Chapter 33 introduce to invertebrates. This chapter describe how a sponge feeds and digests its food, list the characteristics of the phylum Cnidaria that distinguish it from other animal phyla, list the four classes of Cnidaria and distinguish among them based on life cycle morphology, list the characteristics of Platyhelminthes and distinguish among the four classes, describe the features of molluscs and distinguish among the four classes,. | Chapter 33 Invertebrates What function do the red whorls of this organism have? Figure What function do the red whorls of this organism have? Overview: Life Without a Backbone Invertebrates are animals that lack a backbone. They account for 95% of known animal species. Fig. 33-2 Review of Animal Phylogeny ANCESTRAL PROTIST Common ancestor of all animals Calcarea and Silicea Eumetazoa Bilateria Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Figure Review of animal phylogeny Fig. 33-3-1 Invertebrate Diversity Calcarea and Silicea (5,500 species) A sponge Cnidaria (10,000 species) A jelly Acoela (400 species) Acoel flatworms (LM) mm LOPHOTROCHOZOANS Platyhelminthes (20,000 species) A marine flatworm Ectoprocta (4,500 species) Ectoprocts A brachiopod Brachiopoda (335 species) Rotifera (1,800 species) A rotifer (LM) A ctenophore, or comb jelly Ctenophora (100 species) A placozoan (LM) mm Placozoa (1 species) Figure For the Discovery Video Invertebrates, go to Animation and Video Files. Concept : Sponges are basal animals that lack true tissues Sponges are sedentary animals from the phyla Calcarea and Silicea. They live in both fresh and marine waters. Sponges lack true tissues and organs. Fig. 33-UN1 Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Sponges are suspension feeders - capturing food particles suspended in the water that pass through their body. Choanocytes, flagellated collar cells, generate a water current through the sponge and ingest suspended food. Water is drawn through pores into a cavity called the spongocoel, and out through an opening called the osculum. Anatomy of a Sponge Azure vase sponge (Callyspongia plicifera) Spongocoel Osculum Pore Epidermis Water flow Mesohyl Choanocyte Flagellum Collar Food particles in mucus Choanocyte Amoebocyte Phagocytosis of food particles Spicules Amoebocytes Figure Anatomy of a sponge Sponges consist of a noncellular mesohyl layer between two cell layers. . | Chapter 33 Invertebrates What function do the red whorls of this organism have? Figure What function do the red whorls of this organism have? Overview: Life Without a Backbone Invertebrates are animals that lack a backbone. They account for 95% of known animal species. Fig. 33-2 Review of Animal Phylogeny ANCESTRAL PROTIST Common ancestor of all animals Calcarea and Silicea Eumetazoa Bilateria Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Figure Review of animal phylogeny Fig. 33-3-1 Invertebrate Diversity Calcarea and Silicea (5,500 species) A sponge Cnidaria (10,000 species) A jelly Acoela (400 species) Acoel flatworms (LM) mm LOPHOTROCHOZOANS Platyhelminthes (20,000 species) A marine flatworm Ectoprocta (4,500 species) Ectoprocts A brachiopod Brachiopoda (335 species) Rotifera (1,800 species) A rotifer (LM) A ctenophore, or comb jelly Ctenophora (100 species) A placozoan (LM) mm Placozoa (1 species) Figure For the Discovery Video Invertebrates, go to .
