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2.) A Brief List of 21 Animal Phyla
A. Invertebrate Phyla
Parazoa: Simple animals without a digestive cavity.
1. Phylum Porifera (Sponges)
Simple multicellular animals that spend their lives anchored to a rock or ocean bottom; they are mostly marine but some species live in fresh water; sponges have radial symmetry with a cylindrical, globose or irregular body containing an internal skeleton of minute spicules made of calcium carbonate, silica, or a fibrous collagen protein called spongin; the surface contains numerous pores connecting to canals and chambers lined by flagellated collar cells (choanocytes); sponges are filter-feeders, taking in microscopic plankton by miniature currents created by the choanocytes; sponges are divided into three classes: Class Calcarea (chalk sponges) with calcareous spicules; Class Hexactinellida (glass sponges) with siliceous spicules; and Class Demospongiae (horn sponges) with a skeleton of spongin or none; calcareous and siliceous sponge spicules often become components of tropical beach sand.
Two examples of marine sponges. The surface contains numerous pores connected to canals and chambers lined by flagellated cells called choanocytes. Sponges are filter-feeders, taking in microscopic plankton by miniature currents created by the choanocytes.
Enterozoa: Animals with a digestive cavity or tract.
Radiata: Radial symmetry, lacking central nervous system.
2. Phylum Coelenterata (Cnidaria) Corals & Jellyfish
Marine and freshwater animals with radial symmetry; this phylum has two distinct body forms: a solitary or colonial polyp and a bell-shaped, free swimming medusa; both polyps and medusae are often fringed with stinging tentacles; the tentacles bear rows of "stinging cells" or cnidoblasts, each containing a "stinging organelle" known as a nematocyst; some coelenterates (Obelia) have both polyp and medusa stages in their diplontic life cycle; coelenterates are divided into three classes: Class Hydrozoa (hydroids),
A. Invertebrate Phyla
Parazoa: Simple animals without a digestive cavity.
1. Phylum Porifera (Sponges)
Simple multicellular animals that spend their lives anchored to a rock or ocean bottom; they are mostly marine but some species live in fresh water; sponges have radial symmetry with a cylindrical, globose or irregular body containing an internal skeleton of minute spicules made of calcium carbonate, silica, or a fibrous collagen protein called spongin; the surface contains numerous pores connecting to canals and chambers lined by flagellated collar cells (choanocytes); sponges are filter-feeders, taking in microscopic plankton by miniature currents created by the choanocytes; sponges are divided into three classes: Class Calcarea (chalk sponges) with calcareous spicules; Class Hexactinellida (glass sponges) with siliceous spicules; and Class Demospongiae (horn sponges) with a skeleton of spongin or none; calcareous and siliceous sponge spicules often become components of tropical beach sand.
Two examples of marine sponges. The surface contains numerous pores connected to canals and chambers lined by flagellated cells called choanocytes. Sponges are filter-feeders, taking in microscopic plankton by miniature currents created by the choanocytes.
Enterozoa: Animals with a digestive cavity or tract.
Radiata: Radial symmetry, lacking central nervous system.
2. Phylum Coelenterata (Cnidaria) Corals & Jellyfish
Marine and freshwater animals with radial symmetry; this phylum has two distinct body forms: a solitary or colonial polyp and a bell-shaped, free swimming medusa; both polyps and medusae are often fringed with stinging tentacles; the tentacles bear rows of "stinging cells" or cnidoblasts, each containing a "stinging organelle" known as a nematocyst; some coelenterates (Obelia) have both polyp and medusa stages in their diplontic life cycle; coelenterates are divided into three classes: Class Hydrozoa (hydroids),