arthropods – a diverse group of invertebrate animals with jointed legs and segmented bodies, and hard external skeletons

(Pronounced ar-thro-pods)

To remember the meaning of arthropods, it is important to remember there are four classes, represented by spiders (arachnids), crabs (crustaceans), ants (insects), and centipedes (myriapods). Use the following mnemonic:

King Arthur rowed along listening to his iPod (arthropod).

When a giant crab lifted the boat out of the water.

A spider then used a crane to take the boat off the crab.

The spider placed the boat gently onto an army of ants.

The ants were able to take the boat away after the centipede let them through.

Arthropods are the largest and most diverse group of animals on Earth, making up over 80% of all known animal species. They are invertebrates characterised by three main features: a segmented body, jointed legs that allow flexible movement, and a hard external skeleton called an exoskeleton.

The exoskeleton provides protection and support but must be shed periodically as the animal grows in a process called moulting. 

Arthropods include four major groups: Insects (like ants, beetles and butterflies), arachnids (spiders and scorpions), crustaceans (crabs and lobsters), and myriapods (centipedes and millipedes). Their incredible success is due to their adaptability, which has helped them colonise virtually every habitat on Earth.