Thinking Process

Tropical region $23.5^{\circ} {N}-23.5^{\circ} {S}$ show the highest biodiversity as climatic conditions, temperature and moisture conditions favour variety of flora and fauna.

Answer

(a) Climate of countries tropical latitude like Brazil climate remain relatively undisturbed, constant and predictable giving tune for diversification, which favours rich biodiversity.

• South Africa: While South Africa is known for its rich biodiversity, particularly in the Cape Floristic Region, it does not have the same level of overall biodiversity as Brazil. The country’s climate and ecosystems are more varied and less consistently tropical, which limits the extent of biodiversity compared to Brazil.

• Russia: Russia has a vast land area with a wide range of climates, from arctic to temperate. However, much of its territory is covered by taiga and tundra, which are less biodiverse compared to tropical rainforests. The harsh climates in many parts of Russia do not support the same level of species richness as found in tropical regions like Brazil.

• India: India is also known for its significant biodiversity, particularly in regions like the Western Ghats and the Himalayas. However, it does not match the overall biodiversity of Brazil, which benefits from extensive tropical rainforests that support a higher number of species. Additionally, India’s biodiversity is affected by higher population density and greater human impact on natural habitats.

Answer

(c) Keeping animals in zoological parks is not a cause for loss of biodiversity. Some of the major causes of biodiversity loss are

(i) Destruction of natural habitat (primary cause).

(ii) Introduction of exotic (alien species) with indigenous species.

(iii) Over exploitation of natural resources.

(iv) Co-extinction of species.

• (a) Destruction of habitat: This is a major cause of biodiversity loss because it leads to the loss of the natural environment that species need to survive, reproduce, and thrive.

• (b) Invasion by alien species: This can lead to biodiversity loss as alien species can outcompete, prey on, or bring diseases to native species, disrupting the local ecosystem.

• (d) Over-exploitation of natural resources: This results in biodiversity loss because it depletes the resources that species depend on, leading to population declines and extinctions.

Answer

(b) Cynodon (doob grass) is not an invasive alien species. The other three Parthenium (congress or carrot grass), Eichhornia (water hyacinth) and Lantana are alien species which pose threat to native species.

• Lantana: Lantana is an invasive alien species in India. It is known to spread rapidly and outcompete native vegetation, leading to a loss of biodiversity and disruption of local ecosystems.

• Parthenium: Parthenium, also known as congress or carrot grass, is an invasive alien species in India. It is highly aggressive and can dominate landscapes, causing severe ecological and health problems, including allergies and dermatitis in humans.

• Eichhornia: Eichhornia, commonly known as water hyacinth, is an invasive alien species in India. It proliferates quickly in water bodies, obstructing waterways, reducing oxygen levels in the water, and negatively impacting aquatic life and local communities dependent on these water resources.

Answer

(a) Pitcher plant (Nepenthes) an insectivorous plant is found in rain forest of North-East India. These type of plants generally grow in nitrogen deficient soil.

Sunderbans are rich in fauna and flora. Mangroove plants are the characteristic of Sunderbans.

Western ghats are rich in biodiversity. Xerophytes are more common in thar deserts.

• Sunderbans are rich in fauna and flora. Mangrove plants are the characteristic of Sunderbans.
• Western ghats are rich in biodiversity.
• Xerophytes are more common in Thar deserts.

Thinking Process

A biodiversity hotspot is a biogeographic region with a significant reservoir of biodiversity which is under threat from humans.

Answer

(d) Biodiversity hotspots are characterised by large number of flora and fauna, abundance of endemic species and also large number of alien or exotic species. They are mostly found in tropical and temperate regions. There are no biodiversity hotspots in polar regions.

• (a) Large number of species: This is a feature of biodiversity hotspots as they are regions with a high diversity of plant and animal species.
• (b) Abundance of endemic species: This is also a feature of biodiversity hotspots, which are known for having a significant number of species that are found nowhere else in the world.
• (c) Mostly located in the tropics: Biodiversity hotspots are primarily located in tropical and temperate regions, making this statement correct.

Thinking Process

These are the extinct species of particular countries.

Answer

(d) Dodo - Mauritius

Quagga - Africa

Thylacine - Australia

Stellar’s sea cow - Russia

Rest of the given set of extinct animals matched with the provided countries are not true.

• Option (a) is incorrect because:

  • Dodo is not from Africa; it is from Mauritius.
  • Quagga is correctly matched with Africa.
  • Thylacine is not from Russia; it is from Australia.
  • Stellar’s sea cow is not from Australia; it is from Russia.

• Option (b) is incorrect because:

  • Dodo is not from Australia; it is from Mauritius.
  • Quagga is not from Mauritius; it is from Africa.
  • Thylacine is not from Africa; it is from Australia.
  • Stellar’s sea cow is not from Russia; it is from Russia.

• Option (c) is incorrect because:

  • Dodo is correctly matched with Mauritius.
  • Quagga is not from Africa; it is from Africa.
  • Thylacine is not from Russia; it is from Australia.
  • Stellar’s sea cow is not from Australia; it is from Russia.

Answer

(c) All of the above plants are prone to over exploitation due to their respective properties. Nepenthes (pitcher plant) is an insectivorous plant. Psilotum is a pteridophyte and Aconitum is a medicinal plant.

• (a) All are ornamental plants: This is incorrect because not all of the mentioned plants are primarily known for their ornamental value. For example, Nepenthes is known for its insectivorous nature, and Rauwolfia and Aconitum are known for their medicinal properties.

• (b) All are phylogenic link species: This is incorrect because these plants do not serve as phylogenetic link species. Phylogenetic link species are those that provide a connection between different evolutionary branches, which is not a characteristic shared by all these plants.

• (d) All are exclusively present in the Eastern Himalayas: This is incorrect because these plants are not exclusively found in the Eastern Himalayas. They have a wider distribution and are found in various other regions as well.

Answer

(c) Kaziranga National Park is situated in Golaghat and Nagaon districts of (Asom). One horned rhinocerosis specific to this park.

While Corbett National Park is situated in district Nainital (Uttarakhand) and is specific for tiger. It is the first National Park of India, which is famous for tigers.

Bandipur National Park (Mysore) too is specific for tigers. Bhitar Kanika National Park is located in odisha and is specific for salt water crocodile.

• Bhitar Kanika National Park is located in Odisha and is specific for saltwater crocodiles.
• Bandipur National Park (Mysore) is specific for tigers.
• Corbett National Park is situated in district Nainital (Uttarakhand) and is specific for tigers.

Answer

(c) Amphibians have the highest percentage presently, $32 \%$ of all amphibian species in the world face the threat of extinction. Other than these, $23 \%$ of all mammal species and $12 \%$ of all bird species also facing the risk.

• Insects: Insects have a lower percentage of endangered species compared to amphibians. While many insect species are threatened, the overall percentage is not as high as that of amphibians.

• Mammals: Although 23% of all mammal species are facing the risk of extinction, this percentage is still lower than the 32% of amphibian species that are endangered.

• Reptiles: Reptiles also have a lower percentage of endangered species compared to amphibians. The exact percentage is not provided, but it is implied to be less than 32%.

Answer

(d) All of the above mentioned plants are endangered plant species of India. Rauwolfia serpentina (sarpgandha), Santalum album (sandal wood) and Cycas beddonei are facing the threat of extinction due their medicinal and commercial importance.

• Rauwolfia serpentina (sarpgandha) is not incorrect because it is indeed an endangered plant species of India due to overharvesting for its medicinal properties.
• Santalum album (sandal wood) is not incorrect because it is also an endangered plant species of India, primarily due to illegal logging and overexploitation for its valuable wood and oil.
• Cycas beddonei is not incorrect because it is an endangered plant species of India, facing threats from habitat destruction and overcollection for ornamental purposes.

Answer

(d) All the three above mentioned species are neither threatned nor indigenous species of India. Lantana, Eichhornia (water hyacinth) and African catfish (Clarias gariepinus) all are alien (exotic species) which are invasive and have an harmful impact resulting in extinction of the indigenous species.

• (a) All are endangered species of India: This is incorrect because Lantana, Eichhornia, and African catfish are not endangered species. Instead, they are invasive species that pose a threat to native biodiversity.

• (b) All are key stone species: This is incorrect because keystone species play a crucial role in maintaining the structure of an ecosystem. Lantana, Eichhornia, and African catfish are invasive species that disrupt ecosystems rather than support them.

• (c) All are mammals found in India: This is incorrect because Lantana is a plant, Eichhornia is an aquatic plant (water hyacinth), and African catfish is a fish. None of them are mammals.

Answer

(b) Extinction of passenger pigeon (Ectopistes migratorius) was due to over exploitation by human beings. Factors like increase in number of predatory birds, non-availability of food and bird flu virus infection did not contribute to the extinction of passenger pigeon.

• Increased number of predatory birds: This factor did not significantly contribute to the extinction of passenger pigeons as their primary threat was human exploitation rather than natural predators.
• Non-availability of the food: Passenger pigeons had a diverse diet and were not significantly affected by food scarcity; their extinction was primarily due to human activities.
• Bird flu virus infection: There is no historical evidence to suggest that bird flu virus infection played a role in the extinction of passenger pigeons. The primary cause was over-exploitation by humans.

Answer

(c) Stellar’s sea cow (from Russia) is a recently extinct animal.

Parthenium (carrot grass) is an exotic weed, which grows rapidly and adversly affects the native species.

African catfish is also an alien species which adversly affects the growth of indigenous Clarias batrachus - our local species.

Lantana camara, another alien species, is also strongly competing with native species.

• Parthenium is not an endemic species of our country; it is an exotic weed that grows rapidly and adversely affects native species.
• African catfish is a threat to indigenous catfishes as it is an alien species that adversely affects the growth of the local species Clarias batrachus.
• Lantana is not popularly known as carrot grass; it is another alien species that strongly competes with native species.

Thinking Process

Formation of coral reef takes place in favourable climatic conditions in costal regions.

Answer

(c) Coral reefs are the most productive ecosystem $\left(2000-6000 \mathrm{kcal} / \mathrm{m}^{2} / \mathrm{y}\right)$ and form the most diverse part of costal region providing a home to fish molluscs, crustaceans sponges, cnidarians, etc.

Mangroves, found in coastal regions usually have plants growing in swampy and saline water, deserts have mostly xerophytic species and Alpine meadows are related to high altitudes and do not show much tree growth.

• Mangroves, found in coastal regions, usually have plants growing in swampy and saline water, which limits the diversity of species compared to coral reefs.
• Deserts have mostly xerophytic species, which are adapted to arid conditions, resulting in lower biodiversity.
• Alpine meadows are related to high altitudes and do not show much tree growth, leading to less biodiversity compared to coral reefs.

Thinking Process

Tropics possess maximum biological diversity due to undisturbed climatic conditions.

Answer

(c) Amazon is a rain forest that covers most of the Amazon basin of South America and teritory including nine nations. It represents over half of the planet’s rain forests and exhibits the largest and the most diversified tropical rainforest.

It is home to more than 40000 species of plants, 3000 of fishes, 1300 of birds, mammals, amphibians, reptiles and more than 125000 invertebrates. Amazon rainforest is popularly called the ’lungs of the planet earth’ because its vegetation continuously recycles carbon dioxide into oxygen.

Taiga forest, present in broad belt of Northern hemisphere, represents the largest terrestrial biome.

Tundra forest is a biome where tree growth is hindered by low temperature and short growing season. Rain forests of North-East India are tropical forests with a natural reservoir of genetic diversity.

• Taiga forest: The Taiga forest, present in a broad belt of the Northern Hemisphere, represents the largest terrestrial biome, but it is not known for its role in recycling carbon dioxide into oxygen to the extent that the Amazon rainforest is.

• Tundra forest: The Tundra forest is a biome where tree growth is hindered by low temperatures and a short growing season, making it less effective in terms of vegetation that can recycle carbon dioxide into oxygen.

• Rainforests of North-East India: While the rainforests of North-East India are tropical forests with a natural reservoir of genetic diversity, they do not cover as vast an area or have as significant an impact on the global carbon-oxygen cycle as the Amazon rainforest.

Answer

(b) Rauwolfia vomitoria is the source of active chemical drug reserpine, which is prescribed in hypertension and act as tranquilliser. Datura is a plant with hallucinogenic properties. Drug belladonna is obtained from Atropa belladonna and drug. Opium is obtained from Papaver somniferum.

• Datura: Datura is a plant with hallucinogenic properties and is not a source of the active chemical drug reserpine.

• Atropa: Drug belladonna is obtained from Atropa belladonna, not reserpine.

• Papaver: Opium is obtained from Papaver somniferum, not reserpine.

Answer

(d) Fungi are group of eukaryotic heteromorphic organisms with diverse forms, sizes, physiology and mode of reproduction. They exhibits more specific diversity. This is followed by algae, bryophytes and then fens and alliles.

• Gymnosperms: Gymnosperms are a group of seed-producing plants that include conifers, cycads, Ginkgo, and gnetophytes. They exhibit less species diversity compared to fungi because they are primarily adapted to specific environments and have fewer species overall.

• Algae: Algae are a diverse group of photosynthetic organisms found in various aquatic environments. While they do exhibit significant diversity, they are not as diverse as fungi in terms of forms, sizes, physiology, and modes of reproduction.

• Bryophytes: Bryophytes, which include mosses, liverworts, and hornworts, are non-vascular plants that are primarily found in moist environments. They have less species diversity compared to fungi due to their simpler structures and more limited range of habitats.

Answer

(a) Maximum biodiversity is observed in tropics as the tropical region exhibit less seasonal variations, i.e., remain undisturbed.

The temperate region are more seasonal, less constant and exhibit less species diversity. Also, alpines with low temperature and high altitudes show less diversity.

• The temperate region is more seasonal, less constant, and exhibits less species diversity.
• Alpines have low temperatures and high altitudes, which result in less diversity.

Answer

(b) The historic convention on biological diversity held in Rio de Janeiro (Brazil) in 1992 is known as Earth Summit ( Ist). The explanation for other options is CITES (Convention on International Trade in Endangered Species of wild flora and fauna) has helped in restricting poaching and loss of rare species.

MAB stands for Man and Biosphere Programme which undertakes establishment and maintenance of biosphere reserves.

• CITES (Convention on International Trade in Endangered Species of wild flora and fauna) has helped in restricting poaching and loss of rare species.
• G-16 Summit is not related to the convention on biological diversity.
• MAB (Man and Biosphere Programme) undertakes the establishment and maintenance of biosphere reserves.

Answer

(b) All the three above mentioned techniques are ex-situ conservation methods. At present gametes of threatened species can be preserved in viable conditions for longer duration by cryopreservation method (at very low temperature- $196^{\circ} \mathrm{C}$ ).

Fertilisation can be achieved in laboratory-in vitro, and species can be improved or propagated by tissue culture method, a plant breeding principle.

• (a) All are in situ conservation methods.

  • This is incorrect because in situ conservation involves preserving species in their natural habitats, whereas the techniques mentioned (in vitro fertilisation, cryopreservation, and tissue culture) are performed outside the natural environment, making them ex situ methods.

• (c) All require ultra modern equipment and large space.

  • This is incorrect because while these techniques may require modern equipment, they do not necessarily require large space. For example, cryopreservation and tissue culture can be conducted in relatively small laboratory settings.

• (d) All are methods of conservation of extinct organisms.

  • This is incorrect because these techniques are used for the conservation of threatened or endangered species, not extinct ones. Once a species is extinct, these methods cannot be used to bring them back.

Answer

The characteristics that make a community stable are

(i) Less variation in productivity from year to year.

(ii) Resistance or resilience to occasional disturbances (natural or man-made).

(iii) Resistance to invasions by alien species.

Answer

Nobody knows the real reason but the scientists believe that any one of the following could have triggered mass extinction of species in the past.

(i) Fall of sea levels.

(ii) Change in temperature (freezing or warming).

(iii) Asteroid/meteorite hitting the planet.

(iv) Poisonous hydrogen sulphide emissions from the sea.

(v) Nova/super nova/gamma ray burst.

(vi) Plate tectonics.

Answer

The greater ecological diversity of India is because of the geographical diversity in terms of varying topography, e.g., deserts, rain forests, mangroves, coral reefs, wetlands, estuaries and alpine meadows all are present in India. This results in building of different varieties of ecosystems with greater ecological diversity.

Thinking Process

Artificial or anthropogenic ecosystem are man-made terrestrial or aquatic ecosystems. The most important are agriculture field, generally called as agroecosystems.

Answer

The man-made ecosystems like agricultural field of paddy or wheat show very low diversity, but possess high productivity. These are also an example of monoculture.

Answer

Red in the IUCN Red list (2004) refers to the taxa with the highest risk of extinction.

Answer

The biodiversity hot spots are regions with very high level of species richness, especially those under threat from humans, thus their protection can reduce the current rate of extinction. These regions can be protected as biological reserves, national parks and sanctuaries.

Answer

Endemic species are native or indigenous species, which are restricted to a particular geographical region. Exotic or alien species are those species which are introduced from one geographical region to another geographical area. Exotic species may lead to disappearance of native species.

Answer

Species diversity refers to the number and distribution of species in an area. It is expressed in terms of ’number of species per unit area’ and also as number of individuals of different species in an area.

Ecological diversity refers to the diversity at ecosystem level. It is related to different types of ecosystem habitats e.g., terrestrial (forests, grasslands, etc.) and aquatic (freshwater and marine) ecosystems.

Answer

Plant Rauwolfia vomitoria is a source of drug reserpine which acts as tranqulliser. Genetic variation shown by this medicinal plant might be in terms of the potency and concentration of active chemical (resperin) that plant produces.

Answer

Red Data Book is a compilation of data or records of species threatened with risk of extinction (which are known to be endangered). The book is maintained by IUCN (headquartered at gland in Switzerland).

Answer

Gene pool refers to the sum total of all genes of every individual in an inbreeding population.

Answer

Frugivorous term is used for those animals which eat only fruits or eat fruit as their staple diet.

Answer

IUCN stands for ‘International Union for Conservation of Nature and Natural Resources’. Its headquarters are situated at gland in Switzerland.

Answer

(i) Bioprospecting is a term that describes the process of discovery and commercialisation of new products based on biological resources.

(ii) Endemism refers to presence of some species in particular regions only and now here else.

Answer

Both are angiospermic flowering plants.

Answer

Both the species are conserved in their natural habitats.

Answer

In earlier time extinction of species occurred due to natural causes or calamities like flood, volcanic eruption, prolonged drought and landslides, etc. While at present human activities are the major cause of species extinction.

Answer

Out of the four major causes for the loss of biodiversity, loss of habitat and fragmentation is the major cause as

(i) Habitat loss and fragmentation caused by clearing and over-exploitation of forest areas for agriculture, urbanisation and industrialisation, results in destruction of natural habitats.

(ii) Increasing human population has overburdened the forest resources and have destroyed forest land, which means loss of habitat for several species.

(iii) In addition, large habitats are broken up into small fragments, because of which mammals and birds requiring large territories and migratory habits are badly affected, leading to decline inpopulation.

Answer

Co-extinction is the extinction of two mutually related or interelated species for instance a host fish extinction leads to the extinction of all those parasites exclusively found on it. Another example is plant pollinator mutualism, where extinction of one leads to the extinction of other.

Insect, aphids are polyphagous (feed on more than one plant species) or monophagous (feed on a particular species of plant). Monophagous insects may become extinct, if the plant species upon which they feed becomes extinct.

Answer

In very large areas, the number of species is much more that is why the curve is much steeper. This is because the larger area has more, food availability and other resources, so obviously more species may thrive.

Answer

No, it is not possible that productivity and diversity of a natural community remain constant over a certain time period. This is because

(i) The natural habitat is never maintained in real.

(ii) Abundant resources are never available, they are always in short supply or just enough.

(ii) Environmental conditions for survival and reproduction are continuously changing.

Answer

The tropical/subtropical region exhibit maximum biological diversity because these region remain undisturbed due to less variable climatic conditions. So, tropics had a longer evolutionary time for species diversification. The temperate environment are more seasonal, less constant and unpredictable, therefore less niche specialisation and lesser species diversity are observed.

Answer

Many bacteria cannot be cultured under normal conditions in vitro, which creates a problem in studying their morphological and biochemical characteristics.

Morphology and biochemistry along with some other characteristics are used for the assessment of biodiversity of bacteria. Thus, conventional methods are not suitable for the assessment of biodiversity of bacteria.

Answer

The criteria that should be used in categorising a species as threatened are

(i) Number of the members of the species are declining at an alarming rate.

(ii) Their habitat is being modified or destroyed.

(iii) Predator or poacher activities are increasing.

Answer

Amphibians are more vulnerable to extinction

(i) Habitat Modification or Destruction Amphibians generally need aquatic and terrestrial habitats to survive; threats to either habitat can affect populations. Hence, amphibians may be more vulnerable to habitat modification than organisms that require only one habitat type.

(ii) Habitat Fragmentation This means isolation of a few areas by habitat modification. Small populations that survive within such fragments are often susceptible to inbreeding, genetic drift or extinction due to small fluctuations in the environment.

(iii) Large Scale Climate Changes These changes can further modify aquatic habitats, preventing amphibians from spawning.

Answer

There are two methods to estimate and extrapolate the number of species on earth

(i) The primary method used by the scientists to extrapolate the number of species on earth is the estimation rate of discovery of new species.

(ii) Total number of species can also be extrapolated by the statistical comparison of the tropical and temperate species richness of exhaustively studied groups of insects. The ratio is then extrapolated with existing species of plants and animals to predict the gross estimate of the number of species on earth.

Answer

(i) Humans derive numerous economic benefits directly from diversity of organisms.

(a) Food products (cereals, pulses and fruits).

(b) Firewood.

(c) Fibre (cotton, jute from plants and silk, wool from animals).

(d) Construction material (timber for making furniture, houses and sports goods).

(e) Industrial products (tannins, lubricants, dyes, resins and perfumes).

(f) Products of medicinal importance (about 25000 plants are used in traditional medicine).

(ii) There are huge intangible benefits that humans derive from the diversity of life.

(a) Pure oxygen.

(b) Natural pollinators.

(c) Flood and soil erosion control.

(d) Nutrient replenishment.

(e) Waste recycling by microbes and other insects, etc.

(f) Aesthetic pleasure and mental peace.

Answer

The two major causes other than anthropogenic causes of the loss of biodiversity are

(i) Alien Species Invasions When alien species are introduced unintentionally or deliberately in a habitat, some of them can cause decline or extinction of indigenous species.

(ii) Co-extinctions When a species becomes extinct, the plant and animal species associated with it, in an obligatory way, also become extinct.

Answer

An endangered species is a population of organisms, which is facing a high risk of becoming extinct because

(i) Its number being very low.

(ii) It is threatened by changing environment.

(iii) It is facing predator threat.

Endangered plant species-Venus fly trap

Endangered animal species-Siberian tiger

Answer

Sacred groves are sacred tracts which are held in high esteem by local communities.

The sacred groves are dedicated to local deities or ancestral spirits and are protected by local communities through social traditions and taboos that incorporate spiritual and ecological values.

Sacred groves represent native vegetation in a natural or near natural state and are thus, rich in biodiversity and harbour many rare species of plants and animals.

Such sacred groves are found in Meghalaya (Khasi and Jaintia hills), Aravalli hills of Rajasthan, Western Ghats, regions of Karnataka and Maharashtra and Madhya Pradesh (Bastar, Chanda and Sarguja region).

Answer

Places to be suggested for studying coral reefs-Andaman and Nicobar Islands. Mangrove vegetation-Paschim Banga Sunderban, Estuaries-Coastal areas of Karnataka.

Answer

Yes, There is more solar energy available in the tropics because

(i) The sun’s rays are more concentrated.

(ii) The sun’s rays have less atmosphere to pass through, so less energy is lost in absorption and reflection by the atmosphere.

(iii) Tropical rainforest areas absorbs radiations due to presence of dense vegetation. Availability of more solar energy in tropics contribute higher productivity which in turn might contribute greater maximum biodiversity.

Answer

When a species becomes extinct, the plant and animal species associated with it, in an obligatory way, also become extinct, e.g., when a host fish species becomes extinct, its parasites also vanish. This is called co-extinction.

Some other examples of co-extinction are; plant-pollinator mutualism where extinction of one leads to the extinction of other. Monophagous insect that feeds on particular plant species becomes extinct due to extinction of that plant species.

Answer

When alien species are introduced unintentionally or deliberately in a habitat, some of them can cause decline or extinction of indigenous species, e.g., extensive environmental damage caused and threat posed to our native species by invasive weed species like carrot grass (Parthenium), Lantana and water hyacinth (Eichhornia). Another example of exotic species invasion is Nile perch, a large predator fish.

When this alien species was introduced into lake of Victoria in East Africa, it started feeding on native, cichlid fish. As a result indigenous cichlid fish became extinct and due to scarcity of food, predator Nile perch died too.

Answer

Biodiversity is the occurrence of different type of species, habitat, ecosystem, gene, genepool in a particular place and various parts of earth.

As an individual, biodiversity can be conserved with conservation strategies and management of both biotic and abiotic resources.

Some of the conservation strategies are as follows

(i) Protection of useful animals and plants in their natural habitat or in situ conservation.

(ii) Preservation of critical habitats like feeding and breeding areas and resting area of endangered species to promote their growth and multiplication.

(iii) Hunting should be banned or regulated.

(iv) Habitat of migratory animals should be protected by bilateral or multilateral agreements.

(v) People should be made aware of the importance of biodiversity and its conservation.

(vi) Over exploitation of natural resources must be avoided.

(vii) Biodiversity plays an important role in maintaining and sustaining supply of goods and services.

(viii) Conservation of biodiversity ensures well being of all the living creatures and their future generations.

Answer

Scientific explanation for the direct relationship between diversity and stability of an ecosystem could be as follows

Imagine a forest area, where diverse species of plants are growing. Plants harbour a variety of insects on which a lot of bird species would depend for their food.

If a specific plant species dies, the related insect population will be affected that would lead to food unavailability for the birds.

In addition, if the plant species was a nitrogen fixer, the death of these plants would mean no replenishment of soil with nitrogen. This will obviously affect the other plants as well. So, if the cycle continues, the whole habitat/ecosystem will be negatively affected.

Answer

The humans first evolved around 2.5 million years ago and agriculture began about 11 thousand years ago. It is since then that humans have started to exploit the forest land for agriculture. Development in medical technology has increased the lifespan of humans, decreased the mortality rate of mother and child, further aggravating the problem of human population.

Along with this, the industrial revolution caused enormous consumption of earth’s resources but giving back nothing. The monumental amount of waste is destroying the natural habitat of other species, be it aquatic or terrestrial, endangering and later causing extinction thereof.

This is how human activities have led to the increase in conflict between humans and wildlife.

Answer

Ecosystem Services

The products of ecosystem processes are termed as ecosystem services. Forests are the major sources of ecological services. Some of the ecosystem services they provide are

(i) Purification of air and water.

(ii) Mitigating droughts and floods.

(iii) Cycling nutrients.

(iv) Generating fertile soils

(v) Providing wildlife habitat.

(vi) Maintenance of biodiversity.

(vii) Pollination of crops.

(vii) Providing storage site for carbon.

(ix) Providing aesthetic, cultural and spiritual values.

Robert Constanza and his colleagues tried to put price tags on nature’s life support services, which was about US $33 trillion a year. No, i am not in favour of levying a charge on ecological services but it is very important, to understand how much nature is providing us for free and if we overuse or misuse its resources, we’ll have to pay a heavy price for it.

Answer

Biological resources are the basis of life forms on this planet. The countries with maximum biodiversity possess better potential to compete with the rest of the world. Biodiversity has great economic importance to mankind due to its many uses, some of, which with consumptive value are following

Food is obtained from biodiversity sources like livestock, forestry and fish. Biodiversity in modern agriculture is beneficial due as a source of new crops. e.g., just three cereals crop like wheat, rice and maize account for about $55 \%$ of protein and $60 \%$ of calories in humans.

Drugs such as morphine (Papaver somniferum), quinine (Cinchona ledgeriana), reserpine (Rauwolfia vomitaria), belladonna (Atropa belladonna), aconite (Aconitum, napellus), wintergreen and birth bark (Gaultheria procumbens) are derived from plants.

About $70-80 \%$ of entire population is dependent on plants or its extract for medicine. penicillin (Penicillium notatum), tetracycline (bacteria), digitalin (Digitalis) are some examples of medicinal plants.

Plant like Chorchorus, Gossypium are sources of fibre while Jatropha is a source of biofuels. Fossils fuels (e.g., petrolum) are obtained from fossils of organisms.

Answer

Species diversity decreases as we move towards the poles, because

(i) Temperature decreases and conditions become harsh.

(ii) Both the amount and intensity of solar radiation decreases.

(iii) Vegetation decreases.

(iv) Less resources available to support species.

Speciation is generally a function of time and environmental stability, so if conditions are too harsh, it is difficult for the species to survive and adapt. This results in decrease in biodiversity towards the poles.

Answer

Ecologist Paul Ehrlich gave rivet popper hypothesis to help understand the contribution species richness. He compared each species with rivet in the body of an airplane.

(i) This hypothesis explains that ecosystem to be an airplane and the species to be the rivets joining all parts together.

(ii) If every passenger travelling in the airplane start taking rivets home (causing a species to become extinct), initially it may not affect flight safety (proper functioning of ecosystem), but over a period of time the plane becomes weak and dangerous (species become endangered and then extinct.

Answer

According to AV Humboldt, a German scientist within, a region, species richness increased with increasing explored area (only upto a limit). Accordingly the relation between species richness and area for a wide variety of taxa (birds, bat, angiosperms, aquatic fishes) turns out to be a rectangular hyperbola.

The relationship depicts a straight line on a logaithimic scale described by the following equation

$$ \log S=\log C+Z \log A $$

Where, ’ $S$ ’ stands for species richness, ’ $A$ ’ is area and ’ $Z$ ’ and ’ $C$ ’ are slope of line (regression coefficient) and y intercept respectively.