unlvcoe.org€¦ · web viewevolution is the consequence of the interactions of (1) the potential...

TopicBiological Evolution and Problem Solving

Key QuestionHow do you create an evolutionary tree for DNA fragments contained in fossilized samples?

Learning GoalsStudents will: Use information from a table to create

the most time-efficient schedule Make decisions about whether or not

a solution meets the needs of a client Communicate the solution clearly to

the client

Guiding Documents This activity has the potential to address these and other mathematics and science standards, as well as address engineering principles.

Grades 9 -12 NSES Science StandardsUnifying Concepts

- Systems, order and organization- Evidence, Models, and explanation- Change, constancy, and

measurement- Evolution and equilibriumInquiry

- Abilities necessary to do scientific inquiry

o A. Identify Questions and Concepts that guide scientific investigations.

o C. Use technology and mathematics to improve investigations and communications

o D. Formulate and revise scientific explanations and models using logic and evidence

o E. Recognize and analyze alternative explanations and models

o F. Communicate and defend a scientific argument

- Understandings about scientific inquiry

o C. Scientists rely on technology to enhance the gathering and manipulation of data.

o D. Mathematics is essential in scientific inquiry.

o E. Scientific explanations must adhere to criteria such as: a proposed explanation must be logically consistent; it must abide by the rules of evidence; it must be open to questions and possible modification; and it must be based on historical and current scientific knowledge.

o F. Results of scientific inquiry—new knowledge and methods—emerge from different types of investigations and public communication among scientists. In communicating and defending the results of scientific inquiry, arguments must be logical and demonstrate connections between natural phenomena, investigations, and the historical body of scientific knowledge. In addition, the methods and procedures that scientists used to obtain evidence must be clearly reported to enhance opportunities for further investigation.

Life Science

- The molecular basis of heredityo A. In all organisms, the instructions

for specifying the characteristics of the organism are carried in DNA, a large polymer formed from subunits of four kinds (A, G, C, and T).

o C. Changes in DNA (mutations) occur spontaneously at low rates.

- Biological Evolutiono A. Species evolve over time. Evolution

is the consequence of the interactions of (1) the potential for a species to increase its numbers, (2) the genetic variability of offspring due to mutation and recombination of genes, (3) a finite supply of the resources required for life, and (4) the ensuring selection by the environment of those offspring better able to survive and leave offspring.

© 2008 University of Minnesota Evolution Tree Model-Eliciting Activity 1

o C. Natural selection and its evolutionary consequences provide a scientific explanation for the fossil record of ancient life forms, as well as for the striking molecular similarities observed among the diverse species of living organisms.

o D. The millions of different species of plants, animals, and microorganisms that live on earth today are related by descent from common ancestors.

o E. Biological classifications are based on how organisms are related. Organisms are classified into a hierarchy of groups and subgroups based on similarities which reflect their evolutionary relationships. Species is the most fundamental unit of classification.

Earth Science

- Origin and Evolution of the earth system

o B. Geologic time can be estimated by observing rock sequences and using fossils to correlate the sequences at various locations.

o D. Evidence for one-celled forms of life—the bacteria—extends back more than 3.5 billion years.

Science and Technology

- Abilities of technological designo A. Identify a problem or design an

opportunityo B. Propose designs and choose

between alternative solutions.o D. Evaluate the solution and its

consequences.o E. Communicate the problem,

process, and solution- Understandings about science and

technologyo A. Scientists in different disciplines

ask different questions, use different methods of investigation, and accept different types of evidence to support their explanations. Many scientific investigations require the contributions of individuals from different disciplines, including engineering.

o B. Science often advances with the introduction of new technologies. Solving technological problems often

results in new scientific knowledge. New technologies often extend the current levels of scientific understanding and introduce new areas of research.

o C. Creativity, imagination, and a good knowledge base are all required in the work of science and engineering.

History and Nature of Science- Science as a Human Endeavor- Nature of Scientific Knowledgeo A. Scientists strive for the best

possible explanations about the natural world.

o B. Scientific explanations must meet certain criteria. First and foremost, they must be consistent with experimental and observational evidence about nature, and must make accurate predictions, when appropriate, about systems being studied. They should also be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public.

o C. Because all scientific ideas depend on experimental and observational confirmation, all scientific knowledge is, in principle, subject to change as new evidence becomes available.

Common Core Math Standards

7.SP. 8 Find probabilities of compound

© 2008 University of Minnesota Evolution Tree Model-Eliciting Activity2

events using organized lists, tables,tree diagrams, and simulation.

b. Represent sample spaces for compound events using methods such as organized lists, tables and tree diagrams. For an event described in everyday language (e.g., “rolling double sixes”), identify the outcomes in the sample space which compose the event.


Recommended supplies for all MEAsIt is recommended to have all of these supplies in a central location in the room. It is recommended to let the students know that they are available, but not to encourage them to use anything in particular.

Overhead transparencies, transparency markers/pens, and other presentation tools such as a document camera.

Calculators Rulers, scissors, tape Markers, colored pencils, pencils Construction paper, graph paper,

lined paper Paper towels or tissues (for

cleaning transparencies) Manila folders or paper clips for

collecting the students’ work Optional: Computers with

programs such as Microsoft Word and Excel

What are Model Eliciting Activities (MEAs)?Model-Eliciting Activities are problem activities explicitly designed to help students develop conceptual foundations for deeper and higher order ideas in mathematics, science, engineering, and other disciplines. Each task asks students to mathematically interpret a complex real-world situation and requires the formation of a mathematical description, procedure, or method for the purpose of making a decision for a realistic client. Because teams of students are producing a description, procedure, or method (instead of a one-word or one-

number answer), students’ solutions to the task reveal explicitly how they are thinking about the given situation.

The Evolutionary Tree MEA consists of four components: 1) Newspaper article: Students individually read the newspaper article to become familiar with the context of the problem. This handout is on page 7-10.2) Readiness questions: Students individually answer these reading comprehension questions about the article to become even more familiar with the context and beginning thinking about the problem. This handout is on page 11.3) Problem statement: In teams of three or four, students work on the problem statement for 45 – 90 minutes. This time range depends on the amount of self-reflection and revision you want the students to do. It can be shorter if you are looking for students’ first thoughts, and can be longer if you expect a polished solution and well-written letter. The handouts are on pages 12-13. Each team needs the handouts on pages 12-13. There is a follow-up question on page 14 to help students extend their knowledge about evolutionary trees. 4) Process of sharing solutions: Each team writes their solution in a letter or memo to the client. Then, each team presents their solution to the class. Whole class discussion is intermingled

© 2008 University of Minnesota Evolution Tree Model-Eliciting Activity 4

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with these presentations to discuss the different solutions, the mathematics involved, and the effectiveness of the different solutions in meeting the needs of the client. In totality, each MEA takes approximately 2-3 class periods to

implement, but can be shortened by having students do the individual work during out-of-class time. The Presentation Form can be useful and is explained on page 5 and found on page 16.


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Recommended Progression of the MEAPreparation activity: It is useful to prepare the students to work on the Evolutionary Tree MEA by discussing the types of mutations that can affect DNA, as well as defining a general concept of evolution. You may also want to include an activity regarding construction of cladograms.

Newspaper Article and Readiness Questions: The purpose of the newspaper article and the readiness questions is to introduce the students to the context of the problem. Depending on the grade level and/or your instructional purposes, you may want to use a more teacher-directed format or a more student-directed format for going through the article and the questions. Some possibilities include:

a. More teacher-directed (½ hour): Read the article to the students and give them class time to complete the readiness questions individually. Then, discuss as a class the answers to the readiness questions before beginning work on the problem statement. This approach also works well when you can team with a language arts teacher, and they can go through the article in their class. b. More student-directed (10 minutes): Give the article and the questions to the students the day before for homework. If you wish, you may provide some class time for the students to complete the article

and questions. Then, on the day of the case study, discuss as a class the answers to the readiness questions before beginning work on the problem statement. c. More student-directed (10-15 minutes): Give the article and the questions to the students in their teams right before the students begin working on the problem statement. The students answer the questions as a team and then proceed to work on the problem statement.

Working on the Problem Statement (45-90 minutes): Place the students in teams of three or four. If you already use teams in your classroom, it is best if you continue with these same teams since results for MEAs are better when the students have already developed a working relationship with their team members. If you do not use teams in your classroom and classroom management is an issue, the teacher may form the teams. If classroom management is not an issue, the students may form their own teams. You may want to have the students choose a name for their team to promote unity. Encourage (but don’t require or assign) the students to select roles such as timer, collector of supplies, writer of letter, etc. Remind the students that they should share the work of solving the problem. Present the students with the problem statement. Depending on the students’ grade level and previous experience with


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MEAs, you may want to read the problem statement to the students and then identify as a class: a) the client that the students are working for and b) the product that the students are being asked to produce. Once you have addressed the points above, allow the students to work on the problem statement.

Teachers’ role: As they work, your role should be one of a facilitator and observer. Avoid questions or comments that steer the students toward a particular solution. Try to answer their questions with questions so that the student teams figure out their own issues. Also during this time, try to get a sense of how the students are solving the problem so that you can ask them questions about their solutions during their presentations.

Presentations of Solutions (30-45 minutes): The teams present their solutions to the class. There are several options of how you do this. Doing this electronically or assigning students to give feedback as out-of-class work can lessen the time spent on presentations. If you choose to do this in class, which offers the chance for the richest discussions, the following are recommendations for implementation. Each presentation typically takes 3 – 5 minutes. You may want to limit the number of presentations to five or six or limit the number of

presentations to the number of original (or significantly different) solutions to the MEA.

Before beginning the presentations, encourage the other students to not only listen to the other teams’ presentations but also to a) try to understand the other teams’ solutions and b) consider how well these other solutions meet the needs of the client. You may want to offer points to students that ask ‘good’ questions of the other teams, or you may want students to complete a reflection page (explanation – page 6, form – page 17) in which they explain how they would revise their solution after hearing about the other solutions. As students offer their presentations and ask questions, whole class discussions should be intermixed with the presentations in order to address conflicts or differences in solutions. When the presentations are over, collect the student teams’ memos/letters, presentation overheads, and any other work you would like to look over or assess.

Assessment of Students’ WorkYou can decide if you wish to evaluate the students’ work. If you decide to do so, you may find the following Assessment Guide Rubric helpful:

Performance Level Effectiveness: Does the solution meet the client’s needs? Requires redirection: The product is on the wrong track. Working longer or harder with this


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approach will not work. The students may need additional feedback from the teacher.

Requires major extensions or refinements: The product is a good start toward meeting the client’s needs, but a lot more work is needed to respond to all of the issues.

Requires only minor editing: The product is nearly ready for the client to use. It still needs a few small modifications, additions, or refinements. Useful for this specific situation: No changes are necessary to meet the client’s immediate needs.

Share-able or re-usable: The tool not only works for the immediate solution, but it would be easy for others to modify and use in similar situations. OR The solution goes above and beyond meeting the immediate needs of the client.


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Implementing an MEA with Students for the First TimeYou may want to let students know the following about MEAs: MEAs are longer problems;

there are no immediate answers. Instead, students should expect to work on the problem and gradually revise their solution over a period of 45 minutes to an hour.

MEAs often have more than one solution or one way of thinking about the problem.

Let the students know ahead of time that they will be presenting their solutions to the class. Tell them to prepare for a 3-5 minute presentation, and that they may use overhead transparencies or other visuals during their presentation.

Let the students know that you won’t be answering questions such as “Is this the right way to do it?” or “Are we done yet?” You can tell them that you will answer clarification questions, but that you will not guide them through the MEA.

Remind students to make sure that they have returned to the problem statement to verify that they have fully answered the question.

If students struggle with writing the letter, encourage them to read the letter out loud to each other. This usually helps them identify omissions and errors.

Observing Students as They Work on the Evolutionary Tree MEAYou may find the Observation Form (page 15) useful for making

notes about one or more of your teams of students as they work on the MEA. We have found that the form could be filled out “real-time” as you observe the students working or sometime shortly after you observe the students. The form can be used to record observations about what concepts the students are using, how they are interacting as a team, how they are organizing the data, what tools they use, what revisions to their solutions they may make, and any other miscellaneous comments.

Presentation Form (Optional)As the teams of students present their solutions to the class, you may find it helpful to have each student complete the presentation form on page 16. This form asks students to evaluate and provide feedback about the solutions of at least two teams. It also asks students to consider how they would revise their own solution to the Evolutionary Tree MEA after hearing of the other teams’ solutions.

Student Reflection FormYou may find the Student Reflection Form (page 17) useful for concluding the MEA with the students. The form is a debriefing tool, and it asks students to consider the concepts that they used in solving the MEA and to consider how they would revise their previous solution after hearing of all the different solutions presented by the various teams. Students typically fill out


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this form after the team presentations.

Follow-UpActivities (Optional)

Included is a follow-up activities that may extend the activity

beyond the MEA. This allows students to evaluate another solution and an additional opportunity for students to test their models. This activity is on page 14.


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Tree of life continues to evolveGenetic comparisons of different animals realign branches

By Carl Zimmer

Globe Correspondent / April 28, 2008

Casey Dunn has gathered his share of weird animals. He dredged up sea spiders that live around the docks in Waikiki. He dived to the sea floor to scoop up mud, in search of bizarre, spiny creatures called kinorhynchs that are smaller than a grain of sand.

Dunn, a biologist at Brown University, hunts for weird animals to get his hands on their DNA. Hidden in their genes is a record of the history of the entire animal kingdom, some 700 million years of evolutionary change.

By analyzing the DNA of dozens of different kinds of animals, he and his colleagues have made some astounding discoveries about animal evolution. For one thing, the common ancestor of all living animals may have been more complicated than once thought.

While scientists have been analyzing DNA for a few decades now, this work is different. Instead of comparing a fragment of a single gene, as a scientist might have done 10 years ago, Dunn and his contemporaries can search through all of the DNA in an animal - its entire genome.

Comparative genomics, as this young science is known, is having a huge impact on biology, helping scientists answer many of science's deepest questions. It promises, for example, to shed light on how our genes make us prone to diseases, and how the genes of pathogens make them deadly.

"It has created a revolution in our ability to understand biology," said Steven Brenner, a computational biologist at the University of California at Berkeley.

Before comparative genomics, some researchers worried that they might never understand early animal evolution well. It's like watching a card game a mile away through a telescope. The details can be blurry.

"You have to look over this long distance to something that was relatively quick," Dunn said. "A lot of people wondered if we could ever find out how the major groups of animals are related to each other."

Dunn and his colleagues have now shown that they can.

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The scientists have analyzed the biggest collection of data on animals ever assembled. They combined data on DNA from 77 different species, as varied as sponges, oysters, and humans. Some of the data came from earlier research by other scientists. Dunn and his colleagues also searched for obscure animals to get a wider selection. "It took us a couple years to get everything together," Dunn said.

With that information, they were able to reconfigure the tree of life.

They identified pivotal genes in all 77 species that they thought would provide insight into evolution. They then narrowed down this list of 3,000 or so genes to 150 that would provide the most insight into evolution.

"We needed to run over 100 computers for months on end to even make sense of this data," Dunn said.

"One of the most important results is that we get a result," he said. Instead of being lost in an ancient blur, many of the branches of the animal kingdom came into focus in their study. "It was a bit of a relief."

Some of the results confirmed relationships based on anatomy. The closest relatives to vertebrates, for example, include echinoderms (a group that includes starfish). But other results were surprising.

Two of the most species-rich groups of animals are the insects and nematodes, such as roundworms. For years, many scientists argued that insects were more closely related to us than nematodes. For evidence, they pointed to traits that insects and vertebrates share, such as an inner body cavity, which nematodes lack. But the new study supports a different view of animal evolution: Insects and nematodes are more closely related to each other than either is to us.

This result is not just important for understanding how animals evolved. (In this case, it appears that nematodes lost their body cavity after they branched off from the ancestors of insects.) The better scientists understand how insects and nematodes are related to us, the better they can translate the results of experiments on these animals to human biology.

"The human genome sequence would be nearly worthless without the value added by evolutionary comparisons to other organisms," said Mark Pallen, an evolutionary biologist at the University of Birmingham in England.

The biggest surprise of the new study lies at the very base of the animal tree. Traditionally, scientists have considered sponges to belong to the oldest lineage of living animals. The next oldest lineages produced a group of species that included jellyfish and comb jellies, known as ctenophores. According to this view, the common ancestor of living animals was relatively simple. Only after the ancestors of sponges branched off did a nervous system begin to evolve.

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Dunn and his colleagues discovered to their surprise that the comb jelly lineage is the oldest. To test this result, Steven Haddock of the Monterey Bay Aquarium used a remote submersible to catch another species of comb jelly to analyze. It turned out that their original comb jelly had not been a genetic fluke.

Their discovery does not mean that our ancestors looked like comb jellies, Dunn stresses. "That's like saying that your cousin is your grandpa," he said. Much of the comb jelly's anatomy probably evolved after its ancestors split off from the ancestors of other living animals.

But the fact that comb jellies and most other animals share a nervous system suggests that their common ancestor did as well. Rather than being simple, as once thought, the common ancestor of living animals had already evolved to be relatively complex. And once the ancestors of sponges branched off, they must have lost their nervous system and evolved into filter feeders anchored to the sea floor. (They'd hardly be the only animals to have lost traits - consider the missing body cavity in nematodes, or our own vestigial tail bones.)

"It looks like there are both gains of complexity and reductions across the animal tree," Dunn said.

Other experts have praised the new study. "While clearly not the last word, this study represents the state of the art in animal phylogenies," Maximilian Telford of University College London wrote in the journal Developmental Cell.

Dunn predicts that comparative genomics will help tease out the relationships of other major groups of species, such as plants and bacteria. As prices continue to fall and methods continue to improve, the entire tree of life will come increasingly into focus. Scientists will be able to use the tree to trace the history of individual genes. Some of those genes make humans vulnerable to diseases such as diabetes and obesity. Other genes, shared among bacteria, boost their danger to our health.

Computers and DNA sequencers can't substitute for the hard work of searching for life's diversity. "If we're going to get serious about understanding how all things are related to each other, the real challenge is going to be the one that naturalists faced 200 years ago," he said. The one bottleneck Dunn foresees is the need to find more species.

© Copyright 2008 Globe Newspaper Company.

The original article can be found at:

http://www.boston.com/news/science/articles/2008/04/28/tree_of_life_continues_to_evolve/



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Readiness Questions

The attached article was published in the Boston Globe on April 28, 2008. Please read the article and review its diagram. Considering the article, the diagram and what you have learned in class about common mutations of the DNA, answer the following questions individually:

1. What are three surprising findings in the article?

2. Based on the article, did humans evolve from Jellyfish? Explain.

3. What are the three common mutations that we have discussed in class?

4. Consider the following evolution tree:

It is known that the following species posses the following DNA sequences for the same gene location:

A - ATA.CCA.CGT.ACT.TTC.GAG

B – ATA.CCA.CGT.ACT.TTC.GAT

C – TTA.CCA.CGT.ACT.TTC.

D – TTG.CCG.CGT.GCT.TTC.

E – ATA.CCA.CGT.ACT.TTC.

Based on your knowledge of common DNA mutations, list possible reasons that could account for the different modern species at A, B, C, D, and E.

Considering the DNA sequences for A-E and the sources you identified above as a potential mutation sequence, what could be the full base-pair sequence of the common ancestors at points 2 and 3? Justify your answer.

24

3

1

EvoTree DNA Sequencing LTDA

CTG

ATTG

To: Support Team (DNA Experts)

EvoTree Programmers

From: C. D. Arwin, VP of R&D

Subject: Evolution tree instructions

On behalf of EvoTree Company, I wish to welcome you to our team.

As you may know, EvoTree is a start-up company focused around a patented product, the “Extractor”. This is an underwater robot designed to collect rock samples from the bottom of the ocean. What makes the Extractor so unique is its ability to extract DNA samples from fossils within the rocks it collects. This is a great tool to support DNA research in many areas. Our team is currently working on adjusting the ‘Extractor’ to operate in extreme conditions for NASA.

However, we think that the “Extractor” can do much more. We would like to program the “Extractor” to create an evolutionary tree out of the DNA sequences it extracts. As the DNA experts, we need you to design a model that our programmers could use to program the “Extractor” to create evolutionary trees.

Your written instructions will be shared with EvoTree programmers. Provided are DNA samples from three digging sites in different areas of the Pacific Ocean. Although you will be working to create your model from these data, the model that you write should be generalizable to any site. Your model should work with any given samples of DNA.

At each of the three digging sites, the “Extractor” collected rock samples at four different depths: 1000m, 1500 m, 2000m, and 2500m below sea level. Please use these data to create your set of instructions for our programmers. Again, the instructions should be general enough so the final program would be able to create an evolution tree from any set of DNA samples.

Thank you,

C. D. Arwin

depth

DNA samples

Based on the location & depth DNA was found

Please use the DNA table to create:

A cladogram for each site. Based on these cladograms, write a set of instructions for the company’s

programmers describing how to create an evolution tree from multiple DNA samples. Remember, your instructions should be written in a general form, so the Extractor would be able to develop an evolution tree from ANY kind & number of DNA sequences.

* Each line of DNA represents a single species fossil.

Be ready to share your work during the next class period.

Depth/Sample -1,000m -1,500m -2,000m -2,500m

A TTA.ATT.TTT.TTTA.ATG.TTT.TTTTA.ATC.TTT.TTTTA.ATT.TTG.TT

TAA.TTT.TTT.GTTA.ATT.TTT.TG

TAA.TTT.TTT.GGG

TAA.CCC.TTT.GGGTAA.TTT.TTT.GGG

AAA.CCC.TTT.GGAAAA.CCC.TTT.GGG

B CAC.AAT.TTA.AACAC.AAA.TTT.AAA

CGC.AAT.TTG.G

CGC.AAT.TTG.GGCGC.AAT.TTG.G

CGC.AAT.TTT.GGGCGC.TTT.TTT.GGG

CGC.AAT.TTT.GGATGT.AAT.TTT.GGA

C AGG.AGT.TTGCCA.GGA.GCC.CG

CCA.GGA.GCG.CCG

TTA.GGA.GTT.TGAGG.AGT.TTG

TTA.GGA.GTT.T

AGG.AGT.TTGGAG.GAG.TTT.G

GAG.GAG.TTT.GGGGAG.GAG.TTT.G

Model Extension Activity – Evolutionary Tree MEA

Recently, a group of scientists published an evolution tree based on DNA samples from location C.

Review the model below and comment on its accuracy according to your guidelines. Does it follow your list of instructions? Explain.

GAG.GAG.TTT.GGG

GAG.GAG.TTT.G

GAG.GAG.TTT.GGG

AGG.AGT.TTG

TTA.GGA.GTT.T TTA.GGA.GTT.TG

CCA.GGA.GCC.CG CCA.GGA.GCG.CCG

-2500m

-2000m

-1500m

-1000m

OBSERVATION FORM FOR TEACHERS- Evolutionary Tree MEA

Team: _______________________________________

STEM (Science, Technology, Engineering, & Mathematics)What STEM concepts and skills did the students use to solve the problem?

Team Interactions: How did the students interact within their team or share insights with each other?

Data Organization & Problem Perspective: How did the students organize the problem data? How did the students interpret the task? What perspective did they take?

Tools: What tools did the students use? How did they use these tools?

Miscellaneous Comments about the team functionality or the problem:

Cycles of Assessment & Justification: How did the students question their problem-solving processes and their results? How did they justify their assumptions and results? What cycles did they go through?

PRESENTATION FORM – Evolutionary Tree MEA

Name________________________________________________

While the presentations are happening, choose TWO teams to evaluate. Look for things that you like about their solution and/or things that you would change in their solution. You are not evaluating their style of presenting. For example, don’t write, “They should have organized their presentation better.” Evaluate their solution only.

Team ___________________________________

What I liked about their solution:

What I didn’t like about their solution:

Team ___________________________________

What I liked about their solution:

What I didn’t like about their solution:

After seeing the other presentations, how would you change your solution? If you would not change your solution, give reasons why your solution does not need changes.

STUDENT REFLECTION FORM – Evolutionary Tree MEA

Name _________________________________Date__________________________

1. What mathematical or scientific concepts and skills (e.g. ratios, proportions, forces, etc.) did you use to solve this problem?

2. How well did you understand the concepts you used?

Not at all A little bit Some Most of it All of it

Explain your choice:

3. How well did your team work together? How could you improve your teamwork?

4. Did this activity change how you think about mathematics?