Ecology and Evolution - The NSTA Website is …static.nsta.org/pdfs/store/pb153xweb.pdf · The absolute location of Milwaukee is approximately N 43°, W 88°. Your students could

Written and Adapted byRichard Benz

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Introduction

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Introduction vii

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Evolution15. Evolution of Evolutionary Thought 155

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table of contents


Introduction

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Acknowledgments

About the Author

Richard Benz has taught science for 27 years at Wickliffe High School in Lake County, Ohio. During those years he hastaught four levels of biology, Earth science, photography, and a science research course, and has served as the sciencechair since 1978. In addition to teaching at Wickliffe, he teaches in-service classes to teachers throughout the country inscience, science proficiency, technology, and teaching with the Internet. Mr. Benz is currently teaching an Internetcourse that deals with evolution and the nature of science, as part of the Virtual High School project.

The Ohio Academy of Science recently inducted Mr. Benz as a Fellow, and in 1987 named him Ohio Science Teacher ofthe Year. Mr. Benz also received the Presidential Award for Excellence in Science and Mathematics Teaching in 1990, in1996 was selected Outstanding Biology Teacher of America for Ohio by the National Association of Biology Teachers,received the Ohio Milken National Award in 1992, and the Disney American Teacher Award in Science in 1993. He hasalso won recognition for his work mixing media in the classroom, including the Internet and educational television.

Acknowledgments

Richard Benz would like to dedicate this book to three key influences:

• First, to my wife Betsy—my biggest promoter and greatest cheerleader.• Next, to Walter Hintz, my high school biology teacher, friend, fellow explorer, the best field naturalist I have ever

met, and the man who introduced me to the ideas of Darwin, Mendel, and Watson and Crick.• Finally, to Charles Darwin himself, a great observer, an incredible thinker, and an originator of ideas that “shook

the world of science.”

NSTA would like to thank the many people who contributed to the development of this book: Marily DeWall,Frank Watt Ireton and the team who developed The Galápagos: JASON Curriculum which provided a basis for thisproject; Laura McKie and Carole Baldwin of the Smithsonian Institution for their work on this material and theassociated Galapagos in 3D projects; reviewers Sue Cassidy, E. Barbara Klemm, Sharon Radford, Irwin L. Slesnick; fieldtesters Johanna Brandriff, Suzanne Cook, Mary Haskins, Vince Iacovelli, Steve Rich, Marilyn Rightor, Carol L. St. Clair,and Cecilia Wilson; and artist Max-Karl Winkler. Special thanks goes to Tui de Roy for her input. Ecology and Evolution:Islands of Change is produced by NSTA Press: Shirley Watt Ireton, director; Beth Daniels, managing editor; Erin Miller,associate editor; Jessica Green, assistant editor; Anne Early, editorial assistant. Erin Miller is the project editor forEcology and Evolution: Islands of Change. Copyediting by Cara Young; cover design by Linda Olliver.


Introduction

Ecology and Evolution: Islands of change ��

GALÁPAGOS:�� FRAME OF Reference


Introduction

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Ecology and Evolution: Islands of change 3

Activity 1: Where in the world?

Teacher SectionWhere In theWorld?

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Background InformationThe Galápagos Archipelago, or island group, consists of 13 large islands, sixsmaller islands, and a great number of small volcanic islets or rocca. Theseislands in the eastern Pacific Ocean are approximately 960 km west ofmainland Ecuador in South America, situated along the equator. They liealmost directly south of Chicago, Illinois, in the United States. Thegeographic position and isolation of the Galápagos are the key to the islandgroup’s natural history. To understand why the Galápagos Archipelago isfamous as a laboratory of evolution and adaptation, first it is necessary tounderstand a little about the relationship of life forms to location. Yourstudents will learn how absolute location of the islands compares withrelative location, and will discover how isolated are the Galápagos Islandsfrom the rest of the world.

Aboard the HMS Beagle, Charles Darwin traveled west from the coast ofSouth America, exploring the waters of the Galápagos Islands fromSeptember 15 through October 20, 1835. Darwin landed on at least six of thelarger islands, starting at the island now called San Cristóbal on September17, 1835 and ending at Pinta Island. The Beagle left the Galápagos and sailedtoward Tahiti on October 20.

Procedure

Part AAs a class, locate the Galápagos Islands on a globe and measure the distanceto the coast of Ecuador using a piece of string. Now take that same piece ofstring and place one end on your hometown, and find a city that is the samedistance from you as the Galápagos are from the mainland.

Distribute to each student a photocopy of a local or regional road map andthe student handout Absolute and Relative Location, and have them eachlocate a city of their choice, approximately 900–1,000 km from theirhometown. You can let students use this same city in later activities when

Activity 1

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4 National Science Teachers Association


Teacher Section researching climate and local ecology. Students should determine theabsolute location of their hometown and other familiar locations on a mapthat shows latitude and longitude. For example, if you live in Milwaukee,Wisconsin, you can choose Washington, DC, as your comparison city—it isthe same distance away as the Galápagos are from Ecuador. The absolutelocation of Milwaukee is approximately N 43°, W 88°. Your students coulddescribe the relative location of Milwaukee as approximately 1,000 kmnorthwest of Washington or 125 km almost due north of Chicago.

After completing the worksheet, discuss with your students how theythink animals and plants located in the other city would get to yours. Pointout any significant land barriers, such as bodies of water or mountains,which may hinder such traveling. If no such natural barriers exist, askstudents to imagine the two cities are separated by water, and the plants andanimals don’t swim. The colonization process will be addressed in theEcology and Islands chapter, but this activity will get your students thinkingabout these questions.

After completing this exercise, students should know where the GalápagosIslands are located, and they should understand the islands’ location in bothabsolute and relative terms.

Part BThis section of the activity will reinforce student understanding of relativegeography and will introduce students to the role of journal keeping.Students will follow Darwin’s Galápagos adventures by marking some of thelocations where he made journal entries while visiting the archipelago.

Divide students into pairs and give to each pair copies of the Map of theGalápagos Islands and Adventuring in the Archipelago: Excerpts fromDarwin’s Journal. Each site is introduced by a short quote from Darwin’sjournals or from The Voyage of the Beagle. The absolute positions (latitudeand longitude) are listed after each quote. The students should read thequote, note the absolute position, and find the site on the map of theGalápagos Islands. When students find the site they should mark it with asmall dot and list the date of the quote. As an option, students can calculatethe kilometers between stops and add those to the map.

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Teacher SectionWhen all sites have been located, students should “connect the dots” ofDarwin’s voyage around the Galápagos. As an evaluation of this activity, thestudents can discuss this part of Darwin’s journey or create a journal asthough they had accompanied Darwin on his trip.

Part CTo understand the importance of recording observations, ask students tokeep their own Fieldwork Journal. You can limit the students’ keeping ajournal to their study of evolution, or it can be continued throughout theterm. They can observe and make entries in any kind of notebook, but ahard-cover binder or a permanently bound notebook may help them to takethe assignment seriously and encourage them to continue making journalentries after this activity is over.

Distribute the handouts Adventuring in Your Own Backyard and Dr. BetsyJackson’s Journal. Use the former to guide students in setting up theirjournal. The second handout introduces students to Dr. Jackson, a fictionalcharacter who recurs throughout this book. Through her journal entries,students will be provided with information for use in certain activities. Inthis section, Dr. Jackson’s completed journal entry can serve as an examplefrom which students can model their own journals.

You can structure this activity in a number of ways. One option is to directwhere your students observe, e.g., in their own backyard or at a school site.Or, ask them to record their journey to and from school for a few days.Another alternative is to localize their observations to a small modelecosystem in a jar. Students can add a small amount of gravel, pond water,aquarium plants, and a snail to a one-quart jar, seal it, and place it in lowlight. They can start an Aquatic Ecosystem Journal as though they werenaturalists who discovered this habitat while on their own “voyage” ofdiscovery. Encourage the students to draw pictures or “field sketches” to helpillustrate and add detail to their observations. They can share theseobservations with the rest of the class at weekly intervals to encouragecontinued participation.

Develop a set of goals for students in the form of a rubric. Rubrics will varydepending on the structure you choose for each activity; share these goalswith students at the start of each section. Check student journals against therubric at regular, announced intervals throughout the unit or term.




Teacher Section StandardsThe material promoted in this activity enhances and supports studentunderstanding of the following National Science Education Standards forgrades 5–8:

Populations and Ecosystems (Life Science)A population consists of all individuals of a species that occur togetherat a given place and time. All populations living together and thephysical factors with which they interact compose an ecosystem.

Science and Technology in Society (History and Nature ofScience)Science and technology have advanced through contributions of manydifferent people, in different cultures, at different times in history.Science and technology have contributed enormously to economicgrowth and productivity among societies and groups within societies.

Scientists and engineers work in many different settings, includingcolleges and universities, businesses and industries, specific researchinstitutes, and government agencies.

Science as a Human Endeavor (History and Nature of Science)Women and men of various social and ethnic backgrounds—and withdiverse interests, talents, qualities, and motivations—engage in theactivities of science, engineering, and related fields such as the healthprofessions. Some scientists work in teams, and some work alone, but allcommunicate extensively with others.

Science requires different abilities, depending on such factors as the fieldof study and type of inquiry. Science is very much a human endeavor,and the work of science relies on basic human qualities, such asreasoning, insight, energy, skill, and creativity—as well as on scientifichabits of mind, such as intellectual honesty, tolerance of ambiguity,skepticism, and openness to new ideas.

Nature of Science (History and Nature of Science)Scientists formulate and test their explanations of nature usingobservation, experiments, and theoretical and mathematical models.Although all scientific ideas are tentative and subject to change andimprovement in principle, for most major ideas in science, there is much




Teacher Sectionexperimental and observational confirmation. Those ideas are not likelyto change greatly in the future. Scientists change their ideas about naturewhen they encounter new experimental evidence that does not matchtheir existing explanations.

History of Science (History and Nature of Science)Many individuals have contributed to the traditions of science. Studyingsome of these individuals provides further understanding of scientificinquiry, science as a human endeavor, the nature of science, and therelationships between science and society.

In historical perspective, science has been practiced by differentindividuals in different cultures. In looking at the history of manypeoples, one finds that scientists and engineers of high achievement areconsidered to be among the most valued contributors to their culture.

Assessment

Activity Exemplary Emergent Deficient

Part A Students are able to describethe differences betweenabsolute and relative locationof their own hometown. Theywill be able to locate theGalápagos Islands on a map orglobe. They can explainlatitude and longitude.

Students are able to describethe absolute location of theirhometown, but do not grasprelative directions. They havean idea where the GalápagosIslands are. They can explainlatitude and longitude.

Students cannot describerelative location. They havegreat difficulty finding theGalápagos Islands on a globeor a map. They do notunderstand latitude andlongitude.

Part B Students correctly trace Darwin’sjourney, and write a series ofjournal entries written as thoughthey were with Darwin, ordescribe a similar journey.

Students correctly traceDarwin’s journey, butcannot relate to the realjourney. They have a difficulttime describing this kind ofjourney.

Students have difficultylocating Darwin’s landingsites or areas he visited. Theycannot describe a similarjourney.

Part C Students keep a journalregularly and includeobservations of sightings. Theydescribe their journal entries totheir classmates during weeklyreview sessions.

Students keep a journalirregularly. They sometimesinclude illustrations. Theirdescriptions of observationsare sketchy.

Students often forget tomake journal entries.Journal entries are very briefand have few realobservations.




Teacher SectionAbsolute and RelativeLocation

Your teacher will give you copies of a local, regional map and a map of the eastern Pacific Ocean. On your localmap, find a city that is the same distance from your hometown as the Galápagos Islands are from mainlandEcuador. You may have to convert between the different scales on the maps.

1. What is the absolute location of your hometown and of the city you selected? (Hint: The answers are inlatitude and longitude.)

2. Describe the city in relative terms in relation to your hometown.

3. How would plants and animals get from this city to your hometown? What barriers—such as mountains orrivers—would they have to cross?

4. What is the absolute location of the Galápagos Islands? What is the relative location of the islands in relationto mainland Ecuador? What are some ways plants and animals from Ecuador might get to the Galápagos?




Teacher SectionMap of the eastern Pacific




Teacher SectionMap of the Galápagos Islands




Teacher SectionAdventuring in theArchipelago: Excerpts from

Darwin’s JournalNow that you know where the Galápagos Islands are located, you are going to

travel around this island group and get a feeling for what CharlesDarwin found when he visited the islands.

Darwin, aboard the HMS Beagle, traveled west from the coastof South America in September 1835, and arrived in the

waters of the Galápagos Islands on September 15.

Below are some entries from Darwin’s journal, withhis absolute position (defined by latitude and

longitude) following each entry. On the map yourteacher has given you, make a small dot for the

location of each quote, and write the date of thequote next to it.

Degrees are written as “ º ” and minutes as“ ´ ” and 1º equals 60´. The equator is 0º latitude,

anything located above the equator is north, andanything below the equator is south.

After you have made a dot for each quote, play “connect thedots,” starting with the first one, and connect them in order. You

will see the approximate route Darwin took during his five weeks of exploration in the Galápagos Islandsmore than 160 years ago!

Note: When Darwin wrote his journal, he referred to theislands by their English names. Because the islands are partof Ecuador, the names have been changed in Darwin’s quotesto reflect the modern Spanish names (the names Darwin usedare in parentheses). To avoid confusion, the spelling of certainwords has been updated.




Teacher Section

September 23, 1835The Beagle proceeded to Floreana (Charles) Island.This archipelago has long been frequented, first bythe buccaneers, and latterly by whalers, but it is onlywithin the last six years, that a small colony hasbeen established here. The inhabitants are betweentwo and three hundred in number; they are nearlyall people of color, who have been banished forpolitical crimes from the Republic of Ecuador, ofwhich Quito is the capital.Location: 1º15´ S, 90º20´ W

September 29, 1835We doubled the south-west extremity of Isabela(Albermarle) Island, and the next day were nearlybecalmed between it and Fernandina Island. Both arecovered with immense deluges of black naked lava,which have flowed either over the rims of the greatcaldrons, like pitch over the rim of a pot in which it hasbeen boiled, or have burst forth from smaller orifices onthe flanks; in their descent they have spread over milesof the sea-coast. On both of these islands, eruptions areknown to have taken place; and in Isabela, we saw asmall jet of smoke curling from the summit of one of thegreat craters.Location: 0º17´ S, 91º23´ W

September 17, 1835In the morning we landed on San Cristóbal (Chatham)Island, which, like the others, rises with a tame androunded outline, broken here and there by scatteredhillocks, the remains of former craters. Nothing couldbe less inviting than the first appearance. A broken fieldof black basaltic lava, thrown into the most ruggedwaves, and crossed by great fissures, is everywherecovered by stunted, sunburned brushwood, whichshows little signs of life.Location: 0º47´ S, 89º30´ W

September 19–22, 1835The Beagle sailed round San Cristóbal (Chatham),and anchored in several bays. One night I slept onshore on a part of the island, where black truncatedcones [volcanoes] were extraordinarily numerous:from one small eminence I counted sixty of them, allsurmounted by craters more or less perfect. As I waswalking along I met two large tortoises, each of whichmust have weighed at least two hundred pounds: onewas eating a piece of cactus, and as I approached, itstared at me and slowly walked away; the other gavea deep hiss, and drew in its head.Location: 1º S, 89º30´ W

Excerpts from Darwin’s Journal




Teacher Section

October 3, 1835We sailed around the northern end of Isabela(Albermarle) Island. Nearly the whole of thisside is covered with recent streams of dark-colored lavas, and is studded with craters. Ishould think it would be difficult to find in anyother part of the world, an island situatedwithin the tropics, and of such considerable size(namely 75 miles [120 km] long,) so sterile andincapable of supporting life.Location: 0º10´ N, 91º20´ W

October 8, 1835We arrived at San Salvador (James) Island. Mr.Bynoe, myself, and our servants were left herefor a week, with provisions and a tent, whilstthe Beagle went for water. We found here aparty of Spaniards, who had been sent fromFloreana (Charles) Island to dry fish, and tosalt tortoise-meat.Location: 0º10´ S, 90º50´ W

October 18, 1835Finished survey of Isabela (Albermarle)Island.Location: 0º7´ S, 91º15´ W

October 19, 1835To Pinta (Abingdon) Island.Location: 0º32´ N, 90º45´ W

October 19, 1835Darwin and Wolf Islands.Location: 1º30´ N, 91º50´ W

October 20, 1835The survey of the Galápagos Archipelago beingconcluded, we steered towards Tahiti andcommenced our long passage of 3,200 miles[5,120 km]. In the course of a few days we sailedout of the gloomy and clouded ocean-districtwhich extends during the winter far from thecoast of South America. We then enjoyed brightand clear weather, while running pleasantlyalong at the rate of 150 or 160 miles [240–256km] a day before the steady trade-wind. Thetemperature in this more central part of thePacific is higher than near the American shore.Location: 17º37´ S, 149º27´ W (off the map)

Excerpts from Darwin’s Journal




Teacher SectionAdventuring in Your OwnBackyard

Keeping a journal is a crucial part of any fieldwork. Explorers and scientists keep journalsof their investigations and adventures. Scientists keep journals to provide a permanent

record of what they witness in the natural world—like a diary of nature. When scientistslook back at pages from weeks gone by, they will know the exact day they saw a particular

animal or other natural phenomena. If you keep a journal of your observations in the samearea for several years, you will begin to notice patterns; eventually you’ll be able to predict when

certain animals will return to the area or when particular plants will bloom.

“This volume contains, in the form of a journal, a history of our voyage, and a sketch of thoseobservations in Natural History and Geology.” Thus begins The Voyage Of the Beagle, the journal

Charles Darwin kept on his voyages. Throughout his life Darwin kept many volumes of journals from hisobservations and studies of nature. He carried a small notebook wherever he went, and later transferred hisnotes to the master journal that was kept on board the Beagle.

Like Darwin, you are a field scientist studying a newly discovered habitat. To help you remember what youobserve, you will keep a journal. Scientists keep journals of their projects, and they do it for a reason: journalsare invaluable for keeping track of, and making sense of, their work.

In your journal you will share your observations about a particular environment you are investigating. You willobserve nature and ask why or how about the things you see. Why is the male cardinal a bright red, but thefemale a dull brown? Why doesn’t a cactus need a lot of water compared to most plants? How can the ant carrya piece of bread several times its size? What, why, how, and where are the overriding questions that scientistsask. You need to think about the things you observe, and your journal is the place to record your observations,questions, and hypotheses (possible explanations for what you observe).

On your first day, select a place to focus upon, and write a detailed description. Use all of your senses—whatdoes it look like, how does it smell, what sounds can you hear? Make sure to include where your place islocated (in both absolute and relative terms). For all subsequent entries, make sure to list each date and thetime you observed. See if you can find a central theme or idea, such as encountering a bird’s nest and thenrecording the changes with each observation. Make sure to record your observations each time, while yourthoughts are fresh. Your teacher will help direct your observations and your journal writing activity.

Much of what we know about the Galápagos Islands of the eighteenth and nineteenth centuries came fromjournals kept by explorers like Darwin. Remember, to be a good scientist you must be curious and you mustobserve the world around you—and you must record what you see in your field journal.




Teacher SectionDr. Betsy Jackson’s JournalBelow is a journal entry from Dr. Betsy Jackson, an ecologist working as a field researcher at the DarwinResearch Station in the Galápagos Islands. She arrived in the islands in February 1999 to research theGalápagos giant tortoise, Geochelone elephantopus. Dr. Jackson’s journal describes her observations andexperiences in the Galápagos, just as does Darwin’s journal. Here is a sample of one of the journal entries shemade soon after arriving at the Galápagos Islands.

February 12, 1999

The weather is quite different from my native Ohio. February in Ohio is usually very cold and often snowy,whereas here on the equator it is hot. There is a light rain today, but the temperature is almost 27° C. It is anincredible coincidence that I should arrive in the Galápagos on Darwin’s birthday. He was born February 12,1809; he would have been 190 years old today!

I am at the Darwin Research Station on Santa Cruz Island now. I am getting settled in and will soon travel toEspañola Island and begin my studies on the giant tortoise and other animals that are a part of the tortoiseecosystem, such as the marine iguana and the famous Darwin finches. Although Santa Cruz is one of theislands with a large human population, it is still a great place to observe nature. The highlands are interestingbecause the climate is quite different from the desert-like environment around the research station. I amlooking forward to exploring all the diverse mini-ecosystems on Santa Cruz.

I arrived on Santa Cruz after flying into the airport on Baltra Island. The ride from the northern side of theisland was exciting. We drove through many different environments as we climbed through the highlands andthen traveled back down to the arid region to the town of Puerto Ayora. Puerto Ayora is one of the largesttowns in the Galápagos. My first impression of the Darwin Research Station was how dry it is. I saw shrubytrees and cactus growing in dry, sandy soil and noticed a number of the famous small birds that Darwindescribed in his journals. These finches are rather drab and very difficult to distinguish from one another. Ihave read about Darwin’s finches, and here I was observing them flying from bush to cactus to the plantsgrowing along the road.

As I walked from the town to the research station I saw a number of small buildings that housed both theadministrative offices and the laboratories of the station. Just past the labs I came upon three tortoise pens ina visitor center, operated by the Galápagos National Park. The tortoises in these pens are studied by thescientists at the Darwin Station, but cannot be used for breeding purposes because scientists do not knowwhat island they originally came from. Visitors are allowed to get very close to these giants, but they cannottouch them or get in the way of their feeding area. I sat and watched two male tortoises exhibiting a “posturingbehavior” by standing and stretching their necks to the sky while facing one another. They stood with theirmouths wide open. It almost seemed like one was waiting for the other one to back down.




Teacher Section

It was getting late and I still had not checked in at the office of the research station, but I had one more stop Iwanted to make. The Galápagos National Park, along with the research station, has set up a “Tortoise RearingStation.” The park wardens collect tortoise eggs from the wild and bring them here. The eggs are endangeredin the wild because introduced animals that are not native to the islands (such as dogs or goats) will eat them.So, the eggs are collected, marked, and brought to the research station. I also had the fun of seeing youngtortoises that were only one- or two-years old scrambling towards dinner—large bunches of vegetationprovided by their human caretakers. It is hard to believe a small animal less than 10 cm across will somedaygrow into a giant tortoise weighing more than 11 kilos (400 pounds)! Each young tortoise has anidentification number painted on its shell so the scientists can study it and be able to identify which island itcame from so it can be released when it is big enough to defend itself from the introduced animal predators.

This afternoon I am going to observe the most famous Galápagos tortoise of them all—Lonesome George.George is a visitor at the Research Station because he is being studied. He is thought to be the very last tortoiseof the subspecies that inhabited Pinta Island to the north. Just think, the very last one alive. Sad!! But I guessthat is one of the reasons I am going to study the giant tortoise—to find out if they are in danger of extinctionand just what can be done about it. Well George, I’m excited to finally meet you!!!

Dr. Betsy Jackson’s Journal

Tortoise’s Long Distance CallThe Washington Post, November 15, 1999.

The Galápagos Islands off the coast of Ecuador helped inspire Charles Darwin’srenowned theory of evolution.

The islands are home to some of the world’s most exotic creatures, including thegiant Galápagos tortoise, which can grow up to 5 feet long and weight up to 650pounds, making it the world’s largest living tortoise.

Only one male of one subspecies of the tortoise remains alive today.

Conservation scientists have been trying to mate him with females from theislands closest to his to keep the subspecies alive. But “Lonesome George” has never shown any interest. Now,researchers think they know why.

An international team of scientists from Yale University in New Haven, Conn., the State University of New York inSyracuse, and the University of Rome in Italy analyzed the genes of tortoise species around the world. To their surprise,the researchers found that George is more closely related to tortoises found on the islands of Española and SanCristóbal, which are farthest from George’s original home island of Pinta.

“This finding may provide guidance in finding a mate for Lonesome George, who so far has failed to reproduce,” theresearchers wrote in the Nov. 9 issue of the Proceedings of the National Academy.

©1999, The Washington Post. Reprinted with permission.

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Ecology and Evolution - The NSTA Website is …static.nsta.org/pdfs/store/pb153xweb.pdf · The absolute location of Milwaukee is approximately N 43°, W 88°. Your students could