CH 18: Classification

Transcription

1 Name: Per: Date: Row: CH 18: Classification 18-1 Finding Order in Diversity A. Why Classify? 1. and other processes have led to a staggering diversity of organisms. 2. Biologists have identified and named about so far. a. They estimate that million additional species have yet to be discovered. 3. To study the diversity of life, biologists use a classification system to name organisms and group them in a logical manner. 4. Discipline of - scientists classify organisms and assign each organism a. B. Assigning Scientific Names 1. Common names of organisms vary, so scientists assign. 2. Because 18 th century scientists understood, they used those languages for scientific names. 3. This practice is still followed in naming new species. 4. Carolus developed a naming system called. 5. In binomial nomenclature, each species is assigned a two-part scientific name. a. 1 st part of the name- the to which the organism belongs. i. Genus- a group of closely related species. The genus name is. ii. Example: grizzly bear is the genus b. 2 nd part of the name is unique to each within the genus. i. This part of the name often describes an important trait or where the organism lives. ii. The species name is. iii. Example: grizzly bear Ursus maririmus (polar bear) or Ursus artos (brown bear) 6. Linnaeus's seven levels of classification are from smallest to largest a. b. c. d. e. f. g Modern Evolutionary Classification A. Which similarities are most important? 1. Early classification was based on How are evolutionary relationships important in classification? 2. the study of evolutionary relationships among organisms. B. Evolutionary Classification 1. Biologists now which is called evolutionary classification. 2. Species within one genus are more closely related to one another than to species in another genus. 3. All members of a genus share a 4. The higher the level of the taxon, the further back in time is the common ancestor of all the organisms in the taxon. 5. Organisms that. 6. Superficial similarities once led barnacles and limpets to be grouped together. Big idea/questions/notes

2 Name: Date: Per: Row: 7. However, barnacles and crabs share an evolutionary ancestor that is more recent than the ancestor that barnacles and limpets share. 8. Barnacles and crabs are classified as, and limpets are. C. Classification Using Cladograms 1. Many biologists now use a method called. 2. Cladistic analysis identifies and considers only new characteristics that arise as lineages evolve. 3. Characteristics that appear in recent parts of a lineage but not in its older members are called. 4. Derived characters can be used to construct a cladogram, a. 5. Cladograms help scientists understand how one lineage branched from another in the course of evolution. a. Ex: A cladogram shows the evolutionary relationships between crabs, barnacles, and limpets. Activity: Understanding Cladograms - Color the organisms that have a molted external skleton blue - Color the organisms without a molted external skeleton red - Circle the point on the cladogram that shows the most recent common ancestor of the crab and the barnacle - Mark an X on the point on the cladogram that shows the most recent common ancestor of mollusks and crustaceans D. Similarities in DNA and RNA How can DNA and RNA help scientists determine evolutionary relationships? 1. can be used to help determine classification and evolutionary relationships. 2. DNA evidence shows. 3. The more similar the DNA of two species, the more recently they shared a common ancestor, and the more closely they are related in evolutionary terms. 4. The more two species have from each other, the less similar their DNA will be. E. Molecular Clocks 1. Comparisons of DNA are used to mark the passage of evolutionary time. 2. A uses DNA comparisons to estimate the length of time that two species have been evolving independently. 3. A molecular clock relies on. 4. Simple mutations in DNA structure occur. 5. Neutral mutations accumulate in different species at about the same rate. 6. Comparing sequences in two species shows how dissimilar the genes are, and shows when they shared a common ancestor. Big idea/questions/notes

3 Name: Per: Activity: Three Domains Use the diagram to answer the questions 1. Which species is most closely related to Species B? Species A or Species C Date: Row:. Explain how you used the DNA sequences to answer question 1. (2-3 sentences) A: 3. How can you tell that Species C developed from the organism with gene 3? A: Kingdoms and Domains A. The Tree of Life Evolves 1. Systems of classification adapt to new discoveries. 2. Linnaeus classified organisms into two kingdoms. 3. The only known differences among living things were the fundamental traits that separated animals from plants. 4. Scientists realized there were enough differences among organisms to make 5 kingdoms: a. b. c. d. e. B. Six Kingdoms 1. Recently, biologists recognized that were composed of two distinct groups: and. What are the six kingdoms of life as they are now identified? 2. The six-kingdom system of classification includes: a. b. Archaebacteria c. d. Fungi e. f. Animalia C. The Three-Domain System 1. Molecular analyses have given rise to a new taxonomic category that is now recognized by many scientists. 2. The is a more inclusive category than any other larger than a kingdom. 3. The three domains are: Big idea/questions/notes

4 Name: Date: Per: Row: a. - which is composed of protists, fungi, plants, and animals. i. All members have cells b. - which corresponds to the kingdom Eubacteria. i. Unicellular organisms ii. Have cell wall peptidoglydan c. - which corresponds to the kingdom Archaebacteria. i. Unicellular organisms ii. Have cell walls peptidoglydan 4. Modern classification is a rapidly changing science. 5. As new information is gained about organisms in the domains Bacteria and Archaea, they may be subdivided into additional kingdoms. D. Domain Bacteria 1. Members of the domain Bacteria are. 2. Their cells have thick, rigid cell walls that surround a cell membrane. 3. Their cell walls contain peptidoglycan. 4. The domain Bacteria corresponds to the kingdom. E. Domain Archaea 1. Members of the domain Archaea are. 2. They live in. 3. Their cell walls lack peptidoglycan, and their cell membranes contain unusual lipids not found in any other organism. 4. The domain Archaea corresponds to the kingdom Archaebacteria. F. Domain Eukarya 1. The domain Eukarya consists of organisms that have a nucleus. 2. This domain is organized into four kingdoms: a. Protista i. Most members are unicellular ii. Can be b. Fungi i. Are all ii. Most fungi feed on dead or decaying organic matter by secreting digestive enzymes into it and absorbing small food molecules into their bodies. iii. They can be either multicellular ( ) or unicellular ( ) c. Plantae i. are multicellular, photosynthetic autotrophs ii. Plants are - they cannot move from place to place. iii. Plants have cell walls that contain. iv. The plant kingdom includes cone-bearing and flowering plants as well as mosses and ferns. d. Animalia i. Are. ii. The cells of animals do not have cell walls. iii. Most animals can move about. Textbook p. 453 Big idea/questions/notes

5 Name: Per: Date: Row: Answers for Analyze and Conclude: Big idea/questions/notes

6 Name Class Date Chapter 18 Classification Graphic Organizer Compare/Contrast Table Use the terms listed below to fill in the compare/contrast table. The terms may be used more than once, and some sections of the table may have more than one term. Animalia; Eukaryotic; Cell walls with peptidoglycan; Varied types of cell walls and cells without walls; Eubacteria; Fungi; Multicellular; Plantae; Prokaryotic; Protista; Unicellular Characteristics of the Three Domains Domain Bacteria Domain Archaea Domain Eukarya Number of Cells 1. Unicellular 2. Cell Type Prokaryotic Pearson Education, Inc. All rights reserved. Cell Structures 5. Cell walls without 6. peptidoglycan Kingdom(s) 7. Archaebacteria 8. Teaching Resources /Chapter

7 Name Class Date Chapter 18 Classification Chapter Vocabulary Review Completion On the lines provided, complete the following sentences. 1. In the discipline known as, biologists assign each kind of organism a universally accepted name. 2. In, each species is assigned a two-part scientific name. 3. In taxonomy, each level of classification is referred to as a(an). 4. The seven taxonomic categories in Linnaeus s system of classification are: Multiple Choice On the lines provided, write the letter of the answer that best completes the sentence or answers the question. 5. The method of grouping organisms into categories that represent lines of evolutionary descent is called a. taxonomy. c. binomial nomenclature. b. cladistic analysis. d. evolutionary classification. 6. Comparison of DNA to determine how long different species have been evolving independently can be done using a. cladograms. c. kingdoms. b. molecular clocks. d. domains. 7. Characteristics that appear in recent parts of a lineage but not in its older members are called a. taxons. c. cladograms. b. derived characters. d. genes. 8. What type of model is shown below? a. binomial nomenclature c. cladogram b. molecular clock d. domain Crab Molted exoskeleton Barnacle Limpet Pearson Education, Inc. All rights reserved. Segmentation Tiny free-swimming larva 226 Teaching Resources /Chapter 18

8 Name Class Date Pearson Education, Inc. All rights reserved. 9. Which phylum includes humans, snakes, and sharks? a. Ursidae c. Mammalia b. Carnivora d. Chordata 10. The group of organisms that can be larger than a kingdom is called a a. domain. c. phylum. b. species. d. class. 11. A prokaryote whose cell walls contain peptidoglycan belongs to the domain a. Eukarya. c. Bacteria. b. Protista. d. Archaea. 12. Unicellular organisms sometimes found in hot springs are part of the domain a. Eubacteria. c. Protista. b. Archaea. d. Eukarya. 13. The domain Eukarya includes the kingdom(s) a. Protista, Plantae, Fungi, Animalia. c. Eubacteria. b. Protista, Plantae, Bacteria. d. Archaea, Bacteria. 14. The kingdom Protista contains a. only single-celled organisms. b. both single-celled and multi-celled organisms. c. only multi-celled organisms. d. neither single-celled nor multi-celled organisms. 15. Mushrooms belong to the kingdom a. Protista. c. Plantae. b. Bacteria. d. Fungi. 16. The kingdom Plantae contains primarily a. photosynthetic autotrophs. c. photosynthetic heterotrophs. b. single-celled autotrophs. d. protists. 17. The organisms found in the kingdom Animalia are a. photosynthetic heterotrophs. c. multicellular heterotrophs. b. single-celled heterotrophs. d. protists. 18. Into how many domains are organisms divided? a. three c. four b. five d. six 19. The unicellular prokaryotes that make up the domain Bacteria are also classified in the kingdom a. Archaebacteria. c. Fungi. b. Eubacteria. d. Protista. 20. The prokaryotes that live in extreme environments are classifed in the kingdom a. Archaebacteria. c. Fungi. b. Eubacteria. d. Protista. Teaching Resources /Chapter

9 Name Class Date Chapter 18 Classification Using and Constructing a Dichotomous Key You may want to refer students to Chapter 18 in the textbook for a discussion of the classification system used in biology. Time required: 45 minutes Introduction All cultures have developed names for the living things found in their environments. When various everyday names are used for the same organism, confusion is possible. So, scientists have developed an international system for naming and classifying all organisms. Identification guides, called keys, have been developed to help all peoples recognize and identify organisms according to their scientific names. The word dichotomous comes from the word dichotomy, meaning two opposite parts or categories. A dichotomous key gives the reader a series of opposing descriptions of basic features of an organism. The reader studies the specimen and selects the descriptions that apply to it until reaching a statement that characterizes only one species and names it. In this investigation, you will use a typical dichotomous key to identify the genus and species of several different salamanders. Then, you will create your own dichotomous key to categorize a diverse group of wildflowers. Problem How is a dichotomous key used to distinguish among similar organisms? Pre-Lab Discussion Read the entire investigation. Then, work with a partner to answer the following questions. 1. How many choices does a dichotomous key provide at each step? There are two choices at each step. 2. What are some of the apparent differences among the salamanders illustrated? The size, color, shape, numbers and patterns of spots, and the presence or absence of external gills are differences. Students may work alone or with a partner, depending on your preference. 3. Based on the information in Figure 2, what is a distinguishing characteristic of the members of the genus Ambystoma? They all have a body coloring pattern with a black background and variable white spots. Prentice-Hall, Inc. 4. What might be a good strategy for beginning to create a dichotomous key for the six types of wildflowers shown in the diagram? Find a broad difference between them such as the number of petals in the flower or the number of divisions in the leaf. 5. If you were to use live flowers instead of diagrams, what other characteristics could you use to identify the flowers? The color, scent, leaf size, and flower size could be compared. Biology Laboratory Manual A/Chapter

10 Procedure Part A: Using a Dichotomous Key 1. Examine the drawings of the salamanders in Figure 1. Choose one salamander to identify by using the key Figure cm 10 Prentice-Hall, Inc. 148 Biology Laboratory Manual A/Chapter 18

11 Name Class Date 2. Use the dichotomous key (Figure 2) to determine the genus and species of that salamander. Begin by reading statements 1a and 1b. One of the statements describes the salamander; the other statement does not. Follow the directions for the statement that applies to that salamander and continue following the correct statements until you have identified it. Record the scientific and common name of the salamander in the Data Table on page Repeat step 2 for each of the other salamanders in Figure 1. Prentice-Hall, Inc. 1 a Hind limbs absent Siren intermedia, siren b Hind limbs present Go to 2 2 a External gills present in adults Necturus maculosus, mud puppy b External gills absent in adults Go to 3 3 a Large size (over 7 cm long in Figure 1) Go to 4 b Small size (under 7 cm long in Figure 1) Go to 5 4 a Body background black, large white spots variable in size completely covering body and tail Ambystoma tigrinum, tiger salamander b Body background black, small round white spots in a row along each side from eye to tip of tail Ambystoma maculatum, spotted salamander 5 a Body background black with white spots Go to 6 b Body background light color with dark spots and/or lines on body Go to 7 6 a Small white spots on black background in a row along each side from head to tip of tail Ambystoma jeffersonianum, Jefferson salamander b Small white spots scattered throughout a black background from head to tip of tail Plethodon glutinosus, slimy salamander 7 a Large irregular white spots on a black background extending from head to tip of tail Ambystoma opacum, marbled salamander b No large irregular black spots on a light background Go to 8 8 a Round spots scattered along back and sides of body, tail flattened like a tadpole Triturus viridescens, newt b Without round spots and tail not flattened like a tadpole Go to 9 9 a Two dark lines bordering a broad light middorsal stripe with a narrow median dark line extending from the head onto the tail Eurycea bislineata, two-lined salamander b Without two dark lines running the length of the body Go to a A light stripe running the length of the body and bordered by dark pigment extending downward on the sides Plethodon cinereus, red-backed salamander b A light stripe extending the length of the body without dark pigment on the sides Hemidactylium scutatum, four-toed salamander Figure 2 Biology Laboratory Manual A/Chapter

12 Data Table Number Genus and species Common name 1 Plethodon glutinosus slimy salamander 2 Ambystoma jeffersonianum Jefferson salamander 3 Ambystoma maculatum spotted salamander 4 Triturus viridescens newt 5 Eurycea bislineata two-lined salamander 6 Necturus maculosus mud puppy 7 Ambystoma tigrinum tiger salamander 8 Plethodon cinereus red-backed salamander 9 Hemidactylium scutatum four-toed salamander 10 Siren intermedia siren 11 Ambystoma opacum marbled salamander Part B. Constructing a Dichotomous Key 1. Examine Figure 3, which shows some common North American wildflowers. Note different characteristics in flower shape, number of petals, and leaf number and shape. Trillium May apple Arrowhead Violet Figure 3 Clover Bellwort Prentice-Hall, Inc. 150 Biology Laboratory Manual A/Chapter 18

13 Name Class Date 2. Use the space below to construct a dichotomous key for the wildflowers in Figure 3. Be sure to use enough pairs of statements to have a final positive statement for each to identify each of the six flowers shown. Use the key to salamanders as a model for developing your wildflower key. 3. Check the usefulness of your wildflower key by letting another student see if he or she can use it to identify each pictured flower. Wildflower Dichotomous Key A possible key follows: 1a Having numerous small petals Clover 1b Lacking numerous small petals Go to 2 2a Having 3 separate petals only Arrowhead 2b Having more than 3 separate petals Go to 3 3a Having 3 inner petals surrounded by 3 leaflike structures Trillium 3b Having 5 or 6 petals Go to 4 4a Having 5 petals Violet 4b Having 6 petals Go to 5 5a 5b Having 6 petals that form a bell-like shape Bellwort Having 6 petals arranged in a flat circular shape May apple Prentice-Hall, Inc. Analysis and Conclusions 1. Analyzing Data What are some examples of basic differences among the salamanders pictured? Adults with external gills and salamanders with hind limbs absent are two of the most basic differences. Biology Laboratory Manual A/Chapter

14 2. Drawing Conclusions Do the dichotomous keys you have just worked with have any limitations in distinguishing between species? Yes, they are based only on appearance. There may be other important traits that distinguish species. 3. Comparing and Contrasting Do any of the wildflowers shown in Figure 3 appear to be similar enough to be in the same genus? No, the structures of the wildflowers are too different from each other. 4. Evaluating What characteristics should be very similar in order to support an inference that two plants are closely related? They should share strong similiarities in several basic structures such as flowers, leaves, and seeds to be closely related. However, similar traits may be due to convergent evolution instead of a shared ancestry. 5. Drawing Conclusions Could the three salamanders from the genus Ambystoma be more closely related than Necturus, the mud puppy, and Triturus, the newt? Yes, but anatomical features are only one indicator of possible evolutionary relationships. Scientists would have to compare the DNA of the five species to determine how closely they are related to one another. Going Further Construct an evolutionary tree diagram based on the physical similarities and differences of the salamanders shown in Figure 1. Assume that those most similar share a recent ancestor and those that are most different had a common ancestor long ago. Explain why your evolutionary tree is a hypothesis, and describe what kind of evidence might show whether your hypothesis is correct. Prentice-Hall, Inc. 152 Biology Laboratory Manual A/Chapter 18

15 Name Class Date Chapter 18 Classification Identifying Vertebrates Using Dichotomous Keys Introduction Organisms such as vertebrates (animals with backbones) are classified into groups according to certain characteristics. Using these characteristics, dichotomous keys can be developed. Biologists develop these dichotomous keys so they can be used to identify unfamiliar organisms. Such keys are also useful in studying common characteristics and relationships among organisms. In this investigation, you will learn to use a simple dichotomous key to identify some organisms. Problem How is a dichotomous key used to identify various animals? Pre-Lab Discussion Read the entire investigation. Then, work with a partner to answer the following questions. 1. Into which five basic groups will you be classifying vertebrates? Fishes, amphibians, reptiles, birds, and mammals. You may want to refer students to Chapter 18 text and Real-World Lab in the textbook before performing this investigation. Time required: 40 minutes 2. What information do you need in order to classify the animals shown in Figure 1? Where will you find this information? Students will need to have a completed Data Table on page 134. This information will either be given to students in the Procedure or students will obtain it by observing the pictures of the animals in Figure What is a dichotomous key? Students may say that a dichotomous key is a list of characteristics that can be used to identify organisms. Prentice-Hall, Inc. 4. What do the a and b statements in the dichotomous key describe? They are contrasting characteristics, only one of which can apply to the vertebrate being considered. 5. Read statement 1b in the Dichotomous Key for the Extinct Animals shown in Figure 1. If an animal is ectothermic, what is the next step in the key? Explain. If an animal is ectothermic, you skip statements 2 5 and go directly to statement 6 as directed. Statements 2 5 describe characteristics of endotherms. Biology Laboratory Manual B/Chapter

16 Procedure 1. Vertebrates can be divided into five major groups: fishes, amphibians, reptiles, birds, and mammals. (These are not all formal taxonomic groups.) Fishes have gills. The other vertebrates mentioned have lungs. Fishes, amphibians, and reptiles are called ectothermic because they derive body heat mainly from their environment. (Ecto- means outside; -therm means heat.) Birds and mammals are called endothermic because they derive body heat mainly from metabolism. (Endo- means inside.) Some species in each vertebrate group have become extinct. Ten extinct animals are pictured in Figure 1 on pages Study the characteristics of these animals by completing the Data Table on page 134. Fish (North America) Pigeon Prentice-Hall, Inc. Bison Figure Biology Laboratory Manual B/Chapter 18

17 Name Class Date Dodo Elk Prentice-Hall, Inc. Wolf Figure 1 continued Tortoise Biology Laboratory Manual B/Chapter

18 Frog Fish (New Zealand) Snake Figure 1 continued Data Table Name of Animal Appendages Body Temperature Breathing Covering Regulation Mechanism Fins Wings, 2 Legs Forelegs Hindlegs Horns Smooth skin Scales Feathers Hair/Fur Ectothermic Endothermic Gills Lungs Tortoise X X X X X Dodo X X X X Fish (North America) X X X X Wolf X X X X X Pigeon X X X X Elk X X X X X Snake X X X Prentice-Hall, Inc. Frog X X X X X Bison X X X X X X Fish (New Zealand) X X X X 134 Biology Laboratory Manual B/Chapter 18

19 Name Class Date 2. The following key is based on information from Figure 1 and the Data Table. Examine how a key works by using it to identify each animal. Dichotomous Key for the Extinct Animals Shown in Figure a Is endothermic Go to 2 b Is ectothermic Go to 6 a Has feathers Go to 3 b Has hair or fur Go to 4 a Has narrow, straight beak Passenger pigeon b Has wide, crooked beak Dodo a Has horns Go to 5 b Has no horns Texas red wolf a Horns may have many branches Eastern elk b Horns have no branches Oregon bison a Breathes with gills Go to 7 b Breathes with lungs Go to 8 a Has large, fan-shaped fins just behind the head Utah Lake sculpin b Has small pectoral fins New Zealand grayling a Has scaly skin Go to 9 b Has smooth skin Palestinian painted frog a Has front and hind legs Domed tortoise b Has no legs Round Island boa Analysis and Conclusions 1. Classifying Reptiles are ectothermic, have scaly skin, and breathe with lungs. Which of the animals in Figure 1 are reptiles? Domed tortoise, Round Island boa. 2. Classifying The Palestinian painted frog is an amphibian. What is one difference between amphibians and reptiles? Amphibians have smooth skin; reptiles have scaly skin. Prentice-Hall, Inc. 3. Classifying Mammals are endothermic, have hair or fur, breathe with lungs. (They also give birth to live young.) Which of the animals in Figure 1 are mammals? Eastern elk, Oregon bison, Texas red wolf. 4. Classifying Birds are endothermic vertebrates with feathers and wings. Which animals in Figure 1 are birds? Dodo, passenger pigeon. Biology Laboratory Manual B/Chapter

20 5. Drawing Conclusions To which vertebrate group do you belong? Explain. Mammals. Like all mammals, humans are endothermic, have two pairs of limbs, are covered with hair, and breathe with lungs. 6. Classifying Develop a dichotomous key for the following mythical creatures. The key has been started for you. SPHINX: PEGASUS: CHIMERA: CENTAUR: GRIFFIN: UNICORN: body of lion, upper part a human winged horse front part a combination of lion and goat, hind part a serpent, breathes fire human from head to waist, remainder of body a horse body of a lion, head and wings of an eagle, back covered with feathers body of a horse, head of a deer, feet of an elephant, tail of a boar, a single black horn in the middle of its forehead Dichotomous Key for Mythical Animals a Part of body is human Go to 2 b None of body is human Go to 3 a Part lion Sphinx b Part horse Centaur a Wings Go to 4 b No wings Go to 5 a Feathers on back Griffin b No feathers on back Pegasus a Horn Unicorn b No horn Chimera Going Further Choose an organism that you would like to study. Find out how the organism is classified. Try to find out what characteristics are used to classify the organism. Make a chart of your findings. The chart should have columns headed with the terms kingdom, phylum, class, order, family, genus, and species. In each column, write the characteristics of the organism that belong under the heading. Prentice-Hall, Inc. 136 Biology Laboratory Manual B/Chapter 18

21 Name Date Class? INVESTIGATION How Can a Key Be Used to Identify Organisms? Classification is a way of separating a large group of closely related organisms into smaller subgroups. The scientific names of organisms are based on the classification systems of living organisms. The identification of an organism is easy with a classification system. To identify an organism, scientists often use a key. A key is a listing of characteristics, such as structure and behavior, organized in such a way that an organism can be identified. Lab 17-1 Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. OBJECTIVES Hypothesize how organisms can be identified with a key. Use a key to identify fourteen shark families. Examine the method used to make a key. Construct your own key that will identify another group of organisms. PROCEDURE 1. Make a hypothesis to describe how sharks can be identified using a key. Write your hypothesis in the space provided. 2. Use Figure 1 as a guide to the shark parts used in the key on page Read statements 1A and 1B of the key. They describe a shark characteristic that can be used to separate the sharks into two major groups. Then study Shark 1 in Figure 2 for the characteristic referred to in 1A and 1B. Follow the directions in these statements and continue until a family HYPOTHESIS Figure 1 MATERIALS goggles name for Shark 1 is determined. For example, to key a shark that has a body that is not kite shaped and has a pelvic fin and six gill slits, follow the directions of 1B and go directly to statements 2. Follow statement 2B to statements 3. At statement 3A, identify the shark as belonging to Family Hexanchidae. 4. Continue keying each shark until all have been identified. Write the family name on the line below each shark in Figure Have the teacher check your answers. LABORATORY MANUAL CHAPTER 17 BIOLOGY: The Dynamics of Life 117

22 Name Date Class How Can a Key Be Used to Identify Organisms? Lab 17-1 Figure 2 Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 118 CHAPTER 17 BIOLOGY: The Dynamics of Life LABORATORY MANUAL

23 Name Date Class How Can a Key Be Used to Identify Organisms? Lab 17-1 Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 1. A. Body kitelike in shape (if viewed from above) Go to statement 12 B. Body not kitelike in shape (if viewed from above) Go to statement 2 2. A. Pelvic fin absent and nose sawlike Family Pristophoridae B. Pelvic fin present Go to statement 3 3. A. Six gill slits present Family Hexanchidae B. Five gill slits present Go to statement 4 4. A. Only one dorsal fin present Family Scyliorhinidae B. Two dorsal fins present Go to statement 5 5. A. Mouth at front of head rather than back along underside of head Family Rhinocodontidae B. Mouth back along underside of head Go to statement 6 6. A. Head expanded on side with eyes at end of expansion Family Sphyrnidae B. Head not expanded Go to statement 7 7. A. Top half of caudal fin exactly same size and shape as bottom half Family Isuridae B. Top half of caudal fin different in size and shape from bottom half Go to statement 8 8. A. First dorsal fin very long, almost half total length of body Family Pseudotriakidae B. First dorsal fin length much less than half total length of body Go to statement 9 9. A. Caudal fin very long, almost as long as entire body Family Alopiidae B. Caudal fin length much less than length of entire body Go to statement A. Nose with long needlelike point on end Family Scapanorhynchidae B. Nose without needlelike point Go to statement A. Anal fin absent family Squalidae B. Anal fin present Family Carcharhinidae 12. A. Small dorsal fin present near tip of tail Family Rajidae B. Small dorsal fin absent near tip of tail Go to statement A. Hornlike appendages at front of shark Family Mobulidae B. Hornlike appendages not present at front of shark Family Dasyatidae ANALYSIS 1. What is a classification key and how is it used? 2. List four different characteristics that were used in the shark key. 3. a. Which main characteristic could be used to distinguish shark 4 from shark 8? b. Which main characteristic could be used to distinguish shark 4 from shark 7? LABORATORY MANUAL CHAPTER 17 BIOLOGY: The Dynamics of Life 119

24 Name Date Class How Can a Key Be Used to Identify Organisms? Lab 17-1 ANALYSIS continued 4. Prepare your own key for the five fish in Figure 3. Use the same format as on page 119. The family names to be used are the numbers I, II, III, IV, and V. Your key should correctly use traits that will lead to each fish family. To help you get started, the first statements are given. Statement 1 divides the five fish into two main groups, based on body shape. Next, choose another characteristic that will divide the fish not having a tubelike body into two groups. Continue to choose characteristics that will separate a group into smaller groups. Write your key in the space below. Figure 3 1. A. Fish with long tubelike body B. Fish with body shape not tubelike Key 1. A. B. 2. A. B. 3. A. B. 4. A. B. CHECKING YOUR HYPOTHESIS Did your hypothesis describe the key correctly? FURTHER INVESTIGATIONS 1. Exchange keys with a classmate. Work through it to identify the fish. Is the key correct? 2. The library will have many books that include simple keys to different plants and animals, as well as to rocks, fossils, and stars. Select a book that includes keys to local plants or animals. Take a walk and practice using the key to identify some of the organisms that live in your area. Copyright Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc. 120 CHAPTER 17 BIOLOGY: The Dynamics of Life LABORATORY MANUAL