PHYLUM PORIFERA Flashcards
What are the key traits of the metazoa?
Fully multicellular
Ability to move
Collagen
Heterotrophy (able to consume large-bodied organisms)
How is the Phylum Porifera different from the rest of the Metazoans?
Cellular level of organization (no true tissues) No mouth/gut No organs/organ system No circulatory system No clear axes of symmetry
What is the name of the sub-kingdom for the Phylum Porifera?
Parazoa
Defining traits of the Phylum Porifera:
1) water canal system
2) mesohyl
What are the parts of the water canal system of the Phylum Porifera?
ostia (many incurrent pores)
Oscula (large excurrent pores)
Spongocoel
How are the three body plans of the sponges?
Ascon type: single flagellated pumping cavity
Sycon type: many flagellated canals radiate from the spongocoel
Leucon: many flagellated chambers connect by passive canals
What are pinacocytes and why are they not considered as true epithelium?
For the pinacoderm. Inner and outer body covering. Not considered as true epithelium because they lack
1) basal lamina
2) intercellular junctions
3) apical-basal polarity
4) ability as a layer to regulate ion levels
What are archaeocytes?
Amoeboid cells that can transform into any cell type (totipotent). Special amoebocytes make spicules and spongin fibers (collagen) some may transport food and eggs
What are myocytes?
Contractile cells that encircle the oscula and flagellated chambers. Can open and close the oscula in response to the environment stimuli
What are choanocytes?
Collar cells. Form the choanocyte layer. Function in pumping and feeding: a ring of microvilli surrounds the flagellum. The flagellum has a vane like the choanoflagellates flagellum.
What are porocytes?
A tubular cell. Forms the ostia in some group
How does the choanocyte feed?
Phagocytize very tiny particles
Microvilli traps the particles
Pinocytes and amoebocytes may also phagocytize food particle
Some are predatory and hook spicules acts like velcro
How do sponges reproduce?
Both asexual (budding and fragmentation) and sexual
What are the three classes of Porifera and differentiate them.
Calcarea: has calcareous spicules, no spongin, small
Demospongiae: silica spicules, some have spongin, most successful of the three classes
Hexactinellida: “glass sponges”, mostly found in deep sea. Has an odd “modified leucon” canal system