Dissection Club; the Locust

We dissect all sorts at this club, and today it was the turn of the Locust, a fairly large representative of the class Insecta.

Insects are Arthropods with jointed legs, segmented bodies and an exoskeleton made of chitin.

They have three body regions; the head, thorax and abdomen.

The main reason for dissecting insects for A level Biologists is to observe the Gas Exchange system.  Locusts cannot get enough oxygen to their cells by diffusion alone.  (Only fairly small organisms with a relatively large surface area to volume ratio can get enough oxygen through their surface) . 

Insects have a simple tubular system  in which oxygen can enter the body through holes called Spiracles, and can move down a concentration gradient through tubules called tracheoles to the respiring tissues.

Compression of the body brought about by the movements of the legs can aid gas exchange.