Q. No.Which one of the following is one of the characteristics of a biological community ?
1. Stratification
2. Natality
3. Mortality
4. Sex-ratio
The correct sequence of plants in a hyrdosere is
1. Oak→Lantana →Scirpus→Pistia→Hydrilla→Volvax
2. Volvax→Hydrilla→Pistia→Scirpus→Lantana→Oak
3. Pistia→Volvax→Scirpus→Hydrilla→Oak→Lantana
4. Oak →Lantana→Volvax→Hydrilla→Pistia→Scirpus
About 70% of total global carbon is found in
1. grasslands
2. agro-ecosystems
3. oceans
4. forests
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
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 deers
(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. ii and iii
2. iii and iv
3. i and iv
4. i and ii
Quercus species are the dominant component in
1. temperate deciduous forests
2. alpine forests
3. scrub forests
4. tropical rain forests
Which of the following ecosystem types has the highest annual net primary productivity ?
1. Tropical rain forest
2. Tropical deciduous forest
3. Temperate evergeen forest
4. Temperate deciduous forest
Which one of the following is not used for construction of ecological pyramids?
1. Dry weight
2. Number of individuals
3. Rate of energy flow
4. Fresh weight
In a lake that undergoes thermal stratification, blooms of phytoplankton tend to occur
1. before thermal stratification
2. after thermal stratification
3. at the onset of thermal stratification
4. at the mid-phase of thermal stratification
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