Chapter 33 Table of Contents Section 1 Porifera Sponges, Cnidarians, and Ctenophores Chapter 33 Table of Contents Section 1 Porifera Section 2 Cnidaria and Ctenophora

Chapter 33 Objectives Describe the basic body plan of a sponge. Section 1 Porifera Chapter 33 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.

Chapter 33 Body Plan of Sponges Section 1 Porifera 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.

Chapter 33 Sponges Section 1 Porifera Click below to watch the Visual Concept. Visual Concept

Section 1 Porifera Chapter 33 Structure of a Sponge

Chapter 33 Parts of a Sponge Section 1 Porifera Click below to watch the Visual Concept. Visual Concept

Chapter 33 Collar Cells Section 1 Porifera Click below to watch the Visual Concept. Visual Concept

Feeding and Digestion in Sponges Section 1 Porifera Chapter 33 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.

Feeding Habits of Sponges Section 1 Porifera Chapter 33 Feeding Habits of Sponges Click below to watch the Visual Concept. Visual Concept

Reproduction in Sponges Section 1 Porifera Chapter 33 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.

Sexual Reproduction in Sponges Section 1 Porifera Chapter 33 Sexual Reproduction in Sponges

Reproduction in Sponges Section 1 Porifera Chapter 33 Reproduction in Sponges Click below to watch the Visual Concept. Visual Concept

Chapter 33 Gemmules Section 1 Porifera Click below to watch the Visual Concept. Visual Concept

Chapter 33 Objectives Describe the basic body plan of a cnidarian. Section 2 Cnidaria and Ctenophora Chapter 33 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.

Body Plan of Cnidarians Section 2 Cnidaria and Ctenophora Chapter 33 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.

Feeding and Defense in Cnidarians Section 2 Cnidaria and Ctenophora Chapter 33 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.

Classification of Cnidarians Section 2 Cnidaria and Ctenophora Chapter 33 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.

Reproduction in Obelia Section 2 Cnidaria and Ctenophora Chapter 33 Reproduction in Obelia

Chapter 33 Movement of Hydra Section 2 Cnidaria and Ctenophora Click below to watch the Visual Concept. Visual Concept

Reproduction in Hydras Section 2 Cnidaria and Ctenophora Chapter 33 Reproduction in Hydras Click below to watch the Visual Concept. Visual Concept

Reproduction in Aurelia Section 2 Cnidaria and Ctenophora Chapter 33 Reproduction in Aurelia

Reproduction in Jellyfish Section 2 Cnidaria and Ctenophora Chapter 33 Reproduction in Jellyfish Click below to watch the Visual Concept. Visual Concept

Comparing Medusa and Polyp Bodies Section 2 Cnidaria and Ctenophora Chapter 33 Comparing Medusa and Polyp Bodies Click below to watch the Visual Concept. Visual Concept

Section 2 Cnidaria and Ctenophora Chapter 33 Coral Reefs

Chapter 33 Phylum Ctenophora Section 2 Cnidaria and Ctenophora Chapter 33 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.

Two Cnidarian Body Forms Section 2 Cnidaria and Ctenophora Chapter 33 Two Cnidarian Body Forms

Section 2 Cnidaria and Ctenophora Chapter 33 Cnidarian Body Plan

Exploration of a Cnidarian Section 2 Cnidaria and Ctenophora Chapter 33 Exploration of a Cnidarian

Development of Cnidarian Embryo Section 2 Cnidaria and Ctenophora Chapter 33 Development of Cnidarian Embryo

Characteristics of Cnidarians Section 2 Cnidaria and Ctenophora Chapter 33 Characteristics of Cnidarians Click below to watch the Visual Concept. Visual Concept

Chapter 33 Cnidocyte Section 2 Cnidaria and Ctenophora Click below to watch the Visual Concept. Visual Concept

Chapter 33 Types of Cnidarians Section 2 Cnidaria and Ctenophora Click below to watch the Visual Concept. Visual Concept