Chapter-14 Ecosystem

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.

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.

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

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

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

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

Given below is a list of autotrophs and heterotrophs. With your knowledge
about food chain, establish various linkages between the organisms on
the principle of ‘eating and being eaten’. What is this inter-linkage
established known as?
Algae, hydrilla, grasshopper, rat, squirrel, crow, maize plant, deer, rabbit,
lizard, wolf, snake, peacock, phytoplankton, crustaceans, whale, tiger,
lion, sparrow, duck, crane, cockroach, spider, toad, fish, leopard,
elephant, goat, Nymphaea, Spirogyra.

Write a short note on pyramid of numbers and pyramid of biomass.

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.

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.

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”.

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.

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

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

Sometimes due to biotic/abiotic factor the climax remain in a particular
seral stage (pre climax) without reaching climax. Do you agree with this
statement. If yes give a suitable example.

Primary productivity varies from ecosystem to ecosystem. Explain?

In relation to energy transfer in ecosystem, explain the statement "10kg
of deer's meat is equivalent to 1 kg of lion's flesh".

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?

Apart 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?

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

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

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

Is an aquarium a complete ecosystem?

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

Organisms at a higher trophic level have less energy available. Comment.

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

Define self sustainability.

Give any two examples of xerarch succession.

Why are nutrient cycles in nature called biogeochemical cyles?

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

Why are oceans least productive?

Is the common edible mushroom an autotroph or a heterotroph?

What is the ultimate source of energy for the ecosystems?

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

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

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?

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

Justify the pitcher plant as a producer.

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

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

Under what conditions would a particular stage in the process of
succession revert back to an earlier stage?

What does the base tier of the ecological pyramid represent?

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

Detrivores like earthworm are involved in the process of decomposition of dead plants and animals. Describe the different steps involved in the process of decomposition.

Study the table given below and fill the blanks from ‘A’ to ‘F’.

Name any four ecosystem services. Who gave the price tags on nature’s life support services? Which is the most important ecosystem service provider?

What are the limitations of ecological pyramids?

What is the effect on decomposition rate if :–

a)    Detritus is rich in lignin and chitin

b)    Detritus is rich is nitrogen and sugars

Differentiate between Hydrarch and a Xerarch succession.

Gaseous nutrient cycle and sedimentary nutrient cycles have their reservoir. Name them. Why is a reservoir necessary?

Differentiate between primary succession and secondary succession.

Which one occurs faster?

Give an example of an ecological pyramid which is always upright. Justify your answer.

What is the shape of pyramid of biomass in sea? Why?

Name the pioners of primary succession in water.

What percentage of photosynthetically active radiation is captured by plants

Which  metabolic  process  causes  a  reduction  in  the  Gross  Primary

Productivity?

Who are generally the pioneer species in a Xerarch succession and in a

Hyararch succession?

    Differentiate between Sere and Seral communities.

If we count the number of insects on a tree and number of small birds depending on those insects as also the number of larger birds eating the smaller, what kind of pyramid of number would we get?

Decomposition is faster if deteritus is rich in nitrogen and water soluble substance like sugars. When is the decomposition process slower?

Represent schematically & describe carbon cycle in ecosystem?

What is pyramid of biomass? Represent the pyramid of biomass in
i) grassland ecosystem
ii) aquatic ecosystem.

Differentiate between food chain & food web?

Mention some of the ecological services provided by forests?

The productivity of ecosystem increases from polar regions towards
tropics. Why?

List the factors on which pioneer species depend during secondary
succession?

Name the pioneer species in the primary succession on rock?

Name the primary consumers in aquatic ecosystem?

What is sere?

Name two climatic factors that regulate decomposition?

What ecological principles are derived from the study of food chains?

Differentiate between primary productivity & secondary productivity?

Why is productivity of coral reef maximum?

What is the approximate value of net primary productivity of biosphere?

Mention one similarity between hydrach & Xerach secession?

What is 10% law?

What are the products of decomposition?

What is decomposition – Describe the different processes involved in
decomposition?

What do you mean by “productivity of an ecosystem? What are the types of
productivity also mention the factors on which productivity of an ecosystem
depends?

Explain who pyramid of energy of an ecosystem is always uprights never
inverted?

Differentiate between Production & decomposition?

“Energy flow in an ecosystem is always unidirectional justify the statement.

Name the ecological pyramid that is inverted in tree ecosystem?

Define standing crop?

Name the trophic level occupied by secondary consumers & tertiary
consumers?

Describe the components of an ecosystem?

What is meant by ecological succession? Describe the different stages in
which succession occurs?

Explain with an example, why is the length of a food chain in an ecosystem
generally limited to 3-4 tropic level?

Distinguish between upright & inverted pyramids?

Why is secondary sucession faster than primary sucession?

Name the ecological pyramid that is always upright?

Define stratification?

Name any two man – made ecosystem?

Outline salient features of carbon cycling in an ecosystem

Write important features of a sedimentary cycle in an ecosystem.

Give an account of energy flow in an ecosystem.

Define decomposition and describe the processes and products of decomposition.

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

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

Describe the components of an ecosystem.

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

What is the percentage of photosynthetically active radiation (PAR), in the incident solar radiation.

(a) 100%

(b) 50 %

(c) 1-5%

(d) 2-10%

Secondary producers are

(a) Herbivores

(b) Producers

(c) Carnivores

(d) None of the above

The second trophic level in a lake is-

(a) Phytoplankton

(b) Zooplankton

(c) Benthos

(d) Fishes

Which one of the following has the largest population in a food chain?

(a) Producers

(b) Primary consumers

(c) Secondary consumers

(d) Decomposers

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_________.