1. Where’s your backbone?

2. Marine Invertebrates Invertebrates do not have a backbone.
It is estimated that 97% of all animal species are invertebrates.
All major groups of invertebrates have marine representatives, in fact very few have gained the ability to invade land.
We will begin with the one of the simplest of all animals;

4. Sponges are best described as a collection of specialized cells
Sponges are best described as a collection of specialized cells. They are largely independent of each other and do not form true tissues or organs.
All are sessile (do not move but are attached to a surface).

7. Filter Feeders
Sponges have numerous tiny pores that allow water to enter. The water it then filtered as it moves through a network of canals. This unique body plan gives sponges their characteristic spongy texture and classifies then as the phylum Porifera (“pore bearers”).

8. Choanocytes (Collar Cells)
Outside of Inside of
Sponge Sponge
Flagella produce current, collar filters the water, and through phagocytosis food particles enter the collar cells into the amoebocytes.
Water

9. Amoebocytes
Are wandering cells that can transport the food particles to other cells in the sponge structure.

10. Osculum
Water then leaves the inside of the sponge through a large opening called the osculum.

12. As sponges become larger they naturally need more support
As sponges become larger they naturally need more support. Many have spicules that form a supportive skeleton. Some sponges have a skeleton of spongin, a flexable fibers made of protein.

13. Sponge Babies Sponges may reproduce asexually or sexually.
Asexual Reproduction – Pieces break off and then grow into an identical new sponge. Known as Budding
Sexual Reproduction – Sperm and Egg. These gametes are released directly into the water currents and random chance leaves them coming into contact.

15. Types of Sponges
Encrusting Sponges = form thin growths on rocks or dead coral.

16. Types of Sponges
Glass Sponges = grow anchored on deep-water sediments and are characterized by a lace-like skeleton.

17. Types of Sponges
Boring Sponges = actively bore thin channels through calcium carbonate, such as clam shells and corals.

18. Types of Sponges
Coralline Sponges = a calcium carbonate skeleton forms beneath the body of the sponge.

19. Types of Sponges
Bath Sponges = consists of spongin fibers remaining after the cells and debris are washed away.