INVERTEBRATES اللافقريات (ليس لها عمود فِقَري)

1. Kingdom: Animalia INVERTEBRATES اللافقريات (ليس لها عمود فِقَري)

2. 4- Phylum: Nematoda (Round worm) Example: Ascaris sp. • 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. • 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. • They have a complete digestive tract قناة هضمية كاملة. • Nematodes usually engage in sexual reproduction التكاثر الجنسي

3. 5- Phylum: Annelida (Segmented worms) Class: Oligochaeta قليلة الأشواك Example: Earthwormsديدان الأرض • All annelids (“little rings”) have segmented bodies. • Annelids live in the sea, most freshwater habitats, and wet soil. • The coelom of the earthworm is partitioned by septa 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.

4. Earthworms: • The digestive system consists of a pharynx بلعوم, an esophagus مرئ, 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 بدائيةthat remove wastes from the blood and coelomic fluid. • Earthworms are cross-fertilizing hermaphrodites. • Some earthworms can also reproduce asexually by fragmentation بالتقطيعfollowed by regeneration.

5. Earthworm

6. 6- Phylum: Mollusca • Mollusca includes snailsالقواقع and slugs البزاقات, octopus الأخطبوطand squidالحبار. • Most mollusks are marine, some inhabit fresh water, and some snails and slugs live on land. • Mollusks are soft-bodied animals, but most are protected by a hard shellصدفة قويةof calcium carbonate. • All mollusks have a muscular foot for locomotion, and a mantle البُرنّس. • Most mollusks have separate sexes, with gonads, and some are hermaphrodites.

7. 1- Class: Gastropodaالبطنقدميات e.g. snails الحلزون (القوقع الأرضي) • Most Gastropoda are marine, but there are also many freshwater species. • The anus and mantle cavity are above the head in adults.

8. Most gastropods are protected by a spiraled shell صدفة حلزونية. • 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. • They move by their foot.

9. 2- Class: Cephalopoda الرأسقدميات e.g. Octopus الأخطبوط • 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. • Most octopuses live on the seafloor قاع البحر. • Cephalopods have an active, predator مفترسات. • They have a well-developed nervous system with a complex brain and well-developed sense organs.