How-To-Do-It A Toilet Paper Timeline of Evolution 5 E Cycle on the Concept of Scale Thomas O’Brien The theory of evolution of the Earth system including both geological and biochemical parameters is challenging for both teachers to teach and students to learn due to a number of synergisti- cally interactive conceptual, historical, methodological, philosophical, politi- cal and theological factors (see Miller 1998 and National Academy of Sci- ences 1998 & 1999). In fact, the AAAS Benchmarks (1993) argues that: In the twentieth century, no scientific theory has been more difficult for people to accept than biological evolution by natural selection. It goes against some people’s strongly held beliefs about when and how the world and the living things in it were created. It hints that human beings had lesser creatures as ancestors, and it flies in the face of what people can plainly see . . . (p. 122). That this is the case is clearly evident in the long running debate over teach- ing evolution in public schools [see the eight-part series ‘‘Creationism in the United States’’ in The American Biology Teacher, September 1998 to May 1999]. This debate continues to the recent situation in which the state of Kansas has removed any mention of the theory from its curricular stan- dards and assessments. Yet, there is near universal consensus among scien- tists and science educators that evolu- tion is a central explanatory and pre- dictive theory that demands attention in both biology and geology curricula. While teachers cannot be expected to single-handedly resolve the reli- gious and political issues surrounding the misconstrued and ill-constructed ‘‘evolution 4 atheism vs. creationism Thomas O’Brien, Ph.D., is an Associate Professor of Graduate K-12 Science Education in the School of Education & Human Development at Bingham- ton University, Binghamton, NY 13902- 6000; e-mail: [email protected]. 578 THE AMERICAN BIOLOGY TEACHER, VOLUME 62, NO. 8, OCTOBER 2000 debate,’’ they can and should be expected to confront students’ motiva- tional barriers and misconceptions about evolution and the nature of sci- entific inquiry. Unfortunately, all too frequently, core scientific concepts and theories such as evolution are ‘‘taught’’ without adequate attention to: 1. Personal and social relevance and usefulness 2. Analogies and models or physical representations that make other- wise abstract, counter-intuitive and difficult-to-conceive ideas more ‘‘sensible’’ 3. A sense of ‘‘how we know (or at least tentatively believe) what we know,’’ including especially the interconnections with other scien- tific concepts and theories 4. The amount of time it takes to effect conceptual change and meaningful, lasting learning. Without these components, science is presented as a form of indoctrination, wherein students are expected to quickly, mindlessly accept (and subse- quently regurgitate) the ‘‘answers’’ from the unquestioned authority of the textbook and teacher. Such a ‘‘rhetoric of conclusions’’ type approach does not usually raise concerns among par- ents (perhaps regrettably so), because most scientific concepts and theories do not seem to pose a challenge to their more personal, deeply held religious and/or philosophical beliefs, whereas evolution does challenge those who believe in a strict, literal interpretation of the Bible. Clearly, teachers need high-quality hands-on/minds-on activ- ities that make the theory of evolution sensible and relevant via an extended ‘‘dialogue of discovery’’ and reasoned argumentation. Books published by the National Academy of Sciences (1998), the National Association of Biology Teachers (McComas 1994) and The Woodrow Wilson National Fel- lowship Foundation (1995) are won- derful sources of such activities. The following 5 E Teaching Cycle (see Trowbridge et al. 2000 for a gen- eral discussion on 5 E Teaching Cycles) was designed for and tested in a series of two-week teacher institutes titled ‘‘Evolution and the Nature of Scientific Inquiry’’ which ran at Binghamton University in the summers of 1996-99 with the support of a grant from the Howard Hughes Medical Institute. It has subsequently proven to be one of the most used teaching cycles from the institute in both grade 7/life sci- ence and grade 10/biology classrooms. It addresses one of the more basic, discrepant and truly mind-boggling conceptual barriers related to the the- ory of evolution: the idea of geologic time. Most people have trouble con- ceptualizing numbers larger than a thousand, much less the millions and billions of years of Earth history. The National Science Education Standards clearly identify this as an issue: ‘‘in studying the evolution of the Earth system over geologic time . . . [to] . . . unravel the interconnected story of Earth’s dynamic crust, fluctuating cli- mate, and evolving life forms.... The challenge of helping students to learn the content of this standard will be to present understandable evidence from sources that range over immense time scales.... Many students are capable of doing this kind of thinking, but as many as half will need concrete examples and considerable help in fol- lowing the multistep logic necessary to develop the understandings’’ (National Research Council 1995, p. 188). This sentiment was also expressed in the AAAS Benchmarks (1993): ‘‘Most vari- ables in nature . . . show immense dif- ferences in magnitude. ... A million becomes meaningful, however, as a thousand thousands, once a thousand becomes comprehensible. Particularly important senses of scale to develop for science literacy are . . . the enormous
Transcript
How-To-Do-It
A Toilet Paper Timeline of Evolution5 E Cycle on the Concept of Scale
Thomas O’Brien
The theory of evolution of the Earthsystem including both geological andbiochemical parameters is challengingfor both teachers to teach and studentsto learn due to a number of synergisti-cally interactive conceptual, historical,methodological, philosophical, politi-cal and theological factors (see Miller1998 and National Academy of Sci-ences 1998 & 1999). In fact, the AAASBenchmarks (1993) argues that:
In the twentieth century, no scientifictheory has been more difficult for peopleto accept than biological evolution bynatural selection. It goes against somepeople’s strongly held beliefs about whenand how the world and the living thingsin it were created. It hints that humanbeings had lesser creatures as ancestors,and it flies in the face of what peoplecan plainly see . . . (p. 122).
That this is the case is clearly evidentin the long running debate over teach-ing evolution in public schools [seethe eight-part series ‘‘Creationism inthe United States’’ in The AmericanBiology Teacher, September 1998 to May1999]. This debate continues to therecent situation in which the state ofKansas has removed any mention ofthe theory from its curricular stan-dards and assessments. Yet, there isnear universal consensus among scien-tists and science educators that evolu-tion is a central explanatory and pre-dictive theory that demands attentionin both biology and geology curricula.
While teachers cannot be expectedto single-handedly resolve the reli-gious and political issues surroundingthe misconstrued and ill-constructed‘‘evolution 4 atheism vs. creationism
Thomas O’Brien, Ph.D., is an AssociateProfessor of Graduate K-12 ScienceEducation in the School of Education& Human Development at Bingham-ton University, Binghamton, NY 13902-6000; e-mail: [email protected].
578 THE AMERICAN BIOLOGY TEACHER, VOLUME 62, NO. 8, OCTOBER 2000
debate,’’ they can and should beexpected to confront students’ motiva-tional barriers and misconceptionsabout evolution and the nature of sci-entific inquiry. Unfortunately, all toofrequently, core scientific concepts andtheories such as evolution are ‘‘taught’’without adequate attention to:
1. Personal and social relevanceand usefulness
2. Analogies and models or physicalrepresentations that make other-wise abstract, counter-intuitiveand difficult-to-conceive ideasmore ‘‘sensible’’
3. A sense of ‘‘how we know (or atleast tentatively believe) what weknow,’’ including especially theinterconnections with other scien-tific concepts and theories
4. The amount of time it takes toeffect conceptual change andmeaningful, lasting learning.
Without these components, science ispresented as a form of indoctrination,wherein students are expected toquickly, mindlessly accept (and subse-quently regurgitate) the ‘‘answers’’from the unquestioned authority of thetextbook and teacher. Such a ‘‘rhetoricof conclusions’’ type approach doesnot usually raise concerns among par-ents (perhaps regrettably so), becausemost scientific concepts and theoriesdo not seem to pose a challenge to theirmore personal, deeply held religiousand/or philosophical beliefs, whereasevolution does challenge those whobelieve in a strict, literal interpretationof the Bible. Clearly, teachers needhigh-quality hands-on/minds-on activ-ities that make the theory of evolutionsensible and relevant via an extended‘‘dialogue of discovery’’ and reasonedargumentation. Books published bythe National Academy of Sciences(1998), the National Association ofBiology Teachers (McComas 1994) andThe Woodrow Wilson National Fel-
lowship Foundation (1995) are won-derful sources of such activities.
The following 5 E Teaching Cycle(see Trowbridge et al. 2000 for a gen-eral discussion on 5 E Teaching Cycles)was designed for and tested in a seriesof two-week teacher institutes titled‘‘Evolution and the Nature of ScientificInquiry’’ which ran at BinghamtonUniversity in the summers of 1996-99with the support of a grant from theHoward Hughes Medical Institute. Ithas subsequently proven to be one ofthe most used teaching cycles fromthe institute in both grade 7/life sci-ence and grade 10/biology classrooms.It addresses one of the more basic,discrepant and truly mind-bogglingconceptual barriers related to the the-ory of evolution: the idea of geologictime. Most people have trouble con-ceptualizing numbers larger than athousand, much less the millions andbillions of years of Earth history. TheNational Science Education Standardsclearly identify this as an issue: ‘‘instudying the evolution of the Earthsystem over geologic time . . . [to] . . .unravel the interconnected story ofEarth’s dynamic crust, fluctuating cli-mate, and evolving life forms. . . . Thechallenge of helping students to learnthe content of this standard will be topresent understandable evidence fromsources that range over immense timescales. . . . Many students are capableof doing this kind of thinking, butas many as half will need concreteexamples and considerable help in fol-lowing the multistep logic necessary todevelop the understandings’’ (NationalResearch Council 1995, p. 188). Thissentiment was also expressed in theAAAS Benchmarks (1993): ‘‘Most vari-ables in nature . . . show immense dif-ferences in magnitude. . . . A millionbecomes meaningful, however, as athousand thousands, once a thousandbecomes comprehensible. Particularlyimportant senses of scale to develop forscience literacy are . . . the enormous
age of the earth and the life on it’’(p. 276).
The problem of the immense scaleof evolutionary time is exacerbated bythe way it is typically treated in text-books. Specifically, textbooks com-monly show split timelines with wavyor broken lines for the PrecambrianEra (87% of Earth’s history) and datespecific periods back from the present(millions of years ago/mya) ratherthan forward from Earth ‘‘time zero.’’Additionally, the numerous, hard-to-pronounce labels associated with thevarious eras, periods and epochs fur-ther alienate novice learners, as doesthe quick ‘‘one time topic’’ (vs. recur-ring theme) treatment. Of course, trun-cated time scales are a necessary evilgiven the dimensions of a textbook,but teachers should not be limited bythe textbook scale. What is needed isan approach to the scale of time thatis analogous to what Morrison, Mor-rison & Eames (1994) did for the ‘‘rela-tive size of things in the universe’’ intheir groundbreaking book and late1970s film, ‘‘The Powers of Ten.’’
The following 5 E Teaching Cyclegoes beyond artificial constraints of ‘‘2x 4’’ teaching (i.e. two covers of thetextbook and four walls of the class-room) and moves the class out into aschool hallway to enable students tobetter visualize how ‘‘far out,’’ seem-ingly OUTrAGEous, yet FUNdaMEN-TAL scientific concepts and theoriescan be. While other published activitiesmake use of either relatively longscales [a football field (McComas1994)] or scales that are rather short[five meters of adding tape (NationalAcademy of Sciences 1998, pp. 90–92)];this one employs an intermediatelength that requires getting out of theclassroom, but not outside of theschool building. This particular 5 Eapproach also provides a rich opportu-nity to teach the time scale of evolutionin a way that goes beyond the linguis-tic and logical-mathematical levels toinclude the musical, spatial, bodily-kinesthetic, and personal intelligences(Armstrong 1994).
‘‘Wiping Clean’’Misconceptions AboutEvolutionary Time
EngageConsider wearing a ‘‘Whoa, 40 (or
50) is getting pretty serious’’ or similar‘‘old’’ age-related T-shirt into classand/or playing any one of a numberof popular songs from the last 50 yearsthat feature the word ‘‘time’’ and/
EVOLUTION TIMELINE 579
or ‘‘changes’’ (examples of 1960-90ssongs: ‘‘Turn, Turn, Turn’’/Byrds;‘‘Long Time Gone’’/Crosby, Stills,Nash & Young; ‘‘Time in a Bottle’’/Jim Croce; ‘‘Time Keeps on Slipping’’/David Bowie; ‘‘Longer Than’’/DanFogelberg; ‘‘It’s About Time’’/JohnDenver; ‘‘Time Passes By’’ and ‘‘Lone-some Standard Time’’/Kathy Mattea,etc.). If an ‘‘older,’’ less familiar songis used, challenge the students toexplain the phrase ‘‘time is relative’’with respect to the fields of biologyand geology vs. popular music.
Focus Questions1. How ‘‘old’’ is the Earth? What waysdo scientists have of estimating thisnumber? SW2C: So What, Who (or whyshould I) Care(s)?
Have students make guesses aboutthe age of the Earth and compare theirideas to the scientific estimate of 4.5billion years. Briefly discuss how fun-damental concepts and theories in sci-ences as diverse as astronomy, biology,chemistry, climatology, geology, pale-ontology and physics have all contrib-uted to and are somewhat dependenton the idea of a ‘‘very old’’ Earth asindicated by radiometric dating. Con-sider having students ‘‘analyze’’ sci-ence cartoons by Sidney Harris, GaryLarsen and others in terms of howthey ‘‘play with’’ the concept of theEarth’s (vs. human) history. Challengestudents to explain the scientific con-cepts (or misconceptions) that makethe cartoons funny.
2. How much is and how can we con-ceptualize one million? One billion?
The children’s book How Much is aMillion by David M. Schwartz andSteve Kellogg (1985) contains a num-ber of fun, visual representations andanalogies for a million (e.g. a fish bowlbig enough to hold a million goldfishwould be large enough to hold a 60-foot whale), a billion (goldfish wouldneed a bowl as big as a sports stadium)and a trillion (goldfish would need abowl as big as a city harbor). Challengestudents to come up with their ownrepresentations for these large num-bers. A simple model that can be dis-played on the classroom walls is dots(as many as 4000 to 5000) on standard11 x 8 1/2’’ stationery (for a total of 200to 250 pages to represent 1 million).
3. Has the Earth always contained abiosphere with living organisms?What evidence do scientists use toanswer this question? In what waysdid early life forms transform theirenvironment?
Elicit and record student ideas thatwill undoubtedly contain a variety of
misconceptions about the idea of thefossil record and the long time frameduring which microbes were the onlylife forms present. Do not be concernedwith teaching/telling the ‘ ‘r ightanswers’’ at this time, but have stu-dents begin to explore the questionsby consulting their textbook, referencematerials [such as Hoagland & Dodson(1995) and Whitfield (1993)], and Websites (see listing under Explain).
Briefly discuss the notion of decou-pling Earth and human history bylabeling 4.5 billion years ago as ‘‘timezero’’ for our planet vs. the standardmethod of dating the Earth’s eventsin millions (or billions) of years ago(mya) from our current time. Segmentsfrom the videos listed below underthe Explain section may also be usefulhere for motivational purposes.
ExploreRelevant data on the Earth’s evolv-
ing natural history needs to be sup-plied by teacher, textbook, or multime-dia or Internet source to teams work-ing with calculators. Detailed timelinesof key points in evolutionary historyare available in McComas (1994, pp.34–39), National Academy of Sciences(1998, p. 91), Tarbuck (1994, CD-ROM)and most extensively, in the CorrelatedHistory of Earth Poster, a highly de-tailed, full-color poster from Pan Terra,Inc. (available from the WorldwideMuseum of Natural History at 800-216-8130 or www.wmnh.com). Whilethis information is provided to stu-dents as ‘‘received knowledge,’’ it isimportant to emphasize again the con-currence of views arrived at throughmultiple scientific disciplines and tochallenge students to consider if thesequence of interrelated events ‘‘makessense’’ from a developmental per-spective (as such evolution must be atheme that is repeatedly returned tothroughout the entire school year).
With some flair and sense of fun,introduce the ‘‘Toilet Paper Timelineof Science’’ as an inexpensive, longroll of paper that can be used as asimulation for geological time. Priorto unrolling the toilet paper down along hallway and marking key pointsof interest, have groups check eachother’s calculations. The scale can begiven to or derived by the studentsdepending on their experience and theamount of time allotted. Many com-mon brands of toilet paper have 280sheets per roll and will easily fit intypical school hallways. (Alternatively,some cheaper, single-ply brands of toi-let paper come with 1000 sheets.).
SCALE: 4.5 x 109 yrs /280 sheets 4450 x 107/280 4 16 x 106 yrs/sheet
16 x 106 yrs/11.1-cm sheet 4 1.44 mil-lion yrs/1 cm 4 1 million yrs/0.69 cm
Focus Questions1. How does the history of livingorganisms (including eventuallyhumans) compare in length (duration)to Earth’s history? How many sheetsof toilet paper would this be fromEarth time zero?
Microbial Life (prokaryotes) beganapproximately 3.8 x 109 yrs ago or 0.7x 109 yrs from Earth ‘‘time zero’’:
0.7 x 109 yrs/4.5 x 109 yrs 4 0.1555[During the first 15.5% of Earth’shistory, there was no life presentor, conversely, life has been pres-ent for 84.5% of Earth’s history.]
Until recently, it was believed thatprokaryotes were the only forms oflife for roughly the next two billionyears. Research by Brocks et al. (1999)now seems to indicate that eurokary-otes evolved as early as 2.7 billionyears ago. To help students better visu-alize the idea of ‘‘billions of years,’’have them work with a Time TravelAnalogy: Assuming a year of time wasrepresented by one mile and that youcould travel back in time in a conven-tional car traveling at the speed limitof 65 mph (or use 100 mph for easiercalculations if desired).
2. How long would your auto trip backto see the beginning of life on Earthtake? How many typical human life-times is this? How many generations?
3.8 x 109 miles x 1 hr/65 miles x1yr/8760 hours 4 6674 years[Note: The earliest human citieswere built approximately 6000years ago.]
6674 yrs/80 yr lifespan 4 over 83lifetimes of auto speed travel time
6674 yrs/20 yrs reproduction cycle4 approximately 334 generations
3. Given that bacteria can still argua-bly be considered the most prevalentlife form on Earth and assuming bacte-ria can reproduce every 20 minutes,what’s the maximum number of gener-ations of bacteria that could have theo-retically existed over the last 3.8 bil-lion years?
3.8 x 109 yrs x 8760 hrs/1 yr x 60min/1hr x 1 generation/20 min
4 1013 generations 4 a lot of evolu-tionary time
4. Where would the following signifi-cant events occur on the Toilet Paper
580 THE AMERICAN BIOLOGY TEACHER, VOLUME 62, NO. 8, OCTOBER 2000
Timeline? Any of the previously citedevolutionary timelines can be used toidentify the developmental timelinefor all the major plant and animalgroup [fish—amphibians—reptiles(including dinosaurs)—mammals—birds] ‘‘firsts’’ that occur betweenpoints (a) and (b). The Correlated His-tory of Earth poster is especiallydetailed and includes pictures of thecoinciding positions of the Earth’s con-tinents. Look for connections such aslinks between plant reproduction andanimal pollinators and be sure thatstudents note that the poster’s timelineis NOT/cannot be drawn to a uni-form scale.
(a) Cambrian ‘‘Explosion’’: 570 mil-lion yrs ago 4 0.57 x 109 yrs: seg-mented worms, coral anemones, jelly-fish, sponges, lamp shells, clams, snail,squid, trilobites, crabs, etc.
4.5 x 109 yrs—0.57 x 109 yrs 4 3.93x 109 yrs from Earth ‘‘time zero’’
3.93/4.5 4 0.8733 [87% of Earth’shistory occurred before inverte-brates]
sheets from Earth ‘‘time zero’’0.9875 sheets (11.1 cm/sheet) 4
1 0 . 9 6 c m f r o m s t a r t o f l a s tsheet/ #280
Homo sapiens sapiens: The sole‘‘survivors’’ of the Homo line date toapproximately 100,000 yrs ago, appar-ently overlapping in time and locationwith the Neanderthals whom they sub-sequently re/displaced, and show upin the last 0.1 cm (or 1 mm) of thetoilet paper timeline.
ExplainUse discussions, simulations, videos,
virtual trips on the World Wide Web,etc. to explain the idea that currentspecies have evolved via descent withmodification over long expanses oftime and to provide a clearer sense of
the data and reasoning that supportsthis idea.
InternetAmerican Museum of Natural History
in NYC: http://www.amnh.org/Human Origins & Evolution in Africa:
http://www.indiana.edu/;origins/National Museum of Natural History
Online Literature Library (Voyage ofBeagle, Origin of Species & Descentof Man): http://www.literature.org/authors/darwin-charles/
Paleontological Research Institution:http://www.englib.cornell.edu/pri/
Royal Tyrrell Museum: http://www.tyrrellmuseum.com/home
UC-Berkeley Virtual Museum of Pale-ontology: http://ucmp.berkeley.edu
U.S. Geological Survey:Dinosaurs: Fact & Fiction: http://
pubs.usgs.gov/gip/dinosaurs/Fossils, Rocks and Time: http://
pubs.usgs.gov/gip/fossils/Geological Time (online edition):
http://pubs.usgs.gov/gip/geotime
MultimediaLife on Earth: A Natural History.
(David Attenborough). Two 233-min.videos with Chapter Search and on-screen numerical codes for quickaccess to each of the program’s 13chapters (keyed to the accompanyingbook published by Little, Brown &Co., 1979). Carolina Biological: 1-800-334-5551 for $39.95 (K3-49-1150-V).
Planet of Life (Discovery Channel): 6hrs 50 min. on 4 videotapes: #1: Part1/Birth of Earth & Part 2/AncientOceans; #2: Part 1/When DinosaursRuled & Part 2/Creatures of the Skies;#3: Part 1/Insect World & Part 2/Apesto Man; and #4: Evolution’s Next Step.Discovery Channel Video, PO Box4055, Santa Monica, CA 90411-4055; 1-800-207-5775. [$49.95].
A Science Odyssey: The Journey of aCentury (Host: Charles Osgood). Fivetwo-hour videos including ‘‘How WeKnow What We Know’’ about Origins(1st hr: Wegener & continental drift/plate tectonics, geological forces, ageof the Earth, Darwinian evolution, pale-ontology ` 2nd hr: genetics, DNA,Miller & Urey and the first life forms).PBS Home Video, 1-800-645-4727.$79.98/A3078 ` $30/B3078/accompa-nying book by Charles Flowers (Wil-liam Morrow & Co., Inc. 1998, pp.126–177).
ElaborateFormative assessment is ongoing
throughout the various activities. If the
students have not already done so inthe Explore phase, use the aforemen-tioned timelines to ‘‘fill in the details’’of major ‘‘firsts’’ in the evolution oflife. If the toilet paper timeline is tapedto the walls in the hall, students canadd relevant artwork and informationabove and below the timeline for semi-permanent display to catalyze out-of-class conversations about expandingthe idea of ‘‘prehistory’’ to includethe huge expanses of time before thearrival of humans.
EvaluateStudents can be challenged to
develop other models such as a 365‘‘day’’ 4 Earth’s 4.5 billion year calen-dar for display and/or check the accu-racy of geographic analogy scales (1mile 4 million years) such as thatpublished by Packard (1994). Othersummative projects might includegraphic displays, computer simula-tions, cartoons, science songs, fictionalnews releases challenging Darwin’scritics (such as Lord Kelvin’s faultyestimate for the age of the Earth), skits,etc. for individual students and/or stu-dent teams. Another possible extensionis to challenge students to criticallyanalyze the flaws in the arguments of
EVOLUTION TIMELINE 581
young Earth creationists by reviewingInternet sites such as:
The key factors to remember through-out this 5 E Teaching Cycle are:
1. Students need multiple, rationallysequenced experiences that drawon a full array of intelligences tocounter their everyday concep-tions of ‘‘history’’ and its undulyrestrictive association with humansand human lifespans.
2. Engaging students in a ‘‘dialogueof discovery’’ and ‘‘questioningthe answers’’ takes more timethan simply providing themauthoritative, ‘‘just the facts’’
answers. Conceptual change is anevolving, dialectical process aswas the development of the targetscientific theory.
3. Some students will find it difficultto ‘‘believe’’ the scientific view,even if they understand it concep-tually, due to deeply held, con-flicting personal religious beliefswhich must be respected. Mini-mally, assure such students thatscience in general (and evolutiontheory in particular) does notrequire one to be an atheist, butrather is simply agnostic in itsmethodological approaches todeveloping provisionally accepted,proximate causes (‘‘how’’) to nat-ural phenomena. Science does notdirectly address the domain ofultimate, perhaps supernaturalcauses (‘‘why’’) that are the terri-tory of religion.
Evolution, properly addressed as atheme that pervades an entire courseof study, provides a perfect opportu-nity to engage students in criticallyanalyzing the nature of scientific in-quiry, including the scientific meaningof the term ‘‘theory’’ (Rudolph & Stew-art 1998) and other commonly held‘‘myths’’ about science (McComas
1996). The mistaken separateness ofthe numerous topics and chapterswithin textbooks belies the underlyingunity that powerful, interlinked theo-ries provide to science and scienceeducation (Duschl 1990). Science asan evolving product and process isinherently constructivist and economi-cal in its efforts to explain the broadestrange of phenomena in terms of thefewest number of unifying basicassumptions, concepts, and empiri-cally supported laws and theories. The‘‘ever-evolving’’ theory of evolutionmakes a perfect case study for thispoint.
ReferencesAmerican Association for the Advance-
ment of Science. (1993). Benchmarksfor Science Literacy: Project 2061. NewYork: Oxford University Press.(http://project2061.aaas.org/tools/index.html).
Armstrong, T. (1994). Multiple Intelli-gences in the Classroom. Alexandria,VA: Association for Supervision andCurriculum Development.
Brocks, J.J., Logan, G.A., Buick, R. &Summons, R.E. (1999). Archeanmolecular fossils and the early riseof eurokaryotes. Science, 285(5430),1033–1036.
Duschl, R.A. (1990). Restructuring Sci-ence Education: The Importance of The-ories and Their Development. NewYork: Teachers College Press.
Hoagland, M. & Dodson, B. (1995).The Way Life Works: Everything You
582 THE AMERICAN BIOLOGY TEACHER, VOLUME 62, NO. 8, OCTOBER 2000
Need to Know about the Way All LifeGrows, Develops, Reproduces, and GetsAlong. New York: Times Book/Ran-dom House.
McComas, W.F. (1994). How long isa long time: Constructing a scalemodel of the development of lifeon earth. In W.F. McComas (Ed.),Investigating Evolutionary Biology inthe Laboratory. Reston, VA: NationalAssociation of Biology Teachers.
McComas, W.F. (1996). Ten myths ofscience: Reexamining what we thinkwe know about the nature of science.School Science and Mathematics,96(1), 10–16.
Miller, J.B. (1998). An Evolving Dialogue:Scientific, Historical, Philosophical, andTheological Perspectives on Evolution.Washington, DC: American Associa-tion for the Advancement of Science.
Moore, R. (1998–1999). Creationism inthe United States, Parts I–VIII. TheAmerican Biology Teacher, 60(7)–61(5).
Morrison, P., Morrison, P. & the Officeof Charles & Ray Eames. (1994). Pow-ers of Ten: About the Relative Size ofThings in the Universe. New York:Scientific American Library.
National Academy of Sciences, Work-ing Group on Teaching Evolution.(1998). Teaching About Evolution andthe Nature of Science. Washington, DC:National Academy Press. (http://www.nap.edu/readingroom/).
National Academy of Sciences, SteeringCommittee on Science and Creation-ism. (1999). Science and Creationism:A View from the National Academy ofSciences, Second Edition. Washington,
DC: National Academy Press. (http://www.nap.edu/readingroom/).
National Research Council. (1995). TheNational Science Education Standards.Washington, DC: National AcademyPress. (http://www.nap.edu/read-ingroom/).
Packard, E. (1994). Imagining the Uni-verse: A Visual Journey. New York:Perigee Books.
Rudolph, J.L. & Stewart, J. (1998). Evo-lution and the nature of science:On the historical discord and itsimplication for education. Journal ofResearch in Science Teaching, 35(10),1069–1089.
Schwartz, D.M. & Kellogg, S. (1985).How Much is a Million. New York:Lothrop, Lee & Shepard Books.(Also available as a Mulberry BigBook.)
Tarbuck, E.J. (1994). The Theory ofPlate Tectonics/CD-ROM. Albu-querque, NM: TASA Graphics Arts,Inc. (http://www.swcp.com/;tasa)
Whitfield, P. (1993). From So Simple aBeginning: The Book of Evolution. NewYork: Macmillan.
The Woodrow Wilson National Fel-lowship Foundation. (1995). TheHoward Hughes Medical Institutefor High School Biology Teachers1995 Curriculum Module: Evolution AContext for Biology. Available on-lineat http://www.woodrow.org/teachers/bi/1995/.
