by  Diane Catron      Santa Fe High School     Santa Fe, NM            and      Donald Bockler     Arlington High School     Arlington, MA     <dbocklAE@ix.netcom.com>

 

Summary/Abstract 

•  Lesson/class activity - Literature containing life cycle information is available from many sources.  Several examples of this type of literature are listed below with a synopsis and sample questions for each. These examples have been taken from a variety of reading and interest levels in the hopes that there will be something for everyone here.  This brief survey is not meant to be inclusive, but rather to serve as a starting point.

Instructor's Objectives to top
The goals of this lesson are threefold:

• To allow students to read and think about what they are reading and thus learn a little bit about life cycles and reproduction from a source other than their textbook.
• To expose students to popular literature concerning scientific topics.
• To help students gain an appreciation for how the science of biology really is part of every aspect of their lives.

• Biology students - Biology I, Honors Biology, AP Biology
• Grade Level - High School

Notes to the Teacher: to top
Students, especially younger ones, often assume that they cannot understand popular readings concerning biological topics.  This activity should help to dispel that idea by providing suggestions for interesting readings and questions to help the students understand the material.  Having the class read the same article creates a common bond among the students.  Most of these readings can be referred to many times throughout the course of the year.

Summaries:
"Jerry's Maggot" , chapter 13 from Adrian Forsyth's Tropical Nature
This fourteen page story is about a graduate biology student, Jerry, who acquires a botfly maggot in his scalp.  Jerry's original disgust at his role as a link in  the food chain is replaced with interest in the events taking place in his scalp as the botfly grows.  Eventually the larva hatches from Jerry's scalp, but dries out and dies before reaching the pupal stage.  The chapter continues with a discussion of egg placement, adaptation, parasitism, commensalism, mutualism, coevolution and brood parasitism.
 

"On Embryology", from Lewis Thomas's The Medusa and the Snail
A brief three page reflection on reproduction, written in response to the birth of the world's first test-tube baby in 1978.  This article is appropriately coupled with a reading concerning the successful cloning of Dolly. (See following summary & website.)

Abstract from "Viable offspring derived from fetal and adult mammalian cells", from Nature, Volume 385,810-813, February 27, 1997.  I. Wilmut, A.E. Schnieke, J. McWhir, J.A. Kind & K.H.S. Campbell. See http://www.nature.com/Nature2/serve?SID=9020975&CAT=NatGen&PG=sheep/sheep3.html
This is the scientific journal publication about Dolly, the lamb cloned from an adult mammary gland cell that had been made quiescent.  This demonstrates that differentiation of the mammary gland cell did not eliminate any of the genetic information that is necessary for development, thus supporting the idea of genetic equivalency.   It also states that the adult cell must become quiescent before it is capable of expressing all of the genes necessary for development.
 

"Whither the Y?", a commentary by Kenneth R. Miller in Discover, February, 1995 ( pages 36-39).
This commentary begins on a humorous note with the author's description of his childhood impressions of male superiority.  This idea is quickly negated, however, as the author discovers in high school biology that the lack of an X chromosome and the presence of only a Y chromosome is a lethal condition.  The lack of genes on the Y chromosome, the suppression of crossing over with the X chromosome, the subsequent accumulation of damage on the Y chromosome, and the possible loss of the Y chromosome are all discussed.
 

"Flu Pandemic". (1992) Robin Marantz Henig.
    This article relates the history, geography and human culture of influenza pandemics to the genetic recombinations between different strains of the virus found in pigs, ducks and human hosts.  The flu virus contains the genetic information to make new viruses, but it lacks the cytoplasmic means to carry out its own reproduction.  Instead it uses three different animal species to serve as reservoir "mixing bowls" to produce new varieties with greater virulence.  The article is a nice mix of molecular genetics, "primitive" life forms, ecology and the human experience.
 

"In which we consider the birth, childhood, and adolescence of typhus" from Hans Zinsser's Rats, Lice, and History.
    Zinsser considers the origin, variations, and epidemiology of the disease typhus.  The interrelationship between parasitic diseases and historical and cultural events are emphasized throughout the book.  This excerpt describes the life cycle of the "hero" of the book, the typhus pathogen.  The writing style of this classic is unique and charming, but it may be a bit obtuse for modern adolescents.
 

"The Pill" A story by Maggie Nadler in You and Science Fiction:  A Humanistic Approach to Tomorrow.
    "The pill" in this very short science fiction story is an anti-aging "youth pill."  People take the pill to arrest their physical age at a specific age dependent upon when they start the prescription.  However, their mental abilities continue to age as normal.  This story centers around a beautiful "young" woman who is being cared for on the veranda of a rest home for the aged.
 

 Embryology references in Aristotle's "The History of Animals"  (Book VI - Part 3)
    Aristotle describes what he observed in chicken embryos in his studies in the 4th Century BC.  Note the accuracy and detailed observations in his description.  This is especially amazing considering his lack of tools such as microscopes.  Many of Aristotle's interpretations differ from ours because his worldview radically differed from ours.  Nevertheless, his observations and descriptions were remarkably accurate and his interpretations were perceived as true for over two thousand years until experimental science techniques enabled the modern paradigm shift.  Aristotle is considered by many to be the "father of biology."  It is interesting (and important) for modern young scientists to have an appreciation for the changes in perspective of science throughout history.     <http://classics.mit.edu/Aristotle/history_anim.6.vi.html>
 
 
Time Requirements:  The time required varies with the reading level of the students and the reading chosen.  I like to allow one class period for the entire exercise:  reading, answering the questions, and then discussing the reading.  The analysis of longer articles may be assigned as homework.  Completing the reading in class allows the teacher to make only one class set of the reading material.  How the discussion is carried out is entirely up to the teacher.  Small groups allow for maximum student participation.

Additional Considerations:  Some teachers will find these readings useful in more advanced classes to reintroduce or expand upon topics that have been studied during previous years.  In introductory or honors classes,  the readings can be used to expand student knowledge and to provide practice using the terms that have been introduced through lecture or textbook readings.
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Materials & Equipment Needs to top

• Copies of the reading:  original printed material or xeroxed copies.  I use class sets, carefully numbered, that are checked in at the end of the class period.
• Questions for each article.

Background to top
 
This activity gives the students an opportunity to read and learn about science from a source other than their textbook.  The major topics included are life cycles, reproduction, the Y chromosome, development, and symbiosis.

Vocabulary and concepts needed to understand the articles vary from article to article.  Some examples of needed vocabulary follow:
"Jerry's Maggot" - life cycle, food chain, symbiosis, parasitism, commensalism, mutualism, coevolution.

"Whither the Y?" - chromosome, X and Y chromosome, recombination, meiosis, crossing-over, natural selection.

"On Embryology" - In vitro, in vivo, progeny.

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The Student Activity to top

• Introduction  - Scientific information can be obtained from a variety of written sources:  textbooks, magazines, fiction, and non-fiction, to name a few.  This exercise will provide you with the opportunity to read a selection from one of these sources and to then analyze it through writing and discussion.
• Purpose - The purpose of this exercise is to review information you have studied previously and to give you the opportunity to expand that information.
• Equipment -  The only equipment you will need is a copy of the article, the question sheet, a piece of paper to write your answers on, and a writing implement.
• Procedure - Read the article, think about it, and answer the questions.  Be prepared to discuss your answers in class.
Jerry's Maggot Questions
1.  What was your overall reaction to the selection and WHY?  (Interest, disgust, fascination, etc. are possible reactions. You need at least three complete sentences to answer this question.)
2.  Identify the stages in the life cycle of the botfly and tell where each stage takes place.
3.  What was the final developmental stage attained by Jerry's Maggot?
4.  What do you notice about the names of the creatures discussed?  (You should notice at least four things about the names.)
5.  In your relationships with other humans, which of the three symbiotic relationships mentioned do you hope for?  Why?
6.  Discuss the reasoning behind calling the brood parasitism exhibited by the Giant Cowbird a mutualistic relationship.
7.  Explain how a daytime mutualist can become a night-time parasite.
8.  Give an example from this reading of the coevolution of organisms.  Explain why your choice exemplifies coevolution.

"On Embryology" and "Dolly Abstract" Questions
1.  What does the single cell mentioned in paragraph three become?
2.  Why does the author feel that we should be astonished by the existence of that cell?
3.  What is the name of the process that this cell undergoes as it becomes an organ?  Give another example of this process.
4.  If you read the "Dolly" abstract, what is the relationship between the last paragraph and the cloning of Dolly?  Should Lewis Thomas, the author of "On Embryology", be forced to sky write?  Explain your answer.
5.  If you read the "Dolly" abstract, name and describe the condition the donor cell must be in to insure normal embryo development?
6.  Do these two articles support the idea of genetic equivalence or of differential gene content? Explain your answer.

"Whither the Y" Questions
1.  Defend or refute the statement, "The Y chromosome is a genetic wimp."
2.  Explain the statement, "The Y is necessary but not sufficient to make a male."
3.  How do the events of meiosis prevent errors from piling up on a single chromosome?
4.  Explain how the Y chromosome accumulates one mistake after another.
5.  What would ultimately bring about the demise of the Y chromosome?

General Questions to be used with any or all of the readings:
(Some of these questions are more appropriate for some of the works than others.  The idea here is to consider general themes of the readings that relate Science efforts with the humanities.)

1. How does each of these works deal with "life cycles" in general?
2. How is sex, on the biological level, involved in each of these works?
3. How might the topics covered in these works differ if they were  to be written for a science text for a high school biology text?  What additional information might be included?
4. Does the writer of the work portray Science in a positive way, or is Science considered a negative endeavor of humanity?
5.  What aspects of  the "humanities" were considered in these works that would probably be missing if the topic was covered in a biology text?  How is the topic of  "life cycles" related to the  humanities and/or the "human condition?"
6. Considering that you are in a specific stage of the human life cycle now, if you were asked to add or change something in one of these works to make it more appropriate for teenagers , what would you add or change?

 

• Observation - None
• Conclusions  - None

Forsyth, Adrian and Miata, Ken. 1984. "Jerry's Maggot", Tropical Nature , Charles Scribner's Sons, Macmillan Publishing Copmpany.  New York, New York. pages 153-167.

Henig, Robin Marantz. Flu pandemic. New York Times Magazine. November 29, 1992.
(Also in Henig, Robin Marantz. 1993. A Dancing Matrix: Voyages Along the Viral Frontier. NY: Knopf. pages 165-175).

Miller, Kenneth R.  Feb.1995.  Whither the Y?, Discover  v16n2: 36-39.

Nadler, Maggie.1976. The Pill. in  You and Science Fiction: A Humanistic Approach to Tomorrow.  Ed. by Bernard Hollister. Skokie, IL: National Textbook Co.

Thomas, Lewis. 1979. Chapter 13, "On Embryology" pages 155-157.  The Medusa and the Snail.  Viking Press, New York, New York
 
Wilmut, I. ;Schnieke A.E.; McWhir, J.;  Kind, J.A.;  &  Campbell, K.H.S. 1997.  Abstract from Viable offspring derived from fetal and adult mammalian cells.  Nature, Volume 385,810-813.
 See http://www.nature.com/Nature2/serve?SID=9020975&CAT=NatGen&PG=sheep/sheep3.html

Zinsser, Hans. (1935). Rats, Lice, and History. NY: Bantam Books. (pages 173-181).