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The slow rate of decomposition of fallen logs in nature is due to their
1. Low cellulose content
2. Low moisture content
3. Poor nitrogen content
4. Anaerobic environment around them 

Consider the following statements concerning food chains
a. Removal of 80% tigers from an area resulted in greatly increased growth of vegetation
b. Removal of most of the carnivores resulted in an increased population of deers
c. The length of food chains is generally limited to 3-4 trophic levels due to energy loss
d. The length of food chains may vary from 2 to 8 trophic levels
Which two of the above statements are correct?
(1) a,b
(2) b,c
(3) c,d
(4) a,d

The dominant second trophic level, in a lake ecosystem, is
1. Phytoplanktons
2. Zooplanktons
3. Benthos
4. Submerged rooted vegetation 

If we completely remove the decomposers from an ecosystem, its functioning will be adversely affected, because 
1. Mineral movement will be blocked 
2. The rate of decomposition will be very high
3. Energy flow will be blocked
4. Herbivores will not receive solar energy

Which of the following pairs is a sedimentary type of biogeochemical cycle?
1.  Phosphorus and nitrogen
2. Phosphorus and sulphur
3. Oxygen and nitrogen
4. Phosphorus and carbon

The primary succession refers to the development of communities on a
1. Forest cleared alter devastating fire
2. Newly-exposed habitat with no record of earlier life form
3. Freshly cleared crop field
4. Pond freshly filled with water after a dry phase

The 10% energy transfer law of food chain was given by
1. Lindemann
2. Tansley
3. Stanley
4. Weismann

In a terrestrial ecosystem such as forest, maximum energy is available at which trophic level?
1. ${\mathrm{T}}_3$
2. ${\mathrm{T}}_4$
3. ${\mathrm{T}}_1$
4. ${\mathrm{T}}_2$

The main role of bacteria in the carbon cycle involves
1. Chemosynthesis
2. Digestion or breakdown of organic compounds
3. Photosynthesis
4. Assimilation of nitrogenous compounds

The rate at which light energy is converted into chemical energy of organic molecules is the ecosystem's
1. Net secondary productivity
2. Gross primary productivity
3. Net primary productivity
4. Gross secondary productivity

What is a keystone species?
1. A species which makes up only a small proportion of the total biomass of a community, yet has a huge impact on the community's organization and survival
2. A common species that has plenty of biomass, yet has a fairly low impact on the community's organization
3. A rare species that has minimal impact on the biomass and on other species in the community
4. A dominant species that constitutes a large proportion of the biomass and which affects many other species

Which one of the following is not used for construction of ecological pyramids?
1. Fresh weight
2. Dry weight
3. Number of individuals
4. Rate of energy flow

The biomass available for consumption by the herbivores and the decomposers is called
1. Gross primary productivity
2. Net primary productivity
3. Secondary productivity
4. Standing crop

Grazing food chain
1. Provides inorganic matter to detritus food chain
2. Binds the inorganic nutrients into organic matter
3. Is based on energy present in detritus
4. Does not add energy Into ecosystem

Among the following forest types, which one has the highest net primary productivity?
1.  Tropical dry deciduous forests
2. Tropical rain forests
3. Coniferous forests
4.  Subtropical forests

The amount of living matter present in a component population at any time in an ecosystem is called as
1. Standing state
2. Standing quality
3. Standing crop
4. Immobilized nutrients

Which of the following statement not correct about energy flow in an ecosystem?
1. Pyramid of energy is always straight
2. Energy flow is unidirectional
3. Energy flow is cyclic
4. Ecological efficiency is generally 10%

Climax communities
1. Are more diverse than pioneer communities
2. Are less stable than pioneer communities
3. Have a large entropy then pioneer communities
4. have a large number but fewer species than pioneer communities 

Vertical distribution of different species occupying different levels is called 
1. Physiognomy
2. Phenology
3. Stratification
4. Phenotype 

Climax community show
1. $\frac{\mathrm{P}}{\mathrm{R}}$ratio > 1
2. $\frac{\mathrm{P}}{\mathrm{R}}$ratio < 1
3.  $\frac{\mathrm{P}}{\mathrm{R}}$ratio unity
4. $\frac{\mathrm{P}}{\mathrm{R}}$ratio zero

Atmospheric input is negligible in 
1. Carbon cycle
2. Phosphorus cycle
3. Oxygen cycle
4. Nitrogen cycle 

In the hydrosere the reed-swamp stage is followed by
1. Marsh-meadow stage
2. Submerged free floating plant stage 
3. Submerged plant stage 

Annual net productivity of the whole biosphere is
1. 80 billion tons
2. 170 billion tons
3. 55 billion tons
4. 115 billion tons

In an ecosystem, the function of the producers is to:
1. release energy
2. utilize chemical energy
3. convert organic compounds into inorganic compounds
4. trap solar energy and convert it into chemical energy

The correct path of energy flow in the ecosystem is:
1.  producers $\to$ herbivores $\to$ carnivores $\to$ decomposers 
2.  producers $\to$ carnivores $\to$ herbivores $\to$ decomposers
3.  herbivores $\to$ carnivores $\to$ producers $\to$ decomposers
4.  herbivores $\to$ producers $\to$ carnivores $\to$ decomposers 

Food chain is:
1. transfer if chemical energy- from producers to consumers
2. a number of human beings forming a chain for food
3. animals near a source of food
4. none of the above 

In a food chain, as we go from lower to higher trophic level, the energy:
1. becomes doubled at each step
2. increases irregularly
3. remains constant
4. decreases 

In a pond ecosystem, the food chain starts with:
1. small fishes
2. aquatic insects
3. zooplankton
4. phytoplankton 

The first link in any food chain is green plants because:
1. they are firmly fixed to the soil
2. they are widely distributed
3. they alone have the capacity to fix the atmospheric ${\mathrm{CO}}_2$ in the presence of sunlight
4. there are more herbivorous animals than carnivores

Food levels in an ecosystem are called:
1. trophic levels
2. consumer levels
3. producer levels
4. herbivore levels

If the carbon atoms fixed by producers already have passed through three species, the trophic level of the last species; would be.
1. scavenger
2. tertiary producer
3. tertiary consumer
4. secondary consumer

Graphic representation of biomass relationship between the producer and consumer in an ecosystem is called:
1. ecological system
2. trophic levels
3. ecological niche
4. ecological pyramid

During the process of ecological succession the changes that take place in communities are:
1. random
2. very quick
3. orderly and sequential
4. not influenced by the physical environment.

Climax community is in a state of:
1. equilibrium
2. disorder
3. non-equilibrium
4. constant change.

Which of the following is an ecosystem service provided by a natural ecosystem?
1. Pollutant absorption and reduction of the threat of global warming 
2. Prevention of soil erosion
3. Cycling of nutrients
4. All of the above 

The sequence of communities of primary succession in water is:
1.  phytoplankton, sedges, free-floating hydrophytes, rooted hydrophytes, grasses and trees.
2.  phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses and trees.
3.  free-floating hydrophytes, sedges, phytoplankton, rooted hydrophyes, grasses nad trees.
4.  phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees 

Which of the following play an important role in the maintenance of the biogeochemical cycles in the ecosystem?
1. Producers
2. herbivore
3. COnsumers
4. Decompose