1 Phylum Porifera Systematic Position Kingdom Animalia Subkingdom

1 - Phylum: Porifera Systematic Position: Kingdom: Animalia ﺍﻟﺤﻴﻮﺍﻧﺎﺕ Subkingdom: Parazoa ﺗﺤﺖ ﻣﻤﻠﻜﺔ ﻧﻈﺎﺋﺮ ﺍﻟﺒﻌﺪﻳﺎﺕ Phylum: Porifera ( ﺷﻌﺒﺔ ﺍﻻﺳﻔﻨﺠﻴﺎﺕ )ﺍﻟﻤﺴﺎﻣﻴﺎﺕ ex: Sponges

Sponges are sessile with porous bodies ﺃﺠﺴﺎﻡ ﻣﺴﺎﻣﻴﺔ and choanocytes ﺍﻟﺨﻼﻳﺎ ﺍﻟﻤﻄﻮﻗﺔ ﺃﻮ ﺍﻟﻤﺴﻮﻃﺔ. The germ layers ﺍﻟﻄﺒﻘﺎﺕ ﺍﻟﻤﻨﺒﺘﺔ of sponges are not really tissues because the cells are relatively unspecialized ﻏﻴﺮ ﻣﺘﺨﺼﺼﺔ. Sponges do not have nervous, digestive or muscle systems. Most sponges are marine ﺑﺤﺮﻳﺔ and some live in fresh water. The body of a sponge consists of two cell layers separated by a gelatinous region, the mesohyl ﺍﻟﻤﺎﺩﺓ ﺍﻟﻬﻼﻣﻴﺔ. Most sponges are hermaphrodites ( ﺧﻨﺜﻲ bisexual) , with each individual producing both sperm and eggs. The body of a simple sponge resembles a sac ﻳﺸﺒﻪ ﻛﻴﺲ perforated with holes ﻓﺘﺤﺎﺕ All sponges are suspension feeders ﻳﺘﻐﺬﻯ ﻋﻠﻰ ﺍﻟﻌﻮﺍﻟﻖ collecting food particles from water.

Choanocytes use their flagella to create water currents ﺗﻴﺎﺭﺍﺕ ﻣﺎﺋﻴﺔ through external pores called ostia ﻓﻮﻫﺎﺕ. Bring food (bacteria, Protists, etc. ) and oxygen and remove metabolic wastes from the center of the sponge, spongocoel. Choanocytes use collar-like rings to filter food. Wastes and water flow out a central osculum; an excurrent pore. ﺍﻟﺘﺠﻮﻳﻒ ﺍﻟﻤﺮﻛﺰﻱ ﺍﻟﻔﻮﻳﻬﺔ ﺍﻟﻔﻮﻫﺔ ﺃﻮ ﺍﻟﻤﺴﺎﻡ ﺍﻟﺒﺮﻋﻢ

This basic body has two Parts: the sessile polyp ﺍﻟﻘﺮﺹ ﺍﻟﺠﺎﻟﺲ and the floating medusa ﺍﻟﻤﻴﺪﻭﺯﺍ ﺍﻟﻌﺎﺋﻤﺔ. The polyps adhere to the substratum by the aboral end and extend their tentacles, waiting for prey. Medusas(also called jellies) are flattened, mouth-down ﺍﻟﻔﻢ ﻷﺴﻔﻞ. They are carnivores ﻻﺣﻢ that use tentacles ﺍﻟﻠﻮﺍﻣﺲ arranged in a ring around the mouth to capture prey and push the food into the gastrovascular ﺍﻟﻮﻋﺎﺀ ﺍﻟﺠﻮﻓﻤﻌﻮﻱ chamber for digestion. Muscles and nerves exist in their simplest forms.

Hydra sp. The basic body plan is a sac with a central digestive compartment, the gastrovascular cavity ﺍﻟﺘﺠﻮﻳﻒ ﺍﻟﺠﻮﻓﻤﻌﻮﻱ. Hydra exist only in the polyp form. When environmental conditions are favorable, a hydra reproduces asexually by budding ﺍﻟﺘﺒﺮﻋﻢ

Platyhelminthes (Flatworms) ﺍﻟﺪﻳﺪﺍﻥ ﺍﻟﻤﻔﻠﻄﺤﺔ They are acoelomates ﻋﺪﻳﻤﺔ ﺍﻟﺘﺠﻮﻳﻒ ﺍﻟﺴﻴﻠﻮﻣﻲ with gastrovascular cavities ﻣﻌﻮﻱ - ﺗﺠﻮﻳﻒ ﻭﻋﺎﺋﻲ They are living in marine and freshwater. They also include many parasitic species, such as the flukes ﺩﻳﺪﺍﻥ ﺍﻟﺒﻠﻬﺎﺭﺳﻴﺎ and tapeworms ﺍﻟﺪﻳﺪﺍﻥ ﺍﻟﺸﺮﻳﻄﻴﺔ. Flatworms are triploblastic ﺛﻼﺛﻴﺔ ﺍﻟﻄﺒﻘﺎﺕ , with a middle embryonic tissue layer, mesoderm ﺍﻟﻄﺒﻘﺔ ﺍﻟﻮﺳﻄﻰ , which contributes to more complex organs and organs systems and to true muscle tissue.

Schistosoma sp. ﺍﻟﺒﻠﻬﺎﺭﺳﻴﺎ Trematodes parasitizea wide range of hosts, and have complex life cycles with alternation of sexual and asexual stages. It requires an intermediate host in which the larvae ﻳﺮﻗﺎﺕ develop before infecting the final hosts (human) where the adult worm lives. The fluke Schistosoma infects 200 million people.