Arthropoda 1.pdf

Phylum – Mollusca Phylum – Arthropoda Phylum – Echinodermata Protochordate groups Learning outcomes of the lecture series Distinguish arthropods from other invertebrates Explain the structure and function of arthropods Compare the differences between different members of a...

Phylum – Mollusca Phylum – Arthropoda Phylum – Echinodermata Protochordate groups Learning outcomes of the lecture series Distinguish arthropods from other invertebrates Explain the structure and function of arthropods Compare the differences between different members of arthropods Find out the importance of arthropods to man and the environment Some of the important references A life of invertebrates – W.D. Russell- Hunter A text book of Zoology – T.J. Parker and W.A.Haswell Invertebrates – R.D. Barnes Invertebrate Zoology – E.E.Ruppert, R.S.Fox, R.D.Barnes Biology books  Insects (ants, flies, mosquitoes, cockroaches, beetles, spiders, etc.)  Spiders  Scorpions  Centipedes  Millipedes  Crabs  Crayfish  Shrimp  Lobsters  Barnacles  80% Arthropoda Other animals Known animal species of the world The phylum Arthropoda contains a wide diversity of animals with hard exoskeletons and jointed appendages. They live in the widest range of habitats and eat the greatest varieties of food. The number of known species of arthropods vastly exceeds the number of species of vertebrates. ▪ The body structure shows bilateral symmetry. ▪ They are triploblastic. ▪ They can be found in all types of habitats – land, water and soil. ▪ They have jointed limbs. The body is segmented into three regions – Head, Thorax and Abdomen. The body cavity is filled with blood and is called the haemocoel. The blood is white in color. The exoskeleton is hardened and is made of chitin. Theyhave a well-developed central nervous system. Thehead is well developed and bears the sensory organs and brain. They have compound eyes and mosaic vision. The digestive tract is complete with the mouth and anus at opposite ends of the body. They have an open circulatory system with dorsal heart and arteries. Respiration is through the general body surface or by gills in aquatic forms and through trachea or book lungs in terrestrial forms. Sexes are separate and sexual dimorphism is exhibited. Arthropod muscles are primarily striated (like the skeletal muscles of humans). Striated muscle has a much faster contraction rate than smooth muscle, and it is this feature that probably enabled the development of flight in many insects. 8. True coelomic animals, but coelom is replaced by heamocoel