Food Chain in Ecosystem

len Alfred Ajibola - Wed, 24th July, 2019 @ 15:21: PM

Topics in Biology

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Academic Questions in Biology

Please check out our Test Your Knowledge page to see all Questions and Answers

Which of the following is a category of long bones?

  • A. Stunted long bones
  • B. Reduced long bones
  • C. Giant long bones
  • D. Bended long bones
  • E. Curved long bones
  • F. Elongated long bones

The end product of photosynthesis is _____.

  • A. O2
  • B. C​​​​​​2​​​​C5OH
  • C. H2​​​​​O
  • D. CO2
  • E. C6H12O6
  • F. C2H5COOH

The above diagram illustrates a _____.

  • A. Food Chain
  • B. Food Web
  • C. Food Pyramid
  • D. Food Link
  • E. Food Hub
  • F. Food zone

The living cells that makes up cartilages are called _____.

  • A. osteocytes
  • B. osteoblasts
  • C. osteoclasts
  • D. chondroblasts
  • E. chrondocytes
  • F. Osteoprogenitor cells

Which of the following statement is incorrect with regards to chitin?

  • A. Ecdysis is a term associated with chitin
  • B. It is a skeletal material
  • C. It is a type of skeleton
  • D. It is present outside the organism
  • E. It does not grow when the organism grows
  • It is present in ants

Which of the following is NOT a function of the human skeleton?

  • A. Gives Shape
  • B. Provides Protection
  • C. Aids in Locomotion
  • D. Supports Movement
  • E. Assists in Inhalation and Exahalation
  • F. None of the above
  • G. All of the above

Organisms that manufacture their own food through the help of sunlight or chemicals are best referred to as _____.

  • A. autotrophs
  • B. chemosynthetic
  • C. photosynthentic
  • D. chemoautotrophs
  • E. photoautotrophs
  • F. chemoautotrophs

Organisms that begins a food chain and also manufacture their food through photosynthesis are best referred to as _____.

  • A. heterotrophs
  • B. autotrophs
  • C. homotrophs
  • D. producers
  • E. photosynthetic
  • F. chemosynthetic

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Food Chain:

Nutrition is one of the basic characteristics of living organisms.

The process of nutrition may be considered as a form of chain that brings different species of organisms into interaction.

For instance, a zebra will interact with different plants in the savanna biome for the purpose of food.

Similarly, a lion interacts with a zebra for the same purpose (food).

You can read on the Savanna and Tropical Rainforest Biomes here.

Note: The interaction of organisms for food will always commence with producers.

Producers in food chain refers to organisms that manufacture or produce their own food.

Producers also feed from the food they manufacture while other organisms will depend on them for ready made food, either directly or indirectly.

Organisms that manufacture their own food are referred to as autotrophic organisms or autotrophs. In food chain, we often refer to them as producers.

Please read on Autotrophic Mode of Nutrition here.

Examples of autotrophs or producers are the green plants, blue-green algae and chemosynthetic bacteria.

Note: When autotrophs require sunlight to make their food, they are referred to as photoautotrophs and the process involved is termed photosynthesis.

Examples of photoautotrophs are all green plants and the blue-green algae.

Conversely, when autotrophs utilizes chemicals for manufacturing their food, they are referred to as chemoautotrophs and the process involved is termed chemosynthesis.

Chemoautotrophs includes methanogenic archaea, aquificae and sulfur-oxidizing epsilon proteobacteria.

A Food Chain is a diagram that shows the relationship between plants and animals within a habitat on the basis of how they rely on each other for food.

Think of habitat as a place where organisms live. They are put into 3:

  1. Terrestrial Habitat (Land)
  2. Aquatic Habitat (Water)
  3. Arboreal Habitat (Treetops)
  4. Please read on Deserts and Swamp Forest with their Characteristics here.

The diagram below shows a Food Chain:

Food Chain - Len Academy

A food chain begins with the producers. These producers are usually consumed by other organisms (usually herbivores); and are referred to as consumers.

Note: Organisms that directly feed on producers in a food chain are preferably called primary consumers.

Examples of primary consumers are zebra, grasshopper, antelope, rabbit and other plant feeding organisms.

Please read on Differences between Plants and Crops here.

Next, the primary consumers are consumed or eaten by another sets of consumers called secondary consumers.

Secondary consumers include animals like rats, lion, cats and snakes. (They can be carnivorous or ominvorous organisms).

Please read on Reptiles and their Characteristics here.

Secondary consumers may be consumed by a third set of consumers called tertiary consumers.

Vultures and Eagles are examples of tertiary consumers.

Finally, the tertiary consumers are consumed by the last group of organisms called decomposers.

Decomposers in food chain are organisms that feed on dead organisms, bringing about their decomposition in the process. They may also be regarded as saprophytes.

Fungi and Bacteria are typical examples of Decomposers.

Please read on the Basic Introduction to Biology here.

Note: Producers begins the food chain while decomposers signifies the end of a food chain.


Food Web

Food chain can be interlinked in a habitat, giving rise to food web.

Consider the diagram below.

Food Web - Len Academy

Using the above diagram as a point of reference, notice that the feeding pattern is interlinked.

Consider the explanations below (The diagram serves as our reference):


  • Grasshopper feeds on berries.
  • The frog feeds on the grasshopper.
  • A snake feeds on the frog.
  • A titmouse feeds on the snake.
  • The fox eats the titmouse.

The aformentioned observations are illustrated below:

Berries >> Grasshopper >> Frog >> Snake >> Titmouse >> Fox.

This illustration (above) is one food chain in the habitat. Notice that the food chain is linked to other food chains as illustrated in explanation 2.


Recall that the food chain in explanation 1 began with the grasshopper.

Notice that apart from the grasshopper, the greenfly and butterfly also fed on the berries.

  • The ladybird feeds on the greenfly.
  • Dragonfly feeds on the ladybird.
  • The frog feeds on the dragonfly.
  • The snake eats the frog.
  • The Buzzard eats the snake

This is another food chain although it has some links with the above food chain (in explanation 1).

Note: It is this linking of food chains that gives rise to a Food Web.


  • Also, you may have observed that apart from the dragonfly feeding on the ladybird, the titmouse also fed on the lady bird.
  • Also, the butterfly and titmouse fed on the berries along side the greenfly and grasshopper.
  • Similarly, the rabbit, mouse and grasshopper all fed on plantain.
  • Again, the buzzard and fox feeds on the mouse and rabbit. We can go on and on but the point to note is:

A food web shows multiple food chains or multiple feeding relationships or multiple feeding connections all linked together.

Note: Food Web always consist of more than one food chain (at least, a minimum of 2 food chains linked together).


Food Pyramid

All organism get their energy from the food they eat.

A food chain that shows the movement of energy through it is termed a food pyramid.

Note: The food pyramid is always drawn in a triangular form with the narrow edge at the top. This narrowing at the top signifies the loss of energy as we go top of the food pyramid.

The image below shows a Food Pyramid:

Food Pyramid - Len Academy

From the above diagram, the primary consumers (grasshoppers) fed on the grasses and gained 1,000kcal of energy. Most of this energy would probably be used for their metabolic activities like hopping, respiration, movement, reproduction and so on.

All living organism must lose energy in the form of heat to their surroundings. This is as a result of their metabolic activities.

By the time the secondary consumers consumed the grasshoppers, it was only able to get 10kcal of energy simply because the grasshoppers had already lost some energy in the form of heat to it's surroundings.

Similarly, the secondary consumers will also use some of this energy (10kcal) for it’s metabolic activities; thus losing some energy in the form of heat to the surroundings.

Finally, the tertiary consumer consumed the secondary consumers and was able to get 1kcal of energy. This is because the secondary consumers had lost 9kcal of energy in the form of heat to its surroundings.

Note: As a student, you should be able to state the 2nd law of thermodynamics because it has everything to do with the “loss of heat to the surroundings”.

Please read on the Concept of Heat and Temperature here.

The 2nd Law of Thermodynamics, with regards to food chain states that:

In the course of energy transformation or transfer, some energy is lost in the form of heat to the surroundings.

Note: Energy is always lost as heat during metabolism.

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Alfred Ajibola is a Medical Biochemist, a passionate Academician with over 7 years of experience, a Versatile Writer, a Web Developer, a Cisco Certified Network Associate and a Cisco CyberOps Associate.

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For a thing to be considered Living, it must possess all the Basic Characteristics of Life. These include:

  1. Movement

  2. Respiration

  3. Nutrition

  4. Irritability or Sensitivity

  5. Growth

  6. Excretion

  7. Reproduction

  8. Death

  9. Adaptation

  10. Competition

Please read the explanations on all the Basic Characteristics of Life here

During strenuous exercises like sprinting or 🏃 running, your body may actually work in the shortage of oxygen. During this time, your body owes oxygen (called oxygen debt) and it must be replenished or repayed after the exercise is stopped. This is why you breathe excess of oxygen after you stopped the exercise.

This is the concept of anaerobic respiration

A food Chain is a diagram that shows the relationship between plants and animals within a habitat on the basis of how they rely on each other for food.

Note: Habitat is a place where an organism live. It is of three types:

  • Terrestrial (Land)
  • Aquatic (Water)
  • Arboreal (🌲 Treetops)

You can read on Food Chain here

The term Biology originated from two Greek words. They are:

  • Bios: means life. 
  • Logos: means knowledge or to study.

Biology can therefore be defined is the study of life

Anything that has life is generally considered as a living organism (or organism) 🌱🐐🐓. All living organisms must be able to carry the following activities:

  1. Movement
  2. Respiration
  3. Nutrition
  4. Irritability or Sensitivity
  5. Growth
  6. Excretion
  7. Reproduction
  8. Death
  9. Adaptation
  10. Competition

The above listed points are often regarded as the basic characteristics of life. You can memorize them using the acronym (MR. NIGER DAC).

You can read on the introduction to Biology and the basic characteristics of life here

The gas used in the manufacture of food by plants is Carbon dioxide or Carbon(IV)oxide or CO2. 

Plants manufacture food through a process called photosynthesis. Please read on photosynthesis here

Note: Plants are the only orgnisms that take away CO2 from the atmosphere