Reducing Biomass Loss (A-level Biology)

Reducing Biomass Loss

Farming Practices

Various farming practices work to increase the efficiency of energy transfer. They help to increase crop yields by:

• Reducing the energy lost to organisms like pests.
• Reducing the energy lost through respiration.

Simplifying Food Webs

Simplifying food webs helps to reduce energy lost to pests. A food web is an example of how many different food chains overlap in an ecosystem.

If pests feed off a crop, they are reducing the amount of chemical energy that is available for growth or human consumption. The pests must be removed to achieve the most energy transfer possible.

To achieve this, farmers use pest-control methods:

• Chemical pesticides help to kill pests to reduce energy loss. These include:

• • • Insecticides that kill insects that feed on and damage plants.
    • Herbicides that kill weeds that take up nutrients and growing space away from the desired plants – they reduce competition.
• Biological agents are used to kill or reduce the function of pests to reduce energy loss. These include:

• • • Pathogens that are introduced to cause disease and kill insects.
    • Parasites that are introduced to causes disease in insects by laying eggs in the pests (host).

Many farmers use a combination of chemical pesticides and biological agents to provide the most effective method to remove pests and preserve chemical energy.

Reducing Respiration

By reducing the rate of respiration of livestock, less energy is wasted in biological processes so that more can be stored and transferred through the trophic levels.

Methods of this include:

• Animals are kept in small, restrictive pens. This means that less energy is used for muscle contraction as the animals have restricted movement.
• The pens are kept warm. This means that less energy is used up by the animals to regulate their body temperature.
• Animals are fed specialised diets. These diets are high in nutrients and easy to digest, so less energy is lost in excretion.

Whilst keeping animals in these restrictive conditions cuts cost and increases yield, there are serious ethical issues associated with treating animals in this manner.