Porifera and Coelenterates

Chiara Tondini & Nicole Angarano

PORIFERA, kingdom animaliaThe phylum of sponges which are sessile, suspension-feeding, multicellular animals.They are probably an early evolutionary side branch that gave rise to no other group of animals. Except for about 150 freshwater species, sponges are marine animals. This Phylum is divided in four

Class

Class calcarea or calcispongiae

Class hyalospongiae or hexactinellida

Class demospongiae

Class sclerospongiae

Porifera’s characteristics• They have bodies full of pores and channels allowing water to circulate through them;• Sponges have unspecialized cells that can transform into other types;• Sponges do not have nervous, digestive or circulatory systems;•There are different types of cells: flagellated choanocytes, epithelial cells and amebocytes,•They have a radial simmetry.

The reproduction• Asexual: Fragments of sponges may be detached by currents or waves and they re-attach themselves to a suitable surface.• Sexual: Most sponges are hermaphrodites (function as both sexes simultaneously). Sperm are produced by choanocytes while eggs are formed by transformation of archeocytes.

Asexual Sexual

Coelenterates’ characteristics •They have very simple tissue organization;•They can be like a bell, for example jellyfishes, or be like a vase, for example polyps.•There are a type of cells, cnidocytes, these "nettle cells" function as harpoons that are used for prey capture and defense from predators.•There is statocisti and eyepots.•The life cycle of cnidaria is divided in three phases: larval form, planula,polypoid stage and stage medusoide,•Only one opening for digestive systems.

COELENTERATES, kingdom animaliaA group of primitive aquatic

animals that includes jellyfish, corals, hydra and sea anemones.

Coelenterates are sessile (sedentary) and exhibit radial

symmetry (their body parts are symmetrically arranged around

a central point).Coelenterates

Hydrozoans

Floating Fixed Floating Fixed

Scifozoi Anthozoans Cubozoi

Fixed Floating

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