Productivity - Primary and Secondary - Unsolved Practice Set
Chapter: Ecosystem | Topic: Productivity Primary and Secondary
PRODUCTIVITY - PRIMARY AND SECONDARY - UNSOLVED PRACTICE SET
Topic: Productivity Primary and Secondary
Multiple Choice Questions
Q1. Gross Primary Productivity (GPP) refers to:
- The total rate of organic matter production by producers through photosynthesis, before accounting for respiratory losses
- Only the energy consumed by herbivores
- The rate of decomposition in an ecosystem
- The total biomass of all organisms in an ecosystem
Q2. Net Primary Productivity (NPP) is calculated as:
- GPP plus respiratory losses
- GPP minus respiratory losses (R) of producers
- Total consumer biomass
- The total energy entering an ecosystem from sunlight
Q3. Secondary productivity refers to:
- The rate of organic matter production by producers
- The rate of formation of new organic matter by consumers (heterotrophs)
- The rate of decomposition of dead organic matter
- The total amount of sunlight received by an ecosystem
Q4. Which of the following is a key factor that can significantly affect the primary productivity of an ecosystem?
- Availability of nutrients
- Amount of solar radiation received
- Plant species composition
- All of the above
Q5. Primary productivity is generally expressed in units of:
- Litres per hour
- Grams (or kilocalories) per square metre per year (g/m²/yr or kcal/m²/yr)
- Degrees Celsius
- Number of species present
Short Answer Questions
Q6. Define Gross Primary Productivity (GPP) and Net Primary Productivity (NPP), and state the relationship between them.
Q7. What is secondary productivity, and how does it differ from primary productivity?
Q8. Name any two factors that can influence the primary productivity of an ecosystem.
Q9. Why is NPP considered particularly important for supporting the rest of the food chain in an ecosystem?
Long Answer Questions
Q10. Discuss primary productivity, explaining the difference between gross and net primary productivity, and describing the factors that influence it.
Q11. Explain secondary productivity, describing how it depends on the primary productivity of an ecosystem and the efficiency of consumers in converting food into new biomass.
APPLICATION / ANALYSIS
Q12. In a particular ecosystem, the gross primary productivity (GPP) is measured as 500 kcal/m²/year, and the respiratory loss (R) of producers is 200 kcal/m²/year. Calculate the net primary productivity (NPP) of this ecosystem, and explain what this value represents.
Q13. Two forest ecosystems receive similar amounts of sunlight, but one has significantly richer soil nutrients than the other. Explain, using your understanding of productivity, why the ecosystem with richer soil nutrients is likely to show higher primary productivity.