Text Book Back Questions and Answers - Chapter 11 Biodiversity and its Conservation 12th Biology Zoology Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

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On April 24, 2024, 11:35 AM

Biodiversity and its Conservation
Book Back Questions and Answers
Question 1.
Which of the following region has maximum biodiversity?
(a) Taiga
(b) Tropical forest
(c) Temperate rain forest
(d) Mangroves
Answer:
(b) Tropical forest
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
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
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
Question 5.
The organization which published the red list of species is
(a) WWF
(b) IUCN
(c) ZSI
(d) UNEP
Answer:
(b) IUCN

Question 6.
Who introduced the term biodiversity?
(a) Edward Wilson
(b) Walter Rosen
(c) Norman Myers
(d) Alice Norman
Answer:
(b) Walter Rosen
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
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
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.

Question 10.
Define endemism.
Answer:
1. Endemism : A species or a taxon which is confined to a specific area
2. E.g: Nilgiri Thar
Question 11.
How many hotspots are there in India? Name them.
Answer:
India encloses 4 biodiversity hotspots. They are
1. Himalayan
2. Indo-Burma
3. Western ghats
4. Sundalands
Question 12.
What are the three levels of biodiversity?
Answer:
1. Genetic Diversity
2. Species Diversity
3. Community / Ecosystem Diversity
Question 13.
Name the active chemical found in the medicinal plant Rauwolfia vomitoria. What type of diversity it belongs to?
Answer:
Rauwolfia vomitoria can be cited as an example for genetic diversity. Reserpine is an active chemical extracted from Rauwolfia vomitoria.
Question 14.
"Amazon forest is considered to be the lungs of the planet"-Justify this statement.
Answer:
Amazon rain forest is known as the "lungs of the planet" since a great proportion of $\mathrm{CO}_2$ released due to anthropogenic activities are uptaken by their dense tropical forests, which is homologous to the functioning of human beings except for the difference in gases.
Question 15.
Red data book-What do you know about it?
Answer:
Red Data book or Red list is a catalogue of taxa facing risk of extinction. IUCN - International
Union of Conservation of Nature and Natural Resources, which is renamed as WCU - World
Conservation Union (Morges Switzerland) maintains the Red Data book. The concept of Red list was mooted in 1963. The purpose of preparation of Red List are:
1. To create awareness on the degree of threat to biodiversity
2. Identification and documentation of species at high risk of extinction
3. Provide global index on declining biodiversity
4. Preparing conservation priorities and help in conservation of action
5. Information on international agreements on conservation of biological diversity Red list has eight categories of species.
1. Extinct
2. Extinct in wild
3. Critically Endangered
4. Endangered
5. Vulnerable
6. Lower risk
7. Data deficiency
8. Not evaluated
Question 16.
Extinction of a keystone species led to loss of biodiversity - Justify.
Answer:
A keystone species is an organism that helps define an entire ecosystem. Without the keystone species a particular ecosystem would be dramatically disturbed or even ceased. Keystone species either directly or indirectly affects every species in a particular ecosystem. If a keystone species is lost or removed no other organism would compensate its ecological niche.
Example: Jaguar is a keystone species. As a top predator, it plays a crucial role in ecosystem. Without jaguar there is an exponential increase in herbivoral population that would decimate the plants of the ecosystem. At one point even the herbivore populations also get declined due to the lack of vegetation. Thus jaguar acts a keystone species.

Question 17.
Compare and Contrast the insitu and exsitu conservation.
Answer:
In-situ conservation
1. Conservation of plants and animals in their natural habitat.
2. Example: National parks
Ex-situ conservation
1. Conservation of selected or rare plants or animals in place outside their natural habitat.
2. Example: Off site collections.
Question 18.
What are called endangered species? Explain with examples.
Answer:
1. A species which has been categorized as very likely to become extinct.
2. Example: Bengal tiger, Polar bears.
Question 19.
Why do we find a decrease in biodiversity distribution, if we move from the tropics towards the poles?
Answer:
There is a decrease in biodiversity as we move from tropics towards poles due to drop in temperature which makes the condition unfavourable for majority of organisms to survive.
Question 20.
What are the factors that drive habitat loss?
Answer:
Natural habitats are destroyed for the purpose of settlement, agriculture, mining, industries and construction of highways. As a result species are forced to adapt to the changes in the environment or move to other places. If not, they become victim to predation, starvation, disease and eventually die or results in human animal conflict.
Question 21.
Where are biodiversity hotspots normally located? Why?
Answer:
Hotspots are areas characterized with high concentration of endemic species experiencing unusual rapid rate of habitat modification loss. Norman Myers defined hot spots as "regions that harbour a great diversity of endemic species and at the same time, have been significantly impacted and altered by human activities."
Question 22.
Why is biodiversity so important and worthy of protection?
Answer:
Biodiversity reflects the number of different organisms and their relative frequencies in an ecological system and constitutes the most important functional component of a natural ecosystem. It helps to maintain ecological processes, create soil, recycle nutrients, influence climate, degrade waste and control diseases. It provides an index of health of an ecosystem. The survival of human race depends on the existence and well being of all life forms (plants and animals) in the biosphere.
Question 23.
Why do animals have greater diversification than plant diversity?
Answer:
The distribution of plants and animals is not uniform around the world. Organism require require different sets of conditions for their optimum metabolism and growth. Plants in general have the ability to withstand and overcome environmental fluctuations. Moreover, majority of plants are autotrophs so they can synthesize their own food, hence they show minimal modifications. In case of animals, they have to tolerate climatic fluctuations, migrate to other areas in search of food, or adapt themselves or their body parts according food they consume thus varying from ancestors leading to evolution of new species. Hence it is understood that climatic condition food source, predation, competition and other natural forces lead to much diversification among animals than in plants.
Question 24.
Alien species invasion is a threat to endemic species - substantiate this statement.
Answer:
Exotic species are organisms often introduced unintentionally or deliberately for commercial purpose, as biological control agents and other uses. They often become invasive and drive away the local species and is considered as the second major cause for extinction of species. Tilapia fish (Jilabi kendai) (Oreochromis mosambicus) introduced from east coast of South Africa in 1952 for its high productivity into Kerala's inland waters, became invasive, due to which the native species such as Puntius dubius and Labeo kontius face local extinction. Amazon sailfin catfish is responsible for destroying the fish population in the wetlands of Kolkata. The introduction of the Nile Perch, a predatory fish into Lake Victoria in East Africa led to the extinction of an ecologically unique assemblage of more than 200 nature species of cichlid fish in the lake.
Question 25.
Mention the major threats to biodiversity caused by human activities. Explain.
Answer:
Human activities, both directly and indirectly are today's main reason for habitat loss and biodiversity loss. Fragmentation and degradation due to agricultural practices, extraction (mining, fishing, logging and harvesting) and development (settlements, industrial and associated infrastructures) leads to habitat loss and fragmentation leads to formation of isolated, small and scattered populations and as endangered species.
Some of the other threats include specialised diet, specialized habitat requirement, large size, small population size, limited geographic distribution and high economic or commercial value. Large mammals by virtue of their size require larger areas to obtain the necessities of life -food, cover and mates than do smaller mammals. Individual home range of Lion can be about 100 square $\mathrm{Km}$. Mammals have specialized dietary needs such as carnivores, frugivores and the need to forage over much larger areas than general dietary herbivores and omnivores.
Mammals also have low reproductive output other than small rodents

Question 26.
What is mass extinction? Will you encounter one such extinction in the near future.
Answer:
Enumerate the steps to be taken to prevent it.
The Earth has experienced quite a few mass extinctions due to environmental catastrophes. A
mass extinction occurred about 225 million years ago during the Permian, where $90 \%$ of shallow water marine invertebrates disappeared.
Question 27.
In north eastern states, the jhum culture is a major threat to biodiversity - substantiate.
Answer:
In shifting cultivation, plots of natural tree vegetation are burnt away and the cleared patches 1 are farmed for 2-3 seasons, after which their fertility reduces to a point where crop production is no longer profitable. The farmer then abandons this patch and cuts down a new patch of fqrest trees elsewhere for crop production.This system is practiced in north-eastern regions of India. When vast areas are cleared and burnt, it results in loss of forest cover, pollution and discharge of $\mathrm{CO}_2$, which in turn attributes to loss of habitat and climate change which has an 1 impact on the faunal diversity of that regions.
Question 28.
List out the various causes for biodiversity losses.
Answer:
The major causes for biodiversity decline are:
1. Habitat loss, fragmentation and destruction (affects about $73 \%$ of all species),
2. Pollution and pollutants (smog, pesticides, herbicides, oil slicks and GHGs).
3. Climate change.
4. Introduction of alien/exotic species.
5. Over exploitation of resources (poaching, indiscriminate cutting of trees, over fishing, hunting and mining).
6. Intensive agriculture and aquacultural practices.
7. Hybridization between native and non-native species and loss of native species
8. Natural disasters (Tsunami, forest fire, earth quake and volcanoes).
9. Industrialization, Urbanization, infrastructure development, Transport - Road and Shipping activity, communication towers, dam construction, unregulated tourism and monoculture are common area of specific threats.
10. Co-extinction

Question 29.
How can we contribute to promote biodiversity conservation?
Answer:
1. identify and protect all threatened species
2. identify and conserve in protected areas the wild relatives of all the economically important organisms
3. identify and protect critical habitats for feeding, breeding, nursing, resting of each species
4. resting, feeding and breeding places of the organisms should be identified and protected.
5. Air, water and soil should be conserved on priority basis
6. Wildlife Protection Act should be implemented
Question 30.
'Stability of a community depends upon its species diversity' - Justify the statement.
Answer:
Species diversity leads to a stable community because an area with more species diversity always lead to higher productivity thus maintains a stable community.
Question 31.
Write a note on
1. Protected areas
2. Wild life sanctuaries
3. WWF.
Answer:
(i) Protected areas are biogeographical areas, where biological diversity along with natural and cultural resources is protected, maintained and managed through legal measures. Protected areas include national parks, wild life sanctuaries, community reserves and biosphere reserves.
(ii) Any area other than the area comprised with any reserve forest or the territorial waters can be notified by the State Government to constitute as a sanctuary if such area is of adequate ecological, faunal, floral, geomorphological, natural or zoological significance. This is for the purpose of protecting, endangered factual species. Some restricted human activities are allowed inside the sanctuary area. Ecoturism is permitted, as long as animal life is undisturbed.
(iii) WWF stands for World Wide Fund for nature is an international NGO working in the field of wildlife conservation.