Free Man and His Environment MCQs with Answers

1. Consider the given research question.'How do pollutants impact the ecological functioning and sustainability of a pond?'In addition to ecology, this research question encompasses the field of

• A. Microbiology
• B. Biotechnology
• C. Marine biology
• D. Freshwater biology

Explanation: The correct answer is Freshwater biology because this field specifically focuses on the ecological dynamics and sustainability of freshwater ecosystems, such as ponds. Freshwater biologists study how pollutants affect various biotic and abiotic components, including water quality, species diversity, and ecosystem interactions. While Microbiology is relevant in terms of understanding how microorganisms respond to pollutants, it is not the primary focus when discussing the sustainability of a pond. Biotechnology does not directly explore ecological impacts, and Marine biology is concerned with saltwater ecosystems, making it irrelevant to the study of a pond.

2. Which of the following inhabitants of oceans is considered as the "rain forest of oceans"?

• A. Hydra
• B. Sponges
• C. Coral reefs
• D. Colonies of jellyfish

Explanation: The correct answer is Coral reefs. Coral reefs are known as the 'rain forests of the ocean' because they support a vast array of marine life, providing habitat, food, and breeding grounds for numerous species. They are crucial for biodiversity, much like the terrestrial rain forests. The other options, such as Hydra and jellyfish, do not provide the same level of ecological services or support such a wide variety of life forms. Sponges contribute to the ecosystem but do not create complex habitats like coral reefs do.

3. The given diagram shows four food chains.

• A. I
• B. II
• C. III
• D. IV

Explanation: The energy transfer between trophic levels in a food chain is inefficient, with only about 10% of energy being transferred to the next level, and the rest lost as heat or used for metabolic processes. So the food chain with maximum levels will have least energy transferred to human.In this case I. So option A is correct. And option B,C and D are incorrect.

4. In a pyramid of energy, if the energy at a specific trophic level is 1,000 J, the amount of energy available for the next higher trophic level would be:

• A. 10 J
• B. 100 J
• C. 1,000 J
• D. 10,000 J

Explanation: In an energy pyramid, energy decreases as it moves up trophic levels due to the 10% rule, which states that only about 10% of the energy is transferred to the next level. Therefore, if there is 1,000 J at a specific trophic level, 100 J will be available for the next level.Option A is incorrect because it assumes a 1% transfer rate. Option C is incorrect because it suggests no energy loss, which contradicts the natural energy flow in ecosystems. Option D is incorrect because it erroneously suggests an increase in energy, which violates the law of conservation of energy.

5. The terrestrial biome in which the average temperature remains low throughout the year is:

• A. Tundra
• B. Grassland
• C. Tropical rain forest
• D. Temperate deciduous forests

Explanation: The correct answer is the tundra. The tundra biome is known for its extremely cold climate, with average temperatures remaining low throughout the year. This is due to its location near the poles and its lack of tree cover, which contributes to its cold conditions. In contrast, grasslands, tropical rain forests, and temperate deciduous forests all experience warmer temperatures at least part of the year, making tundra the unique biome with consistently low temperatures.

6. The reason that coniferous forests mainly comprise of evergreen coniferous trees is:

• A. Low altitude
• B. Heavy rainfall
• C. Highly fertile soil
• D. Short summer season

Explanation: The correct answer is that coniferous forests mainly comprise evergreen coniferous trees due to the short summer season. In the regions where these forests are found, summers are brief and winters are long and harsh. By keeping their leaves year-round, these trees can take advantage of the limited growing season to photosynthesize whenever conditions are favorable. The other options are not correct: coniferous forests are not typically associated with low altitudes, heavy rainfall, or highly fertile soils. Instead, they thrive in higher altitudes/latitudes, moderate to low rainfall, and poor, acidic soils.

7. Soil moisture is limited in the grassland ecosystem because of:

• A. Low precipitation, High evaporation
• B. Low precipitation, Low evaporation
• C. High precipitation, Low evaporation
• D. High precipitation, High evaporation

Explanation: Grassland ecosystems often experience low precipitation and high evaporation, which together contribute to limited soil moisture. The low rainfall means there is not enough water input to compensate for the high rate of water loss due to evaporation. Option A correctly identifies this combination, leading to limited soil moisture.Option B is incorrect because while low precipitation would reduce soil moisture, low evaporation would retain some of it. Option C is incorrect because high precipitation would increase soil moisture, and low evaporation would conserve it. Option D is incorrect because high precipitation would generally increase soil moisture, even though high evaporation is present.

8. The CORRECT examplification of an abiotic factor in an ecosystem is:

• A. Fish in a river
• B. Minerals in soil
• C. Mosquito larva in a pond
• D. Orchids in tropical rainforest

Explanation: Abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. In this question, 'minerals in soil' is the correct answer because minerals are non-living components. The other options all refer to living organisms, such as fish, mosquito larvae, and orchids, and are thus biotic factors.

9. The first stage of primary succession in an ecosystem is the pioneer community.The characteristic feature(s) of a pioneer community is/ are:I.the biomass starts to increase.II.energy consumption is efficient.III.major species are lichens and mosses.

• A. I only
• B. II only
• C. I and III
• D. II and III

Explanation: The first stage of primary succession involves the establishment of a pioneer community, which is typically composed of species such as lichens and mosses that can colonize bare substrates. These organisms contribute to an increase in biomass by gradually breaking down rocks and accumulating organic material, which paves the way for subsequent communities. While energy consumption is a factor in ecosystems, it is not a distinctive feature of pioneer communities specifically. Hence, options II and its combinations are incorrect.

10. Denitrifying bacteria do not necessarily require abundant oxygen for respiration; therefore, they are:

• A. In well-aerated soils
• B. In water-logged soil
• C. In root nodules of leguminous plants
• D. On the root surfaces of leguminous plants

Explanation: Denitrifying bacteria thrive in environments where oxygen is limited, such as water-logged soils. These bacteria convert nitrates into nitrogen gas in the absence of oxygen. Therefore, option B is correct as it describes the low-oxygen environment that supports denitrification.Options A, C, and D describe environments where denitrifying bacteria are not typically found or are less active.