1. Phyla of Marine Organisms

2. Lower Invertebrates
Kingdom Animalia Domain Eukarya

3. Who can tell me what is an invertebrate?
An animal without a backbone (Multicellular Organism)
Over 95% of organisms are inverts
Classified in numerous different phyla according to shared characteristics
Huge diversity of organisms

4. Animals: Review of Body Plans
Two Types of Symmetry:
Bilateral Symmetry
Radial Symmetry

5. Bilateral Symmetry Bilateral symmetry:
Body can be divided into equal halves
Mirror image of each other

6. Radial Symmetry Radial symmetry:
Body parts repeat around an imaginary line drawn through center of body
E.g.: spokes on a bike wheel
How might the symmetry dictate the structure/function of the organisms?

7. Asymmetry
Asymmetry:
No lines of symmetry
Not divided into parts

8. What type of symmetry?

9. What type of symmetry?

10. What type of symmetry?

11. Phylum: Porifera “pore bearers”
Sponges
Simplest invertebrates
Full of tiny holes or pores
Sessile or non-mobile
No true tissues or organs
Simple skeleton made of protein fibers
Asymmetric, radial symmetry

12. Phylum: Porifera Sponges
Over 5,000 species
Aquatic
Some freshwater/ mostly marine
Simplest of all invertebrates
Transition from unicellular to multicellular organisms
An evolutionary dead end!!
What does this mean?

13. Characteristics No true tissues or organs Little cell specialization
Sessile or non-mobile
Asexual and Sexual reproduction
Composed of 2 layers
Oxygen & CO2 diffuses through layers

14. Sponge Structure Ostia: Incurrent pores
Water and food particles enter here
All over body
Oscula:
Excurrent pores
Water and waste exit here
Usually at top of sponge

15. Nervous System? No nervous system
However, do have specialized guard cells on outer layer that can contract & close pores
Why would it want to do that?

16. Collar Cells
Specialized cells that pump water and food throughout the sponge
Moving flagella creates a current

17. How do sponges feed? Filter Feeders:
Screen food particles out of water
Food/ water pumped in by collar cells
Digestion takes place within cell vacuoles
Other cells move around & transport nutrients to rest of body

18. What gives sponges their shape?
Spicules:
Rigid protein fibers
Provides support
Calcium Carbonate or Silica
Help in identifying sponges
Spongin:
Elastic protein fibers
softer bodies
E.g.: Bath sponges
***What you find on the beach!

19. Florida Sponge Industry
Largest industry in Florida for several years
Started mid 19th century
Key West and Tarpon Springs were centers
Tarpon Springs: Sponge Capital
Industry crashed in 1940’s
Why?
Disease and Introduction of synthetic sponges
Today, industry is small
Still important to Tarpon Springs economy