Food Chain and Food Web

Food Chain and Food Web for Class 5 Science

Through this concept, the students will learn about food chain and food web. Here the students will be introduced to various levels of the ecosystem in order.

After reading the concept, students will be able to:

• Understand the difference between producers and consumers.
• Know that primary consumers are herbivores.
• Analyse why are green plants called producers.
• Explain the role of decomposers in ecosystem.
• Explain the food web with example.
• Know that energy flow in an ecosystem is always unidirectional.
• Define trophic level in the ecosystem.

Each concept is explained to class 5 students using descriptions, illustrations, and concept maps. After you go through a concept, assess your learning by solving the two printable worksheets given at the end of the page.

Download the worksheets and check your answers with the worksheet solutions for the concept of Food Chain and Food Web provided in PDF format.

The chain that shows the transfer of matter and energy from one organism to another
in the form of food is called a food chain.

• Every organism needs energy for survival.
  Plants depend on the sun for energy whereas, animals obtain energy from plants and other animals.
• Green plants utilise the energy from the sun for producing
  food by the process of photosynthesis and are therefore called autotrophs.

Characteristics of a Food Chain:

• Plants lie at the base of all food chains-
  This is because plants can synthesise their food by photosynthesis using water and
  minerals in the presence of sunlight and chlorophyll. They are also called producers.

• Consumers lie at the second and successive trophic levels of a food chain—-
1. The second trophic level is generally occupied by plant-eating animals (herbivores), also called primary consumers.
2. In the following successive trophic levels lie the carnivores and omnivores.
3. The organisms at third and fourth trophic levels are called secondary and tertiary consumers, respectively.

• Carbohydrates are broken down into simple sugars (glucose) after digestion.
• These sugars are utilised by the cells of our body for energy.
• The number of trophic levels in a food chain varies from three to five—
1. The position of an organism in a food chain is defined as the trophic level.
   The number of trophic levels in a food chain is not less than three and not more than five.
2. The reason behind this is that energy is lost at each trophic level of a food chain,
   and there is no energy or little energy left for transfer after five trophic levels.
3. Shorter the food chain, the greater is the available energy.
• Every food chain ends with decomposers—
  The dead plants and animal bodies are decomposed by the decomposers and are converted into simple nutrients.
  These nutrients then get mixed with the soil.

Passage of Energy in a Food Chain:

Energy is transferred along food chains from one trophic level to the next. The amount of energy decreases with each successive trophic level as energy is lost at every trophic level for essential life processes.

What is Food Web:

A food web is the diagrammatic representation of the overall food relationships and interdependence between organisms in an ecosystem.

Features of the food web:

• A food web contains all the constituent food chains of an ecosystem.
• It comprises multiple food chains that can vary in the number of trophic
  levels; some may be short while the others may be long.
• A food web comprises similar trophic levels as that of a food chain.
• There are five main trophic levels—
1. Producers: Plants are called producers as they can make their own food.
2. Primary consumers: Heterotrophs that feed on producers.ExamplesCaterpillar, grasshopper.
3. Secondary consumers: Heterotrophs that feed on primary consumers.Examples: Frog, mouse.
4. Tertiary consumers: Heterotrophs that feed on primary and secondary consumers.Examples: Lion, tiger, humans.
5. Apex predators: Animals who hunt and feed on other animals. Examples: Fox, eagle.
• A food web depicts how organisms on different trophic levels interconnect with each other despite being a part of different food chains.
• This interconnection is analysed to understand the pattern of the flow of energy in an ecosystem.
• Examining food webs helps us understand the concepts of bioaccumulation and biomagnification of toxic substances in the ecosystem about which you will learn in higher grades.

New Words:

Did You Know?

The concept of the food chain was first put forward by the Arab scientist Al-Jahiz in the 9th century,
and the scientist who first proposed the idea of the food web was Charles Elton in 1927.