Introduction to PORIFERA Biology 11 Mrs. Trevelyan

Porifera 1. PRESCRIBED LEARNING OUTCOMES and VOCABULARY 2. VIDEOS: -None  3. TEXTBOOK PGS Section 26.1 pgs 692-697

Examples of Members:

Overview…

Three Classes of Porifera 1. Calcarea (bony sponges) use calcium-carbonate to make the skeleton, their internal hard structure. Usually very small, only 3-4 inches in height. About 400 species are in this group. 2. Hexactinella (glass sponges) use silicon dioxide to make their skeletons. Most live in great depths in the ocean. There are about 500 different kinds of glass sponges; they make for about 7% of all known sponges 3. Demospongiae contains most sponges (all large sponges). Make their skeleton from spongin, a special protein. Includes horny & bath sponges. Marine or freshwater

1. Unifying Characteristics Most primitive of all animals (eukaryotic heterozygote) Predominantly marine except for two freshwater families Multicellular, with loosely aggregated cells Adults sessile (do not move), commonly encrusting. No specialized tissue or organs, but there is some cell specialization Asymmetrical or radially symmetrical

2. Structure Cellular differentiation, but no tissue layers (no organs!)

2. Structure Body permeated with pores, canals, and chambers through which water current flows Internal cavities are, at least partially, lined with flagellated cells Possess an internal skeleton of spicules and/or organic fibers.

2. Structure Inner cavity lined with COLLAR CELLS. These contain flagellum which create water current Water moves into the sponge through INCURRENT PORES Food particles are then digested by collar cells or AMEOBOCYTES. Ameobocytes make the crystal-like skeleton Filtered water leaves the sponge through the OSCULUM (giant hole)

3. Digestion No stomach or digestive system Filter feeders (cells absorb microscopic plants and animals) Video: http://www.youtube.com/watch?v=T7E1rq7zHLc Simulation: http://www.biology.ualberta.ca/courses.hp/zool250/animations/Porifera.swf

4. Respiration/Excretion Sponges have no respiratory or excretory glands/organs. Use diffusion within individual cells. As water passes through the body cell, sponge cells remove oxygen and give off carbon dioxide into the water. The wastes that are produced by cellular respiration are also released into the water. The water then carries the wastes away through the operculum

5. Nervous System No nervous system (no nerves, no brain!) Cells can still respond to stimuli

6. Reproduction Asexual by FRAGMENTATION (a piece falls off) or BUDDING (a small sponge grows on the parent) Sexual by releasing sperm or sperm and eggs into the water. After fertilization the larvae swims to a surface and attaches itself. Video: Spawning of Barrel Sponges http://www.youtube.com/watch?v=rPWXZ7jxUf0

6. Reproduction

7. Additional Interesting Facts Provide habitat for many marine animals And form a symbiotic relationship with some protists Humans used sponges for baths/cleaning Boring sponges release chemicals that break up shell and coral Recent research shows some species may have antibiotic properties

Sponge Bob is No Sponge!!!