1. Lecture 16: Animal Classification
KINGDOM: ANIMALIA
DIVISION:
INVERTEBRATES
اللافقريات (ليس لها عمود فِقَري)

2. Phylum: Mollusca شعبة الرخويات
Mollusca includes snailsالقواقع 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.
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.
Most mollusks have separate sexes, with gonads located in the visceral mass, and some are hermaphrodites.

3. 1- Class: Gastropodaالبطنقدميات
e.g. snails القوقع الحلزوني
Most Gastropoda are marine, but there are also many freshwater species.
The anus and mantle cavity are above the head in adults.

4. 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 الملامس الرأسية.
They move by their foot.
Some species are predators.

5. 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.
The foot of a cephalopod (“head foot”) has been modified into the muscular siphon and parts of the tentacles
Most octopuses live on the seafloor.
Cephalopods have an active, predaceous مفترسات lifestyle.
They have a well-developed nervous system with a complex brain and well-developed sense organs.

6. B)- Phylum: Annelida الحلقيات Class: Oligochaeta قليلات الأشواك e. g
B)- Phylum: Annelida الحلقيات Class: Oligochaeta قليلات الأشواك e.g. earthworm دودة الأرض
All annelids (“little rings”) have segmented bodies.
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.
Most annelids, including earthworms, burrow in sand and silt.

7. e.g. Earthworm
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.
Earthworms are cross-fertilizing hermaphrodites.
Some earthworms can also reproduce asexually by fragmentation بالتقطيع followed by regeneration.

8. Earthworm

9. Phylum Nematoda: شعبة النيماتودا (الديدان الخيطية) Roundworms are pseudocoelomates covered by tough cuticles جليد قوي e.g. Ascaris
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.
They have a complete digestive tract قناة هضمية كاملة.
Nematodes usually engage in sexual reproduction التكاثر الجنسي