BIO SCI 94 Study Guide - Midterm Guide: Sponge, Hexactinellid, Demosponge
Course CodeBIO SCI 94
Note Title 1/11/2010
Porifera Lab (02-10-09)
1. Read Intro pg. 69-73. What is meant by "cellular level of organization"? What is a collar cell (choanocyte)?
cellular level of organization: no one cell must carry on all the life activities, but different cels may
become spcialized for different functions. The various kinds of cells are not rugged individuals like the
protozoans but show definite socialistic of the large hole at the top.
the collar cells (choanocyte) capture and igest food organisms in teh same way as do certain
fagellate protozoans. The spiral beat of the fagellum from base to tip, causes a stream of water to
flow away from its tip and brings particles toward the base of the cell.
- look and behave almost exactly like the collar flagellates described earlier.
2. Know the following classification and their distinguishing characterisitics: Phylum Porifera, class Calcaria
, Class Hexactinellida
, Class Demospongiae
Distinguish characterisitics of phylum porifera:
porous with huge number of pores formed by special "porocyte" cells that allow water to
enter the sponge and one or more large ex-current openings.
some lack body systems (asymetric) & others have concial/ cylindrical (radial) shape, others
expand out into a bowl/vase-like form
dipolblastic with 2 layers of cells (ectoderm and endoderm)
rest of question on other study guide
Diagram of porifera: