15 extra multiple-choice questions for Biodiversity and its Conservation (12th Standard Zoology, Samacheer Kalvi), beyond the ones printed in the textbook — each with the correct option highlighted and a clear, worked explanation. Free to read in English and Tamil.
Q1
India possesses approximately how many genetic variants of paddy (rice) and mango respectively?
- A. 50,000 paddy variants and 1,000 mango variantsCorrect
- B. 1,000 paddy variants and 50,000 mango variants
- C. 5,000 paddy variants and 100 mango variants
- D. 20,000 paddy variants and 500 mango variants
Explanation. India exhibits immense genetic diversity, harboring more than 50,000 genetic variants of paddy and 1,000 genetic variants of mango.
Q2
The variation in the concentration and potency of reserpine in the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges is an example of which level of biodiversity?
- A. Species diversity
- B. Ecosystem diversity
- C. Genetic diversityCorrect
- D. Community diversity
Explanation. The variation in active chemical reserpine in Rauwolfia vomitoria represents genetic diversity, which helps species adapt to changing environmental conditions.
Q3
Which index of biodiversity is obtained by comparing the number of species unique to each of two adjacent ecosystems?
- A. Alpha diversity
- B. Beta diversityCorrect
- C. Gamma diversity
- D. Delta diversity
Explanation. Beta diversity is the species diversity between two adjacent ecosystems, determined by comparing the unique species in each.
Q4
In the species-area relationship on a logarithmic scale, what is the range of the regression coefficient (Z-value) when analyzing species richness across very large areas like entire continents?
- A. 0.1 to 0.2
- B. 0.2 to 0.4
- C. 0.6 to 1.2Correct
- D. 1.5 to 2.0
Explanation. While the normal Z-value ranges from 0.1 to 0.2, analyzing extremely large areas like entire continents yields a much steeper slope with a Z-value of 0.6 to 1.2.
Q5
In Paul Ehrlich's 'Rivet Popper Hypothesis', what do the rivets on the wings of an aeroplane represent?
- A. Endangered species
- B. Invasive alien species
- C. Keystone speciesCorrect
- D. Extinct species
Explanation. In the Rivet Popper Hypothesis, rivets on the wings represent keystone species. Removing them severely destabilizes the structural safety of the ecosystem.
Q6
Which biogeographical zone of India covers the smallest area percentage of about 0.3%?
- A. Western Ghats
- B. Coastal Region
- C. Andaman and Nicobar IslandsCorrect
- D. Trans Himalaya
Explanation. The Andaman and Nicobar Islands represent the smallest biogeographical zone of India, covering only 0.3% of the total land area.
Q7
The endemic Nilgiri tahr, which is the state animal of Tamil Nadu, is a characteristic species of which biogeographical zone of India?
- A. Himalayas
- B. Western GhatsCorrect
- C. Semi-arid zones
- D. Deccan Peninsula
Explanation. The Nilgiri tahr is endemic to the Western Ghats, which covers about 4% of India's biogeographical area.
Q8
Tropical rainforests, which once covered 14% of the Earth's land surface, have now been reduced to cover no more than what percentage?
- A. 10%
- B. 8%
- C. 6%Correct
- D. 4%
Explanation. Due to rapid deforestation and habitat destruction, the coverage of tropical rainforests has shrunk from 14% to less than 6% of Earth's land surface.
Q9
What percentage of New Zealand's wetlands have been destroyed and cleared to cultivate soya beans and raise grass for beef cattle?
- A. 50%
- B. 70%
- C. 90%Correct
- D. 95%
Explanation. Wetlands are highly vulnerable ecosystems; approximately 90% of New Zealand's wetlands have been destroyed for agricultural expansion.
Q10
The invasive Tilapia fish (Oreochromis mosambicus) was introduced into Kerala's inland waters in 1952 from which region?
- A. East coast of South AfricaCorrect
- B. East Africa's Lake Victoria
- C. North America
- D. South America
Explanation. Tilapia fish (Jilabi kendai) was introduced from the east coast of South Africa in 1952 for high productivity, but it became highly invasive.
Q11
The introduction of which predatory fish into Lake Victoria in East Africa led to the extinction of over 200 species of native cichlid fish?
- A. African catfish
- B. Tilapia
- C. Nile PerchCorrect
- D. Sucker fish
Explanation. The introduction of the predatory Nile Perch into Lake Victoria caused a major ecological disaster, wiping out more than 200 species of cichlid fish.
Q12
The Calvaria tree of Mauritius Island faced an imminent danger of extinction after the Dodo bird became extinct because the Dodo was required to:
- A. Pollinate the tree's flowers
- B. Disperse the seeds to distant places
- C. Make the tough seed endocarp permeable for germinationCorrect
- D. Provide specific nitrogenous waste as fertilizer
Explanation. The seeds of the Calvaria tree have a tough endocarp that only became permeable after passing through the Dodo's gizzard, facilitating germination.
Q13
In which year was the International Union for Conservation of Nature (IUCN) established, and where is its headquarters located?
- A. 1948, Gland, SwitzerlandCorrect
- B. 1961, Morges, Switzerland
- C. 1972, Stockholm, Sweden
- D. 1992, Rio de Janeiro, Brazil
Explanation. The IUCN was established in 1948 and is headquartered in Gland, Switzerland. It compiles the Red List of threatened species.
Q14
Where was 'Project Tiger' launched by the Government of India in the year 1973?
- A. Kaziranga National Park, Assam
- B. Jim Corbett National Park, UttarakhandCorrect
- C. Mudumalai Wildlife Sanctuary, Tamil Nadu
- D. Periyar Wildlife Sanctuary, Kerala
Explanation. Project Tiger was launched in 1973 at Jim Corbett National Park in Uttarakhand to protect and maintain viable populations of Bengal tigers.
Q15
In which year was the National Biodiversity Authority (NBA) of India established, and where is its headquarters located?
- A. 1992, New Delhi
- B. 2002, Bengaluru
- C. 2003, ChennaiCorrect
- D. 2006, Dehradun
Explanation. The National Biodiversity Authority (NBA) was established in 2003 in Chennai to implement the provisions of the Biological Diversity Act of 2002.
Frequently asked questions
How many MCQs are there in Biodiversity and its Conservation?
This chapter has 15 book-back multiple-choice questions, each with the correct answer and a step-by-step explanation.
Are these 12th Standard Zoology MCQs free to practise online?
Yes. Every question, answer and explanation here is free, and you can also take them as a timed practice test.
Where can I find the Biodiversity and its Conservation book-back answers?
The correct option for each question is highlighted on this page with a worked explanation, plus a quick answer-key summary at the top.
