Ecosystem

The breakdown of detritus into smaller particles by earthworm is a process called

1. Fragmentation
2. Catabolism
3. Mineralisation
4. Humification

Mass of living matter at a trophic level in an area at any time is called :

1. Humus
2. Detritus
3. Standing state
4. Standing crop

Of the total incident solar radiation the proportion of PAR is

1. About 60%
2. More than 80%
3. Less than 50%
4. About 70%

Which one of the following statements is correct for secondary succession?

1. It follows primary succession
2. It occurs on deforested site
3. It is similar to primary succession except that it has a relatively fast pace.
4. It begins on a bare rock.

Which one of the following statements for pyramid of energy is incorrect, whereas the remaining three are correct?

1. It shows energy content of different trophic level organisms
2. It is upright in shape
3. It is inverted in shape
4. Its base is broad

Which of the following representations shows the pyramid of numbers in a forest ecosystem? [figure]

1. B
2. A
3. D
4. C

Which one of the following is one of the characteristics of a biological community?

1. Mortality
2. Sex-ratio
3. Stratification
4. Natality

The biomass available for consumption by the herbivores and the decomposers is called –

1. Standing crop
2. Net primary productivity
3. Gross primary productivity
4. Secondary productivity

The correct sequence of plants in hydrosere is :

1. Volvox Hydrilla Pistia Scirpus Lantana Oak
2. Pistia Volvox Scirpus Hydrilla Oak Lantana
3. Oak Lantana Volvox Hydrilla Pistia Scirpus
4. Oak Lantana Scirpus Pistia Hydrilla Volvox

Which one of the following types of organisms occupy more than one trophic level in a pond ecosystem?

1. Phytoplankton
2. Zooplankton
3. Frog
4. Fish

Consider the following statements concerning food chains: (i) Removal of 80% tigers from an area resulted in greatly increased growth of vegetation (ii) Removal of most of the carnivores resulted in an increased population of deer (iii) The length of food chains is generally limited to 3-4 trophic levels due to energy loss (iv) The length of food chains may vary from 2 to 8 trophic levels Which two of the above statements are correct?

1. (iii), (iv)
2. (ii), (iii)
3. (i), (iv)
4. (i), (ii)

The slow rate of decomposition of fallen logs in nature is due to their:

1. low moisture content
2. poor nitrogen content
3. anaerobic environment around them
4. low cellulose content

About 70% of total global carbon is found in:

1. Grasslands
2. Agroecosystems
3. Oceans
4. Forests

Which one of the following ecosystem types has the highest annual net primary productivity ?

1. Temperate evergreen forest
2. Temperate deciduous forest
3. Tropical rain forest
4. Tropical deciduous forest

Which one of the following is not used for construction of ecological pyramids ?

1. Rate of energy flow
2. Dry weight
3. Fresh weight
4. Number of individuals

Which of the following is expected to have the highest value (g/m2/yr) in a grassland ecosystem ?

1. Net production (NP)
2. Secondary production
3. Tertiary production
4. Gross production (GP)

Bamboo plant is growing in a far forest then what will be the trophic level of it ?

1. Second trophic level (T2)
2. First trophic level (T1)
3. Fourth trophic level (T4)
4. Third trophic level (T3)

Plant decomposers are:

1. Protista and Animalia
2. Animalia and Monera
3. Monera and fungi
4. Fungi and plants

Which is the reason for highest biomass in aquatic ecosystem?

1. Benthonic and brown algae
2. Nanoplankton, blue green algae, green algae
3. Diatoms
4. Sea grass and slime moulds