In the equation, $\frac{d\mathrm{N}}{d\mathrm{t}} = r\mathrm{N}\left(\frac{\mathrm{K} - \mathrm{N}}{\mathrm{K}}\right)$ where r stands for

• Intrinsic rate of natural increase

• Death rate

• Population density at time t

• Carrying capacity

• Carrying capacity

Which of the following statements about Productivity is true?

• Primary productivity of all ecosystems is a constant

• The annual net primary productivity of the whole of the biosphere is 17 billion tons (dry weight) of organic matter

• Net primary productivity is the amount of biomass available for consumption by carnivores

• Secondary productivity is defined as the rate of formation of new organic matter by decomposers .

• Secondary productivity is defined as the rate of formation of new organic matter by decomposers .

The pioneer species in Xerarch and Hydrarch succession are respectively

• Lichens and sedges

• Lichens and rooted hydrophytes

• Phytoplanktons and lichens

• Lichens and phytoplanktons

• Lichens and phytoplanktons

Which of the following statements does not apply to eutrophication?

• It is the natural ageing of a lake by nutrient enrichment of its water

• In a young lake the water is cold and clear and supports less life

• The nutrients such as sulphur and phosphorus encourage the growth of aquatic organisms in the lake

• Pollutants released by man radically accelerate the ageing process of a lake

• Pollutants released by man radically accelerate the ageing process of a lake

According to Robert Constanza, 50% of the total cost for ecosystem services goes to

• Recreation

• Soil formation

• Nutrient cycling

• Climate regulation

• Climate regulation

Which of the following statement(s) regarding energy flow is/are false?

I. The detritus food chain begins with dead organic matter.

II. In aquatic ecosystem, detritus food chain is the major conduit for energy flow.

III. In terrestrial ecosystem a larger fraction of energy flows through grazing food chain.

IV. Producers belong to the first trophic level of the food chain.

• II and III only

• III and IV only

• I and IV only

• I and II only

• I and II only

The first recombinant DNA was constructed by linking an antibiotic resistant gene with the native plasmid of V

• Escherichia coli

• Salmonella typhimurium

• Clostridium butylicum

• Acetobacter aceti

• Acetobacter aceti

88.

The polymerase chain reaction1 (PCR) is a technique that is used for

• in vivo replication of specific DNA sequence using thermostable DNA polymerase

• in vitro synthesis of mRNA

• in vitro replication of specific DNA sequence using thermostable DNA polymerase

• in vivo synthesis of mRNA

• in vivo synthesis of mRNA

Bioreactors are useful in

• Separation and purification of a product

• Processing of large volumes of culture

• Micro-injection

• Isolation of genetic material

• Isolation of genetic material

Match the following and choose the correct combination from the options given.

• A - 1; B - 2; C - 3; D - 4

• A - 1; B - 3; C - 2; D - 4

• A - 4; B - 3; C - 2; D - 1

• A - 4; B - 1; C - 2; D - 3

• A - 4; B - 1; C - 2; D - 3