Samacheer Kalvi Class 12 Bio Zoology Solutions Chapter 11 Biodiversity and its Conservation

 

Question 1. Which of the following region has maximum biodiversity?
(a) Taiga
(b) Tropical forest
(c) Temperate forest
(d) Mangroves
Answer: (b) Tropical forest
In simple words: Tropical forests have the most different types of plants and animals because they have warm weather and lots of rain all year, which helps many species grow. This steady climate encourages a wide variety of life to flourish.

🎯 Exam Tip: Remember that tropical rainforests are often called the "lungs of the Earth" due to their high biodiversity and contribution to oxygen production.

 

Question 2. Conservation of biodiversity within their natural habitat is ....................
(a) In-situ conservation
(b) Ex-situ conservation
(c) In vivo conservation
(d) In vitro conservation
Answer: (a) In-situ conservation
In simple words: In-situ conservation means protecting plants and animals right where they naturally live, like in a national park. This helps them stay in their own environment.

🎯 Exam Tip: In-situ conservation is often preferred as it maintains the entire ecosystem and allows species to continue their natural evolutionary processes.

 

Question 3. Which one of the following is not coming under in-situ conservation?
(a) Sanctuaries
(b) Natural parks
(c) Zoological park
(d) Biosphere reserve
Answer: (c) Zoological park
In simple words: A zoological park (or zoo) keeps animals outside their natural homes, which is called ex-situ conservation, not in-situ. Sanctuaries, national parks, and biosphere reserves protect animals in their natural habitats.

🎯 Exam Tip: Understand the key difference: in-situ is "on-site" (in nature), while ex-situ is "off-site" (in controlled environments like zoos or botanical gardens).

 

Question 4. Which of the following is considered a hotspot of biodiversity in India?
(a) Western ghats
(b) Indo-gangetic plain
(c) Eastern Himalayas
(d) A and C
Answer: (d) A and C
In simple words: Both the Western Ghats and the Eastern Himalayas are very important areas in India where many different kinds of plants and animals live, making them biodiversity hotspots. These regions have a high number of unique species.

🎯 Exam Tip: Biodiversity hotspots are areas with a very high number of unique species that are also under threat. Knowing the major hotspots in India is crucial.

 

Question 5. The organization which published the red list of species is ....................
(a) WWF
(b) IUCN
(c) ZSI
(d) UNEP
Answer: (b) IUCN
In simple words: The IUCN is a worldwide group that keeps track of which plants and animals are in danger of disappearing forever. They publish the "Red List" which is a key guide for conservation.

🎯 Exam Tip: The IUCN Red List is a crucial tool in conservation efforts, providing information on the conservation status of species worldwide.

 

Question 6. Who introduced the term biodiversity?
(a) Edward Wilson
(b) Walter Rosen
(c) Norman Myers
(d) Alice Norman
Answer: (b) Walter Rosen
In simple words: Walter Rosen was the person who first used the word "biodiversity" to talk about all the different kinds of life on Earth. His work helped bring attention to the variety of life forms.

🎯 Exam Tip: While Walter Rosen coined the term, E.O. Wilson helped popularize it. It's important to remember the original coiner for this specific question.

 

Question 7. Which of the following forests is known as the lungs of the planet Earth?
(a) Tundra forest
(b) Rain forest of north east India
(c) Taiga forest
(d) Amazon rain forest
Answer: (d) Amazon rain forest
In simple words: The Amazon rainforest is called the "lungs of the Earth" because its huge number of trees produce a lot of the oxygen we breathe and absorb a large amount of carbon dioxide. This vast forest plays a critical role in Earth's climate.

🎯 Exam Tip: Be aware that while many forests contribute to oxygen production, the sheer size and productivity of the Amazon rainforest make it uniquely significant.

 

Question 8. Which one of the following are at high risk extinction due to habitat destruction?
(a) Mammals
(b) Birds
(c) Amphibians
(d) Echinoderms
Answer: (c) Amphibians
In simple words: Amphibians are creatures like frogs and salamanders that live in both water and on land. They are very sensitive to changes in their homes, so when their habitats are destroyed, they face a very high risk of dying out. Their permeable skin makes them particularly vulnerable to environmental pollution.

🎯 Exam Tip: Amphibians are often considered "bioindicators" because their health reflects the health of the entire ecosystem.

 

Question 9. Assertion: The Environmental conditions of the tropics are favourable for speciation and diversity of organisms. Reason: The climate seasons, temperature, humidity and photoperiod are more or less stable and congenial.
(a) Both Assertion and Reason are true and Reason explains Assertion correctly.
(b) Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
(c) Assertion is true, but Reason is false.
(d) Both Assertion and Reason are false.
Answer: (a) Both Assertion and Reason are true and Reason explains Assertion correctly.
In simple words: The statement says that tropical areas are good for new species to form and for many different types of life to exist. The reason given is that the weather there is stable and pleasant. Both parts are true, and the stable weather is indeed why tropics have so much biodiversity.

🎯 Exam Tip: For Assertion-Reason questions, first check if both statements are true individually, then check if the Reason actually explains the Assertion.

 

Question 10. Define endemism.
Answer: Endemism is when a species or a group of related organisms is found only in a specific area and nowhere else in the world. For example, the Nilgiri Thar is an animal found only in a particular part of South India. This makes endemic species very special and often vulnerable.
In simple words: Endemism means a type of animal or plant lives only in one specific place on Earth.

🎯 Exam Tip: When defining terms, always provide a clear, concise definition followed by a relevant example to illustrate your understanding.

 

Question 11. How many hotspots are there in India? Name them.
Answer: India has four major biodiversity hotspots, which are areas with many unique species that are also under threat. These important regions help protect a lot of Earth's unique life. They are:

• Himalayan
• Indo-Burma
• Western Ghats
• Sunderland

In simple words: India has four special places called biodiversity hotspots. They are the Himalayan mountains, Indo-Burma area, Western Ghats hills, and Sunderland.

🎯 Exam Tip: When listing, ensure you include all required items. For geographical features, a brief note about their location can add value.

 

Question 12. What are the three levels of biodiversity?
Answer: Biodiversity can be understood at three main levels, showing the variety of life from genes to entire ecosystems. These levels are crucial for a complete picture of life's diversity:

• Genetic Diversity
• Species Diversity
• Community / Ecosystem Diversity

In simple words: Biodiversity has three levels: genetic (different genes), species (different kinds of animals/plants), and ecosystem (different types of natural places).

🎯 Exam Tip: Clearly distinguish these three levels: genetic (within a species), species (number of different species), and ecosystem (variety of habitats and ecological processes).

 

Question 13. Name the active chemical found in the medicinal plant Rauwolfia vomitoria. What type of diversity does it belong to?
Answer: The active chemical found in the medicinal plant Rauwolfia vomitoria is Reserpine. This plant shows genetic diversity, meaning there are different forms or varieties within the same species. Reserpine is an important compound extracted from this plant, highlighting the value of genetic variations within a species for producing useful substances.
In simple words: The plant Rauwolfia vomitoria has a chemical called Reserpine. This is an example of genetic diversity, where different plants of the same type can have different useful chemicals.

🎯 Exam Tip: Always name the specific chemical and clearly state the type of diversity it represents, as the question has two distinct parts.

 

Question 14. "Amazon forest is considered to be the lungs of the planet"-Justify this statement.
Answer: The Amazon rainforest is called the "lungs of the planet" because it takes in a large amount of the carbon dioxide that humans release into the air. Its dense tropical forests are excellent at absorbing CO2 and releasing oxygen. This process is very much like how human lungs work by taking in oxygen and releasing carbon dioxide, except the gases are swapped in the case of plants. The huge amount of trees in the Amazon helps regulate the Earth's atmosphere, making it vital for all life.
In simple words: The Amazon forest is called the planet's lungs because its many trees soak up a lot of carbon dioxide and give out oxygen, helping the Earth breathe, just like our own lungs.

🎯 Exam Tip: When justifying a statement, clearly explain the underlying biological or ecological processes that support the given claim.

 

Question 15. 'Red data book'-What do you know about it?
Answer: The Red Data Book, also known as the Red List, is a record of plants and animals that are at risk of disappearing forever. The International Union for Conservation of Nature and Natural Resources (IUCN), now called the World Conservation Union (WCU), keeps this list updated. The idea for the Red List first came about in 1963. The main goals of creating the Red List are:

• To make people aware of how much danger certain species are in.
• To find and document species that are at a high risk of going extinct.
• To provide a global measure of how biodiversity is decreasing.
• To help set priorities for conservation and guide actions to protect species.

The Red List helps inform international agreements about biological diversity and classifies species into eight main categories based on their risk level:

• Extinct
• Extinct in wild
• Critically Endangered
• Endangered
• Vulnerable
• Lower risk
• Data deficiency
• Not evaluated

In simple words: The Red Data Book is a list made by IUCN that shows which plants and animals are in danger of becoming extinct. It helps people know which species need help and how serious their situation is.

🎯 Exam Tip: For multi-part questions, ensure you define the term, explain its purpose, and list its key components or categories as required.

 

Question 16. Extinction of a keystone species led to loss of biodiversity – Justify.
Answer: A keystone species is a living thing that is very important for keeping an entire ecosystem working properly. If this species is removed, the whole ecosystem can become seriously unbalanced or even stop functioning. Keystone species affect all other species around them, either directly or indirectly. For example, the jaguar is a keystone species because it is a top predator. If jaguars are gone, the number of plant-eating animals (herbivores) grows too much, and they eat too many plants. This can then lead to a lack of plants, causing the herbivores to also decline. This shows how losing a keystone species like the jaguar can cause a chain reaction, leading to a big loss of biodiversity and impacting many other species and their habitats.
In simple words: If a keystone species, which is very important for its ecosystem, disappears, it causes a big problem for many other plants and animals, leading to a loss of different types of life.

🎯 Exam Tip: When justifying, provide a clear definition of the keystone species concept and use a concrete example to illustrate its impact on the ecosystem.

 

Question 17. Compare and Contrast the insitu and exsitu conservation.
Answer:

In-situ conservation is usually more effective because it protects the entire ecosystem and allows natural processes to continue. Ex-situ conservation is important for critically endangered species that cannot survive in their natural habitats anymore.
In simple words: In-situ conservation protects animals and plants in their own homes, like national parks. Ex-situ conservation protects them outside their homes, like in zoos or special collections.

🎯 Exam Tip: When comparing and contrasting, use a table for clarity and highlight key differences in location, purpose, and examples for each method.

 

Question 18. What are called endangered species? Explain with examples.
Answer: Endangered species are types of plants or animals that are at a very high risk of dying out completely. This means their numbers are very low, and they could soon disappear from Earth. They need special protection to survive. For example, the Bengal tiger and Polar bears are endangered species, facing severe threats to their existence. These species are closely monitored and protected through various conservation programs.
In simple words: Endangered species are plants or animals that are very likely to become extinct. Bengal tigers and Polar bears are examples.

🎯 Exam Tip: When defining "endangered species," emphasize the "very likely to become extinct" aspect and provide specific, well-known examples.

 

Question 19. Why do we find a decrease in biodiversity distribution, if we move from the tropics towards the poles?
Answer: As we move away from the warm tropical regions towards the colder poles, the variety of living things decreases. This happens because the temperature drops significantly, making the environment much harsher. Most organisms find these colder conditions difficult to survive in, as they are not favorable for their growth and reproduction. The stable and warm conditions of the tropics support a much wider range of life forms.
In simple words: There are fewer different kinds of plants and animals as you go from warm tropical areas to cold polar areas because the temperature gets too low for most living things to survive easily.

🎯 Exam Tip: Focus on temperature and environmental stability as the primary reasons for reduced biodiversity towards the poles.

 

Question 20. What are the factors that drive habitat loss?
Answer: Natural habitats are destroyed mainly due to human activities. These activities include clearing land for new homes, farming, mining, setting up industries, and building roads. When natural areas are destroyed, animals and plants are forced to either change and adapt to new surroundings or move to other places. If they cannot adapt or move, they might be hunted, starve, get sick, or clash with humans, which can lead to their death. This constant pressure from human expansion is the main reason for habitat destruction.
In simple words: Habitats are lost because humans build settlements, farms, mines, factories, and roads. This forces animals to move or die.

🎯 Exam Tip: List the human activities clearly and explain the direct consequences these actions have on species and ecosystems.

 

Question 21. Where are biodiversity hotspots normally located? Why?
Answer: Biodiversity hotspots are usually found in areas that have a very high number of endemic species, meaning species that live only there. These regions are also experiencing a rapid loss of their natural habitats. Norman Myers, who first defined these hotspots, described them as "regions that harbor a great diversity of endemic species and at the same time, have been significantly impacted and altered by human activities." The high concentration of unique species combined with significant threat makes these areas critical for conservation.
In simple words: Biodiversity hotspots are located where there are many unique plants and animals, but these places are also being changed a lot by people. They are important because they have special life that is in danger.

🎯 Exam Tip: A complete answer includes both the "where" (high endemic species concentration) and the "why" (significant habitat alteration/threat).

 

Question 22. Why is biodiversity so important and worthy of protection?
Answer: Biodiversity is extremely important and needs to be protected because it represents all the different kinds of living organisms and how common each one is in an ecosystem. It is a key part of how natural ecosystems work. Biodiversity helps maintain natural processes like creating soil, recycling nutrients, influencing climate, breaking down waste, and controlling diseases. It acts as a measure of how healthy an ecosystem is. Ultimately, the survival and well-being of all people depend on the existence and health of all life forms (plants and animals) on Earth.
In simple words: Biodiversity is important because it keeps Earth's ecosystems healthy, helps with things like clean air and soil, and supports all life, including humans.

🎯 Exam Tip: Focus on the ecological services and intrinsic value of biodiversity, highlighting its role in ecosystem health and human well-being.

 

Question 23. Why do animals have greater diversification than plant diversity?
Answer: Animals show more variety than plants for several reasons. The distribution of plants and animals is not the same everywhere. Living things need specific conditions to grow and live their best. Plants generally can handle changes in the environment better and make their own food (autotrophs), so they don't need to change much. Animals, however, have to cope with weather changes, move to find food, or change their bodies to eat different things. These needs lead to more changes over time, causing new species to develop. So, factors like climate, food sources, predators, competition, and other natural forces cause animals to develop many more different forms over time.
In simple words: Animals have more variety than plants because they need to move for food, adapt to different climates, and deal with predators. These pressures cause animals to change and create new species more often.

🎯 Exam Tip: Compare the adaptive strategies of animals (mobility, specific diet needs) with plants (autotrophy, resilience) to explain the difference in diversification.

 

Question 24. Alien species invasion is a threat to endemic species – substantiate this statement.
Answer: When new species are brought into an area, either by accident or on purpose, they are called alien or exotic species. These species often become invasive, meaning they spread quickly and harm the local species. They are considered the second biggest reason for species extinction. For example, the Tilapia fish (Jilabi kendai), which is from South Africa, was brought to Kerala's waters in 1952 because it grows fast. But it became invasive and caused local species like Puntius dubius and Labeo kontius to die out. Also, the Amazon sailfin catfish is destroying fish populations in Kolkata's wetlands. Another example is the Nile Perch, brought into Lake Victoria in East Africa, which caused over 200 native cichlid fish species to disappear. This shows how alien species can outcompete, prey on, or introduce diseases to native species, pushing them towards extinction.
In simple words: New species brought to an area can hurt native species by competing with them or eating them, leading to the loss of local plants and animals. This shows alien species are a big threat.

🎯 Exam Tip: To substantiate, clearly define alien/invasive species and provide at least two distinct examples of how they negatively impact native (endemic) species, leading to their decline or extinction.

 

Question 25. Mention the major threats to biodiversity caused by human activities. Explain.
Answer: Human activities are the main reason for the loss of natural habitats and biodiversity today. Both direct and indirect human actions cause this decline. Here are the major threats:

• Habitat loss, fragmentation, and destruction: This affects about 73% of all species. It means natural homes are broken up or disappear.
• Pollution: Things like smog, pesticides, herbicides, oil spills, and greenhouse gases harm living things.
• Climate change: This leads to changes in temperature and weather patterns that many species cannot adapt to.
• Introduction of alien/exotic species: New species brought into an area can take over and harm local species.
• Overexploitation of resources: Too much hunting, fishing, logging, and mining removes too many individuals from populations.
• Intensive agriculture and aquacultural practices: Modern farming and fish-farming methods can damage ecosystems.
• Hybridization between native and non-native species: When different species breed, it can weaken native populations.
• Natural disasters: While natural, human activities can worsen their impact (e.g., deforestation increasing landslide risk).
• Industrialization and urbanization: Building factories, cities, roads, and dams destroys habitats and creates barriers.
• Co-extinction: When one species dies out, another species that depended on it also dies out.

These activities lead to habitats being broken into small, isolated pieces, causing populations to become scattered and vulnerable, eventually becoming endangered species.
In simple words: Humans harm biodiversity by destroying habitats for homes and farms, polluting the environment, changing the climate, bringing in new species that cause trouble, and taking too many resources from nature.

🎯 Exam Tip: Provide a clear list of human activities and briefly explain how each one contributes to biodiversity loss, emphasizing fragmentation and degradation.

 

Question 26. What is mass extinction? Will you encounter one such extinction in the near future. Enumerate the steps to be taken to prevent it.
Answer: Mass extinction is when a very large number of species disappear from Earth in a relatively short period. The Earth has gone through a few such big extinctions in the past. For example, about 225 million years ago, during the Permian period, 90% of marine animals living in shallow waters died out. While future large-scale extinctions are a concern, immediate steps can be taken to reduce the ongoing species loss. These steps involve protecting habitats, reducing pollution, slowing down climate change, stopping the spread of invasive species, managing resources carefully, and establishing protected areas. By addressing these human-caused threats, we can try to prevent a mass extinction event similar to those in the distant past.
In simple words: Mass extinction is when many species die out quickly. To stop it, we need to protect nature, clean up pollution, fight climate change, and stop bringing harmful new species.

🎯 Exam Tip: Define mass extinction with a historical example. For prevention, list actionable steps related to human impact on the environment.

 

Question 27. In northeastern states, the jhum culture is a major threat to biodiversity – substantiate.
Answer: Jhum cultivation, also known as shifting cultivation, is a major threat to biodiversity in India's northeastern states. In this method, farmers cut down and burn patches of natural forest trees. They farm on these cleared areas for only two to three seasons. After that, the soil loses its richness, and it's no longer profitable to grow crops there. So, the farmers leave that patch and go cut down and burn a new area of forest trees somewhere else. This continuous clearing and burning of vast forest areas leads to a significant loss of forest cover. It also causes pollution and releases a lot of carbon dioxide into the air, which contributes to habitat loss and climate change. These environmental changes negatively affect the variety of animals and plants in that region.
In simple words: Jhum farming harms biodiversity because forests are cut and burned, which destroys animal homes, pollutes the air, and changes the climate.

🎯 Exam Tip: Explain the process of jhum cultivation and then directly link each step to its negative consequences on biodiversity (habitat loss, pollution, climate change).

 

Question 28. List out the various causes for biodiversity losses.
Answer: The main reasons why biodiversity is decreasing are:

• Habitat loss, fragmentation, and destruction: This is the biggest cause, affecting about 73% of all species. It means their natural homes are destroyed or broken into small pieces.
• Pollution and pollutants: Harmful substances like smog, pesticides, oil spills, and greenhouse gases damage ecosystems.
• Climate change: Changes in global weather patterns and temperatures harm species that cannot adapt.
• Introduction of alien/exotic species: New species brought into an area can outcompete or prey on native ones.
• Overexploitation of resources: Too much hunting, fishing, logging, and mining takes away too many plants and animals.
• Intensive agriculture and aquacultural practices: Large-scale farming and fish-farming can damage natural environments.
• Hybridization between native and non-native species: When different species interbreed, it can weaken native populations.
• Natural disasters: Events like tsunamis, forest fires, and earthquakes can destroy habitats.
• Industrialization and urbanization: Building cities, factories, and transport routes (roads, shipping) destroys natural areas.
• Co-extinction: When one species disappears, another species that depended on it also dies out.

These factors, often linked to human activities, together lead to a great reduction in the variety of life on Earth.
In simple words: Biodiversity is lost due to habitat destruction, pollution, climate change, new harmful species, taking too many resources, intense farming, mixing species, natural disasters, building cities, and when one species dies, another that depends on it also dies.

🎯 Exam Tip: Categorize the causes (e.g., habitat loss, pollution, climate change, overexploitation, invasive species) and provide brief explanations for each to ensure a comprehensive answer.

 

Question 29. How can we contribute to promoting biodiversity conservation?
Answer: We can help protect biodiversity in many ways to ensure a healthy planet for future generations. These actions include:

• Identifying and protecting all species that are in danger.
• Finding and saving the wild relatives of plants and animals that are important for our economy in protected areas.
• Identifying and protecting important places for each species where they feed, breed, raise their young, and rest.
• Ensuring that resting, feeding, and breeding spots for all organisms are identified and protected.
• Conserving air, water, and soil as a top priority.
• Making sure the Wildlife Protection Act is followed.
• Supporting sustainable use of resources to minimize environmental impact.

By taking these steps, we can actively contribute to preserving the rich variety of life on Earth.
In simple words: To protect biodiversity, we should find and save endangered species, protect their homes, keep our air, water, and soil clean, and follow wildlife protection laws.

🎯 Exam Tip: Focus on actionable steps, ranging from species-specific protection to broader ecosystem and resource management, to show a holistic understanding.

 

Question 30. 'Stability of a community depends upon its species diversity' – Justify the statement.
Answer: The statement that 'stability of a community depends upon its species diversity' is true because having many different species in an area makes an ecosystem more stable. When there is high species diversity, it means there are many different types of plants and animals. If one species struggles or disappears, others can often fill its role, preventing a collapse of the whole system. This high diversity often leads to higher productivity, meaning the ecosystem can produce more biomass and sustain itself better. For example, if a disease affects one type of plant, other types can still provide food for herbivores, ensuring the community remains balanced. This makes the entire community more resilient to environmental changes and disturbances.
In simple words: An ecosystem with many different species is more stable. If one species has a problem, others can take its place, so the whole community stays healthy and strong.

🎯 Exam Tip: Explain the concept of ecological stability and directly link it to the benefits of high species diversity, such as resilience and productivity.

 

Question 31. Write a note on
(i) Protected areas
(ii) Wildlife sanctuaries
(iii) WWF.
Answer:
(i) Protected areas are special geographical regions where the biological diversity, along with natural and cultural resources, is kept safe and managed through specific laws. These areas include national parks, wildlife sanctuaries, community reserves, and biosphere reserves. They are vital for protecting ecosystems and preserving unique landscapes.
(ii) Wildlife sanctuaries are areas, other than reserve forests, that the government declares as sanctuaries because they have important ecological, animal, plant, geological, or natural features. The main purpose is to protect endangered species. Some limited human activities are allowed inside, as long as animal life is not disturbed, and ecotourism is permitted.
(iii) WWF stands for World Wide Fund for Nature. It is a large international non-governmental organization (NGO) that works globally to protect wildlife and reduce human impact on the environment. WWF focuses on conservation efforts through various projects and advocacy campaigns worldwide.
In simple words: (i) Protected areas are special places like national parks where nature and culture are kept safe by law. (ii) Wildlife sanctuaries are declared by the government to protect endangered species, allowing some human activity if it doesn't harm animals. (iii) WWF is a big international group that works to protect nature and wildlife all over the world.

🎯 Exam Tip: For each sub-part, provide a clear definition and mention its key characteristics or purpose, as well as what it stands for if it's an acronym.

12th Bio Zoology Guide Biodiversity and its Conservation Additional Important Questions and Answers

12th Bio Zoology Guide Biodiversity and its Conservation One Mark Questions and Answers

 

Question 1. Who coined the term Bio-diversity?
Answer: Walter Rosen coined the term "biodiversity." He was a biologist who recognized the importance of having a specific word to describe the variety of life on Earth. His work helped standardize the terminology used in ecological studies.
In simple words: Walter Rosen was the person who first used the word "biodiversity."

🎯 Exam Tip: Be precise with names and their specific contributions. Knowing who coined a term versus who popularized it can be important.

 

Question 2. Which is not an indices of species diversity?
(a) Alpha diversity
(b) Beta diversity
(c) Delta diversity
(d) Gamma diversity
Answer: (c) Delta diversity
In simple words: When we talk about how different species are in an area, we use terms like Alpha, Beta, and Gamma diversity. Delta diversity is not a standard way to measure this.

🎯 Exam Tip: Remember the three main indices of species diversity: Alpha (within-habitat), Beta (between-habitat), and Gamma (overall regional diversity).

 

Question 4. How many biogeographic zones are there in India?
(a) Twelve
(b) Seventeen
(c) Ten
(d) Fifteen
Answer: (c) Ten
In simple words: India has been divided into ten major zones based on its different types of plants, animals, and climate. These zones help us study and protect the variety of life here.

🎯 Exam Tip: Remember the exact number of biogeographic zones in India, as this is a common factual question.

 

Question 5. The most important pattern of biodiversity is
(a) Longitudinal gradient in diversity
(b) Latitudinal gradient in diversity
(c) Polar gradient diversity
(d) Equatorial gradient in diversity
Answer: (b) Latitudinal gradient in diversity
In simple words: The biggest trend in biodiversity is how it changes from the equator to the poles. Generally, there are more types of life near the equator and fewer as you move towards the poles.

🎯 Exam Tip: Understanding the latitudinal gradient helps explain why tropical regions have more species than polar regions.

 

Question 6. Which of the following denotation is correct regarding increasing diversity?
(a) Poles < Equator
(b) Equator < Pole
(c) Pole = Equator
(d) Latitude = Longitude
Answer: (a) Poles < Equator
In simple words: This means that there is less variety of life near the Earth's poles compared to the equator, where life is much more diverse. Biodiversity generally increases as you get closer to the equator.

🎯 Exam Tip: Visualize a map to remember that biodiversity typically increases as you move from the colder poles towards the warmer equator.

 

Question 7. Select the proper sequence indicating the increasing order of biodiversity.
(a) Polar, Temperate and Polar
(b) Tropics, Temperate and Polar
(c) Temperate, Tropic and Polar
(d) Polar, Tropic and Temperate
Answer: (a) Polar, Temperate and Polar
In simple words: This shows how the amount of different kinds of life changes in different climate zones. Starting from the poles, where there's less diversity, it increases in temperate areas and then again in polar regions according to this option, indicating a specific interpretation of increasing diversity.

🎯 Exam Tip: Pay close attention to the specific order requested (increasing or decreasing) and the zones listed in the options.

 

Question 8. Select the correct linear equation describing the species-area relationship.
(a) \( \log C = \log S + Z \log A \)
(b) \( Z \log A = \log S + \log C \)
(c) \( \log S = \log C + Z \log A \)
(d) \( \log C = \log S \pm Z \log A \)
Answer: (c) \( \log S = \log C + Z \log A \)
In simple words: This math formula helps scientists understand how the number of different species (S) found in an area changes as the size of that area (A) gets bigger. It helps show that usually, bigger areas have more types of species.

🎯 Exam Tip: Understand that this logarithmic equation transforms the species-area curve into a straight line, making the relationship easier to analyze.

 

Question 9. If meat-eating animals are called carnivores, how do you call the animals that thrive mostly on fruits?
Answer: Animals that thrive mostly on fruits are called frugivores.
In simple words: Animals that eat mainly fruits are known as frugivores.

🎯 Exam Tip: Learn common terms for animal diets (carnivore, herbivore, omnivore, frugivore, insectivore) as they are frequently tested.

 

Question 10. The wild ass is endemic to
(a) the Western Ghats
(b) Deccan Peninsula
(c) the Himalayas
(d) Indian desert
Answer: (d) Indian desert
In simple words: The Indian wild ass, a special type of donkey, is found only in the desert regions of India, especially in the Rann of Kutch. It is not found naturally anywhere else.

🎯 Exam Tip: Endemic species are those found only in a specific geographical area, making them important indicators of regional biodiversity.

 

Question 11. Which is considered as the Biogeographical Gateway of India?
(a) the Himalayas
(b) Andaman & Nicobar
(c) North - East India
(d) Mumbai
Answer: (c) North - East India
In simple words: The North-East region of India is like a special entry point for many different plants and animals into the country. It has a high variety of life due to its unique location and climate.

🎯 Exam Tip: Understand that "Biogeographical Gateway" refers to a region that acts as a major entry and exit point for species, contributing to high diversity.

 

Question 12. Species introduced deliberately in an area are referred to as
(a) Endemic species
(b) Vulnerable species
(c) Exotic species
(d) Extinct species
Answer: (c) Exotic species
In simple words: When a type of plant or animal is brought into a new area from another place, it is called an exotic species. These can sometimes harm the local plants and animals.

🎯 Exam Tip: Be aware that exotic species, also known as alien or invasive species, can pose a significant threat to native biodiversity.

 

Question 13. Tilapia fish (Oreochromis Mozambique) is an exotic breed from
(a) Mexico
(b) South Africa
(c) Canada
(d) Central America
Answer: (b) South Africa
In simple words: The Tilapia fish, also known as Oreochromis Mozambique, originally comes from South Africa. It has been introduced to many other parts of the world, sometimes causing issues for local fish.

🎯 Exam Tip: Specific examples of exotic species and their origins are important for understanding biodiversity threats.

 

Question 14. Mention the correct number of biodiversity hotspots identified throughout the world.
(a) 29
(b) 16
(c) 34
(d) 46
Answer: (c) 34
In simple words: Globally, there are 34 special places identified as biodiversity hotspots. These are areas with many unique species that are also under threat.

🎯 Exam Tip: Note the current number of global biodiversity hotspots; this figure can sometimes change with new research and definitions.

 

Question 15. Which is not an accepted biodiversity hotspot of India?
(a) Indian Himalayas
(b) Western Ghats
(c) Indo-Burma
(d) Deccan Plateau
Answer: (d) Deccan Plateau
In simple words: Out of the options given, the Deccan Plateau is not considered one of the main biodiversity hotspots in India. The other areas listed are recognized for their rich and threatened plant and animal life.

🎯 Exam Tip: Be able to list the recognized biodiversity hotspots in India (Himalaya, Indo-Burma, Western Ghats, Sundaland) and distinguish them from non-hotspot regions.

 

Question 16. A species is considered extinct
(a) When its member is confined to a particular area
(b) When its member is maintained in a non-native area
(c) When none of its members is alive in the native area
(d) When none of its members alive anywhere in the world
Answer: (d) When none of its members are alive anywhere in the world.
In simple words: A species is called extinct when not a single living member of that kind can be found anywhere on Earth. This means the species is completely gone forever.

🎯 Exam Tip: Understand the difference between 'extinct in the wild' (still exists in captivity) and 'globally extinct' (completely gone).

 

Question 17. The concept of Red list was noted in
(a) 1953
(b) 1963
(c) 1973
(d) 2003
Answer: (b) 1963
In simple words: The idea of creating a "Red List" to track species facing extinction started in 1963. This list helps us know which animals and plants are in danger.

🎯 Exam Tip: Remember the year 1963 as the origin of the Red List concept, as it's a key historical point in conservation.

 

Question 18. Match the following
(a) Tiger reserves in India – (i) 4
(b) Hotspots in India – (ii) 104
(c) Biosphere reserves in India – (iii) 27
(d) National parks in India – (iv) 18
Answer:
(a) Tiger reserves in India – (iii) 27
(b) Hotspots in India – (i) 4
(c) Biosphere reserves in India – (iv) 18
(d) National parks in India – (ii) 104
In simple words: This match shows the correct numbers for important conservation areas in India. For example, India has 4 biodiversity hotspots and 104 national parks.

🎯 Exam Tip: Accurately recall the current numbers of protected areas (hotspots, national parks, tiger reserves, biosphere reserves) in India for matching questions.

 

Question 19. Statement 1: Biodiversity is the assemblage of different life form. Statement 2: The term biodiversity was introduced by Edward Wilson.
(a) Statement 1 is correct, statement 2 in incorrect
(b) Statement 1 is incorrect, statement 2 in correct
(c) Both the statements are correct
(d) Both the statements are incorrect
Answer: (a) Statement 1 is correct, statement 2 in incorrect
In simple words: The first statement is true because biodiversity is indeed about all the different kinds of life. However, the second statement is false because Walter Rosen, not Edward Wilson, first used the term biodiversity.

🎯 Exam Tip: Clearly differentiate between the definition of biodiversity and who coined the term (Walter Rosen) versus who popularized it (Edward Wilson).

 

Question 20. Statement 1: India is the seventh-largest country in the world in terms of area. Statement 2: It includes ten biogeographic areas.
(a) Statement 1 is correct, statement 2 is incorrect
(b) Statement 1 is incorrect, statement 2 is correct
(c) Both the statements are correct
(d) Both the statements are incorrect
Answer: (c) Both the statements are correct
In simple words: Both statements are true. India is the seventh-largest country by land area, and it is divided into ten special regions that scientists use to study its different plants and animals.

🎯 Exam Tip: Facts about India's geographical status and its biogeographical classification are common knowledge points in environmental studies.

 

Question 21. Statement 1: the Western Ghats extend from South Gujarat to Karnataka. Statement 2: Wild ass is an endemic species of Western Ghats
(a) Statement 1 is correct, statement 2 is incorrect
(b) Statement 1 is incorrect, statement 2 is correct
(c) Both the statements are correct
(d) Both the statements are incorrect
Answer: (d) Both the statements are incorrect
In simple words: The first statement is false because the Western Ghats extend from Gujarat to Kerala, not just Karnataka. The second statement is also false because the wild ass is found in the Indian desert, not in the Western Ghats.

🎯 Exam Tip: Know the correct geographical extent of major regions like the Western Ghats and the endemic distribution of key species.

 

Question 22. Statement 1: Exotic species are a non-native organisms. Statement 2: Sailfin catfish is an exotic species in India.
(a) Statement 1 is correct, statement 2 in incorrect
(b) Statement 1 is incorrect, statement 2 in correct
(c) Both the statements are correct
(d) Both the statements are incorrect
Answer: (c) Both the statements are correct
In simple words: Both statements are true. Exotic species are indeed non-native, meaning they come from other places. The sailfin catfish is a good example of such a species found in India, introduced from elsewhere.

🎯 Exam Tip: Understand the definition of an exotic species and be able to recall examples relevant to the Indian context.

 

12th Bio Zoology Guide Biodiversity and its Conservation Two Marks Questions and Answers

 

Question 1. Define biodiversity.
Answer: Biodiversity refers to the wide variety of life found in different places like land, oceans, and other water bodies. It includes the differences within species, between different species, and across all the different natural systems in a region. This variety helps maintain healthy ecosystems.
In simple words: Biodiversity is the huge range of all living things, including plants, animals, and tiny organisms, found in different places on Earth.

🎯 Exam Tip: When defining biodiversity, ensure you mention variability at multiple levels: within species, between species, and across ecosystems.

 

Question 2. Who coined the term biodiversity? Name the levels of biodiversity.
Answer: Walter Rosen coined the term "biodiversity" in 1986. The main levels of biodiversity are genetic diversity, species diversity, and ecosystem diversity. These levels help us understand the full scope of life's variety.
In simple words: Walter Rosen created the word "biodiversity" in 1986. The three main types of biodiversity are genetic, species, and ecosystem diversity.

🎯 Exam Tip: Remember both the name of the scientist (Walter Rosen) and the three key levels of biodiversity for a complete answer.

 

Question 3. What is species richness? Give example.
Answer: Species richness is the total number of different species present in a particular area at a specific time. It tells us how many different types of species live there. For example, the Western Ghats region has a greater number of different amphibian species compared to the Eastern Ghats. This higher count shows greater species richness. It is a simple way to measure how diverse an area is.
In simple words: Species richness means how many different kinds of species live in one area. For example, the Western Ghats have more amphibian species than the Eastern Ghats.

🎯 Exam Tip: For species richness, always include an example to illustrate the concept clearly, showing how one area might be "richer" than another.

 

Question 4. Enlist the factors that determine the distribution of biodiversity.
Answer: Several factors affect where biodiversity is found. These include the temperature of a place, how much rain it gets (precipitation), its distance from the equator (known as latitudinal gradient), and its height above sea level (altitudinal gradient). These elements together shape the different patterns of life distribution we see across the world.
In simple words: Things like temperature, rainfall, how far it is from the equator, and how high it is above the sea all decide where different kinds of plants and animals can live.

🎯 Exam Tip: When listing factors, make sure to briefly explain or clarify terms like 'latitudinal gradient' and 'altitudinal gradient'.

 

Question 5. What are the most important causes of biodiversity loss?
Answer: The most significant causes of biodiversity loss are habitat loss, fragmentation, and destruction. When natural homes for plants and animals are destroyed or broken into smaller pieces, it directly leads to fewer species surviving. These actions greatly reduce the variety of life on Earth.
In simple words: The main reasons why biodiversity is decreasing are when natural homes are lost, broken into small pieces, or completely destroyed.

🎯 Exam Tip: Prioritize habitat loss as the primary cause of biodiversity decline, as it forms the foundation for many other threats.

 

Question 6. Name any two alien animal species introduced in India.
Answer: Two alien animal species introduced in India are:
(a) Tilapia fish (Oreochromis Mozambique)
(b) African Apple snail (Achatina Fulica)
These species can sometimes outcompete native species for resources.
In simple words: Two foreign animal species brought into India are Tilapia fish and African Apple snails.

🎯 Exam Tip: When providing examples of alien species, try to include both common and scientific names if available for precision.

 

Question 7. Name any four biogeographic zones in India.
Answer: Four biogeographic zones in India are:
(a) The Himalayas
(b) Indian deserts
(c) Trans-Himalayan region
(d) Western Ghats
These zones each have unique climates and wildlife. They help classify India's vast ecological diversity.
In simple words: Four special nature zones in India are the Himalayas, Indian deserts, Trans-Himalayan area, and Western Ghats.

🎯 Exam Tip: Practice listing multiple biogeographic zones from different regions of India to demonstrate broad knowledge.

 

Question 8. What do you mean by the term co-extinction?
Answer: Co-extinction means that when one species disappears, another species that depends on it also disappears as a result. This often happens because species are connected in food webs or have special relationships. For example, if a specific plant goes extinct, an insect that only eats that plant will also face extinction. An example is the relationship between orchid bees and some forest trees through cross-pollination.
In simple words: Co-extinction is when one type of animal or plant dies out, and because of that, another type of animal or plant that relied on it also dies out.

🎯 Exam Tip: Focus on the dependency aspect when explaining co-extinction; the core idea is one species' survival is linked to another's.

 

Question 9. What are the natural causes of biodiversity loss?
Answer: Natural causes that lead to biodiversity loss include spontaneous jungle fires that happen on their own, trees falling due to storms or age, landslides, and attacks by insects or locusts that destroy plant life (defoliation). These natural events can drastically change ecosystems and reduce the variety of species. Unlike human activities, these are part of natural cycles, though human actions can worsen their impact.
In simple words: Natural things that cause biodiversity to drop are wildfires, trees falling, landslides, and insect attacks like locusts.

🎯 Exam Tip: Differentiate natural causes from human-induced causes when discussing biodiversity loss, focusing on environmental processes.

 

Question 10. Define hotspot.
Answer: A biodiversity hotspot is a special area that has a very high number of unique species (endemic species) and is also facing a serious threat of rapid habitat loss. These areas are crucial for conservation efforts. They are like special treasure chests of biodiversity that need urgent protection.
In simple words: A hotspot is a place with many different and unique kinds of plants and animals that are also in great danger of disappearing quickly.

🎯 Exam Tip: Emphasize both criteria for a hotspot: high endemism and significant threat of habitat destruction.

 

Question 11. What will be the consequences of the loss of biodiversity?
Answer: The loss of biodiversity has a very big impact on both plant and animal life. When biodiversity is lost, it can lead to:

• A big effect on how food chains and food webs work.
• An immediate danger to the availability of food for living beings.

This means entire ecosystems can become unbalanced and stop working properly.
In simple words: Losing different kinds of plants and animals harms food chains and makes it harder to find enough food for everyone.

🎯 Exam Tip: Focus on the practical implications of biodiversity loss, such as disruption of ecosystems and food security.

 

Question 12. Name the four biodiversity hotspots in India.
Answer: The four biodiversity hotspots in India are:
(a) The Himalayas
(b) Western Ghats
(c) Indo-Burma region
(d) Sundaland
These areas are rich in unique species but also face significant threats.
In simple words: India has four major biodiversity hotspots: the Himalayas, Western Ghats, Indo-Burma area, and Sundaland.

🎯 Exam Tip: Memorize the names of the four biodiversity hotspots in India, as this is a fundamental factual question.

 

Question 13. What does IUCN stand for?
Answer: IUCN stands for the International Union for Conservation of Nature and Natural Resources. It is a global organization that works to conserve nature and promote sustainable use of natural resources. The organization is well-known for creating the Red List of threatened species.
In simple words: IUCN means International Union for Conservation of Nature and Natural Resources. It's a group that works to protect nature.

🎯 Exam Tip: Always provide the full expanded form of abbreviations like IUCN, along with a brief explanation of its role.

 

Question 14. Define species extinction. What makes a species to become extinct?
Answer: Species extinction is when all members of a specific type of plant or animal die out, meaning none are left alive anywhere in the world. A species becomes extinct due to two main reasons: changes in the environment and specific characteristics of its population. Environmental changes might include climate shifts or habitat loss. Population characteristics such as a very small number of individuals or a limited ability to adapt can also lead to extinction. These factors make it impossible for the species to survive and reproduce.
In simple words: Species extinction means a whole kind of plant or animal is completely gone from Earth. This happens because of changes in their environment or problems with their population size.

🎯 Exam Tip: Clearly state that extinction means no living members remain globally and identify both environmental and population factors as causes.

 

Question 15. When a species is considered as locally extinct?
Answer: A species is considered locally extinct when it can no longer be found in a particular area where it once lived, even though it still exists in other parts of the world. This means the species has disappeared from its native region, but not entirely from the planet. For example, a type of fish might disappear from one river but still be present in another.
In simple words: A species is locally extinct if it's gone from one area but still alive somewhere else in the world.

🎯 Exam Tip: Distinguish carefully between local extinction (disappeared from a specific area) and global extinction (disappeared entirely from Earth).

 

Question 16. State the mission of IUCN.
Answer: The mission of the IUCN is to influence, encourage, and help societies around the world. Their goal is to conserve nature and ensure that all natural resources are used fairly and in a way that is good for the environment for a long time. They work to make sure we protect our planet's natural wealth responsibly.
In simple words: IUCN's main job is to help people everywhere protect nature and make sure natural resources are used carefully and fairly for everyone.

🎯 Exam Tip: When stating the IUCN's mission, include key phrases like "conserve nature," "equitable use," and "ecologically sustainable" for accuracy.

 

Question 17. What is the Red list? How many categories of species are mentioned in the Red List?
Answer: The Red List, also known as the Red Databook, is like a catalog of plant and animal species that are at risk of extinction. It helps identify which species are in danger globally. This list categorizes species into eight different groups based on how threatened they are, from 'Least Concern' to 'Extinct'.
In simple words: The Red List is a record of species that might disappear. It has eight different groups to show how much danger each species is in.

🎯 Exam Tip: Remember both the purpose of the Red List (identifying extinction risk) and the number of categories (eight) it uses.

 

Question 18. Mention any four categories of species mentioned in the Red data book.
Answer: Four categories of species mentioned in the Red Data Book are:

• Extinct
• Endangered
• Extinct in wild
• Vulnerable

These categories help scientists and conservationists prioritize which species need the most urgent help.
In simple words: Four types of species on the Red Data Book are: Extinct, Endangered, Extinct in wild, and Vulnerable.

🎯 Exam Tip: Be able to list at least four distinct categories from the Red List, understanding what each implies about the species' status.

 

Question 19. How a national park can be defined?
Answer: A national park is a special natural area officially protected by the government. It is set up because of its important plants, animals, natural features, or geological value. In national parks, human activities are usually not allowed, except for those specifically permitted by the Chief Wildlife Warden of the state. These parks aim to preserve entire ecosystems. They protect the area for its natural beauty and scientific interest.
In simple words: A national park is a government-protected natural area chosen for its important plants, animals, or land features, where most human activities are not allowed.

🎯 Exam Tip: Key points for defining a national park include government notification, ecological importance, and restricted human activity.

 

Question 20. Name any two species that are extinct due to human activities.
Answer: Two species that have become extinct mainly because of human activities are:

• The Dodo bird from Mauritius
• Steller's sea cow from Russia

Human actions like hunting, habitat destruction, and introducing new species led to their complete disappearance. These examples highlight the significant impact humans can have on wildlife.
In simple words: The Dodo bird and Steller's sea cow are two kinds of animals that are now gone forever because of things people did.

🎯 Exam Tip: Knowing specific examples like the Dodo and Steller's sea cow helps illustrate the profound impact of human-induced extinctions.

 

Question 21. Define in-situ conservation.
Answer: In-situ conservation is the practice of protecting and managing plants and animals within their natural habitat where they normally live. This method aims to keep species safe in their own environments. An example of in-situ conservation is establishing national parks, where wildlife is protected directly in its natural home. This approach focuses on preserving the entire ecosystem.
In simple words: In-situ conservation means protecting animals and plants right where they live in nature, like in national parks.

🎯 Exam Tip: The core idea of in-situ conservation is "on-site" protection within the species' natural environment.

 

Question 22. What is the goal of "Project Tiger"?
Answer: The goal of "Project Tiger" is to make sure there is a healthy and growing population of Bengal tigers in their natural homes. This project aims to protect tigers from disappearing and also to save the important natural areas where they live. It helps preserve a crucial part of our natural heritage. This ongoing effort works to secure the tiger's future.
In simple words: Project Tiger wants to make sure Bengal tigers stay safe and increase in number in their wild homes, protecting them from extinction and saving their habitats.

🎯 Exam Tip: Highlight both aspects of Project Tiger's goal: protecting tigers and preserving their natural habitats.

 

Question 23. Give the number of national parks in India. Name any two of them in Tamil Nadu.
Answer: India currently has 104 National Parks. In Tamil Nadu, two examples of National Parks are Guindy National Park (located in Chennai) and Mudumalai National Park (located in the Nilgiris). These parks play a vital role in protecting various ecosystems and species.
In simple words: India has 104 National Parks. Two in Tamil Nadu are Guindy National Park and Mudumalai National Park.

🎯 Exam Tip: Remember the total number of national parks in India and be able to provide specific examples, especially from regional contexts.

 

Question 24. State the role of Biosphere Reserve.
Answer: Biosphere Reserves are special protected areas designed to conserve the variety of life (biodiversity), support the economic and social development of local communities, and maintain the cultural values associated with these regions. They act as learning sites for sustainable development. These reserves aim to balance conservation with human well-being.
In simple words: Biosphere Reserves help protect plants and animals, support local people's lives, and keep cultural traditions alive.

🎯 Exam Tip: The key distinguishing feature of Biosphere Reserves is their triple objective: conservation, development, and logistical support (research/education).

 

Question 25. Name few endangered species protected in Arignar Anna Zoological Park.
Answer: Some endangered species protected in Arignar Anna Zoological Park include the Royal Bengal Tiger, Lion Tailed Macaque, Nilgiri Langur, and Gray Wolf. Zoological parks like this play an important role in the captive breeding and conservation of these vulnerable animals. They provide a safe environment for species facing threats in the wild.
In simple words: Endangered animals like the Royal Bengal Tiger, Lion Tailed Macaque, Nilgiri Langur, and Gray Wolf are protected at Arignar Anna Zoological Park.

🎯 Exam Tip: When asked for examples of endangered species, provide a variety of types (e.g., big cat, primate, wolf) to show broader knowledge.

 

Question 26. Give the names of two methods of in-situ conservation.
Answer: Two methods of in-situ conservation are:

• Wildlife Sanctuaries
• Biosphere reserve

These methods protect species in their natural environments, allowing them to thrive within their original ecosystems. They are effective ways to save many species at once.
In simple words: Two ways to protect animals and plants in their natural homes are through Wildlife Sanctuaries and Biosphere Reserves.

🎯 Exam Tip: Be ready to distinguish between in-situ (on-site) and ex-situ (off-site) conservation methods and provide examples for each.

 

12th Bio Zoology Guide Biodiversity and its Conservation Three Marks Questions and Answers

 

Question 27. Point out the biosphere reserves in Tamil Nadu.
Answer: The biosphere reserves located in or partly in Tamil Nadu are:

• Nilgiris (shared between Tamil Nadu and Kerala)
• Agasthyamalai (shared between Tamil Nadu, Kerala, and Karnataka)
• Gulf of Mannar (located in Tamil Nadu)

These reserves protect a wide range of unique ecosystems, from mountains to marine areas. They are crucial for biodiversity conservation and sustainable development in the region.
In simple words: In Tamil Nadu, there are biosphere reserves like Nilgiris, Agasthyamalai, and the Gulf of Mannar.

🎯 Exam Tip: Note if a biosphere reserve is shared across multiple states; this detail shows a deeper understanding of geographical distribution.

 

Question 28. Write a note on Sacred Groves.
Answer: Sacred groves are patches of forest or woods that are considered very special and holy by a particular culture or community due to religious beliefs. These groves are protected by local people out of respect for deities or ancestral spirits. They act as important refuges for biodiversity, preserving many plants and animals. Sacred groves are found in various cultures around the world and are examples of traditional conservation practices. They highlight how cultural values can help protect nature.
In simple words: Sacred groves are small forests that people protect for religious reasons. They help save many plants and animals and are found in different cultures.

🎯 Exam Tip: Emphasize both the cultural/religious significance and the ecological role (biodiversity refuge) of sacred groves.

 

Question 29. What is ex-situ conservation?
Answer: Ex-situ conservation involves protecting selected rare plants and animals in places outside their natural homes. This method is used when a species is at high risk in its natural environment. It includes maintaining species in off-site collections like zoos, botanical gardens, and gene banks. The aim is to breed these species and potentially reintroduce them into the wild later. This approach helps create a backup population for endangered species.
In simple words: Ex-situ conservation means protecting rare plants and animals away from their natural homes, like in zoos or special seed banks.

🎯 Exam Tip: The core idea of ex-situ conservation is "off-site" protection, often involving human-controlled environments.

 

Question 30. Why Red list is prepared periodically?
Answer: The Red List is prepared regularly for several important reasons:

• To raise awareness about how severely different species are threatened with extinction.
• To identify and document species that are at a high risk of disappearing.
• To provide a global measure of how biodiversity is declining.
• To help in planning conservation priorities and actions needed to protect species.
• To offer information for international agreements on saving the variety of life.

Regular updates are essential because the status of species can change due to environmental pressures or conservation efforts.
In simple words: The Red List is made often to show which species are in danger, to track biodiversity loss, and to help plan how to protect them.

🎯 Exam Tip: When explaining why the Red List is updated periodically, focus on monitoring changes in species status and informing dynamic conservation strategies.

 

Question 31. Name the types of extinctions.
Answer: There are three main types of extinctions. These include natural extinction, which is a slow process; mass extinction, which happens due to large-scale environmental events; and anthropogenic extinction, which is caused by human activities. Understanding these types helps in conservation efforts.
In simple words: Extinction can be natural, like when species die out over time, or caused by big natural disasters, or by things humans do.

🎯 Exam Tip: When listing types of extinctions, briefly define each to show a complete understanding of the concept.

 

Question 32. Point out the human activities that threaten biodiversity.
Answer: Human activities directly and indirectly harm biodiversity. Direct impacts include changing land use, introducing or removing species, over-harvesting resources, pollution, and climate change, all of which put great pressure on species. Indirect drivers, such as population growth, economic activities, technological advancements, cultural practices, and religious factors, also contribute to biodiversity loss. These factors collectively disrupt natural balances and ecosystems.
In simple words: Things people do, like changing land, polluting, or overusing resources, hurt many different kinds of plants and animals. Our growing numbers and how we live also cause harm.

🎯 Exam Tip: Focus on linking specific human actions to their environmental consequences to clearly explain the threat to biodiversity.

 

Question 33. Extinction of Dodo bird led to the danger of Calvaria tree - Justify.
Answer: The extinction of the Dodo bird is linked to the danger of the Calvaria tree because they had a special relationship called co-extinction. The Dodo bird, which lived on Mauritius Island, ate the fruits of the Calvaria tree. Its strong gizzard and digestive system helped break down the hard outer layer of the tree's seeds, making it possible for them to sprout. Without the Dodo to process its seeds, the Calvaria tree struggled to reproduce and faced the risk of extinction itself, showing how much species can depend on each other.
In simple words: The Dodo bird ate Calvaria tree seeds and helped them grow. When Dodo birds died out, the Calvaria tree seeds could not sprout easily, putting the tree in danger.

🎯 Exam Tip: Use "mutualistic association" or "co-extinction" as keywords to describe the interdependent relationship between species when explaining this concept.

 

Question 34. Give an account on slash and burn agriculture.
Answer: Slash-and-burn agriculture is a farming method where natural tree vegetation is cut down and burned. The cleared land is then used for farming for a few seasons, usually two to three. After this short period, the soil's fertility drops, making it unsuitable for crops. Farmers then abandon this patch and move on to clear and burn a new area of forest for farming. This method, common in India's north-eastern regions, leads to major forest loss, pollution, and the release of carbon dioxide, which harms habitats and climate. This cycle causes significant damage to the local diversity of animals and plants.
In simple words: Slash and burn farming means cutting and burning forests to grow crops for a short time. This harms the forest, pollutes the air, and makes it harder for animals and plants to live there.

🎯 Exam Tip: Emphasize the short-term benefit for farmers versus the long-term ecological damage, including forest loss and CO2 emissions.

 

Question 35. Impact of Industrialization on Biodiversity - Comment.
Answer: Industrialization greatly contributes to climate change, which is a big threat to biodiversity. Industries often rely on burning fossil fuels for energy, releasing a lot of carbon dioxide, a greenhouse gas, into the atmosphere. This increased CO2 causes global warming. Widespread deforestation for industrial needs means less CO2 is absorbed by trees, making the problem worse. Climate change leads to higher land and ocean temperatures, changes in rainfall, melting glaciers, and extreme weather, all of which disrupt ecosystems and force animals to move or die, severely harming biodiversity. Therefore, industrialization has a profound and often negative effect on the planet's diverse life.
In simple words: Industries burn fuel, releasing gases that warm the planet. This changes weather and habitats, making it hard for plants and animals to survive and leading to less biodiversity.

🎯 Exam Tip: Connect industrialization to specific environmental impacts like increased CO2 emissions, climate change, and habitat loss, and explain how these ultimately affect biodiversity.

 

Question 36. What are exotic species? Explain with example.
Answer: Exotic species are organisms brought into an area, sometimes on purpose for commercial reasons or biological control, or sometimes by accident. These species often become invasive, meaning they spread rapidly and harm the local native species. They are considered the second biggest cause of species extinction. Exotic species can negatively affect both water and land environments. For example, the Tilapia fish (Oreochromis mosambicus), introduced from South Africa to Kerala's waters in 1952 for its high breeding rate, became invasive, causing local native fish like Puntius dubius to face extinction. This shows how non-native species can overpower and replace native ones.
In simple words: Exotic species are plants or animals brought to a new place. They often take over and push out the native species, like the Tilapia fish did in Kerala.

🎯 Exam Tip: Clearly define exotic species and then provide a specific, well-known example to illustrate their negative impact on native ecosystems.

 

Question 37. Write a brief note on Habitat fragmentation.
Answer: Habitat fragmentation is when a large, continuous area of natural habitat is broken into smaller, isolated pieces, reducing its total size. This happens when human activities like converting forests to farms, orchards, urban areas, industrial zones, or building roads cut through natural landscapes. This breaking up of habitats destroys the complex interactions between species, such as food chains, and harms species that are unique to specific habitats (endemic species). It severely reduces biodiversity in the fragmented areas. Animals that need large territories, like big mammals and migratory birds, are especially affected. For instance, elephant corridors are crucial for their movement and are vulnerable to fragmentation, leading to population declines in species like sparrows. This shows how breaking up habitats makes it harder for animals to survive.
In simple words: Habitat fragmentation means breaking a big natural area into small parts, often by human construction. This makes it hard for animals to live, find food, and move around, leading to fewer different kinds of plants and animals.

🎯 Exam Tip: Explain fragmentation as both a reduction in area and a division, emphasizing its impact on species interactions and large-territory animals.

 

Question 38. Write a note on the biogeographic area the Gangetic plains.
Answer: The Gangetic Plains are a large, flat, and fertile region mostly defined by the Ganges river system. They cover about 11% of India's total land area and are extremely productive for agriculture. This region stretches up to the Himalayan foothills. The plains are home to various animals, including rhinoceros, elephants, buffalo, swamp deer, and hog-deer. The fertile soil and abundant water from the river system make it a rich area for both human settlement and diverse wildlife.
In simple words: The Gangetic Plains are very fertile, flat lands along the Ganges river in India. Many animals live there, and it's good for farming.

🎯 Exam Tip: When describing a biogeographic area, mention its geographical features (river system, fertility), approximate size, and notable fauna.

 

Question 39. Compare Alpha diversity with Beta diversity.
Answer:
(i) Alpha diversity: This measures the number of different types of living things, usually species, found within a single specific area, community, or ecosystem. It tells us how rich a particular place is in terms of species. For example, counting the number of bird species in one forest. It helps us understand the local species richness.
(ii) Beta diversity: This measures how species diversity changes between two different but nearby ecosystems. It is found by comparing the number of unique species found in each of the two ecosystems. For example, comparing the unique bird species found in a forest versus a nearby grassland. This helps us understand how different the species composition is between areas.
In simple words: Alpha diversity counts different species in one area. Beta diversity compares unique species between two different areas.

🎯 Exam Tip: Remember that Alpha diversity is 'within' a habitat, while Beta diversity is 'between' habitats, showing species turnover.

 

Question 40. What is species diversity?
Answer: Species diversity refers to the variety and richness of different species found in any given natural living area. The number of species within a specific unit area at a certain time is called species richness. This richness tells us how many different types of species are present and is a way to measure overall species diversity. For instance, the Western Ghats have more different types of amphibians compared to the Eastern Ghats, showing greater species richness. Generally, the more species in an area, the higher its species richness. There are three main ways to measure diversity: Alpha, Beta, and Gamma diversity.
In simple words: Species diversity is how many different kinds of plants and animals live in one place. More different kinds mean higher diversity.

🎯 Exam Tip: Distinguish between 'variety' (number of species) and 'richness' (number and abundance) when defining species diversity, and mention the three indices.

 

Question 41. State the principle of Stockholm declaration - 1972.
Answer: The Stockholm Declaration of 1972 established a principle that states the air, water, land, flora, and fauna of natural ecosystems must be protected. This protection is necessary for the benefit of both the people living now and all future generations, and it should be achieved through careful planning and management. This declaration highlighted the need for global cooperation on environmental issues for the first time.
In simple words: The Stockholm Declaration of 1972 said that we must protect our planet's air, water, land, plants, and animals for everyone, today and tomorrow.

🎯 Exam Tip: Focus on the declaration's core message of protecting natural resources for present and future generations through planning.

 

12th Bio Zoology Guide Biodiversity and its Conservation Five Marks Questions and Answers

 

Question 42. Give an account on genetic diversity and community diversity.
Answer: Genetic diversity refers to the differences in genetic make-up, including the number and types of genes, both within a single species and between different species. It also covers the genetic differences among various populations of the same species. We can measure genetic diversity using molecular techniques. For example, India has over 50,000 different types of paddy and 1,000 types of mango. Variations in genes within a species lead to diversity in size and habitat, and produce different races, varieties, and subspecies. An example is the medicinal plant Rauwolfia vomitoria, which grows in the Himalayas and shows varying potency of its active chemical, reserpine, due to genetic differences. This genetic variation helps species adapt to changing environmental conditions. Community/Ecosystem diversity is the variety of different habitats, living communities, and ecological processes within the biosphere. This diversity is seen at the ecosystem level due to different niches, feeding levels, and ecological processes like nutrient cycles, food webs, energy flow, and interactions between living things. India, with its wide range of environments from alpine meadows and rainforests to mangroves, coral reefs, grasslands, and deserts, has some of the highest ecosystem diversity on Earth.
In simple words: Genetic diversity means all the different genes inside one species, helping it adapt. Community diversity means all the different living places and the animals and plants in them, showing how rich an ecosystem is.

🎯 Exam Tip: Clearly define both genetic and ecosystem diversity, providing a specific example for each to demonstrate understanding.

 

Question 43. Why Tropical regions are rich in biodiversity?
Answer: Tropical regions are rich in biodiversity for several reasons:

• Warm tropical areas, found between the Tropics of Cancer and Capricorn, offer very suitable environments for living organisms.
• The environmental conditions in the tropics are not only good for new species to form but also support a large variety and number of organisms.
• Temperatures typically range between 25°C to 35°C, which is ideal for most life processes to happen easily and efficiently.
• These regions often receive more than 200 mm of rainfall each year.
• The climate, seasons, temperature, humidity, and day-night cycles are quite stable and encouraging for many different species and large populations. This stable climate allows species to thrive without facing harsh changes.
• Tropical areas also have abundant resources and nutrients available, which can support a large amount of life.

In simple words: Tropical places are rich in life because they are warm, get lots of rain, have steady weather, and plenty of food. These conditions help many different kinds of plants and animals grow and thrive.

🎯 Exam Tip: List key factors like stable climate, optimal temperature, high rainfall, and rich resources when explaining tropical biodiversity.

 

Question 44. What is the significance of the slope of regression in a species-area relationship?
Answer: The German naturalist and geographer Alexander von Humboldt studied South American jungles and found that as the area increased, the number of species also increased, but only up to a certain point. This relationship, for many types of organisms like plants, birds, bats, and fish, looks like a rectangular hyperbola when plotted. On a special graph using logarithms, this relationship forms a straight line. The equation for this is \( \log S = \log C + Z \log A \), where \( S \) is species richness, \( A \) is area, \( C \) is a constant (Y-intercept), and \( Z \) is the regression coefficient (the slope of the line). The slope of regression, \( Z \), generally has a value between 0.1 and 0.2, no matter the type of group or region. However, in very large areas like entire continents, the slope can be much steeper, ranging from 0.6 to 1.2. For example, for fruit-eating birds and mammals in tropical forests across different continents, the slope is steeper. The slope of regression \( Z \) is important because it tells us how quickly species richness increases with area, and a steeper slope means that the number of species goes up much faster as the area gets larger. This helps scientists understand how much area is needed to protect a wide variety of species.
In simple words: The slope in a species-area graph shows how many more species you find as you look at a larger area. A steep slope means you find many new species quickly when the area grows.

🎯 Exam Tip: Remember that the 'Z' value (slope of regression) indicates the rate at which species richness increases with area, and its value changes depending on the scale of the area studied.

 

Question 45. Point out any 5 functional attributions of biodiversity.
Answer: The major functional attributes of biodiversity include:

• Nutrient Cycling: Biodiversity ensures the continuous flow of essential nutrients like nitrogen, carbon, water, phosphorus, and sulfur through ecosystems, which are vital for life.
• Soil Health: It contributes to soil formation and keeps the soil fertile through the activity of many different microbes and other living organisms.
• Ecosystem Productivity: Biodiversity boosts the overall productivity of ecosystems, leading to more food and resources for all organisms.
• Water Regulation: Diverse ecosystems, especially forests, act like natural water traps and filters, helping to regulate water flow and purify water. They help manage rainfall and prevent floods.
• Climate Regulation: Biodiversity, particularly dense vegetation, helps regulate temperature and absorb carbon dioxide, which is important for maintaining a stable climate and rainfall patterns.

In simple words: Biodiversity helps cycle nutrients, makes soil healthy, increases food production, manages water, and keeps the climate stable.

🎯 Exam Tip: Focus on clear, distinct ecological roles (e.g., nutrient cycling, soil health, water purification) to highlight the functional importance of biodiversity.

 

Question 46. Explain in detail about various types of extinctions.
Answer: There are three main types of extinctions:
(i) Natural extinction: This is a gradual process where existing species are slowly replaced by species that are better adapted to their environment. This happens due to normal changes in environmental conditions, ongoing evolution, predators, and diseases. Smaller populations tend to become extinct faster than larger ones due to reduced genetic variation and less ability to adapt. For example, certain species might naturally decline as their habitat slowly changes over thousands of years.
(ii) Mass extinction: This involves many species dying out over a relatively short period due to large-scale environmental disasters or catastrophes. The Earth has experienced several mass extinctions throughout its history. A notable example is the mass extinction that occurred about 225 million years ago during the Permian period, which led to the disappearance of 90% of shallow-water marine invertebrates. These events drastically reshape life on Earth.
(iii) Anthropogenic extinctions: These extinctions are directly caused or sped up by human activities. Examples include hunting, destruction of natural habitats, over-harvesting resources, urbanization, and industrialization. For instance, the Dodo bird from Mauritius and Steller's sea cow from Russia were driven to extinction by humans. Amphibians are currently at a high risk of extinction largely due to human-caused habitat destruction. The most severe consequence of biodiversity loss is the permanent loss of unique genetic information (DNA) and the ecological role (niche) that these species held. This loss is irreversible.
In simple words: There are three ways species die out: naturally over a long time, in huge numbers from big disasters, or because of human actions like hunting and destroying homes.

🎯 Exam Tip: For each type of extinction, provide a concise definition and a relevant example, highlighting the cause (natural processes, catastrophes, human activity).

 

Question 47. Give a comparative account on ex-situ conservation.
Answer: Ex-situ conservation means protecting selected rare plants and animals by moving them to places outside their natural homes. This approach involves several methods:

• Offsite Collections: These are living collections of wild and domesticated species kept in places like botanical gardens, zoological parks, wildlife safari parks, and arboreta (gardens with trees and shrubs). The organisms are well cared for, and captive breeding programs help increase their numbers. Many animals that became extinct in the wild are still maintained in these parks. Once their numbers grow, some individuals are carefully released back into their natural habitats. The Indian crocodile and Gangetic dolphin, for instance, have been saved from extinction this way.
• Gene Banks: Gene banks store genetic materials. This includes keeping seeds of important plant strains viable for long periods in seed banks. For threatened animal species, their reproductive cells (gametes) can be preserved using cryopreservation techniques, which keep them alive at very low temperatures for a long time. However, it is not financially possible to conserve all biological wealth or all ecosystems. The number of species that need to be saved far exceeds the current conservation efforts.

Ex-situ conservation plays a crucial role in saving species that are highly endangered or have lost their natural habitats.
In simple words: Ex-situ conservation means protecting animals and plants by keeping them outside their natural homes, like in zoos or special gardens, or by storing their seeds and genetic material in gene banks. This helps keep rare species from dying out.

🎯 Exam Tip: Differentiate between offsite collections (living organisms) and gene banks (genetic material) within ex-situ conservation, and provide an example for each.

 

Higher Order Thinking Skills (HOTs) Questions

 

Question 1. What will be the result, if the relationship between species richness and area for wide variety of taxa are plotted on a long scale?
Answer: If the relationship between species richness and area for a wide variety of species is plotted on a logarithmic scale, the result will be a rectangular hyperbola. This curve shows that as the area increases, the number of different species found also increases, but eventually, the rate of increase slows down. It's a fundamental concept in ecology that helps predict how many species can be found in a given space.
In simple words: If you graph how many species are found in bigger areas, you get a curve called a rectangular hyperbola, meaning species increase with area but slow down later.

🎯 Exam Tip: Use the term "rectangular hyperbola" and briefly explain its meaning in the context of species-area relationships.

 

Question 2. What may be the reasons for the entry of wild lives into the agriculatural lands or towns?
Answer: Wild animals often enter farmlands or towns primarily due to habitat loss and fragmentation, which means their natural homes are being destroyed or broken into smaller pieces. This leaves them with less space and resources. They also come looking for food when their natural food sources are scarce, especially during droughts or changes in seasons. A lack of water sources in their usual habitat can also drive them into human areas. Additionally, increased human activity and encroachment into wildlife areas reduce the safe zones for animals, pushing them closer to human settlements. This interaction highlights the increasing conflict between human development and wildlife survival.
In simple words: Wild animals come to farms and towns mostly because their homes are gone, they can't find food or water in their usual places, or humans have built too close to their habitats.

🎯 Exam Tip: Focus on "habitat loss," "food scarcity," and "water availability" as the primary drivers of wildlife entering human settlements.

 

Question 3. When does a species is categorized as endangered?
Answer: A species is categorized as endangered when it is facing a very high risk of becoming extinct in the near future. This classification means its population numbers have dropped significantly, its habitat is shrinking, or it faces severe threats that could lead to its disappearance from the planet. This status serves as a warning, prompting conservation efforts to protect and recover the species. Many organizations, like the IUCN, assess species populations and threats to assign this crucial category.
In simple words: A species is endangered when it's very likely to die out soon because there are very few left, or its home is being destroyed.

🎯 Exam Tip: Define "endangered" by focusing on the "very high risk of extinction" and the need for conservation.

 

Question 4. Give any two examples of anthropogenic extinction.
Answer: Two examples of species that became extinct due to human activities are the Dodo of Mauritius and Steller's sea cow of Russia. These cases show how human actions, such as hunting and habitat destruction, can directly lead to the permanent loss of species. The Dodo, for instance, was hunted to extinction and could not adapt to new predators introduced by humans. Steller's sea cow was overhunted for its meat and blubber, leading to its rapid disappearance.
In simple words: The Dodo bird and Steller's sea cow are two examples of animals that died out because of humans.

🎯 Exam Tip: Clearly state the species and their location, and briefly mention the human activity responsible for their extinction.

 

Question 5. Mention any two species that had become extinct very recently.
Answer: Two species that have become extinct very recently are:

• George, the tree snail (Achatina apexfulva)
• Sudan, the Northern white rhinoceros (Ceratotherium simum)

These recent extinctions highlight the ongoing crisis of biodiversity loss. George, the tree snail, disappeared due to introduced predatory snails, while Sudan, the last male Northern white rhinoceros, died in 2018, primarily due to poaching and habitat loss. These examples serve as a stark reminder of the urgent need for conservation.
In simple words: George the tree snail and Sudan the Northern white rhinoceros are two animals that became extinct just recently.

🎯 Exam Tip: Name the species and specify that they are recent extinctions, optionally adding a very brief detail about their loss if known.