Distinguish between
(a)Grazing food chain and detritus food chain
(b)Production and decomposition
(c)’Upright and inverted pyramid
(d)Food chain and food web
(e)Litter and detritus
(f)Primary and secondary productivity
(a) Grazing Food Chain (GFC) begins with primary producers or plants and ends in carnivores (tertiary or top carnivores) whereas Detritus Food Chain (DFC) begins with detritus or dead organic matter and it ends in carnivores. In GFC, energy for the food chain comes from sun whereas in DFC, energy for the food chain comes from organic remains or detritus.
(b)Production is the phenomenon in which the energy is produced by the process of synthesis of organic compound from inorganic substances (such as C02, H20 & minerals) utilizing generally the sunlight. It traps energy.
Decomposition refers to the breakdown of complex organic matter into simpler ones. It releases energy.
(c)In upright pyramid (e.g., grassland & cropland ecosystem), biomass or number of organisms or amount of energy decreases
on moving to upper trophic levels while in an inverted pyramid (eg. tree ecosystem) these quantities tend to increase on going to successive trophic levels.
(d)A food chain is a sequence of different types of organisms by which the flow of energy occurs from one trophic level to another whereas food web is the network of various food chains inter-connected to each other. Food webs increase adaptability and competitiveness of the organisms.
(e)Litter is the dead organic material fallen on the surface of the soil like leaves, remains of animals and excreta. Detritus is the dead organic matter found below the soil surface which is eaten up by the detritivores or broken down by decomposers.
(f)Primary productivity is the rate of synthesis of biomass or energy fixation by the plants. It is comparatively quite high.
Secondary productivity is the rate of synthesis of biomass by consumers (herbivores and carnivores). It is small and decreases with rise of trophic level.
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.
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.
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?
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
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
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".
Flow of energy through various trophic levels in an ecosystem is unidirectional and non-cyclic. Explain.
Under what conditions would a particular stage in the process of succession revert back to an earlier stage?
In the North East region of India, during the process of Jhum cultivation, forests are cleared by burning and left for regrowth after a year of cultivation. How would you explain the regrowth of forest in ecological term?
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.
Distinguish between
(a)Grazing food chain and detritus food chain
(b)Production and decomposition
(c)’Upright and inverted pyramid
(d)Food chain and food web
(e)Litter and detritus
(f)Primary and secondary productivity
The rate of decomposition of detritus is affected by the abiotic factors like availability of oxygen, pH of the soil substratum, temperature etc. Discuss.
Name an omnivore which occurs in both grazing food chain and the decomposer food chain.
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?
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".
Give two examples of artificial or mail made ecosystems. List the salient features by which they differ from natural ecosystems.
Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?
The biodiversity increases when one moves from the pioneer to the climax stage. What could be the explanation?
What are. the three types of ecological pyramids? What information is conveyed by each pyramid with regard to structure, function and energy in the ecosystem?
