Arthropoda Part 1
What is tagmatization?
Joining or fusing of body segments into functional groups (Tagmata)
What structure do arachnids use for gas exchange?
Book lungs
....and trachea: system of tubes which open externally through spiracles
What are the benefits and the drawbacks of an exoskeleton?
Benefits:
Reduced water loss
More efficient than hydrostatic skeleton
Jointed legs! (opportunity for specialization)
Drawbacks:
No gas exchange through body wall
Ecdysis (molting) necessary for growth
Size limitation
What are the 3 parts that the trilobite is divided into?
Cephalon
Thorax
Pygidium
What are the two tagmata of the Chelicerate called and what structures are within each tagmaya?
Prosoma
chelicerae: pincers or fangs
5 pairs of legs:
pedipalps: modified legs or claws
4 pairs of walking legs
Opisthosoma
Respiratory structures – book gills or book lung