Organisms and Populations – Daily Practice Problem (DPP)

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🎯 NEET 2026 Daily Practice Problem (DPP)

Class 12 | Unit 5: Ecology | Topic: Organisms and Populations

Q1. The father of ecology in India is:

  1. Ramdeo Misra
  2. Birbal Sahni
  3. M.S. Swaminathan
  4. P. Maheshwari
✅ View Answer & Explanation

Correct Answer: (1) Ramdeo Misra
Explanation: Prof. Ramdeo Misra is revered as the Father of Ecology in India for his extensive research and teaching in this field at BHU.

Q2. The key elements that lead to variations in the physical and chemical conditions of different habitats are:

  1. Temperature and Light
  2. Temperature, Water, Light, and Soil
  3. Water and Soil
  4. Temperature and Soil
✅ View Answer & Explanation

Correct Answer: (2) Temperature, Water, Light, and Soil
Explanation: These are the four major abiotic factors that determine the characteristics of a habitat.

[Image of Biome distribution with respect to annual temperature and precipitation]

Q3. Organisms that can tolerate and thrive in a wide range of temperatures are called:

  1. Stenothermal
  2. Eurythermal
  3. Euryhaline
  4. Stenohaline
✅ View Answer & Explanation

Correct Answer: (2) Eurythermal
Explanation: ‘Eury’ means wide. ‘Steno’ means narrow. Eurythermal organisms tolerate a wide range of temperatures (e.g., mammals).

Q4. In the absence of an external source of water, the Kangaroo rat in North American deserts meets its water requirements through:

  1. External environment moisture
  2. Internal fat oxidation
  3. Eating succulent plants
  4. Storing water in a pouch
✅ View Answer & Explanation

Correct Answer: (2) Internal fat oxidation
Explanation: The oxidation of fat produces water as a by-product (metabolic water), which meets 90% of its water needs.

Q5. According to Allen’s Rule, mammals from colder climates generally have:

  1. Longer ears and longer limbs
  2. Shorter ears and shorter limbs
  3. Longer ears and shorter limbs
  4. Shorter ears and longer limbs
✅ View Answer & Explanation

Correct Answer: (2) Shorter ears and shorter limbs
Explanation: This adaptation minimizes the surface area to volume ratio, thereby reducing heat loss.

Q6. An age pyramid with a broad base typically indicates:

  1. Declining population
  2. Stable population
  3. Expanding population
  4. Zero growth population
✅ View Answer & Explanation

Correct Answer: (3) Expanding population
Explanation: A broad base means a large number of pre-reproductive individuals (children), indicating that the population size will grow in the future.

[Image of Age pyramids for human population – Expanding, Stable and Declining]

Q7. The logistic population growth is expressed by the equation:

  1. $dN/dt = rN$
  2. $dN/dt = rN (\frac{K-N}{K})$
  3. $dN/dt = rN (\frac{N-K}{N})$
  4. $dN/dt = rN (\frac{K}{N})$
✅ View Answer & Explanation

Correct Answer: (2) $dN/dt = rN (\frac{K-N}{K})$
Explanation: This is the Verhulst-Pearl Logistic Growth equation, where $K$ is the carrying capacity and $(K-N)/K$ is the environmental resistance.

Q8. Which interaction is detrimental to both species involved?

  1. Predation
  2. Commensalism
  3. Amensalism
  4. Competition
✅ View Answer & Explanation

Correct Answer: (4) Competition
Explanation: In competition (-/-), the fitness of both species is significantly lower in the presence of the other species.

Q9. Gause’s ‘Competitive Exclusion Principle’ states that:

  1. Two species can coexist indefinitely if resources are unlimited
  2. Two closely related species competing for the same limiting resources cannot co-exist indefinitely
  3. Smaller organisms are excluded by larger organisms
  4. Competition leads to the extinction of both species
✅ View Answer & Explanation

Correct Answer: (2) Two closely related species competing for the same limiting resources cannot co-exist indefinitely
Explanation: The competitively inferior one will eventually be eliminated (e.g., Abingdon tortoise vs Goats).

Q10. The interaction between a Cuckoo laying eggs in a Crow’s nest is called:

  1. Predation
  2. Brood parasitism
  3. Mutualism
  4. Commensalism
✅ View Answer & Explanation

Correct Answer: (2) Brood parasitism
Explanation: The parasitic bird lays its eggs in the nest of its host and lets the host incubate them.

Q11. Mycorrhizae are associations between:

  1. Fungi and algae
  2. Fungi and roots of higher plants
  3. Algae and roots of higher plants
  4. Bacteria and roots of higher plants
✅ View Answer & Explanation

Correct Answer: (2) Fungi and roots of higher plants
Explanation: This is a mutualistic relationship (+/+). The fungi help in nutrient absorption, and the plant provides carbohydrates.

Q12. An orchid growing as an epiphyte on a mango branch is an example of:

  1. Parasitism
  2. Mutualism
  3. Commensalism
  4. Amensalism
✅ View Answer & Explanation

Correct Answer: (3) Commensalism
Explanation: The orchid benefits (support/light) while the mango tree is neither harmed nor benefited (+/0).

Q13. In a population of 1000 individuals, 360 belong to genotype AA, 480 to Aa, and 160 to aa. Based on this data, the frequency of allele A in the population is:

  1. 0.4
  2. 0.5
  3. 0.6
  4. 0.7
✅ View Answer & Explanation

Correct Answer: (3) 0.6
Explanation: Total alleles = 2000. ‘A’ alleles = (360*2) + 480 = 720 + 480 = 1200. Frequency = 1200/2000 = 0.6. Alternatively, $\sqrt{0.36} = 0.6$ (if in HW equilibrium).

Q14. The Mediterranean orchid *Ophrys* employs which mechanism for pollination?

  1. Food reward
  2. Sexual deceit
  3. Safe place to lay eggs
  4. Nectar reward
✅ View Answer & Explanation

Correct Answer: (2) Sexual deceit
Explanation: One petal of the flower resembles the female bee in size, colour, and markings. The male bee ‘pseudocopulates’ with it, transferring pollen.

Q15. Amensalism is an interaction in which:

  1. One species is harmed and other is benefited
  2. One species is harmed and other is unaffected
  3. Both species are harmed
  4. One species is benefited and other is unaffected
✅ View Answer & Explanation

Correct Answer: (2) One species is harmed and other is unaffected
Explanation: Example: *Penicillium* secretes penicillin which kills bacteria, but the mould itself is unaffected (-/0).

Q16. Natality refers to:

  1. Death rate
  2. Birth rate
  3. Number of individuals leaving the habitat
  4. Number of individuals entering the habitat
✅ View Answer & Explanation

Correct Answer: (2) Birth rate
Explanation: Natality is the number of births during a given period. Mortality is the death rate.

Q17. Which of the following is an example of ‘Resource Partitioning’?

  1. Abingdon tortoise and Goats
  2. MacArthur’s Warblers
  3. Flamingos and Fishes
  4. Tiger and Deer
✅ View Answer & Explanation

Correct Answer: (2) MacArthur’s Warblers
Explanation: Five closely related species of warblers living on the same tree avoided competition by changing their foraging activities and times.

Q18. Diapause is a stage of suspended development seen in:

  1. Bears
  2. Snails
  3. Zooplankton
  4. Fishes
✅ View Answer & Explanation

Correct Answer: (3) Zooplankton
Explanation: Under unfavourable conditions, many zooplankton species in lakes and ponds enter diapause. Bears show hibernation; snails show aestivation.

Q19. The Prickly Pear Cactus introduced into Australia in the 1920s caused havoc by spreading rapidly. It was brought under control by introducing:

  1. A cactus-feeding moth
  2. A chemical herbicide
  3. A competing weed
  4. A viral pathogen
✅ View Answer & Explanation

Correct Answer: (1) A cactus-feeding moth
Explanation: This is a classic example of Biological Control of pests using a predator (*Cactoblastis cactorum*).

Q20. In an aquatic environment, the sediment characteristics often determine the type of:

  1. Pelagic animals
  2. Benthic animals
  3. Plankton
  4. Nekton
✅ View Answer & Explanation

Correct Answer: (2) Benthic animals
Explanation: Benthic animals live at the bottom of the water body, and their distribution is heavily influenced by the nature of the sediment.

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