaculture
Answer: B. Industrial effluents
33. Freshwater fish species are threatened by what?
A. Overfishing
B. Flooding
C. Dams and water withdrawals
D. Salinity
Answer: C. Dams and water withdrawals
34. What type of resource limitation is linked to extinction of species?
A. Biological
B. Land
C. Water
D. Mineral
Answer: A. Biological
35. Land resource limitation is primarily associated with which factor?
A. Land use pattern
B. Water use
C. Air pollution
D. Noise pollution
Answer: A. Land use pattern
36. What does reduction in biodiversity increase in developing countries?
A. Poverty
B. Wealth
C. Health
D. Stability
Answer: A. Poverty
37. Frequency of what is increasing due to imbalance in nature?
A. Renewable energy use
B. Natural disasters
C. Tourist visits
D. Crop yields
Answer: B. Natural disasters
38. Which term describes a relatively stable state of equilibrium in an ecosystem?
A. Homeostasis
B. Biodiversity
C. Resilience
D. Tolerance
Answer: A. Homeostasis
39. Which energy source is the basic input for an ecosystem?
A. Solar energy
B. Chemical energy
C. Nuclear energy
D. Wind energy
Answer: A. Solar energy
40. How is a food chain defined?
A. Sequence of organisms through which energy passes
B. Pathway of the water cycle
C. Series of climate zones
D. Chain of command in ecology
Answer: A. Sequence of organisms through which energy passes
41. What process recycles nutrients by breaking down dead matter?
A. Decomposition
B. Photosynthesis
C. Respiration
D. Transpiration
Answer: A. Decomposition
42. What is the estimated total number of flowering plant species in the world?
A. 100 000
B. 250 000
C. 500 000
D. 1 000 000
Answer: B. 250 000
43. Approximately how many flowering plant species are directly used as food resources?
A. 200
B. 2 000
C. 20 000
D. 50 000
Answer: B. 2 000
44. What does a food chain illustrate?
A. Flow of energy
B. Flow of water
C. Flow of carbon
D. Flow of minerals
Answer: A. Flow of energy
45. What is the effect of modern agricultural practices on crop genetic diversity?
A. Increased uniformity
B. Increased diversity
C. No effect
D. Decreased yield
Answer: A. Increased uniformity
46. What does ‘sustenance’ mean?
A. Nourishment
B. Extinction
C. Equilibrium
D. Consumption
Answer: A. Nourishment
