NEET Biology Ecosystem MCQs Set 09

Answer: (b) Charles Elton

Explanation:
1. They are called Eltonian pyramids.

Teacher's Note:
1. Key fact to remember: They are called Eltonian pyramids.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (d) upright

Explanation:
1. Energy decreases at each successive trophic level.

Teacher's Note:
1. Key fact to remember: Energy decreases at each successive trophic level.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (a) 200 J

Explanation:
1. 20,000 to primary consumers is 2000 J, and to secondary consumers 200 J.

Teacher's Note:
1. Key fact to remember: 20,000 to primary consumers is 2000 J, and to secondary consumers 200 J.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (c) inverted

Explanation:
1. The standing crop of phytoplankton is small but supports a larger biomass of zooplankton.

Teacher's Note:
1. Key fact to remember: The standing crop of phytoplankton is small but supports a larger biomass of zooplankton.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (d) inverted

Explanation:
1. One tree supports many birds, which support very many parasites.

Teacher's Note:
1. Key fact to remember: One tree supports many birds, which support very many parasites.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (a) spindle shaped

Explanation:
1. Few trees, many herbivores/insects, then fewer carnivores give a spindle shape.

Teacher's Note:
1. Key fact to remember: Few trees, many herbivores/insects, then fewer carnivores give a spindle shape.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (c) They do not include decomposers

Explanation:
1. Pyramids are based on simple food chains, ignore food webs and give decomposers no place.

Teacher's Note:
1. Key fact to remember: Pyramids are based on simple food chains, ignore food webs and give decomposers no place.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (b) Carbon cycle

Explanation:
1. C, H, N, O cycles have atmospheric or hydrospheric reservoirs; P, S, Ca cycles are sedimentary.

Teacher's Note:
1. Key fact to remember: C, H, N, O cycles have atmospheric or hydrospheric reservoirs; P, S, Ca cycles are sedimentary.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (a) the earth's crust (rocks)

Explanation:
1. Phosphorus occurs in rocks and is released by weathering.

Teacher's Note:
1. Key fact to remember: Phosphorus occurs in rocks and is released by weathering.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (c) orthophosphate

Explanation:
1. Phosphate ions (PO4 3-) are taken up by roots.

Teacher's Note:
1. Key fact to remember: Phosphate ions (PO4 3-) are taken up by roots.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (b) 71 per cent

Explanation:
1. The oceanic reservoir regulates atmospheric carbon dioxide.

Teacher's Note:
1. Key fact to remember: The oceanic reservoir regulates atmospheric carbon dioxide.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (d) excreta of sea birds deposited on rocks

Explanation:
1. It is rich in phosphates.

Teacher's Note:
1. Key fact to remember: It is rich in phosphates.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (c) gaseous exchange of phosphorus with the atmosphere is negligible

Explanation:
1. Phosphorus inputs by rainfall are much smaller than for carbon, and no respiratory release occurs.

Teacher's Note:
1. Key fact to remember: Phosphorus inputs by rainfall are much smaller than for carbon, and no respiratory release occurs.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (a) pioneer community

Explanation:
1. The pioneer community invades first, followed by seral stages leading to the climax.

Teacher's Note:
1. Key fact to remember: The pioneer community invades first, followed by seral stages leading to the climax.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (d) starts on areas where no soil or life existed before

Explanation:
1. Newly cooled lava or bare rock lacks soil, so primary succession is very slow.

Teacher's Note:
1. Key fact to remember: Newly cooled lava or bare rock lacks soil, so primary succession is very slow.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (b) lichens

Explanation:
1. Lichens secrete acids that weather rock and start soil formation.

Teacher's Note:
1. Key fact to remember: Lichens secrete acids that weather rock and start soil formation.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (b) phytoplankton

Explanation:
1. The series begins with phytoplankton and ends in forest.

Teacher's Note:
1. Key fact to remember: The series begins with phytoplankton and ends in forest.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (d) Dominance of the pioneer species

Explanation:
1. Diversity, biomass, complexity and stability increase as succession proceeds.

Teacher's Note:
1. Key fact to remember: Diversity, biomass, complexity and stability increase as succession proceeds.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (a) climax community

Explanation:
1. It remains in near equilibrium with the environment as long as the climate is unchanged.

Teacher's Note:
1. Key fact to remember: It remains in near equilibrium with the environment as long as the climate is unchanged.
2. Revise this point with the matching definition or example in the chapter notes.

Answer: (c) US dollars 33 trillion a year

Explanation:
1. This is nearly twice the global gross national product mentioned in the chapter.

Teacher's Note:
1. Key fact to remember: This is nearly twice the global gross national product mentioned in the chapter.
2. Revise this point with the matching definition or example in the chapter notes.