Chapter 14 – Ecosystem

Decomposers like fungi and bacteria are: i. autotrophs ii. heterotrophs iii. saprotrophs iv. chemo-autotrophs. Choose the correct answer:

• (a)i and iii,
• (b)i and iv
• (c)ii and iii,
• (d)i and ii

The process of mineralisation by micro organisms helps in the release of:

• a.inorganic nutrients from humus
• b.both organic and inorganic nutrients from detritus
• c.organic nutrients from humus
• d.inorganic nutrients from detritus and formation of humus.

Productivity is the rate of production of biomass expressed in terms of: i. (kcal m–3) yr–1 ii. g–2 yr–1 iii. g–1 yr–1 iv. (kcal m–2) yr–1

• (a)ii,
• (b)iii,
• (c)ii and iv,
• (d)i andiii

An inverted pyramid of biomass can be found in which ecosystem?

• a.Forest
• b.Marine
• c.Grass land
• d.Tundra ECOSYSTEM 99

Which of the following is not a producer?

• a.Spirogyra
• b.Agaricus
• c.Volvox
• d.Nostoc

Which of the following ecosystems is most productive in terms of net primary production?

• a.Deserts
• b.Tropical rain forests
• c.Oceans
• d.Estuaries

Pyramid of numbers is:

• a.Always upright
• b.Always inverted
• c.Ether upright or inverted
• d.Neither upright nor inverted.

Approximately how much of the solar energy that falls on the leaves of a plant is converted to chemical energy by photosynthesis?

• a.Less than 1%
• b.2-10%
• c.30%
• d.50%

Among the following, where do you think the process of decomposition would be the fastest?

• a.Tropical rain forest
• b.Antarctic
• c.Dry arid region
• d.Alpine region

How much of the net primary productivity of a terrestrial ecosystem is eaten and digested by herbivores?

• a.1%
• b.10%
• c.40%
• d.90%

During the process of ecological succession the changes that take place in communities are:

• a.Orderly and sequential
• b.Random
• c.Very quick
• d.Not influenced by the physical environment.

Climax community is in a state of:

• a.non-equilibrium
• b.equilibrium
• c.disorder
• d.constant change.

Among the following bio-geo-chemical cycles which one does not have losses due to respiration?

• a.Phosphorus
• b.Nitrogen
• c.Sulphur
• d.All of the above

The sequence of communities of primary succession in water is:

• a.phytoplankton, sedges, free-floating hydrophytes, rooted hydrophytes, grasses and trees.
• b.phytoplankton, free-floating hydrophytes, rooted hydrophytes, sedges, grasses and trees.
• c.free-floating hydrophytes, sedges, phytoplankton, rooted hydrophytes, grasses and trees.
• d.phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees.

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

• a.stratosphere
• b.atmosphere
• c.ionosphere
• d.lithosphere

If the carbon atoms fixed by producers already have passed through three species, the trophic level of the last species would be.

• a.scavenger
• b.tertiary producer
• c.tertiary consumer
• d.secondary consumer ECOSYSTEM 101

Which of the following type of ecosystem is expected in an area where evaporation exceeds precipitation, and mean annual rainfall is below 100mm

• (a)Grassland
• (b)Shrubby forest
• (c)Desert
• (d)Mangrove

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

• a.Pelagic zone
• b.Benthic zone
• c.Lentic one
• d.Littoral zone

Edaphic factor refers to:

• a.Water
• b.Soil
• c.Relative humidity
• d.Altitude

Which of the following is an ecosystem service provided by a natural ecosystem?

• a.Cycling of nutrients
• b.Prevention of soil erosion
• c.Pollutant absorption and reduction of the threat of global warming
• d.All of the above