Ecosystem Productivity and Energy Transfer

Which factors influence net primary productivity in terrestrial ecosystems?

In aquatic ecosystems, light and the availability of nutrients are the only factors limiting productivity.

What is the approximate percentage of energy transferred from one trophic level to the next?

At each trophic level, some energy will be lost to the environment in the form of _____ during cellular respiration.

Match each statement with its corresponding concept:

Terrestrial Ecosystem Productivity

Factors affecting productivity:
- Light
- Temperature
- Rainfall
Increased levels of these factors generally result in increased photosynthesis and productivity.

Aquatic Ecosystem Productivity

Factors affecting productivity:
- Light
- Nutrient availability

Energy Transfer Between Trophic Levels

Ecological pyramid: A diagram representing energy or matter distribution across trophic levels in a food chain/web.
Energy transfer between trophic levels is approximately 10%.
Energy loss reasons:
- Organisms use energy for life processes like respiration, movement, and reproduction.
- Not all organisms at one level are consumed by predators.
- Some consumed molecules are unusable by the predator.
- Cellular respiration energy cannot be passed on.
- Energy loss as heat during energy transformations.
Limited energy transfer explains why food chains have few trophic levels.

Ecosystem Productivity

Measured by:
- Gross primary productivity (GPP): Rate at which producers capture light energy, converted to chemical energy by photosynthesis.
- Net primary productivity (NPP): Energy stored in producer biomass, available to consumers.
NPP = GPP - Respiration
NPP variations:
- Tropical rainforests have significantly higher NPP than deserts.
- Rainforests cover 5% of Earth's surface but account for 30% of global NPP.

This quiz covers the essential concepts of terrestrial and aquatic ecosystem productivity, including the factors that influence productivity such as light, temperature, and nutrients. It also discusses energy transfer between trophic levels and the limitations of energy flow in food chains. Test your understanding of these fundamental ecological principles.