http://www.transformation2013.org/docs/Design%20Challenges/Biology/Classification by Jason Kozel

Transformation 2013 PBL 5E Planning Form Guide PBL Title: How on Earth? Teacher(s): Shane McKay School: East Central High School Subject: Biology Abstract: Students will learn how organisms are classified in taxonomic levels and how organisms are organized based on similarities. The learner will also understand the distinctiveness of kingdoms.

MEETING THE NEEDS OF STEM EDUCATION THROUGH PROBLEM BASED LEARNING ÂŠ 2008 Transformation 2013

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Begin with the End in Mind The theme or “big ideas” for this PBL: Students will learn the applications of taxonomy and will be able to identify its limitations, along with being able to classify organisms into various taxonomic levels. Furthermore, the learner will be able to develop dichotomous keys by following the model using the hierarchical classification system. TEKS/SEs that students will learn in the PBL: (8) Science concepts. The student knows applications of taxonomy and can identify its limitations. The student is expected to: (A) collect and classify organisms at several taxonomic levels such as species, phylum, and kingdom using dichotomous keys; (B) analyze relationships among organisms and develop a model of a hierarchical classification system based on similarities and differences using taxonomic nomenclature; and (C) identify characteristics of kingdoms including monerans, protists, fungi, plants, and animals. Key performance indicators students will develop in this PBL: Develop a working vocabulary of the following terms: taxonomy, phylogeny, cladogram, binomial nomenclature, kingdom, phylum, class, order, family, genus, species; students will be able to create a dichotomous key to classify various objects based on differences and similarities; the learner will be able to interpret a phylogenic tree; students should be able to recognize binomial nomenclature; students should be able to identify the characteristics of the following kingdoms: archeabacteria, eubacteria, protists, fungi, plants, and animals; The learner should also be able to describe the characteristics of each kingdom by feeding method, cell type, number of cells, and reproduction; students will be able to conclude the phylogeny of species and translate a cladogram. 21st century skills that students will practice in this PBL: www.21stcenturyskills.org Productivity and adaptability

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STEM career connections and real world applications of content learned in this PBL:

Career: Taxonomist, Biologist, Librarian Connections: We as a human race continually classify objects and people our entire lives. Things living and non-living are classified by society on an every day basis. In science we are just beginning to explore regions never seen before at the bottom of the ocean and deep in the jungle. These new organisms may help solve the cure for cancer or AIDS. They must be classified.

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The Problem You and your partner are the leading taxonomists in the United States. Your team has been hired by NASA© to develop a slideshow presentation including audio that will be sent on a deep space probe (Voyager III). This is an intelligent life exploration mission…they are reaching out to aliens in outer space. You and your partner will try to explain how organisms on planet Earth are classified. NASA© expects you to explain binomial nomenclature, how living things are organized, phylogeny, how to read a cladogram, and how to differentiate between the six kingdoms. Due to memory capacity on the probe, your CD must be no less than 5 minutes and no more than 7 minutes in length. Feel free to be creative with background music and extra sounds to explain what you want to teach. If you choose you may use software such as iMovie, Photostory, or any other type of software to develop a slide show presentation with pictures included.

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Map the PBL Performance Indicators

1. Develop a working vocabulary of the following terms: taxonomy, phylogeny, cladogram, binomial nomenclature, kingdom, phylum, class, order, family, genus, species 2. Students should be able to interpret dichotomous keys, and be able to design a dichotomous keys 3. The learner will be able to interpret a phylogenic tree 4. Students should be able to recognize binomial nomenclature 5. Students should be able to identify the characteristics of the following kingdoms: archeabacteria, eubacteria, protists, fungi, plants, and animals 6. The learner should also be able to describe the characteristics of each kingdom by feeding method, cell type, number of cells, and reproduction 7. Students will be able to conclude the phylogeny of species and translate a cladogram

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Already Learned

Taught before the project

Taught during the project

X X X X

X X

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Team-Building Activity It is important that teachers provide team-building activities for students to help build the 21st Century Skills that are necessary for success in the workforce. Team-building helps establish and develop a greater sense of cooperation and trust among team members, helps students adapt to new group requirements so that they can get along well in a new group, serves to bring out the strengths of the individuals, helps identify roles when working together, and leads to effective collaboration and communication among team members so that they function as an efficient, productive group. Our students are often not taught how to work in groups, yet we assume that they automatically know how. Use team-building activities with your students so that you can see the benefits which include improvement in planning skills, problem solving skills, decision making skills, time management skills, personal confidence, and motivation and morale. Tower of Power Team Building Activity Purpose: The purpose of this activity is to get the participants to work together as teams to accomplish a timed task. They will need to focus on brainstorming skills, communication skills, and engineering design skills as well. The participants will then reflect on their participation in a teamwork setting. Group Size: 3 to 4 participants (ideal is 4) Materials:  100 3x5 index cards per group  Small stuffed animal to serve as the artifact  Meter stick  Stopwatch or watch with a second hand Procedures: The workshop facilitator will set the scene: “You work for the Boston Museum of Science and have been asked to design a tower that will display an ancient artifact that must be 1 meter tall when sitting on a table. Each group will be given 100 3x5 index cards to use to design a prototype for the actual tower. The tower must be able to support the weight of the ancient artifact (hold up the small, stuffed animal) for a minimum of 10 seconds. You will be given 10 minutes to complete the design challenge, and, upon completion, a member of your group must test the design for the rest of the participants. Are there any questions?” ***The participants may tear the cards, but they are not allowed to use scissors, tape, etc. They must use only the index cards to complete the challenge.***

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5E Lesson Plan PBL Title: How on Earth? TEKS/TAKS objectives: 8A,B,C Engage Activity Students will learn the basis for classification by classifying fruits using various mechanisms for classification using observable characteristics. Break students up into groups of four for this lab. Follow the Dissecting Fruit Engagement Lab below. Engage Activity Products and Artifacts Lab write up in journals Engage Activity Materials/Equipment Five different types of fruit, paring knife, napkins, paper towels, journals, pencils, copy of Fruit Lab Engage Activity Resources None Explore Activity Show students a copy of a dichotomous key. Explain to them how to use a dichotomous key and ask them to do the dichotomous key bug exercise (see below). Once students have completed the bug dichotomous key they will now create their own dichotomous key using shoes from everyone in the classroom. Break students into groups of three. Please, use the shoe dichotomous key lab (see below). Now, break-up the students into groups of two. Introduce the design project by showing them the following website: http://popsci.typepad.com/popsci/2007/05/far_out_nasas_g.html You and your partner are the leading taxonomists in the United States. Your team has been hired by NASAÂŠ to develop a slideshow presentation including audio that will be

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sent on a deep space probe (Voyager III). This is an intelligent life exploration mission…they are reaching out to aliens in outer space. You and your partner will try to explain how organisms on planet Earth are classified. NASA© expects you to explain binomial nomenclature, how living things are organized, phylogeny, how to read a cladogram, and how to differentiate between the six kingdoms. Due to memory capacity on the probe, your CD must be no less than 5 minutes and no more than 7 minutes in length. Feel free to be creative with background music and extra sounds to explain what you want to teach. If you choose you may use software such as iMovie, Photostory, or any other type of software to develop a slide show presentation with pictures included. Before the groups begin, have the teams perform the team building activity “Tower of Power” provided (see above). Explore Activity Products and Artifacts Lab write up for Shoe Dichotomous Key Lab Explore Activity Materials/Equipment Chart paper, markers, copy of Shoe Dichotomous Key Lab, journals, pencils, computer, internet access, LCD projector Explore Activity Resources http://popsci.typepad.com/popsci/2007/05/far_out_nasas_g.html

Explain Activity Ask students to view the following brainpop video, and have each student complete the quiz following the classification video: http://www.brainpop.com/science/diversityoflife/classification/ Upon completion of the video, pass out the kingdom classification chart (see Transformation 2013 website). Break students up into the design project groups and have them complete the chart provided. They may use the internet, school textbook, or any other reference to complete the table. Ask students to view the following website once they complete the kingdom chart and allow the students to play the online game: http://www.hhmi.org/coolscience/critters/ Show students the classification powerpoint (see Transformation 2013 website) and have them record notes in their journals.

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Explain Activity Products and Artifacts BrainPop Quiz, Kingdom Classification Chart, journal notes Explain Activity Materials/Equipment Computers with Internet access, BrainPop subscription, Kingdom Classification Chart, Powerpoint Presentation, LCD projector, journal, pencils Explain Activity Resources http://www.brainpop.com/science/diversityoflife/classification/ http://www.hhmi.org/coolscience/critters/

Elaborate Activity Break students up into the design challenge groups. Have students complete the Classification Lab provided (see below). This lab will help to develop communication skills and will provide an avenue for the project. This is a lab that will require the team to work together for success. Upon completion of the Classification Lab, design teams will create their presentation for the space probe. Allow students ample time to complete the project. Provide students with a copy of the rubric will be used to assess the finished product. Elaborate Activity Products and Artifacts Classification Lab, Presentation Elaborate Activity Materials/Equipment Chart paper, scissors, markers, glue sticks, computers, Internet access, Presentation software Elaborate Activity Resources None Evaluate Activity Groups will present their finished products to the rest of the class and teacher will assess the presentations using the attached rubric.

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Evaluate Activity Products and Artifacts Formal presentation of finished product to the class Evaluate Activity Materials/Equipment Computer, LCD projector, Rubric Evaluate Activity Resources Rubric

Plan the Assessment Engage Artifact(s)/Product(s): Dissecting Fruit Lab

Explore Artifact(s)/Product(s): Shoe Dichotomous Key Lab

Explain Artifact(s)/Product(s): Brainpop quiz, Kingdom Chart

Elaborate Artifact(s)/Product(s): Classification Lab

Evaluate Artifact(s)/Product(s): Design Project for Space Probe

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Rubric NASAÂŠ Space Probe Slideshow Rubric

Teacher Name:

Student Name:

________________________________________

CATEGORY Creativity

25 Lots of creative energy used to present a unique slideshow

20 Some creative energy used to present a unique slideshow

15 Little creativity used in project.

10 No creativity used in project.

Construction - Care Taken

Great care taken in construction process so that the structure is neat, attractive and follows plans accurately.

Constuction was careful and accurate for the most part, but 1-2 details could have been refined for a more attractive product.

Construction accurately followed the plans, but 3-4 details could have been refined for a more attractive product.

Construction appears careless or haphazard. Many details need refinement for a strong or attractive product.

Scientific Knowledge

Explanations indicate a clear and accurate understanding of scientific principles underlying the construction and modifications.

Explanations indicate a relatively accurate understanding of scientific principles underlying the construction and modifications.

Explanations indicate a somewhat accurate understanding of scientific principles underlying the construction and modifications.

Explanations do not illustrate much understanding of scientific principles underlying the construction and modifications.

SlideShow Elements

Slideshow only met 4 to 5 of Slideshow only met 3 of the Slideshow met 2 or less of SlideShow met all six the requirements requirements the 6 requirements requirements: binomial nomenclature, how living things are organized, phylogeny, how to read a cladogram, and how to differentiate between the six kingdoms, 5-7 min.

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Story Board  

Day 1 Engage: Fruit Lab (45 min) Explore: Dichotomous Key Bug Lab (45 min.)

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Week 1 Activities

 Week 2 Activities

Day 6 Finish Classification Lab (90 min.)

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Day 2 Shoe Dichotomous Key Design Lab (45 min.) Show space probe article and discuss design challenge (45 min.)

Day 7 Evaluate: Space Probe slide show design project (90 min.)

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Day 3 Tower of Power team building exercise (45 min) Explain: Brainpop website and quiz (30 min) Begin Classificatio n Chart (15 min) Day 8 Slide show design project (90 min.)

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Day 4 Finish Classificatio n chart (30 min) Let students play online science critters game (60 min.)

Day 9 Slideshow project due (90 min.)

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Day 5 Show Cladogram ppt (30 min.) Elaborate: Start Classific. Lab (60 min)

Day 10      

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The Fruity Five Objective: The students will be able to conclude which of the five fruits are most closely related based on observable characteristics. Materials: 5 different types of fruit, paring knife, napkins, soap to wash hands and fruit (note: pick fruits that most kids would not know the name of; this makes it much more interesting. Choose some fruits that are similar and some that are dissimilar) Safety: Make sure students wash the fruit before the lab and they wash their own hands. Use caution using sharp instruments. Directions: 1. Each group obtains 5 pieces of fruit and return to your lab table. 2. Make sure you wash your hands and wash the outside of the fruit. 3. Obtain paper towels and a paring knife to make your incisions in the fruit. 4. Observe the outside characteristics of each piece of fruit. What do you notice? 5. Cut each type of fruit and observe the insides. What do you notice? If you are not sure is something is a seed or not, ask your teacher. 6. You and your partners develop a way to classify each piece of fruit. 7. Next, develop a name for your fruit. (Be creative) Some fruit may have the same first name, but none can have the same last name. 8. Fill in the table with your information that you have discovered about your fruit. 9. Answer the lab questions at the bottom of the lab.

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Method for classifying

Create a name for your Fruit (must have two words to name)

Classification/Characteristics of Fruit

Name:

Name.

1. What characteristics did you see to describe the fruits?

2. Based on your table, which fruits are most closely related? Explain.

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INTRODUCTION: A dichotomous key is a tool that allows the user to determine the identity of items in the natural world, such as trees, wildflowers, mammals, reptiles, rocks, and fish. Keys consist of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step.

PURPOSE: Students will learn skills in the areas of observing, comparing, communicating, ordering, and categorizing.

PROCEDURE: In constructing keys, keep the following in mind: • Use constant characteristics rather than variable ones. • Use measurements rather than terms like "large" and "small". • Use characteristics that are generally available to the user of the key rather than seasonal characteristics or those seen only in the field. • Make the choice a positive one - something "is" instead of "is not". • If possible, start both choices of a pair with the same word. • If possible, start different pairs of choices with different words. • Precede the descriptive terms with the name of the part to which they apply.

Suppose you have four insects a ladybug, a housefly, a dragonfly and a grasshopper. After studying the insects, you might use wing covering, body shape, and where the wings point towards. To begin the key, you could start separating the four insects based on wing covering - "wings covered by exoskeleton" vs. "wings not covered by exoskeleton."

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The first step in the key will be organized the following way: 1. a. wings covered by an exoskeleton b. wings not covered by an exoskeleton Next, the statements need to lead the observer to the next step to narrow the identification further: 1. a. wings covered by an exoskeleton ………go to step 2 b. wings not covered by an exoskeleton ……….go to step 3 Step 2 needs to consist of a pair of statements that will allow for the identification of the ladybug and the grasshopper: 2. a. body has a round shape ……….ladybug b. body has an elongated shape ……….grasshopper Step 3 needs to consist of a pair of statements that will allow for the identification of the housefly and dragonfly: 3. a. wings point out from the side of the body ……….dragonfly b. wings point to the posterior of the body ……….housefly Notice that there were four organisms to be identified and it only took three steps. There should be one less step than the total number of organisms to be identified in your dichotomous key. When using a key, keep the following in mind:

• Always read both choices, even if the first seems to be the logical one at first. • Be sure you understand the meaning of the terms involved. Do Not Guess. • When measurements are given, use a calibrated scale. Do Not Guess. • Since living things are always somewhat variable, do not base your conclusion on a single observation. Study several specimens to be sure your specimen is typical. • If the choice is not clear, for whatever reason, try both divisions. If you end up with two © 2008 Transformation 2013

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possible answers, read descriptions of the two choices to help you decide. • Having arrived at an answer in a key, do not accept this as absolutely reliable. Check a description of the organism to see if it agrees with the unknown specimen. If not, an error has been • Made somewhere, either in the key or in its use. The ultimate check of identifications is a comparison of the unknown with an authentically named "Type Specimen".

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Shoe Dichotomous Key Lab Something stinks, whatâ&#x20AC;&#x2122;s that smell? Directions: 1. 2. 3. 4.

Everyone take off your shoes (both of them). Place your shoes up into the front of the room in one big pile. Get into groups of 3 students per group. One person from the group go and gather (left or right) 6 different shoes from the pile. (make sure you get several different types of shoes guys, girls, flip flops, sneakers, heels, house shoes, etc.) 5. You and your group will design a dichotomous key for each type of shoe. 6. Using chart paper, create your dichotomous key and be ready to explain to the class your key and how you classified each type of shoe. Questions: 1. How did you and your group break the shoes up?

2. Was this assignment hard or easy?

3. What is the value in creating dichotomous keys and how can they be used in real life?

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Classification Lab Humans classify almost everything, including each other. This habit can be quite useful. For example, when talking about a car someone might describe it as a 4-door sedan with a fuel injected V-8 engine. A knowledgeable listener who has not seen the car will still have a good idea of what it is like because of certain characteristics it shares with other familiar cars. Humans have been classifying plants and animals for a lot longer than they have been classifying cars, but the principle is much the same. In fact, one of the central problems in biology is the classification of organisms on the basis of shared characteristics. As an example, biologists classify all organisms with a backbone as "vertebrates." In this case the backbone is a characteristic that defines the group. If, in addition to a backbone, an organism has gills and fins it is a fish, a subcategory of the vertebrates. This fish can be further assigned to smaller and smaller categories down to the level of the species. The classification of organisms in this way aids the biologist by bringing order to what would otherwise be a bewildering diversity of species. (There are probably several million species - of which about one million have been named and classified.) The field devoted to the classification of organisms is called taxonomy [Gk. taxis, arrange, put in order + nomos, law]. The modern taxonomic system was devised by Carolus Linnaeus (1707-1778). It is a hierarchical system since organisms are grouped into ever more inclusive categories from species up to kingdom. Figure 1 illustrates how four species are classified using this taxonomic system. (Note that it is standard practice to underline or italicize the genus and species names.) KINGDOM PHYLUM CLASS ORDER FAMILY GENUS SPECIES

Animalia Chordata Mammalia Primate Carnivora Hominidae Canidae Homo Canis sapiens lupus (human) (wolf)

Arthropoda Insecta Hymenoptera Apidae Apis mellifera (honeybee)

Plantae Angiospermophyta Monocotyledoneae Liliales Liliaceae Alium sativum (garlic)

Figure 1 In the 18th century most scientists believed that the Earth and all the organisms on it had been created suddenly in their present form as recently as 4004 BC. According to this view, Linnaeus' system of classification was simply a useful means of cataloging the diversity of life. Some scientists went further, suggesting that taxonomy provided insight into the Creator's mind ("Natural Theology"). This view of taxonomy changed dramatically when Charles Darwin published On The Origin of Species in 1859. In his book Darwin presented convincing evidence that life had evolved through the process of natural selection. The evidence gathered by Darwin, and thousands of other biologist since then, indicates that all organisms are descended from a ÂŠ 2008 Transformation 2013

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common ancestor. In the almost unimaginable span of time since the first organisms arose (about 3.5 billion years) life has gradually diversified into the myriad forms we see today. As a consequence of Darwin's work it is now recognized that taxonomic classifications are actually reflections of evolutionary history. For example, Linnaeus put humans and wolves in the class Mammalia within the phylum Chordata because they share certain characteristics (e.g. backbone, hair, homeothermy, etc.). We now know that this similarity is not a coincidence; both species inherited these traits from the same common ancestor. In general, the greater the resemblance between two species, the more recently they diverged from a common ancestor. Thus when we say that the human and wolf are more closely related to each other than either is to the honeybee we mean that they share a common ancestor that is not shared with the honeybee. Another way of showing the evolutionary relationship between organisms is in the form of a phylogenetic tree (Gk. phylon, stock, tribe + genus, birth, origin):

Wolf

Figure 2 The vertical axis in this figure represents time. The point at which two lines separate indicates when a particular lineage split. For example, we see that mammals diverged from reptiles about 150 million years ago. The most recent common ancestor shared by mammals and reptiles is indicated by the point labeled A. The horizontal axis represents, in a general way, the amount of divergence that has occurred between different groups; the greater the distance, the more different their appearance. Note that because they share a fairly recent ancestor, species within the same taxonomic group (e.g. the class Mammalia) tend to be closer to each other at the top of the tree than they are to members of other groups. Several types of evidence can elucidate the evolutionary relationship between organisms, ÂŠ 2008 Transformation 2013

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whether in the form of a taxonomic classification (Fig. 1) or a phylogenetic tree (Fig. 2). One approach, as already discussed, is to compare living species. The greater the differences between them, the longer ago they presumably diverged. There are, however, pitfalls with this approach. For example, some species resemble each other because they independently evolved similar structures in response to similar environments or ways of life, not because they share a recent common ancestor. This is called convergent evolution because distantly related species seem to converge in appearance (become more similar). Examples of convergent evolution include the wings of bats, birds and insects, or the streamlined shape of whales and fish. At first glance it might appear that whales are a type of fish. Upon further examination it becomes apparent that this resemblance is superficial, resulting from the fact that whales and fish have adapted to the same environment. The presence of hair, the ability to lactate and homeothermy clearly demonstrate that whales are mammals. Thus, the taxonomist must take into account a whole suite of characteristics, not just a single one. The fossil record can also be helpful for constructing phylogenetic trees. For example, bears were once thought to be a distinct group within the order Carnivora. Recently discovered fossils, however, show that they actually diverged from the Canidae (wolves, etc.) fairly recently. The use of fossils is not without its problems, however. The most notable of these is that the fossil record is incomplete. This is more of a problem for some organisms than others. For example, organisms with shells or bony skeletons are more likely to be preserved than those without hard body parts.

The Classification and Evolution of Artificial Organisms In this lab you will develop a taxonomic classification and phylogenetic tree for a group of imaginary organisms called Caminalcules after the taxonomist Joseph Camin who devised them. At the bottom of this lab are pictures of the 14 "living" and 58 "fossil" species that you will use. Take a look at the pictures and note the variety of appendages, shell shape, color pattern, etc. Each species is identified by a number rather than a name. For fossil Caminalcules there is also a number in parentheses indicating the geological age of each specimen in millions of years. Most of the fossil Caminalcules are extinct, but you will notice that a few are still living (e.g. species #24 is found among the living forms but there is also a 2 million year old fossil of #24 in our collection). The purpose of this lab is to illustrate the principles of classification and some of the processes of evolution (e.g. convergent evolution). We do these exercises with artificial organisms so that you will approach the task with no preconceived notion as to how they should be classified. This means that you will have to deal with problems such as convergent evolution just as a taxonomist would. With real organisms you would probably already have a pretty good idea of how they should be classified and thus miss some of the benefit of the exercise. Exercise 1: The Taxonomic Classification of Living Caminalcules Carefully examine the fourteen living species and note the many similarities and differences ÂŠ 2008 Transformation 2013

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between them. On a sheet of notebook paper create a hierarchical classification of these species, using the format in Figure 3. Instead of using letters (A, B, ...), as in this example, use the number of each Caminalcule species. Keep in mind that Figure 3 is just a hypothetical example. Your classification may look quite different than this one.

GENUS 1 A G

PHYLUM CAMINALCULA CLASS 1 ORDER 1 FAMILY 1 FAMILY 2 GENUS 2 GENUS 3 GENUS 4 H D B J L

CLASS 2 ORDER 2 ORDER 3 FAMILY 3 FAMILY 3 GENUS 5 GENUS 6 E K C F I

Figure 3 The first step in this exercise is to decide which species belong in the same genus. Species within the same genus share characteristics not found in any other genera (plural of genus). The Caminalcules numbered 19 and 20 are a good example; they are clearly more similar to each other than either is to any of the other living species so we would put them together in their own genus. Use the same procedure to combine the genera into families. Again, the different genera within a family should be more similar to each other than they are to genera in other families. Families can then be combined into orders, orders into classes and so on. Depending on how you organize the species, you may only get up to the level of order or class. You do not necessarily have to get up to the level of Kingdom or Phylum. Exercise 2. The Comparative Approach to Phylogenetic Analysis Construct a phylogenetic tree based only on your examination of the 14 living species. This tree should reflect your taxonomic classification. For example, let us say you have put species A and G into the same genus because you think they evolved from a common ancestor (x). Their part of the tree would look like the diagram on the right.

When there are three or more species in a genus you must decide which two of the E species share a common ancestor not shared by the other(s). This diagram indicates that species E and K are more closely related to each other than either is y to C. We hypothesize that E and K have a common ancestor (y) that is not shared by C. Similarly, two genera that more closely resemble each other than they do other genera presumably share a common ancestor. Thus, even in the absence of a fossil record it is possible to develop a phylogenetic tree. We can even infer what a common ancestor like y might have looked like.

G x K C z

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indicate an interval of one million years. Label each line so that the one at the bottom of the paper represents an age of 19 million years and the top line represents the present (0 years). Cut out all the Caminalcules (including the living species). Put them in piles according to their age (the number in parentheses). Beginning with the oldest fossils, arrange the Caminalcules according to their evolutionary relationship. Figure 4 shows how to get started.

Millions of Years Ago

Figure 4

Hints, Suggestions and Warnings a.

Draw lines faintly in pencil to indicate the path of evolution. Only after your instructor has checked your tree should you glue the figures in place and darken the lines.

Branching should involve only two lines at a time:

Like this Not this Some living forms are also found in the fossil record.

There are gaps in the fossil record for some lineages. Also, some species went extinct without leaving any descendants (remember the dinosaurs, Fig. 1).

The Caminalcules were numbered at random; the numbers provide no clues to evolutionary relationships.

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There is only one correct phylogenetic tree in this exercise. This is because of the way that Joseph Camin derived his imaginary animals. He started with the most primitive form (#73) and gradually modified it using a process that mimics evolution in real organisms. After you complete your phylogeny compare it with Camin's original.

Problems 1.

You will notice that some lineages (e.g. the descendants of species 56) branched many times and are represented by many living species. Discuss the ecological conditions that you think might result in the rapid diversification of some lineages (A real world example would be the diversification of the mammals at the beginning of the Cenozoic, right after the dinosaurs went extinct.)

Some lineages (e.g. the descendants of species 58) changed very little over time. A good example of this would be “living fossils” like the horseshoe crab or cockroach. Again, discuss the ecological conditions that might result in this sort of long-term evolutionary stasis.

Some Caminalcules went extinct without leaving descendents. In the real world, what factors might increase or decrease the probability of a species going extinct?

Find two additional examples of convergent evolution among the Caminalcules. This means finding cases where two or more species have a similar characteristic that evolved independently in each lineage. The wings of bats, birds and bees is an example of convergence since the three groups did not inherit the characteristic from their common ancestor. Write your answers in complete sentences (e.g. “Species x and y both have ____ but their most recent common ancestor, z, did not”).

List two additional real-world examples of convergent evolution (ones that we have not already talked about in class) and discuss what might have caused the convergence. 5.

Describe two examples of vestigial structures that you can find among the Caminalcules. These are structures that have been reduced to the point that they are virtually useless. Ear muscles and the tail bones are examples of vestigial structures in our own species. Explain how vestigial structures provide clues about a species’ evolutionary past. Illustrate your argument with vestigial structures found in humans or other real species.

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LIVING CAMINALCULES

FOSSIL CAMINALCULES (numbers in parentheses indicate age in millions of years)

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FOSSILS (continued)

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