Levels of Biodiversity (Genetic, Species, Ecological)

Attempt the quiz above first, then review every question with its correct answer and a short explanation below.

1. Q1.Who popularized the term 'biodiversity' to describe the combined diversity at all levels of biological organization?

   • A.Edward Wilson✓ Correct Answer
   • B.Alexander von Humboldt
   • C.Robert May
   • D.Paul Ehrlich

   Explanation: NCERT Class 12 Biology Chapter 15 states: 'Biodiversity is the term popularised by the sociobiologist Edward Wilson to describe the combined diversity at all the levels of biological organisation.'

2. Q2.The medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges shows variation in the potency and concentration of the active chemical 'reserpine'. This is an example of:

   • A.Species diversity
   • B.Genetic diversity✓ Correct Answer
   • C.Ecological diversity
   • D.Alpha diversity

   Explanation: NCERT Class 12 Biology Chapter 15 explains: 'A single species might show high diversity at the genetic level over its distributional range. The genetic variation shown by the medicinal plant Rauwolfia vomitoria... is an example of genetic diversity.' India also has >50,000 genetically different strains of rice.

3. Q3.The Western Ghats have a greater amphibian species diversity than the Eastern Ghats. This is an example of which level of biodiversity?

   • A.Genetic diversity
   • B.Species diversity✓ Correct Answer
   • C.Ecological diversity
   • D.Ecosystem diversity

   Explanation: Species diversity refers to the variety of species within a region. As noted in NCERT, the fact that Western Ghats have more amphibian species than Eastern Ghats is a classic example of species diversity (diversity at the species level).

4. Q4.India, with its deserts, rainforests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows, has greater ecosystem diversity than a Scandinavian country like Norway. This represents:

   • A.Genetic diversity
   • B.Species diversity
   • C.Ecological diversity✓ Correct Answer
   • D.Alpha diversity

   Explanation: Ecological diversity refers to the diversity at the ecosystem level. Because India has a wide range of biomes/ecosystems compared to Norway, it has much higher ecological diversity (NCERT Chapter 15).

5. Q5.According to Robert May's global estimates, what is the total number of species on Earth?

   • A.1.5 million
   • B.7 million✓ Correct Answer
   • C.20 to 50 million
   • D.100 million

   Explanation: NCERT Class 12 Biology states: 'A more conservative and scientifically sound estimate made by Robert May places the global species diversity at about 7 million.' In contrast, only slightly more than 1.5 million species have been actually recorded/named so far.

6. Q6.Of all the recorded species on Earth, more than 70 percent are:

   • A.Plants (including fungi and algae)
   • B.Animals✓ Correct Answer
   • C.Bacteria
   • D.Viruses

   Explanation: NCERT Chapter 15 notes: 'Of all the species recorded, more than 70 per cent are animals, while plants (including algae, fungi, bryophytes, gymnosperms and angiosperms) comprise no more than 22 per cent of the total.'

7. Q7.Which taxonomic group is the most species-rich among animals, making up about 70 percent of all animal species?

   • A.Mollusks
   • B.Insects✓ Correct Answer
   • C.Fishes
   • D.Birds

   Explanation: NCERT states: 'Among animals, insects are the most species-rich taxonomic group, making up more than 70 per cent of the total. That means, out of every 10 animals on this planet, 7 are insects.'

8. Q8.Which of the following plant/microbial groups has a global species count that is higher than the combined species count of fishes, amphibians, reptiles, and mammals?

   • A.Algae
   • B.Fungi✓ Correct Answer
   • C.Mosses
   • D.Ferns

   Explanation: NCERT Class 12 Biology explicitly highlights: 'It should be noted that the number of fungi species in the world is more than the combined total of the species of fishes, amphibians, reptiles and mammals.'

9. Q9.India has only 2.4 percent of the world's land area, but its share of the global species diversity is an impressive:

   • A.2.4%
   • B.8.1%✓ Correct Answer
   • C.15%
   • D.22%

   Explanation: NCERT Chapter 15 states: 'India has only 2.4 per cent of the world's land area, its share of the global species diversity is an impressive 8.1 per cent. This makes our country one of the 12 mega diversity countries of the world.'

10. Q10.As we move from the equator towards the poles, the species diversity generally:

    • A.Increases
    • B.Decreases✓ Correct Answer
    • C.Remains constant
    • D.First decreases then increases

    Explanation: NCERT states: 'In general, species diversity decreases as we move away from the equator towards the poles.' Tropics (latitudinal range of 23.5° N to 23.5° S) harbor more species than temperate or polar areas.

11. Q11.Which of the following is a key reason why tropical regions have higher species diversity than temperate regions?

    • A.Frequent glaciations in the past in tropical areas.
    • B.Tropics have remained relatively undisturbed for millions of years, allowing long evolutionary time for speciation.✓ Correct Answer
    • C.Tropical environments are highly seasonal and unpredictable.
    • D.Less solar energy is available in the tropics.

    Explanation: NCERT outlines three reasons for tropical diversity: (1) Speciation is a function of time; tropics remained undisturbed unlike temperate regions which had frequent glaciations. (2) Tropical environments are less seasonal, more constant and predictable. (3) There is more solar energy available, contributing to higher productivity.

12. Q12.Who proposed the species-area relationship, showing that species richness increases with explored area but only up to a limit?

    • A.Edward Wilson
    • B.Alexander von Humboldt✓ Correct Answer
    • C.Robert May
    • D.David Tilman

    Explanation: NCERT Class 12 Biology states: 'During his pioneering and extensive explorations in the wilderness of South American jungles, the great German naturalist and geographer Alexander von Humboldt observed that within a region species richness increased with increasing explored area, but only up to a limit.'

13. Q13.On a logarithmic scale, the species-area relationship is a straight line described by which equation?

    • A.log S = log C + Z log A✓ Correct Answer
    • B.log A = log C + Z log S
    • C.S = C A^Z
    • D.log S = log Z + C log A

    Explanation: As per NCERT, the species-area relationship is represented by the formula: S = CA^Z. On a logarithmic scale, this relationship is linear and expressed as: log S = log C + Z log A, where S = Species richness, A = Area, Z = slope of the line (regression coefficient), and C = Y-intercept.

14. Q14.For small to normal-sized areas, the value of the slope of the line (Z, regression coefficient) in the species-area relationship is typically in the range of:

    • A.0.6 to 1.2
    • B.0.1 to 0.2✓ Correct Answer
    • C.1.5 to 2.0
    • D.0.01 to 0.05

    Explanation: NCERT Class 12 Biology states: 'Ecologists have discovered that the value of Z lies in the range of 0.1 to 0.2, regardless of the taxonomic group or the region...'. However, if we analyze the relationship in very large areas like entire continents, the slope of the line is much steeper (0.6 to 1.2).

15. Q15.For frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents, the slope of the species-area relationship (Z) is found to be:

    • A.0.15
    • B.1.15✓ Correct Answer
    • C.0.25
    • D.2.15

    Explanation: NCERT Class 12 Biology Chapter 15 explicitly notes: 'For example, for frugivorous (fruit-eating) birds and mammals in the tropical forests of different continents, the slope is found to be 1.15.' This is much steeper than the normal 0.1-0.2 range.

16. Q16.Based on David Tilman's long-term ecosystem experiments using outdoor plots, which of the following statements is true?

    • A.Plots with fewer species showed less year-to-year variation in total biomass.
    • B.Plots with more species showed less year-to-year variation in total biomass and increased productivity.✓ Correct Answer
    • C.प्रजाति समृद्धि का पारिस्थितिकी तंत्र की स्थिरता पर कोई प्रभाव नहीं पड़ा।
    • D.जैसे-जैसे प्रजाति समृद्धि बढ़ती है, उत्पादकता घटती जाती है।

    Explanation: David Tilman's experiments showed that plots with more species showed less year-to-year variation in total biomass. He also showed that in his experiments, increased diversity contributed to higher productivity, link species richness directly to ecosystem stability (NCERT).

17. Q17.The 'Rivet Popper Hypothesis', comparing species in an ecosystem to rivets in an airplane, was proposed by:

    • A.Paul Ehrlich✓ Correct Answer
    • B.Edward Wilson
    • C.Robert May
    • D.David Tilman

    Explanation: Stanford ecologist Paul Ehrlich proposed the 'Rivet Popper Hypothesis'. He compared the ecosystem to an airplane and the species to rivets holding the plane together. Popping rivets (extinctions) eventually threatens the flight safety (ecosystem stability), especially if key rivets on the wings (keystone species) are removed (NCERT).

18. Q18.The species diversity within a specific local community or habitat is referred to as:

    • A.Alpha diversity✓ Correct Answer
    • B.Beta diversity
    • C.Gamma diversity
    • D.Delta diversity

    Explanation: Whittaker defined three scales of diversity: Alpha diversity is the species diversity within a particular local habitat or ecosystem. Beta diversity is the difference in species diversity between ecosystems. Gamma diversity is the total species diversity over an entire geographic region.

19. Q19.Which of the following levels of biodiversity is also referred to as genetic diversity?

    • A.Diversity within a species (intraspecific diversity)✓ Correct Answer
    • B.Diversity between different species (interspecific diversity)
    • C.Diversity at the ecosystem level
    • D.Diversity across different continents

    Explanation: Genetic diversity represents the variations at the genetic level (DNA sequence, genes) within individuals of a single species (intraspecific level), which allows them to adapt to environmental changes.

20. Q20.An organism that is found only in a specific geographic area and nowhere else in the world is said to be:

    • A.Invasive
    • B.Endemic✓ Correct Answer
    • C.Exotic
    • D.Cosmopolitan

    Explanation: NCERT Class 12 Biology, Chapter 15 defines endemic species as those species that are confined to a specific region and not found anywhere else. For example, Western Ghats has many endemic amphibian species.