1. 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?

2. 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

3. 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

4. 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

5. 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?

6. 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

7. 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

8. 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

9. 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?

10. 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

11. 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

12. 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