In this module, you will learn:

  • about the hierarchy of cell organisation
  • examples of systems in humans

Resources to help you:

  • Textbook: page 99, 100 and 101
  • Notebook: page 35

Watch the video

See how the cells are organised.


You can change the speed to 0.75x to make it easier to listen.

Amoeba eats two paramecia


Cells in living things

Living things can be simple and made up of only one cell. These are called unicellular organisms.

Examples of unicellular organisms are:

  1. paramecium
  2. amoeba

Most living things are made of many cells. These are called multicellular organisms.

Cells in multicellular organisms are organised to perform specific functions.

Cell Organisation

In multicellular organisms, cells can be organised into:

  • tissues
  • organs
  • systems

Onion epidermis with large cells under microscope

Credit: @PeterHermesFurian via EnvatoElements

Muscle Tissue

Credit: @Nephron via Wikipedia [CC BY-SA3.0]


Tissues are cells of the same type which perform the same function.

Examples of tissues are:

  • in humans - muscle tissues
  • in plants - epidermal tissues


An organ is formed when many different type of tissues work together to perform a specialised function.

Examples of organs are:

  • in humans - heart, stomach and lung
  • in plants - leaf, root and stem

Major Organs of the Human Body


The Digestive System


The Transport System


The Respiratory System


What is Reproduction?



Systems are formed when multiple organs work together for a specific function.

Examples of systems in humans:

  • digestive system - to break down food so that the body can absorb it.
  • transport system - to transport oxygen and digested food to cells as well as carbon dioxide and other waste material to be excreted.
  • respiratory system - to supply blood with oxygen and excrete carbon dioxide.
  • reproductive system - to reproduce for the continuation of the species.

Refer to your textbook page 101, 102 and 103 for the different organs that make up each system.

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