Sponges, Cnidarians, and Ctenophores Table of Contents Section 1 Porifera Section 2 Cnidaria and Ctenophora
Section 1 Porifera Objectives Describe the basic body plan of a sponge. Describe the process of filter feeding in sponges. Contrast the processes of sexual and asexual reproduction in sponges.
Section 1 Porifera Body Plan of Sponges The phylum Porifera is made up of sponges. Sponges are sessile invertebrates that have no true tissues or organs. The simplest sponges are shaped like hollow cylinders. The body wall of a sponge is composed of two layers of cells that are separated by a jellylike substance called mesohyl. Choanocytes in the interior layer draw water through the ostia that penetrate the body wall. The water leaves through the osculum. The body is supported by a skeleton made of spongin, spicules, or both.
Section 1 Porifera Sponges
Section 1 Porifera Structure of a Sponge
Section 1 Porifera Parts of a Sponge
Section 1 Porifera Collar Cells
Section 1 Porifera Feeding and Digestion in Sponges Sponges feed by filtering small organisms and organic matter out of the water that passes through their body. This is called filter feeding. Nutrients are distributed through the body by amoebocytes, cells which crawl about within the body wall.
Section 1 Porifera Feeding Habits of Sponges
Section 1 Porifera Reproduction in Sponges Sponges can reproduce both asexually and sexually. They reproduce asexually through: producing buds or gemmules regeneration of missing parts They reproduce sexually through the joining of egg and sperm. Most sponges are hermaphrodites, which can produce both eggs and sperm.
Section 1 Porifera Sexual Reproduction in Sponges
Section 1 Porifera Reproduction in Sponges
Section 2 Cnidaria and Ctenophora Objectives Describe the basic body plan of a cnidarian. Summarize how cnidarians feed. Describe the nervous system of cnidarians. Identify and give examples of the four classes of cnidarians. Describe the common characteristics of ctenophores.
Section 1 Porifera Gemmules
Section 2 Cnidaria and Ctenophora Body Plan of Cnidarians Animals in the phylum Cnidaria are radially symmetrical aquatic invertebrates that are more complex than the sponges. They have tissues and a few simple organs. The cnidairan body is either a sessile polyp or a swimming medusa. Some cnidarians alternate between both types during their life cycles. The body of a cnidarian consists of two cell layers: an outer epidermis an inner gastrodermis The layers are separated by the mesoglea. The gastrovascular cavity has a single opening (the mouth) surrounded by tentacles.
Section 2 Cnidaria and Ctenophora Feeding and Defense in Cnidarians Cnidarians have cells called cnidocytes. Each cnidocyte contains a nematocyst. When a cnidocyte is stimulated, its nematocyst ejects a filament that can paralyze or ensnare prey. Nervous System in Cnidarians The cnidarian nervous system is a diffuse web of interconnected nerve cells called a nerve net.
Section 2 Cnidaria and Ctenophora Classification of Cnidarians The four classes of cnidarians are: Class Hydrozoa This class includes Obelia, man-o-war, and the hydra. Hydrozoans may live as polyps, medusae, or mixed colonies. Class Cubozoa This class includes box jellies. Cubozoans spend most of their lives as medusae. Class Scyphozoa This class includes jellyfish. Scyphozoans spend most of their lives as medusae. Class Anthozoa This class includes sea anemones and corals. Anthozoans live only as polyps.
Section 2 Cnidaria and Ctenophora Reproduction in Obelia
Section 2 Cnidaria and Ctenophora Movement of Hydra
Section 2 Cnidaria and Ctenophora Reproduction in Hydras
Section 2 Cnidaria and Ctenophora Reproduction in Aurelia
Section 2 Cnidaria and Ctenophora Reproduction in Jellyfish
Section 2 Cnidaria and Ctenophora Comparing Medusa and Polyp Bodies
Section 2 Cnidaria and Ctenophora Coral Reefs
Section 2 Cnidaria and Ctenophora Phylum Ctenophora Animals in the phylum Ctenophora are known as ctenophores and often called comb jellies. Ctenophores move through the water by beating the cilia that occur in eight rows on the outside of their body. Ctenophores capture prey with a sticky substance secreted by their colloblasts. An apical organ at one end of the body enables ctenophores to sense their orientation in the water. Most ctenophores are hermaphroditic. Many ctenophores have bioluminescence.
Section 2 Cnidaria and Ctenophora Two Cnidarian Body Forms
Section 2 Cnidaria and Ctenophora Cnidarian Body Plan
Section 2 Cnidaria and Ctenophora Exploration of a Cnidarian
Section 2 Cnidaria and Ctenophora Development of Cnidarian Embryo
Section 2 Cnidaria and Ctenophora Characteristics of Cnidarians
Section 2 Cnidaria and Ctenophora Cnidocyte
Section 2 Cnidaria and Ctenophora Types of Cnidarians
Standardized Test Prep Multiple Choice 1. Why are spongin and spicules important to a sponge? A. They digest food. B. They remove wastes. C. They provide support. D. They produce offspring.
Standardized Test Prep Multiple Choice, continued 1. Why are spongin and spicules important to a sponge? A. They digest food. B. They remove wastes. C. They provide support. D. They produce offspring.
Standardized Test Prep Multiple Choice, continued 2. Which of the following structures are involved in both feeding and sexual reproduction in sponges? F. spicules and gemmules G. amoebocytes and spongin H. gemmules and choanocytes J. choanocytes and amoebocytes
Standardized Test Prep Multiple Choice, continued 2. Which of the following structures are involved in both feeding and sexual reproduction in sponges? F. spicules and gemmules G. amoebocytes and spongin H. gemmules and choanocytes J. choanocytes and amoebocytes
Standardized Test Prep Multiple Choice, continued 3. Which of the following is not a characteristic of cnidarians? A. tentacles B. choanocytes C. nematocysts D. gastrovascular cavity
Standardized Test Prep Multiple Choice, continued 3. Which of the following is not a characteristic of cnidarians? A. tentacles B. choanocytes C. nematocysts D. gastrovascular cavity
Standardized Test Prep Multiple Choice, continued 4. What do colloblasts do? F. They produce light. G. They secrete a sticky substance. H. They draw water through sponges. J. They form medusae that live in colonies.
Standardized Test Prep Multiple Choice, continued 4. What do colloblasts do? F. They produce light. G. They secrete a sticky substance. H. They draw water through sponges. J. They form medusae that live in colonies.
Standardized Test Prep Multiple Choice, continued The diagram below illustrates a hydra. Study the diagram to answer the questions that follow.
Standardized Test Prep Multiple Choice, continued 5. Identify the substance found at point 3. A. osculum B. mesoglea C. gastrodermis D. gastrovascular cavity
Standardized Test Prep Multiple Choice, continued 5. Identify the substance found at point 3. A. osculum B. mesoglea C. gastrodermis D. gastrovascular cavity
Standardized Test Prep Multiple Choice, continued 6. Which structure is involved in defense? F. 1 G. 2 H. 3 J. 4
Standardized Test Prep Multiple Choice, continued 6. Which structure is involved in defense? F. 1 G. 2 H. 3 J. 4
Standardized Test Prep Multiple Choice, continued 7. Sponge : osculum :: hydra : A. mouth B. tentacle C. nerve net D. nematocyst
Standardized Test Prep Multiple Choice, continued 7. Sponge : osculum :: hydra : A. mouth B. tentacle C. nerve net D. nematocyst
Standardized Test Prep Multiple Choice, continued The diagram below illustrates a medusa. Study the diagram to answer the question that follows.
Standardized Test Prep Multiple Choice, continued 8. In which class is this body form dominant? F. Cnidaria G. Hydrozoa H. Anthozoa J. Scyphozoa
Standardized Test Prep Multiple Choice, continued 8. In which class is this body form dominant? F. Cnidaria G. Hydrozoa H. Anthozoa J. Scyphozoa
Standardized Test Prep Short Response Cnidarians have two tissue layers, which is an important evolutionary advancement. Describe the tissue layers and general body structure of a typical cnidarian.
Standardized Test Prep Short Response, continued Cnidarians have two tissue layers, which is an important evolutionary advancement. Describe the tissue layers and general body structure of a typical cnidarian. Answer: There are two tissue layers: the epidermis and gastrodermis. Mesoglea lies between these layers. The epidermis has cnidocytes for defense and capturing prey. Digestion occurs in the gastrovascular cavity, which is surrounded by the gastrodermis.
Standardized Test Prep Extended Response Base your answers to parts A & B on the information below. Sponges reproduce asexually in a number of ways. Part A Describe three forms of asexual reproduction in sponges. Part B Explain how reproducing asexually is advantageous to sponges.
Standardized Test Prep Extended Response, continued Answer: Part A: Sponges can reproduce sexually or asexually by budding or producing gemmules, which are internal buds with a protective coating and internal food supply. A third way is by regeneration, in which a tiny piece of sponge grows into a new, complete sponge. Part B: Sponges are sessile and unable to search for mates for sexual reproduction. Reproducing asexually also helps sponges survive certain conditions.