2. The 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 Class hyalospongiae Class Class
calcispongiae or hexactinellida demospongiae sclerospongiae
3. • 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.
• 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
4. •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.
5. A 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 Scifozoi Anthozoans Cubozoi
Floating Fixed Fixed Floating
Floating Fixed
