👉Phylum Porifera🦠🦠📖📖
👉Some of the important characteristics of phylum Porifera👇👇👇
1. ROBERT GRANT gave term Porifera.
2. Porifera are multicellular. It's body organization is cellular level. And they have no tissues and organs.
3. The cells of Poriferans are loosely organized.
4. They are mostly found in marine water. Only a few are found in freshwater.
5. These animals are solitary and colonial.
6. They are either radially symmetrical or asymmetrical.
7. Their body is usually cylindrical.
8. The scleroblast secretes spicules while spongin fibres are secreted by spongioblasts.
9. The body is comprised of numerous pores known as Ostia and osculum.
10. The central cavity is called spongocoel or atrium which open outside through the osculum.
11. Body wall with outer pinacoderm (dermal epithelium) inner choanoderm (gastral epithelium) and gelatinous non-cellular mesenchyme in between.
12. They reproduce asexually by budding, and fragmentation.
13. The nutrition is holozoic.
14. They have neurosensory cells but are devoid of any specific nervous system.
15. They have the power to regenerate the lost parts.
16. The development is indirect and the cleavage is holoblastic.
17. The exchange of respiratory gases and nitrogenous wastes occur by the process of diffusion.
Ex. Sycon, Spongilla, Hylonema, Cliona, Clathrina, Scypha, Euplectella, Hyalonema, Spongia, Spongilla
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