Invertebrates: Sponges and Cnidarians

Journal 2 You are an expert taxonomist who has been given an unknown specimen to identify. You suspect that it is an animal. How could you prove your hypothesis? You are an expert taxonomist who has been given an unknown specimen to identify. You suspect that it is an animal. How could you prove your hypothesis? Open your books to page 664 Open your books to page 664

Sponges: Phylum Porifera means- pore bearer Phylum Porifera means- pore bearer Simplest of all animals Simplest of all animals Assymetrical animals that live in shallow waters Assymetrical animals that live in shallow waters Sessile filter-feeders whose bodies have many pores Sessile filter-feeders whose bodies have many pores Acoelomates-no body cavity Acoelomates-no body cavity Obtain oxygen by filtering water Obtain oxygen by filtering water Uses: cleaning, bathing, cosmetics Uses: cleaning, bathing, cosmetics No nervous system or organ systems No nervous system or organ systems

Sponge Reproduction Reproduce Asexually by budding: Reproduce Asexually by budding: Buds form from sides of parent sponge, bud break off and grow into new individual Buds form from sides of parent sponge, bud break off and grow into new individual can grow back missing parts (regeneration) can grow back missing parts (regeneration) Reproduce sexually: Reproduce sexually: Hermaphrodites: produce both eggs and sperm Hermaphrodites: produce both eggs and sperm Gametes are released into water Gametes are released into water

Sponge Body Structures: Osculum: large opening at the top of the sponge Osculum: large opening at the top of the sponge Pore cells: openings to bring in water Pore cells: openings to bring in water Collar cells (choanocytes): line interior, have flagella to help filter water Collar cells (choanocytes): line interior, have flagella to help filter water Spicules: hard, supportive structures found in body of sponge Spicules: hard, supportive structures found in body of sponge LABEL THE SPONGE ON YOUR LEFT PAGE!!!

Section 26-2 Water flow Choanocyte Spicule Pore cell Pore Epidermal cell Archaeocyte Osculum Central cavity Pores The Anatomy of a Sponge

Cnidarians: Phylum Cnidaria: means “stinging cell” Phylum Cnidaria: means “stinging cell” Marine Marine Radial symmetry Radial symmetry Have tentacles Have tentacles Predators: capture and poison prey with stinging cells on tentacles (NEMATOCYST) Predators: capture and poison prey with stinging cells on tentacles (NEMATOCYST) Acoelomates Acoelomates Oxygen diffuses into body from water Oxygen diffuses into body from water

Cnidarian Body Forms Polyp: body with tentacles hanging upward Polyp: body with tentacles hanging upward Ex: hydra, sea anemone Ex: hydra, sea anemone Medusa: body with tentacles hanging downward Medusa: body with tentacles hanging downward Ex: jellyfish Ex: jellyfish

Cnidarian Reproduction: Asexually reproduce by budding Asexually reproduce by budding Sexually reproduce in medusa form only, sperm and eggs are released into water Sexually reproduce in medusa form only, sperm and eggs are released into water Thousands of gametes are released at a time Thousands of gametes are released at a time

Time to Think! Why do sponges and cnidarians release so many gametes into the water? The body plan of an animal relates to its complexity. What does that tell you about sponges and Cnidarians since they are both acoelomates?

Basal disc: sticky end of polyp form which allows them to stay in one spot Basal disc: sticky end of polyp form which allows them to stay in one spot One body opening (mouth) for food to enter and wastes to exit One body opening (mouth) for food to enter and wastes to exit Gastrovascular cavity: interior cavity where food is digested & nutrients are circulated around the body Gastrovascular cavity: interior cavity where food is digested & nutrients are circulated around the body Nerve net: net of nerves that allow impulses to travel around the body, senses the environment Nerve net: net of nerves that allow impulses to travel around the body, senses the environment Muscles: some muscles are present; allows for some movement Muscles: some muscles are present; allows for some movement Label the hydra on your left page Cnidarian Structures: Cnidarian Structures:

Three groups of cnidarians Hydrozoans: colonies which appear to be one organism Hydrozoans: colonies which appear to be one organism Ex: portugese-man-of-war Ex: portugese-man-of-war Scyphorozoans: independent medusas Scyphorozoans: independent medusas Ex: jellyfish, box jellies Ex: jellyfish, box jellies Anthozoans: colonies of polyps Anthozoans: colonies of polyps Ex: corals, sea anemones Ex: corals, sea anemones

Quiz 1. Sponges __ animals. a. are b. are not a. are b. are not 2. Sponges can reproduce asexually by ___. a. budding b. regeneration c. both a. budding b. regeneration c. both 3. Hydras have their tentacles pointing upwards. They are __. a. medusas b. nematocysts c. polyps a. medusas b. nematocysts c. polyps 4. All cnidarians have ___ symmetry. a. bilateral b. radial c. no symmetry a. bilateral b. radial c. no symmetry 5. Cnidarians poison their prey with stinging cells called ___. a. choanocytes b.nematocysts c. osculum a. choanocytes b.nematocysts c. osculum