The Arthropod Defined
We've seen that arthropods are a whole lot more than just cockroaches and lobsters. However, all those descendents of the arthropod ancestor share certain key characteristics that they inherited from that ancestor. Using the information from this section you should be able to tell if an animal is an arthropod based on whether or not it inherited the key arthropod traits.
Now that we have a good idea of what an arthropod is, let's go way back to the Cambrian Period and take a look at arthropod origins.