Food Chains and Food Webs

Food Chains and Food Webs

Food Chains

What is a Food Chain?

• A food chain represents the flow of energy in an ecosystem from one organism to the next.
• It starts with producers (typically plants), that create energy from sunlight through photosynthesis.
• It then moves onto consumers, organisms that eat the producers or other consumers, increasing in trophic level respectively.

Understanding Trophic Levels

• Trophic levels are the stages of a food chain, starting with producers and moving up to various levels of consumers.
• Primary consumers, typically herbivores, eat the producers.
• Secondary consumers, usually carnivores or omnivores, eat the primary consumers.
• Tertiary consumers are predators at the top of the food chain, eating secondary or other tertiary consumers.

Energy Transfer in a Food Chain

• Energy is transferred from one trophic level to the next when one organism consumes another.
• However, only about 10% of energy is typically transferred from one trophic level to the next. The rest is lost in bodily functions or as heat.
• This energy loss limits the length of food chains - there is not enough energy to support large numbers of high-level consumers.

Food Webs

What is a Food Web?

• A food web represents multiple interconnecting food chains within an ecosystem.
• It is a more realistic way of showing energy flow in ecosystems, as most organisms eat and are eaten by more than one species.

Complexity of Food Webs

• Food webs are more complex than food chains, showing a larger number of interactions and dependencies.
• Despite their complexity, food webs highlight the interconnectedness of life - a change to a single species can influence several others.

Interactions within a Food Web

• Each organism in a food web might be a part of several different food chains.
• This means that changes in one part of a food web—such as a decrease in the number of producers due to disease or environmental change—could have broad impacts across multiple chains.

Decomposers and Food Chains/Webs

• Decomposers, such as bacteria and fungi, break down dead organisms or waste and return nutrients to the soil.
• This supports the growth of producers, ensuring a continuous flow of energy through the food chain or web.
• While they don’t directly consume energy like consumers, their role is essential in recycling nutrients and maintaining the cycle of life.