Ecosystem

Both, hydrarch and xerarch successions lead to:

1. Xeric conditions
2. Excessive wet conditions
3. Highly dry conditions
4. Medium water conditions

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