Arthropods including insects and arachnids are characterised by their jointed limbs and bilateral symmetry with a fixed number of metameric segments e.g. head, thorax, abdomen.
They have both a mouth and an anus as part of a digestive tract with specialised regions (the caecae are appendages that contain gastric juice). The arthropod body form has enabled vast diversification of this animal group, including flight i.e. because the extra limbs could change without affecting the function carried out by the rest.
Their outer body is supported via the exoskeleton, which is a strong chitin structure.
This has led to arthropods, more specifically insects, dominating other animals in terms of highest number of different species as well as overall number of individuals. Extensive evolutionary potential was encased in this body form, giving rise to the most diverse animal group on the planet.
OMG them videos are great! You're a goldmine - and I'm a gold digger ;)
OFF TOPIC : I just want to say that your website is brilliant, thank you!!
You explain everything so simply!
SecretDuck The Student Room
I’ve struggled so much with feeling overwhelmed with biology revision, and I don’t know where to start. But your website is just what I need! It tells me all the information I need, and the knowledge I need to then build on, and it’s written in a way that soaks straight up into my brain!
Prettyhetty The Student Room
OMG that’s great! Actually just helped me with my homework
mabelbarc The Student Room