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NSTA PRESS

N A T I O N A L S C I E N C E T E A C H E R S A S S O C I A T I O NArlington, Virginia

AND

THINKING

SCIENTIFICALLY

ABOUT

CONTROVERSIAL ISSUES

CHEMICALSCLONES, CATS,

Copyright © 2004 NSTA. All rights reserved. For more information, go to www.nsta.org/permissions.

Claire Reinburg, DirectorJ. Andrew Cocke, Associate EditorJudy Cusick, Associate EditorBetty Smith, Associate Editor

Copyright © 2004 by the National Science Teachers Association.All rights reserved.06 05 04 4 3 2 1

Library of Congress Cataloging-in-Publication Data

Slesnick, Irwin L. Clones, cats, and chemicals : thinking scientifically about controversial issues / by Irwin L. Slesnick. p. cm. Includes index. ISBN 0-87355-237-7 1. Medical genetics. 2. Science—Public opinion. 3. Cats. 4. Games of chance (Mathematics) 5. Hunting. 6.Manned space flight. 7. Violence in mass media. I. Title. RB155.S54 2004 303.48’3—dc22 2004013337

NSTA is committed to publishing quality materials that promote the best in inquiry-based science education. However,conditions of actual use may vary and the safety procedures and practices described in this book are intended to serveonly as a guide. Additional precautionary measures may be required. NSTA and the author(s) do not warrant or representthat the procedure and practices in this book meet any safety code or standard or federal, state, or local regulations.NSTA and the author(s) disclaim any liability for personal injury or damage to property arising out of or relating to theuse of this book, including any recommendations, instructions, or materials contained therein.

Permission is granted in advance for reproduction for purposes of classroom or workshop instruction. To requestpermission for other uses, send specific requests to: NSTA Press, 1840 Wilson Boulevard, Arlington, Virginia22201-3000. Web site: www.nsta.org.

ART AND DESIGN Linda Olliver, DirectorPRINTING AND PRODUCTION Catherine Lorrain-Hale, Director

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COVER DESIGN Linda Olliver, images from Getty, Photodisc, and BrandX

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NSTA PRESSNAT I O N A L S C I E N C E T E A C H E R S A S S O C I AT I O N


Contents

vii Introduction

1 t Here Come the Clones

5 s Are We Ready for Clones?

7 t Cats and Their Impact onWildlife Populations

11 s Cats: What’s the Dilemma?

13 t Stem Cell Transplants

19 s Should Embryonic Stem CellResearch be Permitted?

21 t Chemical and Biological Weaponsof Mass Destruction

25 s Can New Incapacitating WeaponsLead to Humane Warfare?

27 t Robotic Versus Manned Space Travel

31 s Space Exploration: Man or Machine?

t t e a c h e r s s t u d e n t


33 t Genetic Screening

37 s Should We GeneticallyScreen Newborns?

39 t Violence in the Media

43 s Violence on Television:How Much is too Much?

45 t Managed Retreat

49 s Managed Retreat:How Does it Work?

51 t To Hunt or Not to Hunt

55 s Should Modern Humans Hunt?

59 t A Closer Look at the Lottery

65 s The Lottery: Is It Really Worth It?

69 Index

t t e a c h e r s s t u d e n t


Introduction

cience and technology continue toadvance human knowledge at arapid—some say too rapid—pace,challenging accepted beliefs and spur-

native resolutions. The second part is writtenfor the student and may be photocopied anddistributed to the class. It includes a brief pre-sentation of the issue and questions or activi-ties to guide the student in the decision-mak-ing process.

Teachers should not feel restricted by thequestions and activities of each issue, or by thelimits of the background. The details of the sci-ence and the mood of society that impinge uponthe issues change rapidly. For example, Koreanresearcher Hwang Woo Suk’s announcement ofhaving produced a clone of a human blasto-cyst occurred during the reading of these gal-ley proofs. And President George W. Bush’s sud-den declaration of plans for a manned flight toMars within 20 years added political clout tothe seemingly stalled manned space program.

It is quite likely that in every school districtthere are issues that arouse greater interest andpassion than do these. Following the format ofthe topics in this book, however, a resourcefulteacher can collect the facts of a local issue andthen present the issue to the students to discuss,investigate, and work toward a resolution.

The goal of this publication is to give thescience student an opportunity to discuss andinvestigate the scientific and social issues of con-cern on a regular basis, and to learn to be com-fortable with difficult decisions.

Sring debate across many fields. Often, it seemsscientific research is advancing faster than lawscan be created to ensure it proceeds in a safe,humane manner. Human cloning, for example,ignites the passion of both experts and the gen-eral population on ethical, moral, religious,economic, and political grounds. All membersof society are called upon to make decisionsabout their health, their recreation, how theiractions can affect the environment, whetherto play the lottery, whether to support mannedor unmanned space flight, whether to seek ge-netic testing for babies, or how strictly to con-trol violence in the media. These are the is-sues that are examined in Clones, Cats, and

Chemicals: Thinking Scientifically About Con-

troversial Issues.

The National Science Education Standardsrecommend that students have experience grap-pling with issues that society must ultimatelyresolve. This publication examines such issuesin the fields of biology, chemistry, physics, Earthscience, technology, and mathematics. Each is-sue is presented in two parts: The first part iswritten for the teacher and contains backgroundon the science of the issue and presents alter-

D I F F I C U L T D E C I S I O N S viiCopyright © 2004 NSTA. All rights reserved. For more information, go to www.nsta.org/permissions.

N A T I O N A L S C I E N C E T E A C H E R S A S S O C I A T I O Nviii

This book was originally published in a pre-vious edition under the title Real Science, Real

Decisions. I would like to acknowledge thecontributions of Jal S. Parakh and John A.Miller, who co-authored some of the pieces inthe first edition.

Irwin L. SlesnickProfessor of BiologyWestern Washington UniversityBellingham, Washington


C L O N E S , C A T S , A N D C H E M I C A L S 1

Clones

The foot of a sea anemone holds thestalk of the animal to the rocks ona shoreline or to the inside glasswalls of an aquarium. As the sea

anemone slithers across the rock or glass surfaces,an observer may find that pieces of the tissue ofthe foot appear to be ripped off the body andadhere as debris to the trail of the slowly movingcreature. When one examines these pieces of dis-carded tissue, at first, they seem to be ordinaryadult body cells. But then they appear to changeinto embryonic cells. Soon the fragments of cellsbegin to develop and grow into individual sea

tt e a c h e r

anemones that are genetically identical to the par-ent. Zoologists call this natural kind of asexualreproduction pedal laceration. All offspring of theparent are clones as they share the same set ofgenes as the one parent.

Natural cloning is more common amongplants. Clones of single parent plants can arisefrom bulbs, spores, stems, and leaves. Plantbreeders may develop a superior variety ofapple (Red Delicious) and then, by producingmillions of genetically identical trees that growidentically delicious apples, establish a success-ful fruit market.

Here Come the Clones

Tentacles

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Clones of sea anemone

F I G U R E 1

The cloning (pedal laceration) of a sea anemone

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The sea anemone reproduces through the process of pedal laceration, also known aslongitudinal fission. As the anemone moves, pieces of the foot break off and develop intogenetically identical individuals, or clones. Pedal lacerations are best viewed on the undersideof the sea anemone, on the glass wall of an aquarium, for example.


N A T I O N A L S C I E N C E T E A C H E R S A S S O C I A T I O N2

t

Well, it’s only human nature toask, “If sea anemones can clonethemselves without hardly trying,and the natural cloning powers ofplants are so easily exploited, whycan’t we begin learning how toclone ourselves?” The answer tothat question is hidden in the se-crets of the cell. All plants have onekind of cell that remains forever inthe embryonic condition. These celllayers of embryonic tissue are toti-potent and can give rise to new dif-ferentiated cells. Cut the stem of aplant and these cells will produceroot, stem, and leaf tissues. In someanimals, totipotent cells—as in thefoot of a sea anemone—when cut,will dedifferentiate, and return toan embryonic condition. Then they

Frog embryo or tadpole (larva) Frog egg cell

Nucleus

UV

Intestinal cellNucleus

Nucleusdestroyed

Tadpole

Eight-cellembryo

Transplantationof nucleus

F I G U R E 3

Nuclear transplantation

Root ofcarrot plant

Transversesectionof root

2-mgfragments

Fragments culturedin nutrient medium

Free cellsin suspensionbegin to divide

“Embryoid”develops fromcultured free cells

Plantlet culturedon agar medium andlater transferred to soil

Adultplant

F I G U R E 2

Test-tube cloning of carrots

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C L O N E S , C A T S , A N D C H E M I C A L S

Mammary cell donor

Mammary cell in culture; cell cycle arrested

3 Cell fused

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5 Implanted in uterus of a third sheep

Nucleus frommammary cell

Nucleus removed

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Lamb (“Dolly”)chromosomallyidentical to mammary cell donor

Egg celldonor

1 2

will redifferentiate into foot, muscle, and nervetissue and the entire organism is cloned.

Could this natural cloning process be dupli-cated in the lab? At Cornell University in 1950,F. E. Stewart and his team of graduate studentstook tiny fragments from a fully differentiatedroot of a carrot and forced it to dedifferentiate

F I G U R E 4

Cloning a mammal (Dolly the sheep)

into embryonic cells (an embryoid) and thenredifferentiate into a fully adult carrot plant.

John Gurdon, a British biologist, pursuedthe next question: Can a differentiated cellfrom the intestine of a frog egg dedifferenti-ate and then redifferentiate into an adult frog?The result demonstrated in 1966 that the

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younger the totipotent donor cell, the greaterthe survival of the transplant.

In 1997, Scottish researcher Ian Wilmutand his team announced that they had clonedan adult sheep by transplanting the nucleusfrom an udder of a mammary gland of anadult sheep into an egg cell from anothersheep. The cloned animal, named Dolly, wasnot identical to the donor mammary cellmother, as the mitochondrial DNA of the eggcell belonged to the egg cell donor. Techniquesused by Wilmut to clone the sheep dependedupon the breakthrough involved in starvingthe udder body cell of nutrients, thus inter-rupting the normal cycle of growth and divi-sion of the cell. In this quiet stage the cellcan be reprogrammed to function as a newlyfertilized egg.

Dolly bred twice, once giving birth to aewe, and later having three lambs, a ewe andtwo rams.

Then in 1998, researchers in Hawaii an-nounced that they had cloned 50 mice, usingnuclei from ovary cells, and bred the mice forthree generations. Since then, numerous mam-mals have been cloned, including monkeys.Currently there is a strong injunction againstthe cloning of human beings. Federal fundscannot be used to carry a cloned embryo toterm, and private laboratories are under se-vere pressure not to do so. In February 2004,Korean scientist Hwang Woo Suk announcedthat his team had successfully cloned humanblastocysts and were able to extract viable stemcells that may be used in disease treatment.The scientist stressed, however, that he wasagainst reproductive cloning of humans. Nev-ertheless, under government sanction or not,someone out there will one day successfullyclone a human. And when that occurs, a mul-

titude of questions about the consequences ofthe event will be asked.

Questions for Discussionn How will society change under conditions

of reproduction by cloning?

n What can happen to the structure of thefamily?

n What value will sexual reproduction havein the face of the certainties of asexual re-production?

n Will cloning lead to the loss of diversity, atendency for homogeneity?

n How can society accommodate a popula-tion of clones destined to serve the needs ofthe few?

n How would the society reorganize itself toinclude clones of the brilliant, the talentedin entertainment, the political leaders, thescientists, and the technicians?

For Further ReadingBurbel, P. August 18, 2003. Clone, World Book

Online Reference Center. Available onlineat www.worldbookonline.com.

Campbell, N. A., J. B. Reece, and L. G.Mitchell. 1999. Biology. Menlo Park, CA:Benjamen/Cummings.

Suk Hwang, W., Y. J. Ryu, J. H. Park, E. S.Park, E. G. Lee, J. M. Koo, H. Y. Chun, B.C. Lee, S. K. Kang, S. J. Kim, C. Ahn, J. H.Hwang, K. Y. Park, J. B. Cibelli, and S. Y.Moon. Evidence of a pluripotent humanembryonic stem cell line derived from a clonedblastocyst. Published February 12, 2004 onlinein Science Express at www.sciencemag.org/sciencexpress/recent.shtml.

Thompson, B., and B. Harrub. 2001. Humancloning and stem-cell research—Science’s“slippery slope.” Montgomery, AL:Apologetics Press.


5

t

C L O N E S , C A T S , A N D C H E M I C A L S

As late as 1984, scientists DavidMcGrath and Davor Solterwrote in the journal Science,“The cloning of mammals by

simple nuclear transfer is biologically im-possible.” That assertion has been provenfalse, and since that date sheep, mice, cows,monkeys—a virtual menagerie of mam-mals—have been cloned. A moratorium onthe cloning of humans has been enforcedby law and by intimidation. Yet the an-nouncement of the first true human clone—from somatic cell and egg cell fusion toembryonic birth—is only a question of time.Whether it occurs in a federal laboratoryor in a private clinic, it will happen.

And when it happens, will society be pre-pared? Here’s a hypothetical example: Let’ssay Clone #1 is successfully created. Theclonal cells were stomach cells of a seven-year-old male. The egg cell with the nucleus re-moved came from a 35-year-old woman. Themale donor has a 205 IQ with an interest inastrophysics. The female donor is also un-usual with superior skills in Olympic trackand field. The embryo developed and the fe-tus grew in the uterus of a birth mother fornine months. The birth was normal, the child

ss t u d e n t

Clones

was normal, but from the instance of birth,Clone #1 began a most unusual life.

Who was his father? His mother? Whatis his name? What is his genealogy? Canhe reproduce? Who are his children’sgrandparents?

Let us now see how his life is developing.First, with whom does he spend his life? Withhis father and mother, or the nearest relatives?Or, does he become a ward of the state?Harder questions lie ahead. Take on the taskof writing the biography of this first humanclone. Try to anticipate his experiences as thevery first human clone, and possibly his ad-ventures with a new kind of life in an un-charted society. What are his experiences withlongevity? Genetic memory? Social action?Social interaction? Marriage?

Now if Clone #1 becomes one of a largepopulation of identical clones performing atask for the good of the community, how ishe to be integrated into the society? For ex-ample, say Clone #1, along with thousandsof nearly identical clones, is selected by soci-ety to protect Earth from impending hazardsfrom outer space. Do the clones become hu-man shields, putting their lives at risk to saveour own? Or are the clones to be treated as

Are We Ready for Clones?



s

human as anyone else? Or will the clones, byreason of their select superior skills, becomethe chosen few to make the ultimate decisionsand lead the way?

Compose your essay of the world withclones—their impact on us and our impacton them. What will their presence be like?Share your thoughts with the class. Herecome the clones, with problems or promisesfor the future.


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