Arthropoda is the largest phylum in the animal kingdom. the phylum includes about 805 of the known animal species.. The phylum includes prawns, crabs, lobsters, cockroaches, scorpions, spiders, ticks, insects etc. Arthropods are economically of great importance to man. Animals like honey bees, silkworm moth etc, are beneficial.
General Characters of Phylum Arthropoda
1. Arthropods are bilaterally symmetrical and triploblastic.
2. The body bears paired, jointed appendages and they are variously modified for different functions.
3. The body is covered with a thick chitinous cuticle forming an exoskeleton which is shed at regular intervals.
4. Compund eyes are present in most of the members
5. Respiration is by gills or book lungs or trachea
6. Excretion is by green glands or malpigian tubules.
7. Open circulatory system
Classification of Phlum Arthropoda
The phylum is divided into different classes namely: Crustacea, Arachnids, Myriapods and Insects (BE4U Tips: CAMI)
- Crusta means hard shell
- More than 4 pairs of jointed legs
- Example: Prawns, Crabs, Lobsters
- Body divided into head cephalothorax
- 4 pairs of jointed legs
- Example of Arachids: Spider, Scorpion, Limulus, Ticks and mites
- Many similar segments, each with at least one pair of jointed legs
- Example of Myriapods : Centipedes and Millipedes
- Body divided into head, thorax and abdomen,
- 6 jointed legs attached to the thorax
- 4 wings attached to the thorax
- Example of insects: Cockroach, butterflies, grass hopper