APES primary productivity GPP and NPP review
Review key concepts of Gross Primary Productivity (GPP) and Net Primary Productivity (NPP) essential for AP Environmental Science, including definitions, calculations, and ecological significance.
Quiz(36 questions)
1. What is the primary factor that determines the rate of photosynthesis in plants?
Terms in this Study Set(36)
Definitions and Concepts(16)
Define Gross Primary Productivity (GPP).
GPP is the total amount of energy captured by photosynthesis in a given area and time. It reflects the raw energy input into an ecosystem.
What is Net Primary Productivity (NPP)?
NPP is the energy remaining after plants have met their own respiratory needs. It is calculated as: NPP = GPP - Respiration.
True or False: NPP can be negative.
True. If respiration exceeds GPP, NPP is negative, indicating energy depletion.
How is NPP calculated?
NPP = GPP - Respiration. Example: If GPP = 1000 kcal and Respiration = 300 kcal, then NPP = 700 kcal.
What does high NPP indicate?
High NPP indicates a productive ecosystem, suggesting favorable conditions for plant growth and biomass accumulation.
Compare GPP and NPP.
GPP is total energy produced, while NPP is the energy available for consumers. NPP = GPP - Respiration.
Fill in the blank: NPP is primarily used by ___ in an ecosystem.
Consumers (herbivores, carnivores, and decomposers) rely on NPP for energy.
What factors influence GPP?
Factors include sunlight, temperature, water availability, and nutrient levels.
True or False: GPP is always greater than NPP.
True. GPP accounts for all energy produced, while NPP is after respiration losses.
Explain the relationship between GPP and respiration.
Respiration uses energy for plant functions, reducing GPP to yield NPP. More respiration means less NPP.
Calculate NPP: GPP = 1500 kcal, Respiration = 600 kcal.
NPP = GPP - Respiration = 1500 kcal - 600 kcal = 900 kcal.
Define primary productivity.
Primary productivity refers to the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances.
What does a negative NPP imply?
A negative NPP indicates that an ecosystem is losing biomass, suggesting environmental stress or degradation.
What is the significance of measuring NPP?
NPP provides insight into ecosystem health, resource availability, and carbon cycling.
Fill in the blank: GPP is measured over a specific ___ and ___.
Area and time period, often annually or seasonally.
What role does sunlight play in GPP?
Sunlight is the primary energy source for photosynthesis, directly affecting GPP levels.
Factors Influencing Productivity(12)
What does GPP stand for?
Gross Primary Productivity; the total amount of energy captured by photosynthesis in an ecosystem.
True or False: NPP is always higher than GPP.
False; NPP (Net Primary Productivity) is GPP minus the energy used by producers for respiration.
List three factors affecting NPP.
1. Light availability 2. Nutrient levels 3. Temperature
How does light intensity affect productivity?
Higher light intensity generally increases GPP, allowing more photosynthesis, until saturation is reached.
Fill in the blank: NPP = ______ - Respiration.
NPP = GPP - Respiration.
Comparison: Tropical vs. Temperate forests in productivity.
Tropical forests typically have higher NPP due to warmer temperatures and more sunlight.
What role do nutrients play in GPP?
Nutrients like nitrogen and phosphorus are essential for plant growth, directly influencing GPP rates.
Cause → Effect: Increased temperature on NPP.
Increased temperature can enhance rates of photosynthesis but may also increase respiration, affecting NPP.
How does water availability impact NPP?
Adequate water increases plant growth and photosynthesis, thus enhancing NPP, while drought reduces it.
True or False: NPP is higher in aquatic ecosystems than terrestrial.
False; while some aquatic systems are productive, terrestrial ecosystems often have higher overall NPP.
What is the impact of herbivory on NPP?
Herbivory can decrease NPP by reducing the biomass of producers, affecting overall energy capture.
Example: Calculate NPP if GPP is 1000 kcal and respiration is 200 kcal.
NPP = 1000 kcal - 200 kcal = 800 kcal.
Ecological Implications(8)
Why is NPP important for ecosystems?
NPP represents the energy available to consumers. It determines ecosystem productivity, biodiversity, and food web dynamics.
True or False: High GPP always leads to high biodiversity.
False. While high GPP indicates abundant primary production, biodiversity depends on various factors, including habitat structure and species interactions.
Fill in the blank: NPP is a key indicator of __________ sustainability.
ecosystem
Compare GPP and NPP in terms of energy.
GPP = Total photosynthetic energy captured. NPP = GPP - energy used in respiration. NPP is what supports herbivores.
How does NPP affect food chains?
NPP provides the energy base for food chains. Higher NPP means more energy for herbivores, leading to larger populations of higher trophic levels.
What can low NPP indicate about an ecosystem?
Low NPP can suggest poor nutrient availability, drought conditions, or ecosystem degradation, impacting food web stability.
Cause → Effect: High NPP effects.
- Supports more herbivores - Increased predator populations - Enhances ecosystem resilience
How does GPP relate to climate change?
Changes in climate can alter GPP by affecting temperature and precipitation patterns, impacting overall ecosystem health and carbon storage.
Questions in this Study Set(36)
1. What is the primary factor that determines the rate of photosynthesis in plants?
2. What does GPP stand for in ecology?
3. What does NPP stand for in ecological terms?
4. Which of the following factors is NOT directly associated with influencing NPP?
5. Which of the following best describes NPP?
6. Which of the following is NOT a consequence of high NPP in an ecosystem?
7. In a region where temperatures are increasing, what effect is likely seen on NPP?
8. True or False: GPP can be considered a measure of energy loss in an ecosystem.
9. If GPP is 1000 kcal and respiration is 600 kcal, what is the NPP?
10. Which ecosystem typically exhibits the highest NPP?
11. If GPP is 800 kcal and respiration is 250 kcal, what is the NPP?
12. How does low NPP impact trophic levels in an ecosystem?
13. How does nutrient enrichment affect GPP in an ecosystem?
14. What does a high NPP indicate about an ecosystem?
15. True or False: GPP is greater than NPP in all ecosystems.
16. Which of the following scenarios would likely result in the lowest NPP?
17. Which of the following factors does NOT influence GPP?
18. Which factor can significantly influence GPP in an ecosystem?
19. True or False: Higher herbivory rates always lead to lower NPP.
20. Fill in the blank: NPP is primarily utilized by ___ in an ecosystem.
21. What role does NPP play in ecosystem sustainability?
22. Which is a direct consequence of increased carbon dioxide levels in an ecosystem?
23. Which scenario indicates a negative NPP?
24. Which of the following statements is true about the relationship between GPP and climate change?
25. What is the impact of water scarcity on GPP?
26. What is the formula for calculating NPP?
27. Fill in the blank: The formula for NPP can be expressed as NPP = GPP - ______.
28. Which of the following statements best compares GPP and NPP?
29. What role does temperature play in primary productivity?
30. What is the significance of measuring NPP in ecosystems?
31. Which of the following is NOT a factor that affects light availability in an ecosystem?
32. True or False: GPP is always less than NPP.
33. In which type of ecosystem would you likely find the highest GPP?
34. How does temperature influence GPP?
35. Fill in the blank: GPP is measured over a specific ___ and ___.
36. Which of the following statements correctly describes the relationship between GPP and NPP?
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