Transcript seed plants
1 ANIMAL KINGDOM PHYLUM CNIDARIA Page 76 ABBOTTSCOLLEGE 2 copyright cmassengale 3 PHYLUM CNIDARIA 4 Includes between 9 000 and 11 000 species Includes the plant like hydroids, the flower like sea anemones, the jellyfish, bluebottles and the hard corals BODY PLAN OF CNIDARIA 5 Acoelomate (have no body cavity) Radial symmetry Diploblastic tissue layers Digestive cavity with a single opening The body wall is made up of three layers But there are only two layers of cells (the ectoderm and endoderm) The middle layer (mesogloea) is jelly PAGE 76 DIPLOBLASTIC TISSUE LAYERS 6 The ectoderm forms the epidermis The endoderm forms the gastrodermis (around the gut) There is a layer of jelly between the two = mesogloea BODY WALL CNIDARIA 7 RADIAL SYMMETRY 8 Suits their sessile or free floating mode of living Makes them aware of what is happening all around them DIGESTIVE CAVITY WITH A SINGLE OPENING 9 Serves as both a mouth and an anus Inefficient digestive system Have a ring of tentacles around the opening to catch food Have specialised stinging cells or cnidocytes Which contain stinging organelles called nematocysts to capture their prey and defend themselves against predators Hydra is a genus of small, simple, fresh-water animals that possess radial symmetry. Hydra are predatory animals belonging to the phylum Cnidaria 10 11 12 13 14 copyright cmassengale 15 copyright cmassengale REPRODUCTION Page 76 16 Have a dimorphic life cycle (develop two basic body forms) Medusa Free swimming and umbrella shaped Develops gonads Reproduces sexually to produce a free-swimming planula larva Polyp Develops from the larva May occur singly (eg anemones) Or in enormous marine colonies (eg corals) 17 copyright cmassengale Life cycle Cnidaria 18 19 20 Coral Coral Reef Corals are marine invertebrates in phylum Cnidaria typically living in compact colonies of many identical individual "polyps". 21 copyright cmassengale 22 23 copyright cmassengale 24 copyright cmassengale TO DO 25 PASTE IN DIAGRAMS IN YOUR WORKBOOK TEXTBOOK PAGE 78 LEARNING ACTIVITY 1 QUESTIONS 1, 2 AND 3 BODY PLANS OF ANIMALS 26 THE END