Biology NEET - XII: Chapter 14- Ecosystem
The biosphere is considered the global ecosystem, as it includes all living organisms along with their interactions in land, water, and air. It integrates every ecosystem on Earth into one interconnected system.
What is considered as a global ecosystem?
Biosphere
Key Terms
What is considered as a global ecosystem?
Biosphere
The vertical distribution of species occupying different levels is called
stratification
Name the components of an ecosystem.
Productivity
Decomposition
Energy flow
Nutrient cycling
What is the annual productivity of the whole biosphere?
170 billion ton
Of the total net primary productivity, what percent NPP is of land?
70%
Of the total net primary productivity, what is the productivity of oceans?
55 billion tonnes
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| Term | Definition |
|---|---|
What is considered as a global ecosystem? | Biosphere |
The vertical distribution of species occupying different levels is called | stratification |
Name the components of an ecosystem. | Productivity Decomposition Energy flow Nutrient cycling |
What is the annual productivity of the whole biosphere? | 170 billion ton |
Of the total net primary productivity, what percent NPP is of land? | 70% |
Of the total net primary productivity, what is the productivity of oceans? | 55 billion tonnes |
The raw material for decomposition is called | Detritus |
Name the steps in the process of decomposition of detritus. | Fragmentation Leaching Catabolism Humification Mineralisation |
Why can humus serve as a reservoir for soil? | Because it is colloidal |
Is decomposition an anaerobic process? | Decomposition is largely an oxygen requiring process |
Decomposition is slower is detritus is rich in nitrogen. True/false? | False. Decomposition is faster is detritus is rich in nitrogen. |
What percent of the total PAR do plants capture? | 2-4% |
What is the order of seral communities in case of hydrarch succession? | Phytoplanktons Rooted submerged plants Rooted floating angiosperms Free floating plants Reed swamp Marsh meadow scrub trees |
What kind of biogeochemical cycle does sulphur follow? | Sedimentary cycles |
What kind of biogeochemical cycle does carbon follow? | Gaseous cycles |
What percent of the dry weight of organism is constituted by carbon? | 49% |
What percent of carbon is dissolved in the oceans? | 71% |
What mass of carbon is fixed in the biosphere through photosynthesis annually? | 4 x 10^13 kg |
Which scientist along with his team put a price tag on ecological services? | Robert Constanza |
Of the total cost of various ecosystem services, soil formation accounts for about | 50% |
Of the total cost of various ecosystem services, recreation and nutrient recycling account for about | <10% |
Of the total cost of various ecosystem services, climate regulation and habitat for wildlife account for about | <6% |
What is lentic ecosystem? | Ecosystem in stagnant water |
What is lotic ecosystem? | Ecosystem in running water. |
What type of ecosystem is a drop of water? | Nano ecosystem |
Give examples of microecosystem | Ponds, lakes |
Give examples of macroecosystems. | Forests, deserts |
Give examples of Megaecosystem. | Ocean |
Which is the littoral zone in a pond ecosystem? | The littoral zone is the near shore area where sunlight penetrates all the way to the sediment and allows aquatic plants (macrophytes) to grow. |
Which is the limnetic zone in deep lakes? | The limnetic (pelagic) zone is the open water area where light does not penetrate to the bottom. |
Which is the euphotic zone? | The 1 % light level defines the euphotic zone of the lake, which is the layer from the surface to the depth where light levels become too low for photosynthesis. |
Which is the benthic zone? | the water is too deep for light to reach the ground |
Which is the aphotic zone of ocean ecosystem? | Diffused light penetrates but is not enough for photosynthesis |
Which organisms are found in the disphotic zone? | Zooplanktons |
How deep is the abyssal zone present in an ocean? | Below 2000 m |
How deep is the euphotic zone in an ocean? | 2-20 m |
How deep is the disphotic zone in an ocean? | 20-200 m |
How deep is the aphotic zone in an ocean? | 200-2000 m |
According to the thermal stratification, name the layers in a lake? | Epilimnion (topmost) Metalimnion Hypolimnion (bottom most) |
What is autumn spring turnover? | During the summer, the epilimnion, or surface layer, is the warmest. It is heated by the sun. The deepest layer, the hypolimnion, is the coldest. The sun's radiation does not reach this cold, dark layer. During the fall, the warm surface water begins to cool. As water cools, it becomes more dense, causing it to sink. This dense water forces the water of the hypolimnion to rise, "turning over" the layers. |
What is the difference between two layers in the thermal stratification of a lake? | 4 celsius |
What are macroconsumers? | mainly animals (herbivores, carnivores, and detritivores), which wholly or partly ingest other living organisms or organic particulate matter |
What are microconsumers? | Decomposers, saprophytes (help in nutrient cycling by returning the minerals to the biosphere) |
What type of consumer is a whale? | Secondary consumer (feeds on plankton) |
What type of consumer is a human who eats curd? | Secondary consumer |
Which consumers are animal parasites? | Secondary consumers |
Which are the most productive agroecosystems? | 1) Sugarcane (Best) | 2) Rice |
What is the simplified detritus formed by earthworms called? | Duff |
What type of humus is mor? | Coarse and textured, |
What type of humus is mal? | Fine textured (best for plants) |
In an aquatic ecosystem, what is the major conduit for energy? | Grazing food chain |
In a terrestrial ecosystem which is the major conduit for energy? | Detritivorous food chain |
What is the shape of a pyramid of number for a forest ecosystem? | Urn shaped |
What is the succession on an acidic soil called? | Oxalosere |
What is the succession on sand called? | Psammosere |
What is the succession of microbes on decomposed materials called? | Serulo |
What is known as prisere? | Primary succession |
WHat is known as subsere? | Secondary succession |
The succession in which the community reacts with the environment and changes it is called | Autogenic succession |
The succession in which the community is replaced due to external environmental factors is called | Allogenic succession |
The succession on a place which was previously dominated by autotrophs is called | Autotrophic succession |
The succession on a place which was previously dominated by hetertrophs is called | Heterotrophic succession |
What is the size of organisms during succession in initial seral stages? | Small |
What is the size of organisms during succession in climax stage? | Large |
What is the diversity of organisms during succession in initial seral stages? | Low |
What is the diversity of organisms during in climax stage of ecological succession | High |
What are the number of heterotrophic organisms during succession in initial seral stages? | Few |
What are the number of heterotrophic organisms during succession in climax seral stages? | Many |
What is the net primary productivity of organisms during succession in climax stage? | Low |
What is the net primary productivity during succession in initial seral stages? | High |
Can plants use nitrates directly in metabolic pathway? | No, they cannot because nitrates are highly oxidised |
Which is the larger water cycle- global water cycle of biological water cycle? | Global water cycle |
What was the total price tag put on ecological services? | 33 trillion dollars |