Name: energy transfer as biomass efficiency
Uploaded: 2025-10-23T11:48:55.000Z
Duration: 1 min 1 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Life Science

interdependent-relationships-in-ecosystems

Interdependent Relationships in Ecosystems

3.1.9-12.I

Production Efficiency

L'efficacité avec laquelle les organismesincorporent l'énergie reçue en biomassepour le niveau trophique suivant s'appelleEfficacité de production nette ou EPN. 
L'énergie peut être perduependant les processus métaboliquescomme la respiration et la digestion en tant que déchetset aussi en tant que biomasse non consommée,par exemple, lorsqu'un renard ne consommequ'une partie d'un lapinlaissant les ressources riches en énergie inutilisées. 
Les animaux ectothermes, comme les reptiles,consomment moins d'énergie pour les activités métaboliques,en particulier la respirationet le maintien de la température corporelleet ont donc un EPN qui est environ 10 fois plus élevéque les endothermes, les mammifères ou les oiseauxqui doivent générer plus de chaleurpour maintenir les processus métaboliques. 
Dans le cas du renard et du serpent,l'écart dans les EPN signifie que le renarddoit consommer 10 fois plus de lapin que le serpentpour recevoir la même quantité d'énergiepour construire de la biomasse.

Shurin, Jonathan B, Daniel S Gruner et Helmut Hillebrand. "Tout mouillé ou séché ? Différences réelles entre les réseaux trophiques aquatiques et terrestres. Actes de la Royal Society B : Biological Sciences 273, n° 1582 (7 janvier 2006) : 1-9. [<a href="https://doi.org/10.1098/rspb.2005.3377 » target="__blank">Source</a>]

efficacité de la production

L’efficacité nette de la production (ENP) est l’efficacité à laquelle les organismes assimilent l’énergie en biomasse pour le prochain niveau trophique. En raison de faibles taux métaboliques et de l’énergie réduite consacrée aux processus thermorégulateurs, l’ENP des organismes ectothermes (animaux à sang froid) est 10 fois plus élevée celle que des endothermes (animaux à sang chaud). 
 
 <h4>Efficacité nette de la production</h4> 
 
 L’énergie circule à travers les écosystèmes, d’un organisme à l’autre. Cependant, seule l’énergie stockée dans un organisme en tant que biomasse est disponible comme aliment pour le niveau trophique suivant. Le reste de l’énergie est perdu au fil du temps en tant que chaleur comme un sous-produit des processus métaboliques et en tant que déchets excrétés. L’efficacité avec laquelle les organismes assimilent cette énergie utilisable en biomasse est appelée efficacité nette de production (ENP), ou le pourcentage d’énergie stockée dans la biomasse qui n’est pas utilisé pour la respiration. Par exemple, dans une étude sur un écosystème de broussailles désertiques, il a été constaté que seulement 0,016 % de l’énergie produite par les producteurs primaires était ensuite assimilée en petits tissus de mammifères herbivores et disponible pour les carnivores dans ce système.
 
 <h4>Endotherme par rapport à ectotherme</h4>
 
 Les endothermes comme les oiseaux et les mammifères ont généralement de faibles efficacités de production en raison des plus grandes quantités d’énergie dépensées pour maintenir des températures corporelles élevées constantes et des taux métaboliques élevés. D’autre part, l’ENP des organismes ectothermes est d’un ordre de grandeur plus élevé en raison de leurs taux métaboliques et de leurs comportements thermorégulateurs moins importants. Par conséquent, un mammifère doit consommer plus d’énergie pour assimiler la même quantité de biomasse qu’un reptile.

Efficacité de la production

L’efficacité nette de production (NPE) est l’efficacité à laquelle les organismes assimilent l’énergie en biomasse pour le niveau trophique suivant. En raison des faibles taux métaboliques ...

Education

Enseignement

JoVE Core

Biology

Biologie

Ecology

Écologie

Ecosystems

Écosystèmes

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

energy transfer as biomass efficiency

Net production efficiency shows how much energy organisms turn into biomass for the next trophic level. It focuses on the usable energy stored in body tissue, not the energy lost as heat or excreted wastes. This makes it a key idea for understanding energy flow through ecosystems.

As energy moves from one organism to the next, only biomass can serve as food for the next trophic level. The rest of the energy is used in metabolism and is lost over time. Net production efficiency, or NPE, is the percentage of stored biomass energy that is not used for respiration.

NPE is often much higher in ectotherms, or cold-blooded animals, than in endotherms, or warm-blooded animals. Ectotherms have lower metabolic rates and spend less energy on thermoregulation, so their NPE can be about 10 times higher. Endotherms like birds and mammals usually have lower production efficiencies because they use more energy to keep body temperature constant.

A desert scrub ecosystem gives one clear example of this energy loss. In that system, only 0.016% of the energy made by primary producers was later built into small herbivore mammal tissue and available to carnivores. Because mammals need more energy to store the same amount of biomass than reptiles do, a mammal must eat more to match the biomass a reptile could produce.

Energy Transfer as Biomass Efficiency

what is an ecosystem?

Ecosystem Zones and Climate

Ecosystems are shaped by living and nonliving parts of an environment, and they can be grouped as terrestrial or aquatic. Terrestrial ecosystems depend on climate. Aquatic ecosystems are divided into freshwater and marine systems, and depth affects water temperature and how much sunlight reaches the water. Terrestrial ecosystems are called biomes. A biome is defined by climate and by the organisms that live there. Near the equator, rainforests have high, aseasonal temperatures and high annual...

trophic levels

Food Chains and Energy Flow

Food chains show how energy and nutrients move through an ecosystem. Each organism holds a trophic level, or a specific place in that chain. The lowest level includes primary producers, which make their own food using energy from the sun or from chemicals. Organisms at the next levels are heterotrophs, which get energy from other organisms below them. Primary consumers are herbivores, and they feed on autotrophs, also called primary producers. Secondary and tertiary consumers are carnivores...

primary production

GPP, NPP, and Ecosystem Energy

Gross primary production and net primary production describe how energy enters and moves through ecosystems. Primary producers, or autotrophs, make their own food. They can do this by photosynthesis or chemosynthesis, and they can also gain energy by consuming other organisms. The rate at which producers capture and store this energy is called gross primary production, or GPP. Not all of the energy in GPP stays available to the rest of the ecosystem. Primary producers use some energy for...

production efficiency

Net production efficiency shows how much energy organisms turn into biomass for the next trophic level. It focuses on the usable energy stored in body tissue, not the energy lost as heat or excreted wastes. This makes it a key idea for understanding energy flow through ecosystems. As energy moves from one organism to the next, only biomass can serve as food for the next trophic level. The rest of the energy is used in metabolism and is lost over time. Net production efficiency, or NPE, is the...

trophic efficiency

Energy Loss in Food Chains

Trophic level transfer efficiency describes how much energy moves from one level of a food chain to the next. It shows why energy drops sharply as organisms eat and are eaten. In most ecosystems, only about 10% of the energy passes on. This energy loss follows the second law of thermodynamics. In living systems, much of the energy is lost as metabolic heat during respiration. Trophic level transfer efficiency, or TLTE, measures this transfer by comparing the energy produced at one trophic...

what are biogeochemical cycles?

Nutrient Recycling in Ecosystems

Nutrient recycling in ecosystems keeps the elements needed for life moving through living and nonliving parts of the environment. Elements such as water, carbon, nitrogen, sulfur, and phosphorus are present in limited amounts, so they must be conserved and reused. These movements are called biogeochemical cycles. These nutrients can exist in several chemical forms. They may spend long periods in the atmosphere, on land, under the land, or in aquatic environments. Decomposition is a key part of...

the water cycle

Water Movement Through Earth Systems

Water movement through Earth systems connects the hydrosphere, the atmosphere, the land, and living things. The hydrosphere includes every place where water is stored or moves. Because water supports living processes, its movement is important for ecosystem dynamics. The cycle starts when the sun warms surface water on land and in the oceans. That water evaporates and enters the atmosphere as vapor. Water can also move into the air by sublimation, which is ice changing directly into vapor, and...

the carbon cycle

Carbon Movement in Living Systems

Carbon moves through living systems and Earth over short and long time scales. It is the basis of all organic matter on Earth, and it cycles through ecosystems by passing between organisms and by moving through rocks, oceans, and the atmosphere. Human activities, including farming and burning fossil fuels, have changed this balance. In the biological carbon cycle, carbon dioxide in the atmosphere reacts with water to form bicarbonate. Primary producers, or autotrophs, use carbon dioxide and...

the nitrogen cycle

Nitrogen in Soil and Living Things

Nitrogen in soil and living things moves through ecosystems in several forms. Nitrogen atoms are found in proteins and DNA. Most animals and plants cannot use nitrogen gas, which is the main form of nitrogen on Earth. Nitrogen must first be changed into a usable form by nitrogen-fixing bacteria before it can move through food webs. About 78% of the air we breathe is nitrogen gas, but few organisms can use it in that form. Nitrogen fixation changes nitrogen gas (N2) into ammonia (NH3).

the phosphorus cycle

Phosphorus Movement in Soil and Water

Phosphorus moves through ecosystems mostly as phosphate ions in soil, water, sediment, and rocks. Unlike carbon, water, and nitrogen, it is not found in the atmosphere as a gas. It is also often a limiting nutrient, which means it is in short supply in many environments. Phosphorus is important in DNA, cell membranes, bones, and teeth. It is found in minerals, sediment, volcanic ash, and aerosols. As rocks and sediment weather over time, they release inorganic phosphate. That phosphate then...

the sulfur cycle

Sulfur in Ecosystems and Acid Rain

Sulfur moves through ecosystems as part of the chemical cycle that supports life. It is an important element in proteins and in amino acids such as cysteine, which helps give proteins their structure. On land, sulfur reaches ecosystems in several ways. Weak sulfuric acid can fall with precipitation, sulfur can drop directly from the atmosphere, rocks can weather and release sulfur, and geothermal vents can add it as well. Plants and microorganisms take sulfur up from the soil and change it...

bioremediation

Bioremediation in Soil and Oil Cleanup

Bioremediation uses prokaryotes, fungi, or plants to remove pollutants from the environment. It is a practical way to reduce harmful chemicals in contaminated soil and water. In agriculture, fertilizers and pesticides can leach into groundwater, streams, and lakes. Microbes and bacteria can help break down these toxins. One example is atrazine, an environmental toxin found in many fertilizers, which can be removed from soils by the bacterial species Rhizobium and Tricoderma sp. Bioremediation...

key terms and concepts

Learn how net production efficiency tracks energy stored as biomass, why ectotherms are more efficient than endotherms, and how energy moves up trophic levels.

Energy Transfer as Biomass Efficiency | JoVE K12

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La collection JoVE Core Biologie donne vie à la biologie à travers plus de 300 leçons vidéos animées concises et faciles à comprendre qui expliquent les concept clés de la biologie, mais aussi plus de 150 vidéos de scientifiques à l'action effectuant des expériences de recherche dans des laboratoires modernes.

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

3.1.9-12.F

3.1.9-12.H

Louisiana Student Standards for Science

High School

Life Sciences

from-molecules-to-organisms-structures-and-processes

From Molecules To Organisms: Structures And Processes

HS-LS1-7

ecosystems-interactions-energy-and-dynamics

Ecosystems: Interactions, Energy And Dynamics

HS-LS2-1

Environmental Science

HS-LS2-4

Tennessee Academic Standards

Ecosystems: Interactions, Energy, and Dynamics

BIO1.LS2.4

Virginia  Standards of Learning

HIgh School

BIO.8

BIO.8.b

LS.5

LS.5.b

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

Arizona Science Standards

HS.L2

HS.L2U1.19

Alabama Course of Study Science

Ecosystems: Interactions Energy and Dynamics

9-12.B.2.6

9-12.EVS.1.1

Next Generation Science Standards

Florida Department of Education

SC.912.L.17

SC.912.L.17.9

Texas Essential Knowledge and Skills

BIO.13

BIO.13.B

Georgia Standards of Excellence

Botany

SBO6.

All Standards

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

B-LS2-1.

B-LS2-2.

SEV1.

SEV1.d

new-york-state-science-learning-standards

New York State Science Learning Standards

HS-LS2-3.

HS-LS2-4.

Entomology

SEN3.

SEN3.b

Oceanography

SO3.

SO3.2

SEC4.

SEC4.d

SB5.b

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What is an Ecosystem?

Overview

An ecosystem is the interaction between all abiotic and biotic factors in an environment and can be classified as terrestrial or aquatic. ...

Trophic Levels

All organisms in an ecosystem occupy a trophic level in the food chain. The lowest level consists of primary producers, which synthesize their food from ...

Primary Production

The total amount of energy acquired by primary producers in an ecosystem is called gross primary production (GPP). However, of this energy, producers use ...

Net production efficiency (NPE) is the efficiency at which organisms assimilate energy into biomass for the next trophic level. Due to low metabolic rates ...

Trophic Efficiency

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Students who demonstrate understanding can use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales. Assessment Boundary: Assessment is limited to provided data.

3.1.9-12.L

Students who demonstrate understanding can evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem. Assessment Boundary: N/A

3.1.9-12.M

What is Weather?

Overview

Weather refers to the current state of atmospheric conditions at a specific time and place. Weather is temporary and is influenced by the ...

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Global Climate Change

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Conservation of Declining Populations

Conservation of declining population focuses on ways of detecting, diagnosing, and halting a population decline. The approach uses methods to prevent ...

Habitat Fragmentation

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Threats to Biodiversity

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Biodiversity and Human Values

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Sustainable Development

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Conservation of Small Populations

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Externalities

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Private Cost and Benefit

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Social Cost and Benefit

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Negative Externalities

A negative externality is a cost suffered by an unrelated third party due to an economic transaction.
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Students who demonstrate understanding can design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity. Assessment Boundary: N/A

3.1.9-12.N

Energy Transfer as Biomass Efficiency

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