L10.pdf - Annelids PDF

KINGDOM : ANIMALIA SUBKINGDOM: METAZOA PHYLUM : ANNELIDA ‫شعبة الحلقيات‬ 2- CLASS: Polychaeta ‫طائفة عديدة االشواك‬ Ex. Neries ‫دودة الرمل‬ ‫الوضع التصنيفي‬ Kingdom: Animalia Subkingdom: Eumetazoa Phylum: Annelida Class: Polychaeta Subclass: Palpata Order: Phyllo...

KINGDOM : ANIMALIA SUBKINGDOM: METAZOA PHYLUM : ANNELIDA ‫شعبة الحلقيات‬ 2- CLASS: Polychaeta ‫طائفة عديدة االشواك‬ Ex. Neries ‫دودة الرمل‬ ‫الوضع التصنيفي‬ Kingdom: Animalia Subkingdom: Eumetazoa Phylum: Annelida Class: Polychaeta Subclass: Palpata Order: Phyllodocida Family: Nereidae Genus: Nereis Polychaeta ex: Nereis (Sand worm) Characterization of the class polychaeta: It lives in sea-shores or sand in sea-bed It has special mouth includes sense organs It moves by parapodia Excretion by nephridia Sexes usually separate  Movement: -They are found in temporary hiding places, such as under stones, where they stay with their bodies covered and their heads protruding. -They are most active at night, when they wiggle out of their hiding places and swim or crawl over the sand in search of food. -Parapodia are used in crawling, swimming, or for anchoring the animal in its tube. Excretory system: It consists of nephridia (like earthworm) segmentally arranged nephridia, one pair in each segment except the first three and the last. Note that the nephrodium has a small inner opening found at the end of a ciliated funnel which lies in front of the septum. The latter body is in the form of convoluted tube which is mostly ciliated and opens to the outside on its own segment by a nephridia pore. Circulatory system: Blood red color and contain hemoglobin dissolved in plasma and the system consists of: 1. Dorsal blood vessels 2. Ventral blood vessels These vessels run mid-dorsally above the alimentary canal and connected together through transverse vessels. Blood flows between these two vessels via segmental networks in the parapodia, septa, and around the intestine. Sense Organs: Sense organs are highly developed in polychaetes and include eyes, nuchal organs, and statocysts. Eyes, when present, may range from simple eyespots to well-developed organs. Reproductive system: Polychaetes have no permanent sex organs, and they usually have separate sexes. Reproductive systems are simple: Gonads appear as temporary swellings of the peritoneum and shed their gametes into the coelom. The gametes are then carried to the outside through gonoducts, or by rupture of the body wall. Fertilization is external, and the early larva is a trochophore  KINGDOM : ANIMALIA SUBKINGDOM: METAZOA PHYLUM : ANNELIDA ‫شعبة الحلقيات‬ 3- CLASS: Hirudinae ‫طائفة العلقيات‬ Ex Hirudo medicinales ‫العلق الطبي‬  ‫الوضع التصنيفي‬ Kingdom: Animalia Phylum: Annelida Class: Clitellata Order: Hirudinida Family: Hirudinidae Genus: Hirudo Species: H. medicinalis Class Hirudinea (Leeches) - Mostly Lives in freshwater lakes and ponds - few are marine - Head less differentiated - Setae absent - having well developed suckers for attachment while sucking blood from their hosts - Clitellum appears only during breeding season - Usually hermaphrodites Ex. Hirudo medicinalis (Medical leech) - - greenish-brown in color, 5-10 cm in length - Ectoparasitic sucks blood from vertebrate hosts. - Body consists of 33 segments but body surface contains numerous annuli greatly more than the number of segments The locomotion Swims in the water Walks by using suckers https://youtu.be/465PCVwRO40 Digestive system The mouth is surrounding by buccal region which consists of three serrated chitinous jaws, one dorsa and two latero-ventral. The pharynx is muscular sucking. The crop is extends along 11 segments and comprises 11 thin walled chambers, each produced laterally into a pair of diverticula or caeca. The stomach is the small digestive region and the intestine is a short narrow tube, and opens through a short rectum to the outside by anus  Digestive system The leech stick the anterior sucker of body of host and uses the jaws to do characteristic tri-radiate wound on the body of the host and sucking the blood by muscular pharynx then the salivary gland which near to mouth opening secrete hirudin, an enzyme which prevents blood clotting through pitration.  Excretory system: 17 pairs of nephridia Circulatory system: Several sinuses and vessels containing red blood Dorsal & ventral blood sinuses. Two lateral blood vessels Nervous system An anterior nerve ring, has two cerebral ganglia Ventral nerve cord, has ganglion in each segment of the body Reproductive system: The leech is a hermaphrodite. The male reproductive system: 1- 9 pairs of testes lying along the sides of the ventral blood sinus in segments 13-21. 2- The vasa efferentia comes out from every testis. 3- Vasa deferens. 4- Vesicula seminalis. 5-Ejaculatory duct, the two ejaculatory ducts opens to the exterior by penis on segment 11. The female genital system: It consists of two ovaries and two short oviducts follow and unite in a common oviduct which leads into vagina which bends anteriorly and opens to the outside on segment 12.  Reproductive system Male: Nine pairs of testes, lying along the sides of the ventral blood sinus in segments 13-21. Female: Two ovaries, open on segment 12