King Prawns were on the table today! We spent some time observing their external features. 
We removed the exoskeleton from the head and dissected out the eyes which are on stalks. Interestingly, the stalks are responsible for the production of the hormone that causes moulting. When the prawn outgrows it hard exoskeleton, it takes on a lot of water to create a gap between the exoskeleton and its soft tissues. The exoskeleton is shed as a new one takes it place.
Prawns are of the Arthropod phylum, which are animals that have jointed segmented bodies. The sub group is Crustacean, which have an exoskeleton of chitin and calcium carbonate, and are generally aquatic. The class is Malacostraca, which typically have five head segments, eight thoracic segments and six abdominal segments. The head has a pair of compound eyes, two pairs of antennae for detection of vibrations and odours, and compound mouthparts. Some of the appendages are specialised for food gathering. The thorax has swimming and walking legs, and the abdomen has uropods that act like paddles.
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