Which of the following is/are incorrect:
A. All ecosystems are constant in sizeB. In nature food chains exist, not food webC. Flow of energy in ecosystem is unidirectionalD. Gene flow occurs between 2 different population (of 2 species)
A, C
A, D
A, B, D
A, B, C, D
The important step in the process of decomposition in order is:
Catabolism → Fragmentation → Leeching → Humification → Mineralization
Catabolism → Fragmentation → Humification → Leeching → Mineralization
Fragmentation → Humification → Catabolism → Leeching → Mineralization
Fragmentation → Leeching → Catabolism → Humification → Mineralization
What do you mean by the standing crop?
Crop in a field at a given time
Each trophic level has a certain mass of living material at a particular time.
Each trophic level has a certain mass of organic material at a particular time.
Top trophic level has a certain mass of organic material at a particular time.
The standing crop is measured as the-
Mass of living organisms in a unit area.
The number of living organisms in a unit area.
Calculated from the net primary productivity
Both 1 and 2.
Why does the number of trophic levels in the grazing food chain is restricted ?
As the transfer of energy follows 10 per cent law
So that food chain remains short
As there are few species the community
So that transfer of energy could be more efficient.
What does 10 per cent law say?
Less than 10 per cent of the energy is transferred to each trophic level from the lower trophic level
Only 10 per cent of the energy is transferred to each trophic level from the lower trophic level
Only 10 per cent of the energy is assimilated from the eaten food
Consumer gains 10 per cent mass of the consumed food
At the trophic level of consumers, the rate at which food energy is assimilated, is called:
Secondary productivity
Gross primary productivity
Net primary productivity
None of these
The term "detritivore" includes
Net primary productivity is the gross primary productivity less
that which is consumed by herbivores
that which is consumed by producer in metabolism
secondary productivity
loss due to mortality
The major reservoir for phosphorous is
Aquifers
Soil and rocks
The atmosphere
Clouds
Which of the following pyramids can never be inverted in a natural ecosystem?
pyramid of numbers
pyramid of energy
pyramid of biomass
all can be inverted
The earth is an open system with respect to
organisms
chemicals
energy
all of the above
Plants capture approximately __________________ of the sun's energy while other trophics levels capture about _________________ of the energy available to them in their food.
1%, 10%
10%, 60%
10%, 1%
60%, 10%
Which trophic level is incorrectly defined?
Carnivores- secondary or tertiary consumer
Decomposer- microbial heterotrophs
Herbivores - primary consumer
Omnivores - Molds, yeast and mushrooms
Nitrogen gas makes up nearly 80% of Earth's atmosphere, yet nitrogen is often a limiting factor for plant growth. Why ?
In general, the biomass in an ecosystem will be greatest at the trophic level comprising.
secondary consumers
primary consumers
producers
tertiary consumers
Consider the following two statements:
l. The annual net primary productivity of the whole biosphere is approximately 170 billion tons (dry weight) of organic matter.
ll. Majority of this is contributed by the oceans as they occupy larger area of earth.
Both l and ll are correct and ll explains l
Both l and ll are correct but ll does not explain l
l is correct but ll is incorrect
l is incorrect but ll is correct
What percent of energy in the sunlight availble to the primary producers is converted by them into net primary productivity ?
Both hydrach and xerarch successions:
Take same time
Have similar sere
Lead to mesic conditions
Have same pioneer species
The second trophic level in a lake is:
Phytoplankton
Zooplankton
Benthos
Fishes
The rate of formation of new organic matter by consumers is called as:
The limitations of ecological pyramids include all the following except:
The do not take into account the same species belonging to two or more trophic levels
They do not represent relationships between organisms at different trophic levels
They assume a simple food chain and do not consider food webs
Saprotrophs are not given any place in the ecological pyramids
About what percent of the global carbon is contained in the atmosphere?
71
49
17
about 1
Which of the following organisms will be the first to colonize a bare rock?
Annual plants
Lichens
Perennail plants
Herbs and shrubs
Most food chains are composed of
1 or 2 species
3 or 4 species
9 or 10 species
More than 16 species
The phosphorus cycle is unusual in that it is entirely:
Within aquatic ecosystems
Within terrestrial ecosystems
Sedimentary
Gaseous
Most primary productivity in the surface water of lakes and oceans is by:
During ecological succession
the gradual and predictable change in species composition occurs in a given area
the establishment of a new biotic community is very fast in its primary phase
the numbers and types of animals remain constant
the changes lead to a community that is in near equilibrium with the environment and is called pioneer community
Which ecosystem has the maximum biomass?
Forest ecosystem
Grassland ecosystem
Pond ecosystem
Lake ecosystem
Th primary producers of the deep-sea hydrothermal vent ecosystem are
green algae
chemosynthetic bacteria
blue-green algae
coral reefs
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