Evaluate Basic External Animal Anatomy and Morphology - AgriSETA

Evaluate Basic External Animal Anatomy and MorphologyPrimary Agriculture NQF Level 1 Unit Standard No: 116173352.2 CrustaceaThe Crustacea are well known animals and spend most of their lives in water. Theyinclude animals like lobsters and crabs. We will study the crab.The Crab HabitatWe find crabs in the sea and in various fresh water rivers, dams, pools andplaces where there is constant water. Body divisionsThe body of a crab is divided into two clearly defined regions, thecephalothorax (cephalo = head / thorax = chest - meaning the head andchest parts are one) and the abdomen (the part of the body that liesbetween the chest (thorax) and the beginning of the legs (pelvic area)).The abdomen is folded in under the cephalothorax. The crab has acalcareous (hard calcium rich) exoskeleton (hard structure on the outsideof the body). The body wall is not hardened in certain areas and will allowlittle movement. Movement can take place at the joints of the legs andbetween the segments of the abdomen.• The cephalothoraxThe head and thorax are fused together to form the cephalothorax thatmakes up the upper part of the body. It is broad and flattened from topto bottom. The upper part (surface) of the cephalothorax is coveredwith a shell like shield called the carapace.The following can be found on the cephalothorax:oThe antennaeIn the middle of the cephalothorax at the front are one pair oflong antennae and one pair of short antennae. They serve asorgans of touch and smell.Version: 01 Version Date: July 2006