Interest Grabber What’s the Difference? Section 26-1 What’s the Difference? In the course of the day, you probably have encountered animals and other types of organisms. 1. Make a list of five animals that you saw today. 2. Then, make a list of five organisms other than animals that you saw today. 3. What characteristics do animals have that the other types of organisms do not?

Section Outline 26–1 Introduction to the Animal Kingdom A. What Is an Animal? B. What Animals Do to Survive 1. Feeding 2. Respiration 3. Circulation 4. Excretion 5. Response 6. Movement 7. Reproduction C. Trends in Animal Evolution 1. Cell Specialization and Levels of Organization 2. Early Development 3. Body Symmetry 4. Cephalization 5. Body Cavity Formation

Concept Map Animals Section 26-1 have are carry out Eukaryotic cells Heterotrophs Essential functions with such as No cell walls Feeding Respiration Circulation Excretion Response Movement Reproduction

Figure 26–5 Body Symmetry Bilateral Symmetry Radial Symmetry Section 26-1 Bilateral Symmetry Radial Symmetry Posterior end Dorsal side Anterior end Ventral side Plane of symmetry Planes of symmetry

Interest Grabber No Sinking or Swimming Section 26-2 No Sinking or Swimming You likely have a green, yellow, blue, or pink sponge in your kitchen sink at home. This is a synthetic (human-made) sponge, not a natural sponge. But you may have used a natural sponge in the bath or when washing the car. These sponges are usually brownish and are irregularly shaped. 1. Natural sponges live in the water, and are attached to a single spot. Although they cannot move from place to place like many other animals, sponges are still animals. Because they are animals, what characteristics must sponges have? 2. What characteristics does a kitchen sponge have? Which of these characteristics do you think a natural sponge has?

Section Outline 26–2 Sponges A. What Is a Sponge? B. Form and Function in Sponges 1. Body Plan 2. Feeding 3. Respiration, Circulation, and Excretion 4. Response 5. Reproduction C. Ecology of Sponges

Sponge Life Cycle Section 26-2 MEIOSIS Haploid (N) Diploid (2N) Sperm from a sponge are released into the surrounding water. Water currents carry the sperm to other sponges. New sponge Sperm (N) Mature sponge (2N) Egg (N) Swimming larva Larva (2N) The zygote develops into a free-swimming larva. Water currents carry the larva until it attaches to a surface and grows into a new sponge. Sperm enter another sponge through pores. The sperm are carried to eggs inside the body wall. Sperm fertilize eggs. FERTILIZATION

Figure 26–8 The Anatomy of a Sponge Section 26-2 Water flow Osculum Choanocyte Central cavity Pores Spicule Pore cell Pore Epidermal cell Archaeocyte

Interest Grabber What’s in a Name? Section 26-3 What’s in a Name? Perhaps you have heard about creatures called jellyfishes on television, in school, or at an aquarium; maybe you live near the ocean and have actually seen jellyfishes. 1. Do jellyfishes look like what their name describes? Make a simple drawing of what you think a jellyfish looks like. 2. Some scientists suggest that jellyfishes should be called “jellies.” What might this new name tell you about jellyfishes?

Section Outline 26–3 Cnidarians A. What Is a Cnidarian? B. Form and Function in Cnidarians 1. Body Plan 2. Feeding 3. Respiration, Circulation, and Excretion 4. Response 5. Movement 6. Reproduction C. Groups of Cnidarians 1. Jellyfishes 2. Hydras and Their Relatives 3. Sea Anemones and Corals D. Ecology of Corals

Jellyfish Life Cycle Section 26-3 Female medusa (2N) MEIOSIS Fertilization occurs in the open water, producing many diploid zygotes. Egg (N) Adult medusas reproduce sexually by releasing gametes into the water. FERTILIZATION Sperm (N) Each zygote grows into a ciliated larva. The larva eventually attaches to a hard surface and develops into a polyp. Zygote (2N) Male medusa (2N) Young medusa Swimming larva Polyp The polyp buds to release young medusas. Haploid Diploid Budding polyp

Figure 26–12 The Polyp and Medusa Stages Section 26-3 Epidermis Mesoglea Gastroderm Tentacles Mouth/anus Gastrovascular cavity Mesoglea Gastrovascular cavity Mouth/anus Tentacles Medusa Polyp