All About Arthropods

© Contributed by Leanne Guenther


What is an arthropod? 

You live with them almost everyday, even in the very cold winter months! They are everywhere and are the largest animal phylum -- about 85% of all known animals in the world are part of this class.  

There are far more species of arthropods than there are species in all the other phylums(phyla) combined.


Photo Source:  Corel Web Gallery


Photo Source:  Corel Web Gallery

They are spiders, insects, centipedes, mites, ticks, lobsters, crabs, shrimp, crayfish, krill, barnacles, scorpions and many, many others.


Two Segments

Can you see two segments?
Photo Source:  Corel Web Gallery

Three Segments

Can you see three segments?
Photo Source:  Corel Web Gallery

The easiest way to tell an arthropod from any other animal is to see if they have:

1) A segmented body.

This means that they will have a body made up of more than one part.  Spiders have two segments and flies have three segments.




2) Many jointed legs or limbs.

Spiders have 8 legs, millipedes can have...  Hundreds!



Photo Source:  Corel Web Gallery

3)  An exoskeleton.

This is an external skeleton. Like armor, it protects the arthropods body.  When arthropods are born the exoskeleton is soft but hardens quickly and it can be shed as the creature grows.  Arthropods are invertebrates; which means that they do not have a backbone.


Photo Source:  Corel Web Gallery

4)  Cold blooded

Arthropods are cold blooded -- which means, their body temperature depends on the temperature of the environment surrounding them.


Photo Source:  Corel Web Gallery

Arthropods are some of the most interesting animals in the world!

They fly, they creep, and they crawl.  They live on land, in ponds and in the ocean.  From ants to bumblebees, crabs to crayfish, spiders to centipedes -- which are your favorites!?


Mantis Shrimp >

Scientific stuff:  Arthropods include eleven animal classes

  • Subphylum Chelicerata
    • Class Merostomata (horseshoe crabs, eurypterids) 
    • Class Pycnogonida (sea spiders) 
    • Class Arachnida (spiders, ticks, mites) 
  • Subphylum Crustacea
    • Class Remipedia 
    • Class Cephalocarida 
    • Class Branchiopoda (fairy shrimp, water fleas) 
    • Class Maxillopoda (ostracods, copepods, barnacles) 
    • Class Malacostraca (isopods, amphipods, krill, crabs, shrimp) 
  • Subphylum Uniramia
    • Class Chilopoda (centipedes) 
    • Class Diplopoda (millipedes) 
    • Class Insecta (all of the insects including ants, bees, beetles and butterflies)


Take a Break!

On-Line Jigsaw Puzzle:   Spider
On-Line Jigsaw Puzzle:   Crab
On-Line Jigsaw Puzzle:   Shrimp



(more arthropods) >
Carpenter Ants >
Mantis Shrimp >
Monarch Butterflies >
Spiders >