Teaching sequence

Lesson objective

In this lesson students identify how the system of classification has developed over time and identify the five major kingdoms that are currently in use in the Linnean system of classification. They develop an understanding of the changing nature of scientific classification.


Present students with images of bacteria, plants, fungi, amoeba and animals.

Ask how scientists might separate these organisms into different groups.

Teacher note: For links to images and websites with images for this activity see Background information (PDF, 399 KB).


  1. Ask students to place the pictures of all the green plants in one pile.
  2. Complete the experiment on the worksheet What makes a plant green? (Word, 448 KB).
  3. Ask students to place the pictures of all the non-green plants in a second pile and all the animals in a third pile.
  4. Suggest to students that these are 3 of 5 classification groups. Introduce terms kingdom, phylum, class, order, family, genus and species as levels of classification.
  5. Ask students to make a sentence using the first letters of these words (eg King Phillip Can Order [the] Family Green Sausages) to help them remember this.
  6. Complete the worksheet Cracking the classification code (Word, 413 KB). 
  7. Examine the remaining pictures of single-celled organisms. Ask students how these single-celled organisms could be broken into two groups. (Identify the nucleus and cell walls in the pictures.)
  8. Complete the worksheet Colouring kingdoms (Word, 390 KB).
  9. Complete the worksheet The Venn kingdoms (Word, 381 KB).
  10. Reintroduce the images of single-celled organisms. Ask students to break them into the two groups. Encourage students to discuss their opinions. Point out that scientists often have different opinions in how things should be classified.
  11. Complete the worksheet Classification timeline (Word, 395 KB). 


Explain the current debate between taxonomists. Ask the students to decide which is better, having a new classification level before kingdom (domain) that splits Monera into Archaea and Bacteria or, adding Archaea as a sixth kingdom. Ask students to find where archaebacteria live and design a travel brochure for other bacteria to visit.

Lesson Resources


Student activities


What makes a plant green? 
(Word, 448 KB) 

Cracking the classification code 
(Word, 413 KB) 

Colouring kingdoms (Word, 390 KB) 

The Venn kingdoms (Word, 381 KB) 

Classification timeline (Word, 395 KB) 

Useful links

Animal phyla, The Biology Corner. Worksheets