Phyla of Marine Organisms

Lower Invertebrates Kingdom Animalia Domain Eukarya

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

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

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

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?

Asymmetry Asymmetry: No lines of symmetry Not divided into parts

What type of symmetry?

What type of symmetry?

What type of symmetry?

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

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?

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

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

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?

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

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

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!

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