Question

Question 4 (Please note that you do NOT need to write a scientific answer to the question in bold below. Simply use the question to demonstrate your ability to break down a question into its key parts. Write your answers in the spaces indicated below) For the question below, identify the a) key topic word, b) the influencer words and c) the instruction words. Describe the major structural differences between Arachnids and Crustaceans and explain how their mouthparts work.

Answer 1

Arachnids have prosoma (cephalothorax) and an opisthosoma (abdomen) with six pairs of segmented appendages, whereas crustaceans have cephalothorax and abdomen. The appendages of crustaceans are found in every segment. Arachnids have no antennae and mandibles while crustaceans bear them. Examples for arachnids include scorpions, spiders, mites, and ticks. Examples of crustaceans are prawns, lobsters, shrimps, barnacles, and crabs.The respiratory organs of arachnids are book lungs or trachea, whereas that of crustaceans are gills. Unlike the arachnids, crustaceans possess stalked compound eyes.Crustaceans possess carapace, but arachnids do not.

Crustaceans possess paired mandibles with opposing biting and grinding surfaces. The mandibles are followed by paired first and second maxillae. Both the mandibles and the maxillae for filter feeding with the use of setae.

Arachnida (spiders, scorpions, ticks and mites); and class Pycnogonida (sea spiders). Chelicerates are in part defined by possessing chelicerate appendages, although crustaceans also possess chelate appendages. Chelicerates are easily distinguished from other arthropods in lacking antennae and mandibles.There is a tubular proboscis forward from the body trunk, at the end of which is the opening to the mouth. In those species that lack chelifores and palps, the proboscis is well developed, it can be equipped with sensory bristles and strong rasping ridges around the mouth.