Lecture 16 Animal Classification KINGDOM ANIMALIA DIVISION INVERTEBRATES

Lecture 16: Animal Classification KINGDOM: ANIMALIA DIVISION: INVERTEBRATES ( ﺍﻟﻼﻓﻘﺮﻳﺎﺕ )ﻟﻴﺲ ﻟﻬﺎ ﻋﻤﻮﺩ ﺭﻱ

Phylum: Mollusca ﺷﻌﺒﺔ ﺍﻟﺮﺧﻮﻳﺎﺕ • 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. • 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.

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

�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.

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 welldeveloped nervous system with a complex brain and welldeveloped sense organs.

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 silt.

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.

Earthworm

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