Ecology and Environment — Practice

Question 1

Bears entering a state of reduced metabolic activity during winter is an example of

Accepted Answer

A

Question 2

The logistic population growth model differs from the exponential model in that it incorporates

Accepted Answer

A

Question 3

A population of 500 bacteria grows exponentially with r = 0.02 per hour. Using Nt = N0(1 + rt) as an approximation for small rt, estimate the population after 10 hours.

Accepted Answer

Nt ≈ N0(1 + rt) = 500 × (1 + 0.02×10) = 500 × 1.2 = 600 bacteria (approximately).

(Note: the exact exponential form Nt = N0e^rt gives 500 × e^0.2 ≈ 611; NEET typically expects the concept — that population increases multiplicatively with r and t — rather than exact exponential arithmetic.)

Question 4

An orchid growing as an epiphyte on a mango tree, deriving support without harming or benefiting the tree, illustrates

Accepted Answer

A

Question 5

Gause's Competitive Exclusion Principle states that

Accepted Answer

A

Question 6

The biomass or energy available to herbivores (primary consumers) in an ecosystem is best represented by

Accepted Answer

A

Question 7

If the producers in a grassland ecosystem fix 100,000 kcal of energy, how much energy is available to tertiary consumers (three trophic transfers from producers), assuming the standard 10% transfer efficiency?

Accepted Answer

100,000 → primary consumers: 10,000 kcal → secondary consumers: 1,000 kcal → tertiary consumers: 100 kcal.

Each trophic transfer retains only ~10% of the energy from the level below (Lindeman's 10% law); dividing by 10 three times gives 100 kcal.

Question 8

Which ecological pyramid is always upright, with no known exception in any ecosystem?

Accepted Answer

A

Question 9

An inverted pyramid of biomass is typically observed in which ecosystem?

Accepted Answer

A

Question 10

Ecological succession that begins on a bare rock surface with no pre-existing soil is called

Accepted Answer

A

Question 11

In the species-area relationship log S = log C + Z log A, the value of Z (slope) for smaller, local areas is typically

Accepted Answer

A

Question 12

Variation in the medicinal potency of Rauwolfia vomitoria growing in different Himalayan ranges is an example of

Accepted Answer

A

Question 13

Depletion of the stratospheric ozone layer is primarily caused by chlorine atoms released from

Accepted Answer

A

Question 14

In a DDT-contaminated lake, the highest concentration of DDT accumulates in

Accepted Answer

A

Question 15

Which of the following is NOT one of India's four recognised biodiversity hotspots?

Accepted Answer

A

Practice — Ecology and Environment

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