Free Man and His Environment MCQs with Answers

• A. closely related organisms growing in different niches
• B. closely related organisms growing in the same area/niche
• C. distantly related organisms growing in the same habitat
• D. distantly related organisms growing in different niches.

Explanation: Competition is the rivalry for obtaining the same resource. Competition is of two types, intraspecific and interspecific.

• A. green algae
• B. chemosynthetic bacteria
• C. blue­green algae
• D. coral reefs.

Explanation: Hydrothermal vents are cracks in the ocean floor that emit jets of hot water loaded with minerals and chemosynthetic bacteria.

• A. Mosses
• B. Green algae
• C. Lichens
• D. Liverworts

Explanation: The bare rocky habitat is extremely hostile to living beings. There is no water, as the substratum does not absorb rain water.

• A. Absence of weeds
• B. Ecological succession
• C. Absence of soil organisms
• D. Least genetic diversity

Explanation: Cropland ecosystem is an artificial or man­ made terrestrial ecosystem which is created and maintained by human beings for their maximum…

• A. E. Haeckel
• B. E.Warming
• C. E.P. Odum
• D. A. G. Tansley.

Explanation: The term ecosystem was coined by A.G. Tansley in 1935.

• A. tertiary consumers
• B. detritivores
• C. primary consumers
• D. secondary consumers.

Explanation: Benthos is the community of organisms which live on, in, or near the sea bed, also known as the benthic zone.

• A. The numbers and types of animals remain constant
• B. The changes lead to a community that is in near equilibrium with the environment and is called pioneer community
• C. The gradual and predictable change in species composition occurs in a given area
• D. The establishment of a new biotic community is very fast in its primary phase

Explanation: Biotic or ecological succession is the natural development of a series of biotic communities at the same site, one after the other till a…

• A. (a)
• B. (b)
• C. (c)
• D. (d)

Explanation: Biogeochemical cycles are of two types: gaseous and sedimentary. In gaseous nutrient cycles, the materials involved in circulation between…

• A. net primary productivity
• B. standing crop
• C. gross primary productivity
• D. standing state.

Explanation: Standing crop is the total amount of living material in a specified population at a particular time, expressed as biomass (standing…

• A. newly created pond
• B. newly cooled lava
• C. bare rock
• D. degraded forest.

Explanation: Secondary succession (subsere) is the biotic succession that occurs in an area that becomes secondarily bare due to the destruction of a…

• A. temperate deciduous forest
• B. tropical rainforest
• C. coniferous forest
• D. thorn woodland.

Explanation: Tropical rainforests have a very dense plant cover. They also experience a large amount of precipitation, thus the forest floor is always…

• A. secondary productivity
• B. net productivity
• C. net primary productivity
• D. gross primary productivity.

Explanation: The amount of energy accumulation in green plants as biomass or organic matter per unit area over a time period is known as primary…

• A. 0.02 J
• B. 0.002 J
• C. 0.2 J
• D. 0.0002 J

Explanation: Herbivores are eaten by primary carnivores. Only 10% of the herbivores productivity is utilized for raising productivity of primary…

• A. rock
• B. fossils
• C. sea water
• D. animal bones.

Explanation: The reservoir pool of phosphorus is in phosphate rocks while the cycling pool is soil and water for terrestrial and aquatic ecosystems…

• A. consumers
• B. decomposers
• C. producers
• D. parasites.

Explanation: The rate of photosynthesis of organic matter by the consumers is known as secondary productivity.

• A. Catabolism - Last step in decomposition under fully anaerobic conditions
• B. Leaching - Water soluble inorganic nutrients rise to the top layers of soil
• C. Fragmentation - Carried out by organisms such as the earthworm
• D. Humification - Leads to the accumulation of a dark coloured substance humus which undergoes microbial action at a very fast rate.

Explanation: Decomposition is the process in which decomposers break down complex organic matter into inorganic substances like carbon dioxide, water…

• A. Aerobic nitrate oxidation and nitrite reduction
• B. Decomposition of organic nitrogen and conversion of dinitrogen to ammonium compounds
• C. Enteric fermentation in cattle and nitrogen fixation by Rhizobium in the root nodules of legumes
• D. Anaerobic ammonium oxidation and denitrification.

Explanation: Denitrification is a chemical process in which nitrates in the soil are reduced to molecular nitrogen (N2 ) which is released into the…

• A. Grasshopper
• B. Wolf
• C. Phytoplankton
• D. Lion.

Explanation: Primary consumers are herbivorous organisms that feed on producers. Carnivores are termed secondary, tertiary etc., consumers depending…

• A. small plants
• B. fish
• C. man
• D. zooplankton.

Explanation: The transfer of food energy from producers to consumers through a series of organisms with repeated eating and being eaten is known as…

• A. Sulphur cycle
• B. Phosphorus cycle
• C. Nitrogen cycle
• D. Carbon cycle

Explanation: Biogeochemical cycles are of two types: gaseous and sedimentary. In gaseous nutrient cycles, the materials involved in circulation between…