Sponges Cnidarians and Platyhelminthes BIOL 1407 Invertebrates Animals

Sponges, Cnidarians and Platyhelminthes BIOL 1407

Invertebrates • Animals without backbones • Most animals

Sponges • Porifera ≠ clade • Two possible phyla: – Silicea (most sponges) – Calcarea • Photo Credit: BIOL 1407 Student

Characteristics of Sponges • Cellular organization • Radial or no symmetry • Photo Credit: BIOL 1407 Student

Characteristics of Sponges • Filter feeders • Aquatic • Sessile • Photo Credit: Mila Zinkova, 2008, Wikimedia Commons

Cell Types • • Choanocytes Amoebocytes Epidermal cells Porocytes (in some)

Choanoflagellates and Choanocytes

Skeleton • Spicules – Calcium carbonate – Silica • Spongin – Collagen protein • • Photo Credit for bath sponges: Alcinoe, 2005, Wikimedia Commons Photo Credit for Venus’ Flower Basket: NOAA, 2002

Phylum Cnidaria • Hydroids (Hydra, Obelia) – http: //www. youtube. com/watch? v=12 Omsz. Ob. Ak. M&feature=related • Corals and Sea Anemones • Jellies • Cubozoans (sea wasps)

Hydroids Photo Credit for Portuguese Man o’ War: UNK Vieques 2008 Field Trip

Corals and Sea Anemones Photo Credit for Hard Coral: BIOL 1407 Student

Jellies and Cubozoans

Characteristics of Cnidarians • Radial symmetry • Diploblastic – Epidermis – Gastrodermis – Mesoglea • Gastrovascular Cavity • Tentacles with cnidocytes

Two Body Forms

Exchange Processes • Body wall Two layers of cells • Cell transport occurs at both layers – – Water Balance Ion Balance Waste Disposal Gas Exchange

Digestion • Two forms – Intracellular – Extracellular • Extracellular digestion major evolutionary advance • Allows animals to eat things larger than their cells • Video: http: //www. youtube. com/watch? v=M 3 VSvyxrw. XA

Intracellular vs. Extracellular Digestion

Transport • As cnidarian moves, water moves through GVC • GVC serves as transport system • Video: http: //www. youtube. com/watch? v=o. CJ w. Hog. Xt. KE&eurl=http: //video. aol. com/v ideo-detail/jellyfish-swimmingmonterey-bay-aquarium/1285587528

Platyhelminthes • Free-living Flatworms – Planarians – Marine Flatworms • Flukes • Tapeworms

Planarian and Marine Flatworm Photo Credit of planarian: Dr. Stephen Bostic, 2008

Fluke

Tapeworm

Characteristics of Platyhelminths • • Bilateral Symmetry Triploblastic Acoelomate Gastrovascular Cavity – Extensive branching • Flat body • Photo Credit: Richard Ling, 2005, Flickr

Exchange Processes • Body is flat and thin ↑ Surface Area • Highly branched GVC ↑ Surface Area • Cell transport occurs at both places – – Water Balance Ion Balance Waste Disposal Gas Exchange Photo Credit of planarian: Dr. Stephen Bostic, 2008

Transport • GVC serves as transport system • Video: http: //www. youtube. com/watc h? v=A 6 N 8 KZq. GAJg&feature =related • Photo Credit: Richard Ling, 2006, Flickr