Download General Characteristics of Animals

Sponges
 Common in coastal waters, tropical reefs and other marine habitats
 Small fish, shrimp, barnacles and worms make their home in or on
sponges
 They don’t have organs or a nervous system
 They vary greatly in size and shape - tubular, flat, or vase-like
 Body is organized in a system of pores, canals and chambers
 Generally sessile-but some can move; some bore into shells of other
animals
Three Classes of Sponges
1. Class Calcarea- a small slender sponge with a skeleton made of calcium
carbonate
2. Class Hexactinellida - Vase or funnel shaped sponges
- known as the "glass sponge" because it has a skeleton made of silica
- found in the deep water
3. Class Demospongiae- the natural sponge
- the familiar bath sponge
- skeleton composed of organic fibers (spongin)
Morphology
- Sponge cells must carry out the daily activities to sustain life (the same way
that other animals use organs)
- All have a canal system which they pump water. Water enters through
pores called ostia, then flows through canals to a spacious chamber called
spongocoel. It then exits the sponge through the oscula (the large opening).
Specialized cells in the sponge
Pinococytes- "skin cells" of the sponge that line the body wall
Choanocytes - line the interior body wall of the sponges, also develop into gametes
Collar cell - primary area where nutrients are absorbed.
Flagella - assist in pumping water through the sponge
Mesohyl - Area between the two walls
Archaeocyte - Important because they have the ability to change into other types of
cells; they ingest and digest food and transport nutrients
Porocytes and Myocytes - help with he regulation of the flow of water through the
sponge.
Feeding
- Water flows through the sponge to provide food and oxygen (and also allows for
waste removal)
- The flow is generated by the beating of the flagella
- Sponges are able to regulate flow of water through their body
- Feed by filtering bacteria, green algae, dinoflagellates, cyanobacteria from the
water.
Reproduction
- Sponges reproduce both sexually and asexually
Sexually
- The sperm are "broadcast" into the water column and then captured by the female
sponge.
- The sperm is then transported to the egg by the archaeocytes
- The larvae are then released into the water column and settle to form juvenile
sponges.
Asexually
-Produce buds that develop into adult sponges during the
spring