

InterviewSolution
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Write a short note about porifera |
Answer» Phylum Porifera consist if of primitive invertebrate ANIMALS comprising the sponges ⭥ The cells of PORIFERANS are loosely organized. ⭥ They are mostly found in marine water. Only a few are found in freshwater. ⭥ They are either radially symmetrical or asymmetrical. ⭥ Their body is usually cylindrical. ⭥ The scleroblast SECRETES spicules while spongin fibres are secreted by spongioblasts. ⭥ They have no organs in their body. ⭥ They depict cellular grade of organization. ⭥ The body is comprised of numerous pores known as Ostia and osculum. ⭥ The central cavity is CALLED spongocoel or atrium which open outside through the osculum. ⭥ They reproduce asexually by budding, and fragmentation. ⭥ The nutrition is holozoic. ⭥ They have neurosensory cells but are devoid of any specific nervous system. ____________________________________________________➟ Poriferans don't have mouths; instead, they have tiny pores in their outer walls through which water is drawn. ➟ They have the POWER to regenerate the lost parts. ➟ The development is indirect and the cleavage is holoblastic. ____________________________________________________ |
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