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

1

(a)

Producers

(b)

Primary consumers

(c)

Secondary consumers

(d)

Decomposers

The second trophic level in a lake is

1

(a)

Phytoplankton

(b)

Zooplankton

(c)

Benthos

(d)

Fishes

Which of the following process helps in nutrient conservation?

1

(a)

Mineralisation

(b)

Immobilisation

(c)

Leaching

(d)

Nitrification

Which of the following represents the sedimentary type of nutrient cycle?

1

(a)

Nitrogen

(b)

Carbon

(c)

Phosphorus

(d)

Oxygen

Photosynthetic active radiation (PAR) has the following range of wavelengths

1

(a)

340-450 nm

(b)

400-700 nm

(c)

500-600 nm

(d)

450-950 nm

Maximum absorption of rainfall water is done by 

1

(a)

tropical deciduous forest

(b)

tropical evergreen forest

(c)

tropical savannah

(d)

scrub forest

Nitrifying bacteria

1

(a)

oxidize ammonia to nitrates

(b)

convert free nitrogen to nitrogen compounds

(c)

convert proteins into ammonia

(d)

reduce nitrates to free nitrogen

The upright pyramid of numbers is about in 

1

(a)

Pond

(b)

Forest

(c)

Lake

(d)

Grassland

The reservoir for the gaseous type of bio-geochemical cycle exists in

1

(a)

stratosphere

(b)

atmosphere

(c)

ionosphere

(d)

lithosphere

The zone at the edge of lake or ocean which is alternatively exposed to air and immersed in water is called.

1

(a)

Pelagic zone

(b)

Benthic zone

(c)

Lentic one

(d)

Littoral zone

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

1

(a)

Man, Eagle, Kite

Write two examples where man has interfered in ecosystem.

1

(a)

1. Cutting of forests 
2. Construction of dams

Oxygen content of the air is not affected by human activities. Why?

1

(a)

Oxygen is replenished by photosynthesis.

What does nature's carrying capacity for a species indicate?

1

(a)

(In nature) a given habitat has enough or limited resources to support a maximum possible number and nature's carrying capacity indicates that no further growth in population is possible.

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

2

(a)

Primary productivity varies from ecosystem to ecosystem. Explain.

2

(a)

Name the type of food chains responsible for the flow of larger fraction of energy in an aquatic and terrestrial ecosystem respectively. Mention one difference between the two food chains.

2

(a)

Describe the different classes of consumers.

3

(a)

In a botanical garden of a city there is a huge banyan tree growing on which hundreds of birds and thousands of insects live. Draw the pyramids of numbers and also biomass represented by this community. Comment giving reasons on the two different pyramids drawn.

3

(a)

State the function of a reservoir in a nutrient cycle. Explain the simplified model of carbon cycle in nature.

3

(a)

(a) Draw an ideal pyramid of energy upto four trophic levels,where 10,00,00 J are available  from sunlight to the primary producer.Indicate the amount of energy available at each trophic level.
(b) Why is pyramid of energy always upright?Explain
(c) Mention the limitation of an ecological pyramid.

5

(a)

Describe a pond as an ecosystem.

5

(a)