AP BIOLOGY

Detailed explanation-1: -Gross primary productivity, or GPP, is the rate at which solar energy is captured in sugar molecules during photosynthesis (energy captured per unit area per unit time). Producers such as plants use some of this energy for metabolism/cellular respiration and some for growth (building tissues).

Detailed explanation-2: -The rate at which photosynthetic producers incorporate energy from the Sun is called gross primary productivity. However, not all of the energy incorporated by producers is available to the other organisms in the food web because producers must also grow and reproduce, which consumes energy.

Detailed explanation-3: -The primary producers convert only 1% of the energy in the sunlight available to them into NPP. Out of this, only 10% is available for the organisms at the next trophic level.

Detailed explanation-4: -Plants typically capture and convert about 1.3% to 1.6% of the solar energy that reaches Earth’s surface and use about a quarter of the captured energy for metabolism and maintenance. So, around 1% of the solar energy reaching Earth’s surface-per unit area and time-ends up as net primary productivity.