Energy and Food Production


Net productivity

Gross productivity – respiratory loss 

Chemical pesticides and biological agents

Intensive rearing of animals

Prioritising land

Controlling the effects of chemicals

Drawing ethical boundaries




As seen in the previous topic on energy transfer, plants produce a great deal of energy which is used up increasingly at every trophic level. This is the basis on which decisions are made in agriculture and rearing of domestic livestock.


In the wild, both plants and animals are subject to a lot of energy loss due to pests, physical activity or insufficient nutrients. This results in a relatively inefficient flow of energy between trophic levels. We think of this in terms of net productivity.


Net productivity is equal to gross productivity minus respiratory loss.


In both terms, productivity refers to the amount of leftover useful tissue such as cereals or animal flesh.


As opposed to the wild, in human-made growth environments this respiratory loss is kept as low as possible. Extreme measures are taken to achieve this, which Include:

Chemical pesticides and biological agents


The use of chemical pesticides and biological agents to kill all or certain organisms which may infect or feed on plants e.g. insects, fungi, small animals.


Intensive rearing of animals


Intensive rearing of animals which includes keeping them indoors and in confined spaces to prevent their energy being lost on movement; and administering antibiotics to prevent mass spread of infection

To enhance plant growth fertilisers are used, whether natural (manure) or artificial.

A strategy to maximise net productivity is an…..

Test Call to Action!