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?
The three ecological pyramids that are usually studied are (a) pyramid of number (b) pyramid of biortiass and (c) pyramid of energy.
• Any calculations of energy content, biomass, or numbers has to include all organisms at that trophic level. No generalisations we make will be true if we take only a few individuals at any trophic level into account. Also a given organism may occupy more than one trophic level simultaneously. One must remember that the trophic level represents a functional level, not a species as such. A given species may occupy more than one trophic level in the same ecosystem at the same time; for example, a sparrow is a primary consumer when it eats seeds, fruits, peas, and a secondary consumer when it eats insects and worms.
• In most ecosystems, all the pyramids, of number, of energy and biomass are upright, i.e., producers are more in number and biomass than the herbivores, and herbivores are more in number and biomass than the carnivores. Also energy at a lower trophic level is always more than at a higher 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.
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?
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
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".
Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?
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.
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 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?
Name an omnivore which occurs in both grazing food chain and the decomposer food chain.
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.
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.
Give two examples of artificial or mail made ecosystems. List the salient features by which they differ from natural ecosystems.
The biodiversity increases when one moves from the pioneer to the climax stage. What could be the explanation?
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".
