Living things are highly organised and complex organisms. Inorganic matter and organic matter are formed by the same chemical components; however in living things, these chemical components are grouped into structures with different levels of complexity known as levels of organisation. These levels are:
Human beings are living things and as such they have the following characteristics:
Human beings are multicellular organisms: they have many cells. Not all cells are the same and cells have different structures and functions.
Human beings are also animals and have the following characteristics:
Cells are elemental units of independent life and are different from each other. They have specialised features and group together to form more complex structures (in multicellular organisms).
The level of organisation found in human beings are: cells, tissues, organs, or systems and organism.
Key concepts
Activity 1
Do you know any other systems apart from the skeletal and reproductive systems?
Activity 2
Match all the systems of the human body with its corresponding job.
Activity 3
Explain the meaning of the following statement: “Every living thing is or has been a cell”.
Activity 4
Why are bones considered to be organs? Choose the correct answer.
