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 ﺍﻟﻴﺎﺑﺴﺔ. • Mollusks are soft-bodied animals ﺣﻴﻮﺍﻧﺎﺕ ﺭﺧﻮﺓ , 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 ﺣﻴﻮﺍﻧﺎﺕ ﻣﻔﺘﺮﺳﺔ. 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 ﻣﺨﺎﻟﺐ. • 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 ﺃﻨﺒﻮﺑﺔ and parts of the tentacles Most octopuses live on the seafloor ﻗﺎﻉ ﺍﻟﺒﺤﺮ. Cephalopods have an active, predaceous ﻣﻔﺘﺮﺳﺎﺕ lifestyle. They have a welldeveloped nervous system with a complex brain and welldeveloped sense organs.

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 ﺗﺮﺑﺔ ﺭﻃﺒﺔ. 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 ﺗﺤﻔﺮ in sand ﺍﻟﺮﻣﺎﻝ and silt ﺍﻟﻄﻤﻲ.

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 ﺃﻨﺎﺑﻴﺐ ﺇﻓﺮﺍﺯﻳﺔ , 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 ﺍﻟﺒﻴﺌﺎﺕ ﺍﻟﻤﺎﺋﻴﺔ , wet soil ﺍﻟﺘﺮﺑﺔ ﺍﻟﺮﻃﺒﺔ , 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