Chapter 25: What Is an Animal? Unit 2, Side 1, 4 Min

UnitUnit 88 Unit 8 UnitUnit 88 Advance Planning Invertebrates InvertebratesInvertebrates Chapter 25 Order slides for the Quick Unit Overview Demo and Alternative Lab. Almost all animals on Earth—95 percent In this unit, students become Purchase rotifers and vinegar familiar with invertebrates. —are invertebrates, animals without eels for the two MiniLabs. Chapter 25 introduces the gen- backbones. Tidal pools and the oceans that Order Daphnia for the Project. Collect earthworms and pla- eral characteristics of animals as sustain them are home to many of the well as their body plans. narians for the Reinforcement. In Chapter 26, students begin world’s invertebrates. The enormous diver- Chapter 26 their examination of specific sity in form and function of invertebrates Order slides for the Quick invertebrate groups through the is the result of a long evolutionary history. Demo and Biology Journal. study of the structure, adapta- As you study invertebrates, you will Order live hydra for the Mini- tions, ecology, and phylogeny of Lab and Close. sponges, cnidarians, flatworms, discover adaptations that are evolutionary Order sponges and cnidarians and roundworms. In Chapter 27, milestones. for the Reinforcement. students examine the characteris- Order a live vinegar eel culture tics, ecology, and phylogeny of for the Quick Demo. mollusks and segmented worms. Unit Projects UNIT CONTENTS Chapter 27 Chapter 28 allows students to U C None explore the largest group of animals—the arthropods. In this 25 What Is an Animal? Chapter 28 Obtain arthropods for the chapter, the diversity of arthro- 26 Sponges, Cnidarians, pods is examined, while features Flatworms, and Roundworms Quick Demo. that enabled many arthropods to Obtain bess beetles for the 27 Mollusks and Segmented become land dwellers are ex- Alternative Lab. Worms plained. Obtain preserved crayfish for The unit concludes in Chapter 28 Arthropods the MiniLab. 29 with a presentation of echino- Obtain live crayﬁsh and a but- 29 Echinoderms and Invertebrate terfly chrysalis for the Quick derms and invertebrate chor- Chordates dates. Demos and MiniLab. BIOIODIGESTIGEST Invertebrates Chapter 29 Introducing the Unit Purchase a slide of sea star pedicellariae for the MiniLab. Ask students to examine the photo Obtain sea stars for Quick of the tidal pool. Ask them to UNIT PROJECT Demos. identify several of the organisms Purchase echinoderm fossils shown in the photo. Have the Use the Glencoe Science for the Portfolio. class brainstorm to create lists of Web Site for more project Purchase slides of a lancelet how these organisms are alike activities that are connected to this unit. www.glencoe.com/sec/science and sea urchin development and how they are different. Try for the Alternative Lab. to lead students to include char- Purchase Branchiostoma cali- acteristics of each organism that forniense for the MiniLab. show its adaptation to its envi- Obtain live sea urchins for the ronment. L2 690 BioLab.

Unit Projects UnitUnit ProjectsProjects Use the Library Design and Build Display Make a Map Final Report The Life Cycle of a Butterfly Intrapersonal Ask students to re- Kinesthetic Have students obtain Visual-Spatial Have students make Visual-Spatial Have students map Have student groups make a poster that search information about butterfly the materials and develop an enclo- a poster showing a plan for devel- the migration of monarch butter- illustrates their observations of the meta- Have studentsP do one of the projects for metamorphosis. L2 sure to observe butterfly metamorphosis. opment of a butterfly garden that would flies. L3 morphosis of a butterfly. this unit as described on the Glencoe L1 ELL attract local butterflies. L2 ELL Science Web Site. As an alternative, students can do one of the projects described on theseLS two pages. P P 690 P 691 P LS P LS P LS LS LS LS

Unit Projects Chapter 25 Organizer What Is an Animal?

Refer to pages 4T-5T of the Teacher Guide for an explanation of the National Science Education Standards correlations. Teacher Classroom Resources Activities/FeaturesObjectivesSection MastersSection TransparenciesReproducible

Reinforcement and Study Guide, pp. 111-112 L2 Section Focus Transparency 61 L1 ELL Section 25.1 1. Describe the characteristics of animals. Careers in Biology: Marine Biologist, p. 694 Section 25.1 2. Sequence the development of a typical MiniLab 25-1: Observing Animal Critical Thinking/Problem Solving, p. 25 L3 Basic Concepts Transparency 44 L2 ELL Typical Animal animal Characteristics, p. 695 Typical Animal BioLab and MiniLab Worksheets, p. 113 L2 Reteaching Skills Transparency 38 L1 ELL Characteristics Problem-Solving Lab 25-1: p. 696 Characteristics Laboratory Manual, pp. 179-182 L2 P National Science Education Inside Story: Early Animal Development, Content Mastery, pp. 125-126, 128 L1 P p. 698 Standards UCP.1, UCP.2, P UCP.5; A.1, A.2; C.1, C.5, Internet BioLab: Zebra Fish Development, P 1 Reinforcement and Study Guide, pp. 113-114 L2P Section Focus Transparency 62 L1 ELL C.6; G.1-3 (1 session, /2 p. 706 Section 25.2 LS Concept Mapping, p. 25 L3 ELL Basic Concepts Transparency 44 L2P ELL block) Biology & Society: Protecting Endangered P LS Species, p. 708 Body Plans and BioLab and MiniLab Worksheets, pp. 114-116P L2 LS Adaptations Laboratory Manual, pp. 183-186 L2P LS P LS P Content Mastery, pp. 125, 127-128P L1 P Section 25.2 3. Compare and contrast radial and Problem-Solving Lab 25-2: p. 702 LSLS bilateral symmetry with asymmetry. MiniLab 25-2: Check Out a Vinegar Eel, P P LS Body Plans and 4. Trace the phylogeny of animal body p. 703 Assessment Resources LS AdditionalP Resources LS PLS Adaptations plans. Chapter Assessment, pp. 145-150 LS Spanish Resources ELL P LS National Science Education 5. Compare body plans of acoelomate, P MindJogger Videoquizzes English/Spanish Audiocassettes ELL Standards UCP.1, UCP.2, pseudocoelomate, and coelomate LS PLS PerformanceAssessment Assessment Resources in the Biology Classroom Cooperative Learning in the Science Classroom UCP.4, UCP.5; A.1, A.2; C.3, animals. AdditionalLS Resources COOP LEARN C.5; E.1, E.2; F.4, F.5, F.6; Alternate Assessment in the Science Classroom Lesson Plans/Block SchedulingP LSLS 1 P G.1-3 (2 sessions, 1 /2 blocks) Computer Test Bank P LS BDOL Interactive CD-ROM, Chapter 25 quiz LS LS Need Materials? Contact Carolina Biological Supply Company at 1-800-334-5551 KeyKey toto TeachingTeaching StrategiesStrategies LS or at http://www.carolina.com LS LS L1 Level 1 activities should be appropriate MATERIALS LIST for students with learning difficulties. Teacher’s L2 Level 2 activities should be within the BioLab Alternative Lab ability range of all students. Corner p. 706 aquarium, zebra fish, turkey p. 702 microscope, prepared slides of L3 Level 3 activities are designed for above- The following multimedia resources are available from Glencoe. baster, beaker, dropper, petri dish, cross sections of hydra, planarian, average students. Products Available From Tigers of the Snow Biology: The Dynamics of Life stereomicroscope, wax pencil or labels nematode, and earthworm ELL ELL activities should be within the ability Glencoe White Wolf CD-ROM ELL To order the following products, Wild Survivors: Camouflage and range of English Language Learners. Animation: Embryo Development MiniLabs Quick Demos call Glencoe at 1-800-334-7344: Mimicry COOP LEARN Cooperative Learning activities Video: Fetal Development p. 695 microscope, microscope slide, p. 694 microscope, prepared slides of P CD-ROM P P are designed for small group work. Exploration: Symmetry coverslip, toothbrush bristles, rotifer nerve, muscle, blood, and stomach cells P Mammals: A Multimedia Index to National P P These strategies represent student prod- culture, dropper, water p. 701 kitchen bowls, vases, and Encyclopedia Geographic Magazine Videodisc Program ucts that can be placed into a best-work Embryo Development p. 703 microscope, microscope slide, spoons; dried marine sponge, pre- P portfolio. Videodisc The following articles may be coverslip, dropper, vinegar eel culture served jellyfish, live goldfish LS These strategies are useful in a block STV: Animals used for research relating to this LS LS scheduling format. chapter: The InfiniteLS Voyage LS Products Available From “Poison-Dart Frogs: Lurid and The Geometry of Life LS National Geographic Society Lethal,” by Mark W. Moffet, To order the following products, May 1995. The Secret of Life Series call National Geographic Society “Animals at Play,” by Stuart L. Dividing Cells, Early Embryo at 1-800-368-2728: Brown, December 1994. Sex and the Single Gene: Cell Development Book “The Amazing Frog-Eating Bat,” Evolution of Symmetry National Geographic Book of by Merlin D. Tuttle, January Flatworm Cross Section Mammals 1982. Developing Zebra Fish Videos Predators of North America Strange Creatures of the Night 692A 692B ChapterChapter 2525 ChapterChapter SECTION PREVIEW Section Objectives Section 25.1 Describe the character- 25.1 Typical Animal istics of animals. ETTING TARTED EMO What Is an Animal? Sequence the GETTING STARTED DEMO 25 development of a Prepare Characteristics typical animal. Naturalist Ask students Vocabulary Key Concepts to observe two of the sessile following animals in clear plas- What You’ll Learn hat do you think of when you hear the blastula Students will study typical animal word animal? Many people envision gastrula tic containers: a hamster, an You will distinguish animal characteristics and the develop- an organism with hair or fur and a ectoderm characteristics from those of W endoderm ment of animals from eggs. They earthworm, a cricket, or a other life forms. bony skeleton. Yet more than 95 percent of the grasshopper. Ask them to list mesoderm will compare and contrast animal You will identify the stages of 1.5 million species of animals that have been protostome ways in which these animals features and the differences in early animal development. described have neither bones nor hair. deuterostome are both alike and different. You will interpret body plans types of development. P If you saw the organism in the inset Remind students to treat live of animals. photograph for the first time, would animals gently. Planning L2 ELL Why It’s Important you classify it as an animal? This Gather live animals for the The animal kingdom includes organism is a sponge, an animal organisms as diverse as that remains attached to rocks Getting Started Demo. LS Buy zebra fish for the BioLab. Theme DevelopmentP sponges, earthworms, clams, or coral reefs in the ocean for crickets, and birds. Humans are This chapter stresses the themes also animals. An understanding all of its adult life. It doesn’t Coral polyps of unity within diversity and of animals will provide a better have a bony skeleton or hair, (above) and understanding of ourselves. evolution. Students will gain the yet it is still an animal. red sponges 1 Focus understanding thatP within the LS (left) Bellringer tremendous variety of animals, GETTING STARTED there are common threads or Before presenting the lesson, Comparing Animals shared features. They will also display Section Focus Trans- Examine two different animals. learn how animalLS characteristics are heterotrophic, meaning they parency 61 on the overhead pro- Make a list of four similarities Characteristics of Figure 25.1 must consume food to obtain energy jector and have students answer and adaptations have evolved. and four differences between Animals The barnacle and these animals. What traits iden- and nutrients. All animals depend lizard each get their the accompanying questions. tify an organism as an animal? All animals have several character- either directly or indirectly on food in different L1 ELL istics in common. Animals are autotrophs for food. ways. To find out eukaryotic, multicellular organisms more about If time does not permit teach- that have ways of moving that help animals, visit the Glencoe P ing the entire chapter, use the Typical Animal ECTION OCUS them reproduce, obtain food, and Transparency 61 S F Science Web Site. A A barnacle extends Characteristics Use with Chapter 25, Section 25.1 BioDigest at the end of the unit www.glencoe.com/sec/science protect themselves. Animals also have bristles from its as an overview. specialized cells that form tissues and shell to catch Barnacle Frog organs—such as nerves and muscles. small organisms Gerbil Unlike plants, animals are composed as they drift by LS in the water. Jellyfish of cells that do not have cell walls. P Most adult animals are fixed in size Sponge and shape; they do not continue to You know that the bat grow throughout their lives. B A lizard and jellyfish are animals, Porcupine captures flies but can you name the Methods for obtaining food vary LS Spider characteristics they share? with its long, sticky tongue. There are millions of species Examine the animals shown in Sea star of animals, but they all have Figure 25.1. One characteristic several features in common. common to all animals is that they 1 Which of these organisms do you think are animals? Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.

2 On what characteristics did you base your answer?

692 WHAT IS AN ANIMAL? BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES

AssessmentAssessment PlannerPlanner Look for the following logos for strategies that emphasize different learning modalities. Multiple Portfolio Assessment Knowledge Assessment ResourceResource Kinesthetic Project, p. 694; Intrapersonal Check for Under- Portfolio, TWE, pp. 697, 704 MiniLab, TWE, p. 695 ManagerManager Learning Building a Model, p. 697; standing, p. 697 MiniLab, TWE, p. 703 Section Assessment, SE, pp. 699, 705 Reteach, p. 697; Meeting Individual Linguistic Tech Prep, p. 697; Alternative Lab, TWE, p. 703 Chapter Assessment, SE, pp. 709-711 Section Focus Transparency 61 Needs, p. 698 Portfolio, pp. 697, 704 Styles BioLab, TWE, p. 707 Skill Assessment and Master L1 ELL Visual-Spatial Display, p. 694; Naturalist Biology Journal, Performance Assessment Problem-Solving Lab, TWE, p. 702 Quick Demo, p. 694; Biology p. 696; Check for Understand- Alternative Lab, TWE, p. 703 Journal, p. 700; Reteach, p. 704; ing, p. 704 BioLab, SE, p. 707 Extension, p. 704 MiniLabs, SE, pp. 695, 703 692 Problem-Solving Lab, TWE, p. 696 693 P P LS P

LS LS AREERS IN IOLOGY Figure 25.3 MiniLab 25-1 C B animals first evolved in water. Water P 2 Teach is more dense and contains less oxy- In animals such as planarians Marine Biologist gen than air, but water contains more and earthworms, food is Purpose Display digested in a digestive tract. B Earthworms ingest soil and ould you enjoy spending your suspended food. In the water, station- digest the organic matter Students will observe animal Visual-Spatial Make a bul- W days studying the organisms ary animals don’t expend much contained in it. Food enters traits in rotifers. found in the oceans? Perhaps you LS letin board display of a vari- energy to obtain food. But there is Mouth the mouth and travels along ety of vertebrate and invertebrate should become a marine biologist! little suspended food in the air; thus, the digestive tract in one Process Skills animals. Calendars and catalogs land animals use more oxygen and direction. Indigestible waste classify, observe and infer, collect Skills for the Job is eliminated at the anus. from biological supply companies Many marine biologists do go expend more energy to find food. data, draw conclusions may have animals such as the SCUBA diving in the oceans to find speci- The osprey and sidewinder snake Digestive Teaching Strategies mens, but they also spend time examining in Figure 25.2 are examples of verte- tract hydra and planaria mentioned in Extended those organisms in labs and do library research. They focus on Rotifers are available from this chapter. Ask students to brates, animals with backbones, pharynx topics such as the effect of temperature changes and pollu- whereas the sea star is an inverte- biological supply houses. bring in photographs to display tion on ocean inhabitants. Many marine biologists work for brate. Yet all these animals move A Planarians feed on small, live organisms Digestive tract Rotifers are classified in the government agencies, such as the National Oceanic and that they may have taken of ani- or on the dead bodies of larger animals. animal phylum Rotifera. These Atmospheric Administration (NOAA), and the Environmental about in their environments. Find out mals other than pets. L2 ELL The planarian’s digestive tract has only Protection Agency (EPA). Some work for private industries, how an animal’s environment affects animals are used as representative one opening through which food enters such as fisheries and environmental consulting firms. Most its survival in the Biology & Society at animals because students are and wastes exit. Anus Quick Demo marine biologists have a master’s degree or a doctorate, plus the end of this chapter. unfamiliar with this phylum. P skill in analyzing data and solving problems. Some aquatic animals, such as Review the technique used for sponges and corals, move about only digestion is carried out within indi- measuring organisms under the Visual-Spatial Ask stu- For more careers in related fields, be sure vidual cells; in other animals, diges- Observing and Inferring dents to examine a pre- to check the Glencoe Science Web Site. during the early stages of their lives. MiniLab 25-1 microscope. They hatch from eggs into free-swim- tion takes place in an internal cavity. pared slide of animal cells www.glencoe.com/sec/science Remind students to treat live P ming larval forms; as adults, most Some of the food an animal con- such as nerve, muscle, blood,LS Observing Animal Characteristics Animals come in animals gently. attach themselves to rocks or other sumes and digests is stored as fat or and cells lining the stomach. a variety of sizes and shapes, and can be found living in a Expected Results Animals such as lizards and birds objects. Organisms that don’t move glycogen and used when food is not number of different habitats. Ask them to make a labeled can move from place to place in an from place to place are known as available. Recall that glycogen is a Students will observe movement P Procedure sketch of these cells in their active search for food. Other animals, sessile (SES ul) organisms. They rely on polysaccharide, like starch, that is and feeding. They will ﬁnd a size LS ! journals. L2 ELL such as barnacles, remain stationary water currents to carry food to them. used for food storage. Copy the data table. range from about 0.04 to 2.0 mm @ and are adapted to capture food from Examine digestive tracts of a flat- Add a few bristles from an old toothbrush to a glass in length. Students will infer that Animals must digest food slide. Add a drop of water containing rotifers to your the water in which they live. worm and earthworm in Figure slide. The drop should cover the bristles. Add a coverslip. these animals are multicellular. LS Whether an animal moves quickly Animals are heterotrophs that 25.3. Notice that there is only one P CAUTION: Use caution when working with a microscope, Analysis CAREERS IN BIOLOGY or slowly depends partly on its envi- ingest their food; after ingestion,they opening to the flatworm’s digestive slides, and coverslips. Figure 25.2 ronment. Scientists hypothesize that must digest it. In some animals, tract, a mouth. An earthworm has a # Observe your rotifers under low-power magnification. 1. They are not green, thus are Career Path Animals move in a probably not autotrophs. remarkable variety digestive tract with two openings, $ Use the data table to record the characteristics that you CoursesP in high school: of ways. with a mouth at one end and an anus were able to see. Describe the evidence for each trait. 2. Student answers will vary. biology, botany,LS chemistry, at the other. Most rotifers will be actively C A sea star moves using Data Table math, computers a unique system of feeding on bacteria; the College: at least bachelor’s and Animal cell adaptations Animal Observed? wheel-like action of cilia A The soaring tube feet. Characteristic (Yes or No) Evidence master’s degrees in marine biolo- osprey dives Most animal cells are adapted to implies that these animals are LS Multicellular gy or other specialized areas to snatch a fish carry out different functions. Animals pulling water and food into from the waters have specialized cells that enable Feeding their bodies. Career Issue of a lake or stream. them to sense and seek out food and Movement 3. Students won’t see individual The citizens of the United States mates, and allow them to identify and Size in mm cells, so they infer that the live on land, not in the ocean. Ask protect themselves from predators. In B A sidewinder rotifers are multicellular. students why our federal govern- B the human body, nerve cells conduct Analysis rattlesnake barely 1. Are these organisms autotrophs or heterotrophs? ment should spend our tax money touches the ground information and red blood cells trans- 2. Were you able to see evidence of feeding? Explain. on marine biologists. as it follows the port oxygen. Observe the tiny animals Assessment trail of a mouse. in the MiniLab. Can you identify any 3. Are rotifers multicellular? Explain. For More Information Knowledge Ask students specialized cells in these animals? For more information on marine to find references regarding the biology, students can write to: classification and anatomy of 694 695 American Society of Limnology WHAT IS AN ANIMAL? 25.1 TYPICAL ANIMAL CHARACTERISTICS rotifers and to write a report on and Oceanography their classification. Use the Virginia Institute of Marine Performance Task Assessment Science PROJECT Cultural Diversity List for Writing in Science in PASC, p. 87. L2 College of William and Mary What do Daphnia eat? determine which cultures seem to be the Animals in a Cross-Cultural all cultures view animals in this way. For Route 1208 Kinesthetic Ask students to maintain most healthy (as measured by activity). Ask Perspective example, Native American traditions often Gloucester Point, VA 23062 Daphnia cultures for two weeks. Each them to write a report of their experimental Discuss the diverse views different societies portray animals as important as or even culture should have ten Daphnia. Have stu- designs, observations, and conclusions and and cultures have about the place of animals more important than humans. Obtain books dents choose different food materials to test. include this report in their portfolios. in nature. Begin your discussion by asking about the legends and myths of different For example, one group might use cooked Daphnia should be released underwater. If students how animals are viewed and used cultures, and discuss with students the role egg white, another might use wheat grain, poured from the container, air becomes P in the United States. Next, point out that not of animals in these stories. P and a third might use live protozoans. At the trapped under their exoskeletons and they 694 end of the two-week period, students should die. L3 P 695

LS LS LS P

LS Building a Model Development Fertilization illustrated in Figure 25.4. First, the Problem-Solving Lab 25-1 Kinesthetic Give students P of Animals Most animals reproduce sexually. clay is formed into a solid ball. Then, Male animals produce sperm and the potter presses in on the top of the salt dough that you have Purpose Most animals develop from a sin- Figure 25.4 female animals produce eggs. ball to form a cavity that becomes the You can think prepared (one part salt, one part Students will determine that gle, fertilized egg cell called a zygote. Fertilization occurs when a sperm interior of the bowl. In the same way, of a blastula as flour, one part water). Have them cytoplasmLS differences can influ- But how does a zygote develop into penetrates the egg, forming a unicel- the cells at one end of the blastula a hollow ball cover a space on their desktops ence development in frogs. the many different kinds of cells that lular zygote. In animals, fertilization fold inward, forming a cavity lined of cells. By with a few paper towels and dip make up a snail, a fish, or a human? with a second layer of cells. The layer pushing in on their fingers into flour so that the may be internal or external. one side, a gas- Process Skills After fertilization, the zygotes of dif- of cells on the outer surface of the dough will not stick to them. Ask ferent species of animals all have sim- trula is formed. interpret scientific diagrams, Cell division gastrula is called the ectoderm.The students to make models of a fer- compare and contrast, draw a con- ilar stages of development. layer of cells lining the inner surface tilized egg, a blastula, and a gas- The unicellular zygote divides by is called the endoderm.The ecto- clusion, think critically, predict mitosis to form two new cells in a trula. They should make cross derm cells of the gastrula continue to sections of the stages in sequence, process called cleavage. Find out how grow and divide, and eventually they Teaching Strategies with one stage turning into the Interpreting Scientific important this first cell division is in develop into the skin and nervous tis- Explain to students that the Problem-Solving Lab 25-1 Diagrams next stage, rather than lining up frog development by studying the sue of the animal. The endoderm normal pattern for cell division Problem-Solving Lab. Once cell division cells develop into the lining of the all three stages at once. They will occurs as shown on the left in the How important is has begun, the organism is known as have to add more dough to show the first cell animal’s digestive tract and into diagram. The last phase shown in Gray an embryo. Recall that an embryo is organs associated with digestion. that the fertilized egg becomes division in frog crescent an organism at an early stage of both diagrams shows the larval development? larger; but after that time, dough stage of frog development. During development, growth and development. The two Formation of mesoderm should not be added because the a fertilized egg cell cells that result from cleavage then In some animals, the development total amount of cytoplasm does Thinking Critically P divides into two cells divide to form four cells and so on, of the gastrula progresses until a not increase as the early embryo by the process of 1st 1. until a hollow ball of cells called a layer of cells called the mesoderm is When the gray crescent is mitosis. The first divi- cleavage develops. L1 ELL present, normal development blastula (BLAS chuh luh) is formed. formed. Mesoderm is found in the sion of a cell some- In some animals, such as a lancelet, occurs. If the gray crescent is times results in two middle of the embryo; the term meso cells with an unequal the blastula is a single layer of cells means “middle.” The mesoderm LS not present, development surrounding a fluid-filled space. In P does not occur. amount of cytoplasm. (MEZ uh durm) is the third cell layer 3 Assess Does the amount of other animals, such as frogs, there found in the developing embryo uh stohm) is an animal in which the 2. The first cell division in cytoplasm in each cell may be several layers of cells sur- between the ectoderm and the endo- mouth develops from cells elsewhere Check for Understanding development is critical for after the first division Dies rounding the space. The blastula is derm. The mesoderm cells develop on the blastula. WORD Origin normal embryo development. have any impact on formed early in the development of Intrapersonal Give students the development of into the muscles, circulatory system, Scientists hypothesize that proto- protostome a live insect.LS Ask them to list 3. Neither cell would continue an organism? It does an animal embryo. In sea urchin stome animals were the first to From the Greek excretory system, and, in some ani- the characteristicsP that show that the to develop into an embryo. in frogs. development, for example, the for- mals, the respiratory system. How appear in evolutionary history, and words proto, meaning “before,” and insect is an animal. Remind them mation of a blastula is complete does the mesoderm form? You can that deuterostomes followed at a later Analysis stoma, meaning L2 about ten hours after fertilization. In find out by reading the Inside Story time. Biologists today often classify to treat live animals gently. In a frog cell, a small section of colored cytoplasm forms humans, the blastula forms about five “mouth.” Assessment just after fertilization. This area is called the gray crescent. on the next page. an unknown organism by identifying deuterostome LS Note its appearance in the diagram. Follow the changes in days after fertilization. In some classes of animals, the its phylogeny. Recall that phylogeny Reteach Performance Have stu- From the Greek development as the first division of cytoplasm occurs equally dents use a stereomicroscope or opening of the indented space in the is the evolutionary history of an words deutero, Kinesthetic Make clay mod- through the gray crescent and unequally through the gray Gastrulation gastrula becomes the mouth. These organism. Determining whether an meaning “sec- hand lens to examine preserved crescent. els of stages of development. frog eggs. Have them diagram After blastula formation, cell divi- animals, which include earthworms animal is a protostome or deuteros- ondary,” and stoma, Ask students working in groups meaning “mouth.” what they observe and label the Thinking Critically sion continues. The cells on one side and insects, are called protostomes. A tome can help biologists identify its to place the models in sequence of the blastula then fold inward to protostome (PROHT uh stohm) is an group. Even though sea urchins, for P gray crescent. (Note: Preserved 1. Explain how each set of diagrams illustrates the role of A protostome and and describe what happens in the gray crescent in early frog development. form a gastrula. The gastrula (GAS animal with a mouth that develops example, are invertebrates and fishes a deuterostome frog eggs are available from bio- each stage. L1 ELL 2. Answer the question posed at the beginning of this lab. truh luh) is a structure made up of from the opening in the gastrula. are vertebrates, both are deuteros- differ in the loca- logical supply houses.) Use the 3. Predict the effect on frog development if the first division two layers of cells with an opening at In other animals, such as fishes, tomes and are, therefore, more tion of the cells that become the organ- Performance Task Assessment occurred on the horizontal plane rather than on the one end. Gastrula formation can be birds, and humans, the opening of closely related than you might con- Extension ism’s mouth. LS List for Scientific Drawing in vertical plane. compared to the way a potter creates the gastrula does not develop into a clude from comparing their adult Encourage studentsP to visit a sci- PASC, p. 55. L1 ELL a cup or bowl from a lump of clay, mouth. A deuterostome (DEW tihr body structures. ence museum that has displays about development. Have them 696 WHAT IS AN ANIMAL? 25.1 TYPICAL ANIMAL CHARACTERISTICS 697 make a photo essay of the exhibit ResourceResourceP that can be displayedLS in class. ManagerManager Have studentsP include captions BIOLOGYIOLOGY JOURNAL PortfolioPortfolio for the photos. L2 ELL BioLab and MiniLab Work- Linguistic Have students work in sheets, p. 113LS L2 Demonstrating Development and parts that develop from mesoderm red. Basic Concepts Transparency Naturalist Provide students with dia- Provide them the following information: Spina Bifida pairs to look up words in the dictio- Assessment P nary that begin with the prefixes ecto- LS P 44 and Master L2 ELL grams of the human body showing ectoderm produces brain, spinal cord, nerves, Portfolio Have students Linguistic Ask students to interview and endo-. Ask students to make a list of Laboratory Manual, bone, muscle, spinal cord, brain, kidneys, outer skin, eye lens, nose, and ears. Endo- summarize the development of a a doctor about spina bifida. Ask stu- the words. Have students exchange lists pp. 179-182 L2 liver, lungs, and pancreas. Give them colored derm produces pancreas, liver, lungs, and sea urchin egg from fertilization dents to write a report of their findings and write their own definitions of the P pencils and have them shade parts of the lining of the digestive system. Mesoderm to the planula stage.P Have them LS P and to prepare diagrams that show normal words. Then ask each student to compare LS body that develop from ectoderm yellow, produces skeleton, muscles, excretory system, P include this summary in their P and abnormal stages of development. L3 actual definitions with their own defini- parts that develop from endoderm green, inner skin. L1 ELL P P COOP LEARN portfolios. L2 P 696 tions. L2 ELL P COOP LEARN 697 P LS P LS LS LS P P P LS LS P LS P LS LS LS LS LS LS P LS P LS P LS

LS LS LS a Figure 25.5 NSIDE NSIDE Free-swimming larvae develop 4 Close NSIDE NSIDE II II Magnification: 258 from fertilized sea urchin eggs STORY STORY in just 48 hours (a). The larvae Activity P will develop into adult sea urchins over the next Linguistic Ask students to Purpose Early Animal Development few months (b). write a note to a friend Students study the stages of early explaining what they do and do embryonicLS development. he fertilized eggs of most animals follow a similar not understand about develop- Tpattern of early development. From a single cell, many ment. Have them exchange notes Teaching Strategies divisions occur until a hollow ball of cells forms. The hollow and help each other with areas of Ask students to study the dia- ball folds inward and continues to develop. difﬁculty. L1 grams, then write a numbered list Critical Thinking How do cells change as an embryo develops? describing the developmental The BioLab at the stages shown. They can use the Sea urchin blastula end of the chapter INTERNET list as a study guide. Magnification: 1200 can be used at this 1 Fertilization A zygote b 1 point in the lesson. Visual Learning is formed when an egg is fertilized by a sperm. Continued growth and through this fertilization membrane. Have students describe the development Animals that are generally sessile as changes in appearance at each Cells in developing embryos con- adults, such as sea urchins, often have P stage of development. L1 2 First cell division tinue to change shape and become a free-swimming larval stage, shown The zygote divides CD-ROM by mitosis to form specialized to perform different func- in Figure 25.5. You can observe Critical Thinking 6 Formation of mesoderm In proto- View an ani- 6 two cells. From this tions. Most animal embryos continue development in fishes in the BioLab CD-ROM Cells continue to divide, becom- stomes, the mesoderm forms from mation of embryo point, the developing to develop over time, becoming juve- at the end of this chapter. Biology: The Dynamics ing smaller and smaller with each cells that break away from the organism is called an development in the LS endoderm near the opening of niles that look like smaller versions of Presentation Builder of Life cell division. Endoderm embryo. Forming an adult animal the gastrula. In deuterostomes, the adult animal. In some animals, of the Interactive Video Selections: Fetal CD-ROM. the mesoderm forms from such as insects and echinoderms, the Once the juvenile or larval stage has Development Disc 5 pouches of endoderm cells on embryo develops into an intermedi- passed, most animals continue to grow the inside of the gastrula. ate stage called a larva (pl. larvae) and develop into adults. This growth VIDEODISC P After the formation of mesoderm, development that often bears little resemblance to and development may take just a few The Inﬁnite Voyage continues with each the adult animal. In these animals the days in some insects, or up to fourteen The Geometry of Life VIDEODISC cell layer forming 3 Further cell larva is still surrounded by a mem- years in some mammals. Eventually Development of the Egg after Biology: The Dynamics specialized tissues. division brane formed right after fertilization. the adult animals reach sexual matu- Cell division Fertilization (Ch. 3) of Life LS Ectoderm Mesoderm continues. The When the larva hatches, it breaks rity, mate, and the cycle begins again. 3 min. 30 sec. Disc 1, Side 2, 1 min. 10 sec. eight-cell stage !7ALD" Embryo Development (Ch. 30) is shown here. Section Assessment !:,Å" Understanding Main Ideas Thinking Critically CD-ROM 1. Describe the characteristics that make a 5. Name a land animal that is sessile. Why would mouse an animal. being sessile be a disadvantage to an animal that ResourceResource Biology: The Dynamics 2. Explain why movement is an important lives on land? ManagerManager of Life characteristic of animals. SKILL REVIEWEVIEW Animation: Embryo 4 Formation of a blastula 3. Explain the difference between a protostome Reinforcement and Study Development Disc 4 Continuous cell division results and a deuterostome. 6. Sequencing Place the following words in Guide, pp. 111-112 L2 5 Gastrulation As the embryo continues in a fluid-filled ball of cells, the 4. Compare and contrast planarian and earthworm sequence, beginning with the earliest stage: Reteaching Skills Trans- VIDEODISC digestive tracts. gastrula, larva, adult, fertilized egg, blastula. to grow, some of the cells of the blastula blastula. Notice that during these parency 38 and Master The Secret of Life fold inward, forming the gastrula. All early developmental stages, the For more help, refer to Organizing Information in the Skill Handbook. Dividing cells, early animal embryos except sponges pass total amount of cytoplasm has L1 ELL through this gastrula stage. Critical Thinking/Problem embryo not increased. Solving, p. 25 L3 Content Mastery, p. 126 698 WHAT IS AN ANIMAL? 25.1 TYPICAL ANIMAL CHARACTERISTICS 699 P L1 !7PT'n$E" P

MEETING INDIVIDUAL NEEDS Section Assessment LS P Visually Impaired while pushing in on one side of the ball with 1. It is a multicellular heterotroph that deuterostomes, the mouth develops carried to all body cells by the circula-LS P Kinesthetic Obtain several old tennis their thumbs. Explain that now the balls rep- uses food for energy. It moves to get elsewhere on the gastrula. tory system, and wastes are expelled balls or other type of hollow rubber resent the gastrula stage. Ask students to use food and its cells do not have cell walls. 4. In planarians, food is sucked in through through the anus. balls. Have visually impaired students handle their free hand to point to the parts of the 2. Animals do not make their own food, the pharynx and ground up by move- 5. Students will probably not be able to P LS P the balls and explain that the blastula ball that represent ectoderm and endoderm. but depend upon other organisms for ment; digestion occurs by phagocytosis name a land animal that is sessile. All appears just like the hollow balls. Then have L1 ELL food. They must search for food, so in individual cells. In an earthworm, animals on landLS must move to obtain these students hold the ball in one hand movement is necessary for survival. food is taken in by the mouth, ground food. LS 3. In protostomes the mouth develops up in the gizzard, and moves through 6. fertilized egg, blastula, gastrula, larva,LS 698 P from the opening in the gastrula. In the rest of the digestive system. Food is adult 699

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LS SECTION PREVIEW Section 25.2 2 Teach Objectives Section Compare and Dorsal contrast radial and Quick Demo bilateral symmetry with 25.2 Body Plans and asymmetry. Prepare Anterior Bring in kitchen items such as Trace the phylogeny Adaptations bowls, vases, and a variety of Key Concepts of animal body plans. Compare body plans spoons. Explain that each item Students compare and contrast of acoelomate, bjects made by a potter can be many is suited to a particular func- pseudocoelomate, and types of symmetry and study coelomate animals. different shapes and sizes. There Ventral tion. For example, the bowls basic body plans of animals. Ois a plan for making each type hold soft or liquid foods, the Vocabulary Posterior symmetry of pottery. One plan results in a bowl, spoons pick up or stir soft or Planning radial symmetry another in a vase, and still another in a liquid foods, and the vases hold bilateral symmetry flat plate. Each piece of pottery is suited Collect a variety of kitchen anterior flowers for display. Explain items that display different posterior for a particular function. Animals’ bodies that, in a similar way, animals dorsal also have plans—body shapes that are suited types of symmetry for the have structures that are suited ventral to a particular way of life. In this section, Quick Demo. acoelomate to specific functions such as you will study a variety of animal body Gather dried marine sponges, pseudocoelom locomotion, food-getting, and coelom plans and see how a specific body structure is P a preserved jellyfish, and live exoskeleton circulating materials through- adapted to life in a particular environment. goldfish in clear plastic con- endoskeleton out their bodies. invertebrate tainers for the Quick Demo. A This irregularly shaped sponge B An example of an animal with C In bilaterally symmetrical vertebrate is an example of an animal with radial symmetry, a hydra feeds animals, such as butterflies, an asymmetrical body plan. on tiny animals it immobilizes sensory tissue is commonly LS organism. All animals have some kind with venomous stinging cells concentrated in the head, or What Is Symmetry? found along its tentacles. anterior, end. Quick Demo of symmetry. Different kinds of sym- 1 Focus Look at the animals shown in metry enable animals to move about Pass around the dried bodies of Figure 25.6. You know that all ani- Bellringer in different ways. about once they have reached the mouth. As you can see, animals with Figure 25.7 marine sponges, a live goldfish mals share certain characteristics, but adult stage. radial symmetry (RAYD ee uhl) can All animals have a Before presenting this lesson, Asymmetry in a sponge in a clear plastic container, and these animals don’t look like they have The bodies of most sponges con- be divided along any plane, through a kind of symmetry that enables them a large preserved jellyfish. Ask display Section Focus Trans- much in common. The sponge seems Many sponges have an irregularly sist of two layers of cells. Unlike all central axis, into roughly equal to survive in their students to describe the shapes parency 62 on the overhead pro- to have no particular shape, whereas shaped body, as seen in Figure 25.7A. other animals, a sponge’s embryonic halves. Radial symmetry is an adapta- surroundings. of the animals and explain if jector and have students answer the fish has a head, body, and several An animal that is irregular in shape development does not include the tion in hydra that enables the animal one side of the animal is the accompanying questions. pairs of fins. The jellyfish doesn’t have has an asymmetrical body plan. formation of an endoderm and meso- to detect and capture prey coming L1 ELL a head or tail, and is circular in form. Animals with no symmetry often are equally balanced by the other. Figure 25.6 derm, or a gastrula stage. Fossil toward it from any direction. Each animal can be described in terms sessile organisms that do not move marine sponge, no; live gold- A sponge (a), a fish sponges first appeared in rocks dating Have you ever had your groceries (b), and a jellyfish (c) of symmetry according to its shape. from place to place. back to more than 700 million years double bagged at the store? The body fish, yes; preserved jellyfish, yes. all exhibit different Symmetry (SIH muh tree) refers to a Most sponges Explain to students that the Body Plans ago. They represent one of the oldest plan of a hydra can be compared to a TransparencyP 62 SECTION FOCUS P and Adaptations Use with Chapter 25, kinds of symmetry. balance in proportions of an object or do not move Section 25.2 groups of animals on Earth—evidence sack within a sack. These sacks are quality they have just observed Group A is called symmetry. L1 ab c that their two-layer body plan makes cell layers organized into tissues with them well adapted for life in aquatic distinct functions. A hydra develops environments. from just two embryonic cell layers— LS ectoderm and endoderm. LS Group B P Radial symmetry in a hydra A hydra, a tiny predator pictured Bilateral symmetry in Figure 25.7B, feeds on small ani- The butterfly in Figure 25.7C has mals it snares with its tentacles. A bilateral symmetry. An organism with Group C VIDEODISC hydra has radial symmetry. Its tenta- bilateral symmetry (bi LAT uh rul) LS The Secret of Life cles radiate out from around its can be divided down its length into P Evolution of symmetry

2 How is the shape of each organism suited to the environment !7;EVE" in which it lives? CD-ROM LS BIOLOGY: The Dynamics of Life SECTION FOCUS TRANSPARENCIES BIOLOGYIOLOGY JOURNAL Resource Manager Internet Address Book Biology: The Dynamics of Life Symmetry in Objects Note Internet addresses that you ﬁnd useful in the space Exploration: Symmetry Disc 4 Concept Mapping, p. 25 L3 ELL Visual-Spatial Divide the class into below for quick reference. Section Focus Transparency 62 and groups. Have each group list in their Master L1 ELL journals as many items with radial symme- P try as they can ﬁnd in the classroom within a given time period. Repeat the activity P P P with asymmetrical and bilaterally symmetrical objects. L1 COOP LEARN 700 701 LS P LS LS LS P LS

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LS Animals with bilateral symmetry Pseudocoelomates have MiniLab 25-2 Problem-Solving Lab 25-2 Magnification: 292 P can find food and mates and avoid a body cavity Observing P Problem-Solving Lab 25-2 Classifying MiniLab 25-2 and Inferring predators because they have sensory A roundworm is another animal Purpose Purpose organs and good muscular control. Is symmetry associated with other animal traits? that has bilateral symmetry. However, Check Out a Vinegar Eel Vinegar Students observe the pattern and Students identify the type of Animals show different patterns in their symmetry. Symmetry Test your ability to identify animal unlike the solid body of a flatworm, eels are roundworms with pseudo- speed of locomotionLS of vinegar symmetry LSin three animals. patterns are often associated with certain other characteris- symmetry in the Problem-Solving Lab. the body of a roundworm has a body coeloms. They exhibit an interesting eels and relate these patterns to a tics or traits found in the animal. cavity that develops between the pattern of locomotion because they pseudocoelomate body plan. Process Skills endoderm and mesoderm. This body have only longitudinal (lengthwise) Analysis muscles. Process Skills classify, observe and infer, com- Study these three animal diagrams. Determine the type Bilateral Symmetry cavity is called a pseudocoelom. A collect data, observe and infer, pare and contrast, think critically of symmetry being shown. and Body Plans pseudocoelom (SEWD uh see lum) is Procedure Vinegar eel a fluid-filled body cavity partly lined predict Animals that are bilaterally sym- ! Prepare a wet mount of vinegar eels. CAUTION: Use Teaching Strategies A B C with mesoderm. metrical also share other important caution when working with a microscope and slides. Teaching Strategies The pseudocoelom enables ani- Review the three types of sym- characteristics. All bilaterally symmet- @ Observe them under low-power magnification. Vinegar eels, Turbatrix aceti, mals, such as roundworms, to move metry present in animals. rical animals developed from three # Note their pattern of locomotion. Prepare a are classified as roundworms, quickly. How does this work? Think series of diagrams that illustrate their pattern of embryonic cell layers—ectoderm, phylum Nematoda. Thinking Critically about the way your muscles work. movement. endoderm, and mesoderm. Some The muscles in your arm lift your $ Time how fast they move by timing in seconds how long it Use depression slides when 1. bilateral—body can be bilaterally symmetrical animals also hand by pulling against your arm takes for one roundworm to move across the center of your making wet mounts or add a few divided along its length into have fluid-filled spaces called body field of view. Find out the diameter of your low-power field bones. If there were no rigid bones in bristles from an old toothbrush two equal halves Thinking Critically cavities inside their bodies in which in mm. Calculate vinegar eel speed in mm/sec. You may your arms, your muscles would not to a regular slide to prevent 1. Animal A shows what type of symmetry? Explain your internal organs are found. The devel- want to time several animals and average their speed. 2. head and tail regions present, be able to do any work. Although the crushing the roundworms. answer. opment of body cavities made it pos- body cavity present, good roundworm has no bones, it does Review the meaning of “field 2. Describe other traits associated with animal A. sible for animals to grow larger and Analysis muscular control have a rigid, fluid-filled space, the of view.” Remind students that in 3. Name some objects other than animals that show the to develop organs and organ systems, 1. Name the type of symmetry present in vinegar eels. A pattern of symmetry. pseudocoelom, which is partly sur- order to correctly judge speed of 3. pencil, pen, doll such as digestive systems. 2. Describe the pattern of locomotion for vinegar eels. 4. asymmetry—body is irregular 4. Animal B shows what type of symmetry? Explain your rounded by mesoderm. Its muscles 3. How does the pseudocoelom aid vinegar eels in these worms, they must time the answer. attach to the mesoderm and brace locomotion? animal as it moves across the 5. does not move about, body Acoelomate flatworms have no 5. Describe other traits associated with animal B. against the pseudocoelom. You can 4. What is the speed of locomotion for a vinegar eel? Based diameter of their field of view. consists of two cell layers body cavities 6. Name some objects other than animals that show the observe movement in a pseudo- on the speed of your vinegar eel, predict the speed in Remind students to treat live B pattern of symmetry. Flatworms are bilaterally symmet- mm/sec for a flatworm. Explain your answer. 6. blob of clay, cottage cheese coelomate animal in the MiniLab on animals gently. 7. radial—body can be divided 7. Animal C shows what type of symmetry? Explain your rical animals with solid, compact this page. answer. along any plane through a bodies, as shown in Figure 25.8. Expected Results 8. Describe other traits associated with animal C. Animals that have three cell layers— Figure 25.8 Acoelomate Pseudocoelomate Coelomate Students will observe the move- central axis into equal halves 9. Name some objects other than animals that show the ectoderm, endoderm, and meso- Animals with acoelo- Flatworm Roundworm Segmented Worm ment of vinegar eels as a series of 8. tentacles radiate from mouth, C pattern of symmetry. derm—but no body cavities are mate bodies usually jerking contractions. The speed tissues present called acoelomate (ay SEE lum ate) have a thin, some- of these animals will be in the what flattened shape 9. wheel with spokes, open animals. Acoelomate animals may range of 2 to 5 mm/second. umbrella, apple corer similar right and left halves that form have been the first group of animals (a). Pseudocoelomate mirror images of one another. in which organs evolved from cells of animals are larger Analysis and thicker in body Bilaterally symmetrical animals can the mesoderm. Like other acoelo- shape than their Pseudocoelom Coelom 1. bilateral symmetry Assessment be divided only along one plane mate animals, the organs of flat- acoelomate ancestors 2. series of jerky contractions Skill Have students pre- to form equal halves, in contrast to worms are embedded in the solid (b). The coelom 3. The body cavity is filled with provides a space ab c pare a concept map that uses the radially symmetrical animals that can tissues of their bodies. Although fluid. Body muscles can brace be divided along any plane. In bilat- for complex following terms: sponge, hydra, acoelomate animals have no body and contract against this fluid. eral animals, the anterior, or head cavities, they do have a digestive tract internal flatworm, roundworm, earth- organs (c). 4. The speed will range between end, often has sensory organs. The that extends throughout the body. A worm, radial symmetry, bilateral 2 and 5 mm/sec. The speed posterior of these animals is the tail flattened body and a digestive tract of a flatworm will be slower symmetry, asymmetry, pseudo- end. The dorsal (DOR sul), or back allow for the diffusion of nutrients, due to the fact that flatworms coelomate, coelomate, acoelo- surface, also looks different from the water, and oxygen to supply all body have no body cavity. A mate. Use the Performance ventral (VEN trul), or belly surface. cells and to eliminate wastes. Ectoderm Mesoderm Endoderm Body cavity Digestive tract Task Assessment List for Concept pseudocoelom allows more efficient muscle contraction. Map in PASC, p. 89. L2 702 WHAT IS AN ANIMAL? 25.2 BODY PLANS AND ADAPTATIONS 703

Assessment Alternative Lab Materials animal. Also label the drawings with 3. If you were to observe these animals’ Assessment Assessment microscope, prepared slides of cross sec- the names of organisms. movements, predict what you might Portfolio Have students Portfolio Ask students to sum- tions of hydra, planarian, nematode, earth- see. Explain in terms of their body study vinegar eels under low- and Body PlansP Analysis marize what they have learned about worm plans. Students’ descriptions should high-power magnification. Have 1. Order the animals’ body plans from body plans in this lab. Have them con- Purpose P match those given in the chapter. them diagram and label body Procedure least to most complex. hydra, pla- sider the survival value of each type of Students examine prepared slides of cross structures they observe. Use the Give students the following directions. narian, nematode, earthworm body plan. Instruct them to put their sections of a hydra, ﬂatworm, roundworm, Performance Task Assessment LS 1. Examine the cross-section slides. 2. In what way is each animal’s body plan summaries in their portfolios. Use the and earthworm to determine if the animals List for Scientific Drawing in 2. Sketch and label each cross section an adaptation to its environment? Performance Task Assessment List for are acoelomate, pseudocoelomate, or PASC, p. 55. L1 ELL P LS with the following labels: animal with Hydra and planarians are adapted to Writing in Science in PASC, p. 87. L2 coelomate. two cell layers, pseudocoelomate ani- movement in water. Nematodes and 702 mal, acoelomate animal, coelomate earthworms are adapted to life in soil. 703 P LS

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LS LS Reinforcement Animal Protection Figure 25.10 Assessment Show students a live planarian in Invertebrate animals such as an octopus and Support (a) and a sea slug (b) have no backbones. Portfolio Ask students a deep-well projection slide Vertebrates with backbones include a During the course of evolution, as to each remember from child- (available from biological supply monkey (c) and a flamingo (d). hood their favorite stuffed animal. companies). Fill the well with development of body cavities resulted c in a greater diversity of animal species, Have them make a sketch of it, pond or stream water. Use an describe its symmetry, and its overhead projector to project the many animals became adapted to life in different environments. Some ani- basic body plan. They should swimming planarian onto a mals, such as mollusks, evolved hard include this report in their portfo- screen. Next, place a small earth- shells that protected their soft bodies. lios. L1 ELL P worm in a wet petri dish with a Other animals, such as sponges, few small pebbles. Project it with evolved hardened spicules between your overhead projector. Ask stu- their cells that provided support. a dents to relate the movements of P P Some phyla of animals developed d 4 Close both animals to their body plans. LS exoskeletons. An exoskeleton is a A vertebrate hard, waxy covering on the outside of (VURT uh brayt) is Discussion the body that provides a framework an animal with a Have studentsLS examine the phy- LS for support, shown in Figure 25.9. backbone. All verte- logenetic diagram in Chapter 14. Exoskeletons also protect soft body brates are bilaterally Ask themP to discuss the evolu- Figure 25.9 Pseudocoelomate animals have a b tissues, prevent water loss, and pro- symmetrical animals that tionary trends of symmetry, cell The exoskeleton of complete, one-way digestive tract vide protection. Exoskeletons are have endoskeletons. Examples layers, and patterns of develop- VIDEODISC this crab has been with organs that have specific func- secreted by the epidermis and extend shed in order for of vertebrates include fishes, birds, of the Cambrian period. The Secret of Life tions. The mouth takes in food, the into the body, where they provide a ment of the animal groups shown the crab to grow. reptiles, amphibians, and mammals, Although it may seem that on theLS diagram. Flatworm cross section A new exoskeleton middle section breaks it down and place for muscle attachment. including humans. Figure 25.10 bilaterally symmetrical forms in a few absorbs nutrients, and the anus expels Other phyla of animals have shows examples of invertebrate and animals appeared much hours to provide wastes. evolved different structures for sup- vertebrate animals. later, all the major animal !7;EtH" protection again. port and protection. Sea urchins and ResourceResource The coelom provides space body plans that exist today Manager sea stars, for example, have an inter- were already in existence Manager for internal organs nal skeleton that is covered by layers Origins of Animals 545 million years ago. Reinforcement and Study The body cavity of an earthworm of cells. An endoskeleton is an Where did animals come from? Since then, many new Guide, pp. 113-114 L2 develops from a coelom (SEE lum), a internal skeleton that provides sup- Most biologists agree that the animal species have evolved. All 3 Assess Content Mastery, pp. 125, fluid-filled space that is completely port inside an animal’s body. An kingdom probably evolved from colo- new species appear to be variations WORD Origin surrounded by mesoderm. endoskeleton may be made of cal- 127-128 L1 Check for Understanding nial protists. Scientists trace this evo- on the animal body plans that devel- coelom Humans, insects, fishes, and many cium carbonate, as in echinoderms; lution back in time to the beginning oped during the Cambrian period. Naturalist Ask students to From the Greek other animals have a coelomate body cartilage, as in sharks; or bone. Bony make a table describing the word koiloma, plan. The greatest diversity of ani- fishes, amphibians, reptiles, birds, meaning “cavity.” mals is found among the coelomates. and mammals all have endoskeletons features of the three basic body A coelom is a body Section Assessment plans. L2 cavity completely The coelom provides space for the made of bone. The endoskeleton P surrounded by development of specialized organs protects internal organs and provides Understanding Main Ideas Thinking Critically Reteach mesoderm. and organ systems. In coelomate ani- an internal brace for muscles to pull 1. Explain the difference between radial and 5. Explain how having a coelom enables an animal mals, the digestive tract and other against. bilateral symmetry in animals, and give an to have complex organ systems. Visual-Spatial Give students internal organs are attached by dou- Exoskeletons are often found in example of each type. P SKILL REVIEWEVIEW LS a variety of kitchen utensils ble layers of mesoderm and are sus- invertebrates. An invertebrate is an 2. Compare the body plans of acoelomate and and ask them to describe what coelomate animals. Give an example of an 6. Making and Using Tables Construct a table pended within the coelom. Like the animal that does not have a back- animal with each type of body plan. that compares the body plans of the sponge, type of symmetry each has. L1 pseudocoelom, the coelom cushions bone. Many invertebrates, such as P 3. Explain how an adaptation such as an exoskele- hydra, flatworm, roundworm, and earthworm. ELL and protects the internal organs and crabs, spiders, grasshoppers, dragon- ton could be an advantage to land animals. For more help, refer to Organizing Information LS provides room for them to grow and flies, and beetles, have exoskeletons. 4. Compare movement in acoelomate and in the Skill Handbook. Extension move independently within an ani- Echinoderms are examples of inver- coelomate animals. mal’s body. tebrates that have endoskeletons. P Visual-SpatialLS Ask a group of students to collect speci- 704 705 mens from a freshwater pond. WHAT IS AN ANIMAL? 25.2 BODY PLANS AND ADAPTATIONS Have them make drawings of the specimensLS and demonstrate theirP PortfolioPortfolio body plans and symmetry to the Resource Manager Section Assessment class. L3 ELL Coelom Development 1. Animals with radial symmetry, such as cavity. Animals with coelomate bod- can brace their muscles against the Linguistic Have students write an BioLab and MiniLab Worksheets, the hydra, can be divided along any ies, such as an earthworm, have a coelom, thereby giving them more LS account of the evolutionary devel- p. 114 L2 plane into equal halves. Animals with coelom in which internal organs are powerful movements. P opment of the coelom. They should ﬁrst Laboratory Manual, pp. 183-186 L2 bilateral symmetry, such as the flat- suspended within the coelom. 5. The coelom provides space for special- determine the time period, explain how worm, can be divided only along one 3. An exoskeleton prevents water loss ized organs and organ systems. P the coelom developed, identify animals P plane to form two equal halves. from body organs and supports an 6. Make sure students’ tables indicate with coeloms, and explain how the 2. Animals with acoelomate bodies, such animal’s body on land. cell layers, and presence of a coelom, LS coelom has survival value. L3 P as a ﬂatworm, have three cell layers 4. Acoelomate animals have no body a pseudocoelom, or no body cavity. 704 with a digestive tract but no body cavity, whereas coelomate animals 705 LS P LS P LS P LS LS

LS NTERNET INTERNET IN T INTERNET Zebra Fish 7. Go to the Glencoe Science Web Development Site as shown in the Sharing Your Data box below to post your data. P 8. Continue to observe your embryos he zebra fish (Danio rerio) is a common fresh- daily for a minimum of one week. Time Allotment T water fish sold in pet shops. They are ideal Note the appearance of new organs AANALYZENALYZE ANDAND CCONCLUDEONCLUDE 30 minutes on day 1, 15 minutes animals for study because they undergo developmental and when movement is first seen. on days 2 throughLS 5 If you wish to continue watching 1. They are inexpensive, easy to changes quickly and major stages can be observed within developmental changes, consult Process Skills hours after fertilization. care for, form many embryos, with your teacher for directions. and show rapid development. interpret scientific illustrations, CAUTION: Wash your hands 2. The early stages occur observe and infer, organize data, with soap and water immediately rapidly after fertilization. sequence, experiment PPREPARATIONREPARATION after completing observations. 3. Students could reset the PPREPARATIONREPARATION Problem Materials Data Table timer, or use embryos that were collected and preserved What do the developmental stages aquarium Date hpf Diagram Observations Zebra fish are available from of the zebra fish look like? zebra fish by an earlier class. pet shops or biological supply turkey baster 4. For questions a-c, student Objectives houses. Purchase six of each beaker answers should agree with the In this BioLab, you will: dropper information in Data and sex. Fish must be young Observe stages of zebra fish devel- (between 6 and 24 months petri dish Observations. Encourage stu- opment. binocular old). Remind students to treat dents to print out Internet Record all observations in a data microscope live animals gently. diagrams and include them in table. wax pencil or labels Prepare an aquarium with fil- Use the Internet to collect and com- their answers to this question. ter, lights, timer, and heater. pare data from other students. Safety Precautions ANALYZENALYZE ANDAND CONCLUDEONCLUDE Marbles should be placed Always wear safety goggles in the A C Skill Handbook Assessment along the bottom. Embryos lab. Use caution when working with a 1. Communicating Explain why b. between 10 and 28 hpf. Include will fall between the marbles. Use the Skill Handbook if you need binocular microscope and glassware. Portfolio Ask students to additional help with this lab. zebra fish are ideal animals for labeled diagrams. Set timer and lights as follows: studying embryonic development. c. between 28 and 72 hpf. Include prepare a report of their findings 14 hours light to 10 hours 2. Thinking Critically Explain why labeled diagrams. using their own data and diagrams dark. Set the heater at 28.5ºC. PPROCEDUREROCEDURE you may not have been able to see as well as the diagrams available Feed fish flakes in the morning stages such as a blastula or gastrula. from their Internet sources. Use and brine shrimp or live blood 3. Thinking Critically the Performance Task Assessment 1. Copy the data table. 5. Your teacher will advise you Suggest how Sharing Your Data worms in the afternoon. 2. Using the turkey baster, draw as to the approximate time you could change the experi- List for Writing in Science in up water containing zebra fish that fertilization took place. All ment’s design to allow for observ- Find this BioLab as well PASC, p. 87. L2 P embryos from the bottom of the ages should be reported in your ing these stages. as links to sites with aquarium. data table as hpf (hours past 4. Using the Internet Visit the diagrams of zebra fish development on 3. Release the water into a beaker fertilization). Glencoe Science Web Site for links the Glencoe Science Web Site at Sharing Your Data www.glencoe.com/sec/ science. Post your and allow the embryos to settle 6. Using a binocular microscope, to Internet sites that will help you data in the data table provided for this activ- LSTo navigate VIDEODISC to the bottom. observe the embryos. Make complete sequences of the major ity. Use the additional data from other stu- to the The Secret of Life 4. Label a petri dish with your a diagram in your data table changes during development of dents to answer the questions for this lab. Internet BioLabs, choose the Developing zebra fish name and class period. Fill the of the embryos’ appearances zebra fish. Were there large variations in data posted by P bottom of the dish with aquarium and indicate the age of the a. between 1 and 10 hpf. Include other students? What might have caused Biology: The Dynamics of Life water. Using a dropper, place embryos in hpf. labeled diagrams of these these differences? icon at the Glencoe Science !7qg+2~I" several embryos in your dish. changes. Web Site. Click on the student Developing zebra fish, close-up icon, then theLS BioLabs icon. The 706 WHAT IS AN ANIMAL? 25.2 BODY PLANS AND ADAPTATIONS 707 advantage to having large numbers of trials in an experi- !7}4,B~F" ment is that the results will be PPROCEDUREROCEDURE more accurate.

Teaching Strategies tank as eggs are released. Fertilization is Use binocular microscopes to view the Between 2-5 hpf: blastula formation. ResourceResource Use the baster to remove excess debris external. development of embryos. Between 5-10 hpf: gastrulation formation is ManagerManager from the bottom of the tank on the evening Classes that occur later in the day may Use this Internet address if you have complete with appearance of somites. prior to spawning. not be able to find early stages of embryonic trouble with breeding these fish: Between 10-28 hpf: tissues and organs form. BioLab and MiniLab Work- Females will release eggs about 30 min- development because fertilization has taken http://weber.u.washington.edu/~fishscop/ Between 28-72 hpf: fins, gills, mouth form. sheets, pp. 115-116 L2 utes after the light comes on. Time this light place in the morning. Embryonic develop- pattern to correspond with your first morn- ment is rapid. Data and Observations ing class. Students may be able to see males Feeding is not necessary for the first Between 1-2 hpf: dividing cells will appear 706 following females along the bottom of the week. Later, feed the young live paramecia. above yolk sac. 707

LS Chapter 25 Assessment Peregrine Chapter 25 Assessment Chapter 25 Assessment falcon Protecting Endangered Species SSUMMARYUMMARY Main Ideas Section 25.1 Main Ideas Vocabulary Summary statements can be used by P The American peregrine falcon is a fast-flying, streamlined hawk that Animals are heterotrophs, digest their food blastula (p. 696) students to review the major con- feeds primarily on birds it catches in the air. During the mid-1900s, the Typical Animal inside the body, typically have a type of locomo- deuterostome (p. 697) cepts of the chapter. ectoderm (p. 697) Purpose tion, and are multicellular. Animal cells have no falcon’s ability to reproduce was seriously weakened by the insecticide Characteristics endoderm (p. 697) Students explore ways in which cell walls. DDT. In 1972, DDT was banned in the United States. Banning the gastrula (p. 696) Using the Vocabulary human actionsLS can affect the sur- use of DDT gave peregrine falcons a chance to recover. Embryonic development from a fertilized egg is mesoderm (p. 697) vival of other species. They are similar in many animal phyla. The sequence protostome (p. 697) To reinforce chapter vocabulary, use exposed to differing opinions after division of the fertilized egg is: the forma- sessile (p. 694) the Content Mastery Booklet and about the level of effort expended n 1973, the United States government passed a Different Viewpoints tion of a blastula with one layer of cells; a gas- the activities in the Interactive Tutor trula with two layers of cells, ectoderm and for Biology: The Dynamics of Life on to rescue endangered and threat- Ilaw, the Endangered Species Act, to help pre- How far should we go to protect endangered endoderm; and finally a gastrula with meso- vent the extinction of threatened or endangered species? Some people argue that the Endangered the Glencoe Science Web Site: ened species. derm, a layer of cells between the ectoderm and species, and to preserve the habitats needed for Species Act places too much importance on www.glencoe.com/sec/science endoderm. Background their survival. An endangered species is one plants and animals at the expense of human whose numbers have fallen so low that it could The Endangered Species Act re- needs. The recovery plan for the peregrine fal- become extinct in the near future. A threatened con included protecting any known nesting sites quires the preservation of habitat, Section 25.2 Main Ideas Vocabulary All Chapter species is one that would soon become endan- from disturbance by humans. For example, if fal- Assessment often the primary source of dis- gered if steps are not taken to protect it. In 1998, Animals have a variety of body plans and types acoelomate (p. 702) cons were found nesting in a forest that was to be anterior (p. 702) questions and answers have been agreements about the law. Land about 965 species in the United States were logged, logging had to be delayed until after the Body Plans and of symmetry that are adaptations. bilateral symmetry validated for accuracy and suitabil- use issues may be especially diffi- listed as endangered or threatened. young falcons left the nest. Loggers sometimes Adaptations Animals may be asymmetrical, radially symmet- (p. 701) cult to resolve when the species disagree with regulations like this because they rical, or bilaterally symmetrical. coelom (p. 704) ity by The Princeton Review. Preserving or restoring habitat in question is small and unfamil- Under the fear losing their ability to make a living. But A coelom is a fluid-filled body cavity that sup- dorsal (p. 702) endoskeleton (p. 704) terms of the Endangered Species Act, it is illegal actions called for by the Endangered Species Act, ports internal organs. iar, such as a wildflower, butterfly, exoskeleton (p. 704) NDERSTANDING AIN DEAS to kill or harm protected species. Protection including nest protection, elimination of DDT UUNDERSTANDING MMAIN IIDEAS or small fish. under the act also means that efforts must be Flatworms and other acoelomate animals have invertebrate (p. 704) use, and introduction of captive-bred birds into flattened, solid bodies with no body cavities. posterior (p. 702) made to preserve or restore the species’ habitat. the wild, have given the falcon a second chance. 1. b Teaching Strategies Animals such as roundworms have a pseudo- pseudocoelom (p. 703) A recovery plan written for each species outlines radial symmetry (p. 701) c coelom, a body cavity that develops between the 2. Encourage students to do steps to be taken to help reestablish it. Periodi- Successful reintroduction An introduction symmetry (p. 700) Internet or library research to cally, the status of each species is reviewed, and it program that began in the 1980s in New York endoderm and mesoderm. ventral (p. 702) find out whether the Endangered may be reclassified. City has been a particular success. By 1998, there Coelomate animals such as humans and insects vertebrate (p. 705) Species Act has been altered by were 12 breeding pairs of falcons nesting on city have internal organs suspended in a body cavity that is completely surrounded by mesoderm. legislation. L2 buildings and bridges. By the end of the twenti- eth century, falcons were on their way off the Have students obtain current Exoskeletons provide a framework of support endangered species list. on the outside of the body, whereas information about local or state endoskeletons provide internal support. laws that deal with protection of INVESTIGATING THE ISSUE Animals probably evolved from colonial species that are endangered or protists in the Cambrian period. threatened. L2 Analyzing the Issue Use your research skills to find out the current status of peregrine falcon InvestigatingP the Issue populations in the United States. Prepare a brief Students should discover that report that describes the results of reintroduction efforts to date. UUNDERSTANDINGNDERSTANDING MMAINAIN IIDEASDEAS 2. Which animal pair shares the most captive breeding and reintroduc- characteristics? tion efforts, plus the banning of To find out more about 1. Which of these organs forms from the a. earthworm—sea star the pesticideLS DDT, are having a endangered species, visit ectoderm? b. earthworm—insect positive impactP on the status of the Glencoe Science Web Site. a. stomach c. intestines c. earthworm—leech peregrine falcon populations in www.glencoe.com/sec/science b. skin d. liver d. earthworm—clam the United States. 708 WHAT IS AN ANIMAL? CHAPTER 25 ASSESSMENT 709 LS Going Further Resource Manager VIDEODISC Several species listed as threatened or VIDEOTAPE STV: Biodiversity endangered at one time have begun to Chapter Assessment, pp. 145-150 MindJogger Videoquizzes Preserving Diversity make a comeback. Invite students to find MindJogger Videoquizzes Chapter 25: What is an animal? Unit 2, Side 1, 4 min. 45 sec. out about the current status of the bald Computer Test Bank Have students work in groups as they play The Peregrine Falcon eagle, red wolf, California sea otter, BDOL Interactive CD-ROM, Chapter 25 Louisiana black bear, or the American alli- the videoquiz game to review key chapter quiz !9_oE%~0" gator. What controversies surrounded the concepts. recovery efforts for these species? L2 708 709

LS Chapter 25 Assessment Chapter 25 Assessment Chapter 25 Assessment Chapter 25 Assessment

3. b 3. All animals must search for food because they 9. Which animal obtains food by filtering it out 22. How are body plans of animals related to the 22. Fishes have coeloms that their AASSESSINGSSESSING KKNOWLEDGENOWLEDGE && SSKILLSKILLS 4. c are ______. of water? environment in which they live? Give two muscles can push against as a. autotrophic c. sessile a. clam c. sidewinder examples. 5. a The following diagrams represent three leverage in swimming motions. b. heterotrophic d. photosynthetic b. sea star d. flatworm 6. b 23. Why are asymmetrical organisms often different animal body plans. Acoelomate flatworms have 7. b 4. A(n) ______is an example of an animal that 10. Of these, which is NOT an example of a sessile? Explain. thin bodies that aid diffusion 1 3 8. d is sessile as an adult. vetebrate animal? 24. How is obtaining food different in animals through the cell layers. 9. a a. osprey c. coral a. nurse shark c. coral snake and fungi? 23. Asymmetrical organisms have b. flatworm d. sea star b. black bear d. garden spider 10. d 25. Under a microscope, you observe an unfamiliar no front or back end; thus, they 11. planarian 5. Which of the following is NOT a character- 11. The ______shown in the diagram below organism from a tide pool. When you offer have little direction to their istic of animals? has only one opening in its digestive system. 12. coelomate live invertebrate food, the organism seems movement and cannot pursue a. cells with cell walls to pursue and consume this prey. How could exoskeleton food. They often wait for food 13. b. multicellular organisms you tell whether the organism is a protist 14. coelomate c. are consumers or an animal? to come to them—which works 15. gastrula d. break down food for a sessile animal. 16. mesoderm 24. Most animals move to get food 6. When do mesoderm cells begin to form from TTHINKINGHINKING CCRITICALLYRITICALLY 2 17. deuterostome the endoderm? or cause food to be drawn a. 26. Observing and Inferring You are looking at 18. dorsal during the blastula stage 12. A(n) ______body plan enables muscles to Interpreting Scientific Illustrations toward them. Most animals b. a preserved specimen of an unidentified ani- 19. sessile during the gastrula stage brace against a rigid structure, thereby Use the diagram to answer the following digest their food inside their c. mal. It is easy to see that it has radial symme- 20. radial before the blastula stage enabling faster movement. questions. bodies. Fungi usually live on or d. after the gastrula stage try. What would you predict about its direc- in their food source and do not 13. A cat has an endoskeleton, whereas a tion of movement when alive? Explain. 1. Which body plan would be capable of 7. Which animal shown in the diagram below is more complex and powerful movement? move to find food. Fungi dragonfly has a(n) ______for protection 27. Observing and Inferring Explain why the APPLYINGPPLYING MAINAIN IDEASDEAS an example of an animal with radial symmetry? a. 1 c. 3 secrete chemicals that dissolve A M I and support. development of a body cavity enabled ani- b. 2 d. all of these 14. Your pet hamster has a(n) ______body plan. mals to move and feed more efficiently. food outside their bodies 21. No, because this pattern is that 2. Which type of body plan belongs to before they take it in. 15. A butterfly’s mouth develops from the 28. Concept Mapping Complete the concept acoelomate animals such as flatworms? of a protostome. A bird is a a. c. opening of the indented space in the map by using the following vocabulary terms: 25. If it is multicellular, it is an ani- a. 1 c. 3 deuterostome. ______of the developing embryo. blastula, ectoderm, gastrula, endoderm, mal. b. 2 d. none of these 16. The muscles in the legs of a horse develop mesoderm. 3. Which type of body plan belongs from the embryonic tissue called ______. Animals develop from a b. d. to pseudocoelomate animals such as TTHINKINGHINKING CCRITICALLYRITICALLY 17. A swordfish is a ______because its mouth zygote roundworms? did not develop from the opening in the a. c. to a 1 3 26. Radially symmetrical animals gastrula. b. 2 d. none of these 8. Fishes have one fin along their backs. 1. don’t have an anterior or poste- 18. A saddle is placed on the ______surface of 4. Which type of body plan is more likely Because fishes are ______symmetrical, stage in which these tissues form rior end; they don’t move for- a horse. to be seen in animals that inhabit land this fin is called the ______fin. ward or backward as easily as 19. Sponge larvae are free-swimming, whereas 2. 3. environments? a. radially, anterior c. bilaterally, posterior bilaterally symmetrical animals. b. radially, ventral d. bilaterally, dorsal most adult sponges are ______. which forms the a. 1 c. 3 20. b. 2 d. all of these 27. Animals with no body cavities An adult sea star has ______symmetry. 4. during the5. stage 5. Making a Table Make a table that depend upon diffusion to move compares the three body plans. For food into and wastes out of TESTEST–TAKINGAKING TIPIP AAPPLYINGPPLYING MMAINAIN IIDEASDEAS T –T T CD-ROM each body plan, indicate an example of cells; animals with body cavities For additional review, use the assessment Make Yourself Comfortable 21. During the development of an embryo, a an animal with that type; whether or not have space to develop organ blastula forms first, followed by formation of options for this chapter found on the Biology: The a body cavity is present, and if so, which systems that deliver food and When you take a test, try to make yourself as com- Dynamics of Life Interactive CD-ROM and on the a gastrula. The mouth of the embryo devel- type; and how the animal’s body plan fortable as possible. You will then be able to focus Glencoe Science Web Site. take away wastes. Movement in all your attention on the test. ops from the opening in the gastrula. Could www.glencoe.com/sec/science affects its locomotion. acoelomate animals depends the embryo develop into a bird? Explain. upon structures such as cilia, whereas coelomate animals 710 CHAPTER 25 ASSESSMENT CHAPTER 25 ASSESSMENT 711 have structures that muscles can work against for locomotion. 28. 1. Blastula; 2. Endoderm; 3. Ectoderm; 4. Mesoderm; 5. Gastrula 1. c 5. Comparison of Three Body Plans 2. a Relative 3. b Body Plan Example Coelom Speed 4. c Acoelomate Flatworm none slow Pseudocoelomate Roundworm fluid-filled, partly lined with mesoderm faster Coelomate Fish fluid-filled, lined with mesoderm faster

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