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1.8 Primary Productivity

2 min readdecember 26, 2022

Sumi Vora

Sumi Vora

Sumi Vora

Sumi Vora

Primary Productivity

The amount of energy in an ecosystem determines how many members of how many species an ecosystem can support. The amount of energy that the producers in an ecosystem capture is called the gross primary productivity (GPP). The GPP is a lot like revenue; in a business, revenue is the total income it receives, without accounting for expenses needed to allow the business to run.

When plants take in sunlight, some of the energy is always lost through . This means that, when an organism converts glucose from the sun into energy, some of it is rendered unusable since it escapes into the atmosphere. As a result, one can find the more accurate amount of available energy, otherwise known as the net primary productivity (NPP), by subtracting the amount of energy respired from the GPP. Since the net primary productivity factors in , it can more accurately demonstrate the energy capacity of any given ecosystem. This can be compared to profit (while revenue is entire, profit takes into consideration the limits and boundaries of what is actually available for expenditure).

Ecosystems are generally very unproductive. 99% of the sunlight that hits the earth is reflected, or it passes through the producers without being absorbed. Only the remaining 1% is captured by and becomes part of the GPP. However, 60% of the GPP is lost to , so only 40% of the GPP, or 0.4% of total solar energy, supports the growth and reproduction of producers. 

In short, very little energy is actually available to ecosystems, but after occurs, an ecosystem's productivity levels and species richness levels can be assumed according to their NPP.

Ecosystems with higher levels of productivity are often associated with higher levels of and the ability to satiate the needs of more consumers on higher and higher .

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2Fnet-primary-production.jpg?alt=media&token=5cbfe545-1481-4185-acc7-a480bda0d7cd

Source: Mr. G's Class

Key Terms to Review (6)

Gross Primary Productivity (GPP)

: GPP refers to the total amount of energy that is captured by plants through photosynthesis in a given area or ecosystem.

Net Primary Productivity (NPP)

: NPP refers to the amount of energy that remains after plants have used some of their captured energy for their own respiration.

Photosynthesis

: Photosynthesis is the process through which green plants use sunlight, carbon dioxide, and water to produce glucose (sugar) and oxygen. It is vital for plant growth and releases oxygen into the atmosphere.

Respiration

: Respiration refers to the process by which living organisms, including plants, release stored energy from organic compounds to carry out life functions.

Species Diversity

: Species diversity refers to the variety of different species present in a particular ecosystem or on Earth. It includes both the number of species present and their relative abundance.

Trophic Levels

: Trophic levels refer to the different levels in a food chain or food web where organisms obtain energy. Each level represents a different position in the transfer of energy, with producers at the bottom and top predators at the highest level.

1.8 Primary Productivity

2 min readdecember 26, 2022

Sumi Vora

Sumi Vora

Sumi Vora

Sumi Vora

Primary Productivity

The amount of energy in an ecosystem determines how many members of how many species an ecosystem can support. The amount of energy that the producers in an ecosystem capture is called the gross primary productivity (GPP). The GPP is a lot like revenue; in a business, revenue is the total income it receives, without accounting for expenses needed to allow the business to run.

When plants take in sunlight, some of the energy is always lost through . This means that, when an organism converts glucose from the sun into energy, some of it is rendered unusable since it escapes into the atmosphere. As a result, one can find the more accurate amount of available energy, otherwise known as the net primary productivity (NPP), by subtracting the amount of energy respired from the GPP. Since the net primary productivity factors in , it can more accurately demonstrate the energy capacity of any given ecosystem. This can be compared to profit (while revenue is entire, profit takes into consideration the limits and boundaries of what is actually available for expenditure).

Ecosystems are generally very unproductive. 99% of the sunlight that hits the earth is reflected, or it passes through the producers without being absorbed. Only the remaining 1% is captured by and becomes part of the GPP. However, 60% of the GPP is lost to , so only 40% of the GPP, or 0.4% of total solar energy, supports the growth and reproduction of producers. 

In short, very little energy is actually available to ecosystems, but after occurs, an ecosystem's productivity levels and species richness levels can be assumed according to their NPP.

Ecosystems with higher levels of productivity are often associated with higher levels of and the ability to satiate the needs of more consumers on higher and higher .

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2Fnet-primary-production.jpg?alt=media&token=5cbfe545-1481-4185-acc7-a480bda0d7cd

Source: Mr. G's Class

Key Terms to Review (6)

Gross Primary Productivity (GPP)

: GPP refers to the total amount of energy that is captured by plants through photosynthesis in a given area or ecosystem.

Net Primary Productivity (NPP)

: NPP refers to the amount of energy that remains after plants have used some of their captured energy for their own respiration.

Photosynthesis

: Photosynthesis is the process through which green plants use sunlight, carbon dioxide, and water to produce glucose (sugar) and oxygen. It is vital for plant growth and releases oxygen into the atmosphere.

Respiration

: Respiration refers to the process by which living organisms, including plants, release stored energy from organic compounds to carry out life functions.

Species Diversity

: Species diversity refers to the variety of different species present in a particular ecosystem or on Earth. It includes both the number of species present and their relative abundance.

Trophic Levels

: Trophic levels refer to the different levels in a food chain or food web where organisms obtain energy. Each level represents a different position in the transfer of energy, with producers at the bottom and top predators at the highest level.


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© 2024 Fiveable Inc. All rights reserved.

AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.