1 Principals of General Zoology (Zoo-103) Zoology Department, H

KINGDOM: ANIMALIA DIVISION: INVERTEBRATES اللافقريات ( ليس لها عمود فِقَري )

Mollusca includes snails القواقع المائية and slugs القواقع الأرضية, octopuses الأخطبوط and squids الحبار.Mollusca includes snails القواقع المائية and slugs القواقع الأرضية, octopuses الأخطبوط and squids الحبار. Most mollusks are marine, though some inhabit fresh water, and some snails and slugs live on land.Most mollusks are marine, though some inhabit fresh water, and some snails and slugs live on land. Mollusks are soft-bodied animals, but most are protected by a hard shell صدفة قوية of calcium carbonate.Mollusks are soft-bodied animals, but most are protected by a hard shell صدفة قوية of calcium carbonate. All mollusks have a muscular foot for locomotion, a visceral mass جزء حشوي with most of the internal organs, and a mantle البرنس.All mollusks have a muscular foot for locomotion, a visceral mass جزء حشوي with most of the internal organs, and a mantle البرنس. Most mollusks have separate sexes, with gonads located in the visceral mass, and some are hermaphrodites.Most mollusks have separate sexes, with gonads located in the visceral mass, and some are hermaphrodites. Phylum: Mollusca شعبة الرخويات

1- Class: Gastropoda البطنقدميات e.g. snails e.g. snails القوقع الحلزوني Most Gastropoda are marine, but there are also many freshwater species.Most Gastropoda are marine, but there are also many freshwater species. The anus and mantle cavity are above the head in adults.The anus and mantle cavity are above the head in adults.

1- Class: Gastropoda Most gastropods are protected by a spiraled shell صدفة حلزونية.Most gastropods are protected by a spiraled shell صدفة حلزونية. Other species have lost their shells entirely and may have chemical defenses against predators.Other species have lost their shells entirely and may have chemical defenses against predators. Many gastropods have distinct heads with eyes at the tips of tentacles الملامس الرأسية.Many gastropods have distinct heads with eyes at the tips of tentacles الملامس الرأسية. They move by their foot.They move by their foot. Some species are predators.Some species are predators.

The foot of a cephalopod (“head foot”) has been modified into the muscular siphon and parts of the tentaclesThe foot of a cephalopod (“head foot”) has been modified into the muscular siphon and parts of the tentacles Most octopuses live on the seafloor. Most octopuses live on the seafloor. Cephalopods have an active, predaceous مفترسات lifestyle.Cephalopods have an active, predaceous مفترسات lifestyle. They have a well- developed nervous system with a complex brain and well-developed sense organs.They have a well- developed nervous system with a complex brain and well-developed sense organs. 2- Class: Cephalopoda الرأسقدميات e.g. Octopus الأخطبوط e.g. Octopus الأخطبوط Cephalopods use rapid movements toward their prey which they capture with several long tentacles.Cephalopods use rapid movements toward their prey which they capture with several long tentacles. A mantle covers the visceral mass, but the shell is reduced and internal in squids الحبار, missing in many octopuses.A mantle covers the visceral mass, but the shell is reduced and internal in squids الحبار, missing in many octopuses.

All annelids (“little rings”) have segmented bodies.All annelids (“little rings”) have segmented bodies. Annelids live in the sea, most freshwater habitats, and damp soil.Annelids live in the sea, most freshwater habitats, and damp soil. The coelom of the earthworm, a typical annelid, is partitioned by septa مقسم بفواصل, but the digestive tract, longitudinal blood vessels, and nerve cords penetrate the septa and run the animal’s length.The coelom of the earthworm, a typical annelid, is partitioned by septa مقسم بفواصل, but the digestive tract, longitudinal blood vessels, and nerve cords penetrate the septa and run the animal’s length. Most annelids, including earthworms, burrow in sand and silt.Most annelids, including earthworms, burrow in sand and silt. B)- Phylum: Annelida الحلقيات Class: Oligochaeta قليلات الأشواك e.g. earthworm دودة الأرض

The digestive system consists of a pharynx مريء, an esophagus بلعوم, crop حوصلة, gizzard قانصة, and intestine أمعاء. The closed circulatory system carries blood with oxygen- carrying hemoglobin through dorsal and ventral vessels connected by segmental vessels. In each segment is a pair of excretory tubes, metanephridia, كلية بدائية that remove wastes from the blood and coelomic fluid. cross-fertilizing hermaphroditesEarthworms are cross-fertilizing hermaphrodites. asexuallySome earthworms can also reproduce asexually by fragmentation بالتقطيع followed by regeneration. e.g. earthworm

Earthworm

Roundworms are found in most aquatic habitats, wet soil, moist tissues of plants, and the body fluids and tissues of animals. Some species parasitize animals تتطفل على الحيوان. They range in length from less than 1 mm to more than a meter. The body of Nematode is covered with a tough exoskeleton, the cuticle.The body of Nematode is covered with a tough exoskeleton, the cuticle. They have a complete digestive tract قناة هضمية كاملة.They have a complete digestive tract قناة هضمية كاملة. Nematodes usually engage in sexual reproduction التكاثر الجنسيNematodes usually engage in sexual reproduction التكاثر الجنسي Phylum Nematoda: شعبة النيماتودا ( الديدان الخيطية ) Roundworms are pseudocoelomates covered by tough cuticles جليد قوي e.g. Ascaris