Biology

Ecosystem

Question:

Give two examples of artificial or mail made ecosystems. List the salient features by which they differ from natural ecosystems.

Answer:

Crop fields and an aquarium considered as man-made ecosystems. In artificial ecosystems the biotic and abiotic components of ecosytems are maintained artificially by regular feeding and clearing of aquarium and regular irrigation and sowing of seeds in crop field ecosystem. Natural ecosystem self sustains biotic and abiotic components of an ecosystem.

previuos
next

Ecosystem

Q 1.

Given below is a figure of an ecosystem. Answer the following questions.
ncert-exemplar-problems-class-12-biology-ecosystem-2
(i) What type of ecosystem is shown in the figure?
(ii) Name any plant that is characteristic of such ecosystem.

Q 2.

Write important features of a sedimentary cycle in an ecosystem.

Q 3.

Give any two examples of xerarch succession.

Q 4.

Name any two organisms which can occupy more than one trophic level in an ecosystem.

Q 5.

What is primary productivity? Give brief description of factors that affect primary productivity.

Q 6.

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.

Q 7.

Among bryophytes, lichens and fern which one is a pioneer species in a xeric succession?

Q 8.

What is common to earthworm, mushroom, soil mites and dung beetle in an ecosystem.

Q 9.

Primary productivity varies from ecosystem to ecosystem. Explain.

Q 10.

Human activities interfere with carbon cycle. List any two such activities.

Q 11.

Why are nutrient cycles in nature called biogeochemical cycles?

Q 12.

Name an organism found as secondary carnivore in an aquatic ecosystem.

Q 13.

Why is the rate of assimilation of energy at the herbivore level called secondary productivity?

Q 14.

What is the ultimate source of energy for the ecosystems?

Q 15.

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

Q 16.

Is the common edible mushroom an autotroph or a heterotroph?

Q 17.

What does the base tier of the ecological pyramid represent?

Q 18.

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————- .

Q 19.

Arrange the following as observed in vertical stratification of a forest: Grass, Shrubby plants, Teak, Amaranths

Q 20.

Define self sustainability.

Q 21.

Fill in the trophic levels (1, 2, 3 and 4) in the boxes provided in the figure.
ncert-exemplar-problems-class-12-biology-ecosystem-3

Q 22.

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.

Q 23.

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".

Q 24.

The number of trophic levels in an ecosystem are limited. Comment.

Q 25.

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?

Q 26.

Climax stage is achieved quickly in secondary succession as compared to primary succession. Why?

Q 27.

Is an aquarium a complete ecosystem?

Q 28.

What are the shortcomings of ecological pyramids in the study of ecosystem?

Q 29.

Name an omnivore which occurs in both grazing food chain and the decomposer food chain.

Q 30.

Define decomposition and describe the processes and products of decomposition.

Q 31.

Flow of energy through various trophic levels in an ecosystem is unidirectional and non-cyclic. Explain.

Q 32.

The rate of decomposition of detritus is affected by the abiotic factors like availability of oxygen, pH of the soil substratum, temperature etc. Discuss.

Q 33.

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?

Q 34.

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.

Q 35.

Give an account of energy flow in an ecosystem.

Q 36.

Justify the pitcher plant as a producer.

Q 37.

"The energy flow in the ecosystem follows the second law of thermodynamics."Explain.

Q 38.

What is an incomplete ecosystem? Explain with the help of suitable example.

Q 39.

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.

Q 40.

How do you distinguish between humification and mineralisation?

Q 41.

Give two examples of artificial or mail made ecosystems. List the salient features by which they differ from natural ecosystems.

Q 42.

The biodiversity increases when one moves from the pioneer to the climax stage. What could be the explanation?

Q 43.

Outline salient features of carbon cycling in an ecosystem.

Q 44.

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?

Q 45.

Describe the components of an ecosystem.

Q 46.

Define’ecological pyramids and describe with examples, pyramids of number and biomass.

Q 47.

What could be the reason for the faster rate of decomposition in the tropics?

Q 48.

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".

Q 49.

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?

Q 50.

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