Food chains / Food webs

Food chains

show the feeding relationships between organisms in a certain area or habitat.

• Always start with producer

• Each organism occupies a trophic level

Food web

made up of overlapping food chains, gives us a better picture of the relationships between organisms in a community and the different pathways that energy and nutrients can take as they flow through an ecosystem

Factors that affect energy and organic matter loss

• incomplete consumption:

• inefficient digestion —> waste of biomass

• inefficient energy conversion and storage

• use in 

  metabolic processes

  : Organisms use energy for their own metabolic processes, including respiration, movement, and growth.

• heat loss:

Ecological pyramids

 demonstrate the trophic levels in an ecosystem, by representing the relative numbers of organisms, biomass, or energy.

pyramid of biomass

represents the biomass of organisms at each trophic level in mass per unit of area or g m^–2 (grams per metre squared). Typically, these pyramids exhibit a pyramid shape, reflecting the decreasing biomass along food chains due to the release of CO₂ and waste

Pyramid of energy

indicates the amount of energy flowing through the ecosystem at each trophic level. This shows the flow of energy over a period of time and represents the amount of energy that is available to each trophic level.

kJ m^-2 yr^-1.