Write a short note on pyramid of numbers and pyramid of biomass.
Pyramid of Number
• Pyramid of number deals with number of individuals in a trophic level.
• In Grassland ecosystem only 3 top carnivores are supported in an ecosystem based on production of nearly 6 million plants.
• Pyramid of number in grassland or forest or pond ecosystem is upright.
• In parasitic food chain, the pyramid of number is inverted.
• In an ecosystem dominated by trees the pyramid of number shaped/inverted.
• Among the grassland, pond and forest ecosystem, the number of primary producers per unit area would be maximum in pond ecosystem.
Pyramid of Biomass
• Total amount of living material at various trophic level of a food chain is depicted by pyramid of biomass.
• In most of the ecosystem, the pyramids of number and biomass are upright.
• In terrestrial ecosystem pyramid of biomass is generally upright.
• The pyramid of biomass in sea or lake is generally inverted because the biomass of fishes for exceeds that of phytoplankton.
Given below is a figure of an ecosystem. Answer the following questions.
(i) What type of ecosystem is shown in the figure?
(ii) Name any plant that is characteristic of such ecosystem.
What is primary productivity? Give brief description of factors that affect primary productivity.
Among bryophytes, lichens and fern which one is a pioneer species in a xeric succession?
A farmer harvests his crop and expresses his harvest in three different ways.
(a) I have harvested 10 quintals of wheat.
(b) I have harvested 10 quintals of wheat today in one acre of land.
(c) I have harvested 10 quintals of wheat in one acre of land, 6 months after sowing.
Do the above statements mean one and the same thing. If your answer is yes, give reasons. And if your answer is ‘no' explain the meaning of each expression.
Why is the rate of assimilation of energy at the herbivore level called secondary productivity?
Fill in the blanks.
(a)Plants are called as————- because they fix carbon dioxide.
(b)In an ecosystem dominated by trees, the pyramid (of numbers) is————- type.
(c)In aquatic ecosystems, the limiting factor for the productivity is————- .
(d)Common detritivores in our ecosystem are————- .
(e)The major reservoir of carbon on earth is————- .
Arrange the following as observed in vertical stratification of a forest: Grass, Shrubby plants, Teak, Amaranths
What will happen to an ecosystem if:
(a) All producers are removed;
(b) All organisms of herbivore level are eliminated; and
(c) All top carnivore population is removed
Sometimes due to biotic/abiotic factor the climax remain in a particular serai stage (pre climax) without reaching climax. Do you agree with this statement? If yes, give a suitable example.
A part from plants and animals, microbes form a permanent biotic component in an ecosystem. While plants have been referred to as autotrophs and animals as heterotrophs, what are microbes referred to as? How do the microbes fulfil their energy requirements?
In relation to energy transfer in ecosystem, explain the statement "10 kg of deer's meat is equivalent to 1 kg of lion's flesh".
Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?
Which of the following ecosystems will be more productive in terms of primary productivity? Justify your answer. A young forest, a natural old forest, a shallow polluted lake, alpine meadow.
The rate of decomposition of detritus is affected by the abiotic factors like availability of oxygen, pH of the soil substratum, temperature etc. Discuss.
Flow of energy through various trophic levels in an ecosystem is unidirectional and non-cyclic. Explain.
Name an omnivore which occurs in both grazing food chain and the decomposer food chain.
The biodiversity increases when one moves from the pioneer to the climax stage. What could be the explanation?
Poaching of tiger is a burning issue in today's world. What implication would this activity have on the functioning of the ecosystem of which the tigers are an integral part?
What is a biogeochemical cycle? What is the role of the reservoir in a biogeochemical cycle? Give an example of a sedimentary cycle with reservoir located in earth's crust.
What will be the P/R ratio of a climax community and a pioneer community? What explanation could you offer for the changes seen in P/R ratio of a pioneer community and the climax community?
Give two examples of artificial or mail made ecosystems. List the salient features by which they differ from natural ecosystems.
Justify the following statement in terms of ecosystem dynamics. "Nature tends to increase the gross primary productivity, while man tends to increase the net primary productivity".
