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SUBJECT: LIFE SCIENCE
GRADE:   12
MODULE: 2 - Structure, control and processes in basic life systems of
             plants and humans
UNIT:    2 - The Human Reproductive System – Control of fertility,
             Technology in reproduction


UNIT OUTCOMES:


LO1: AS 1, 2, 3; LO2: AS 1, 2; LO3 AS 1, 2 and 3
By the end of this unit the Learner should be able to:
 Compare various forms of contraception – 15 minutes
 Discuss the problem, impact and possible solutions for infertility – 10 minutes
 Analyse and motivate views on abortion – 10 minutes
 Class Exercises – 25 minutes


LESSON OVERVIEW: (Knowledge areas)

1.       Contraception and control of human fertility
2.       Abortion
3.       Infertility and technology in reproduction

 LESSON:

Introduction:
There are various forms of contraception and birth control available. Some people argue that contraception
is against the laws of nature. Natural methods of birth control require abstinence and are accepted by the
Catholic Church. Physical methods not only prevent conception but also protect against sexually transmitted
diseases like HIV. Preventative methods like the IUD prevent implantation into the uterine wall. The Pill
prevents ovulation, but it was originally argued that the use of the pill would result in sexual permissiveness.
Contraception is required to restrict the growth of the human population and to prevent the spread of HIV
and other STDs. Women are given the opportunity to plan their careers and choose when to have babies.
Producing a small, planned family will mean a better standard of living and allows the population to stabilize.


Contraception and the control of human fertility:
Teacher note: Emphasise that promiscuity may lead to unwanted pregnancies and the transfer of
HIV. Be careful of getting involved in moral and ethical issues around abortion, contraception,
invitro fertilization and surrogacy. Allow and encourage Learners to debate the issues but be aware
of possible arguments and keep tight control of the brief discussions as time will be a problem.
Encourage Learners to consider their answers should they be asked to debate an issue or be
required to give their view point in an exam. Learners must know the various forms of contraception
and how to discuss and compare them.

Be sure to learn the table below on birth control methods because you may be asked to compare various
types of birth control.


Method                  Action                               Failure       Advantages and disadvantages
                                                             rate




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Teacher Notes

Barrier methods

Condom                  A rubber sheath, which fits over      3% to 10% May slip off or break during
                        the penis and prevents sperm          depending intercourse. Must be fitted before
                        from entering the vagina.             on whether intercourse.
                                                              it is used
                                                              properly

Diaphragm or            A flexible rubber dome which fits     3% to 15%   Can be inserted a few hours before
Dutch cap               over the cervix of the female and                 intercourse. Must be fitted by a
                        prevents sperm from entering the                  doctor the first time to ensure that it
                        uterus. It must be used with a                    is the correct size.
                        spermicide, which kills sperm.




Hormonal methods

The Pill                Contains oestrogen and                1%          Very reliable. Side effects like water
                        progesterone. The pill inhibits the               retention, weight gain, skin
                        secretion of FSH, thereby                         pigmentation, headaches and
                        preventing the development of the                 strokes. Not recommended for
                        eggs and ovulation.                               smokers and women over the age
                                                                          of 40.

Mini-pill               Contains progesterone only so     2%              Very reliable with a lower dose of
                        ovulation takes place but                         hormones. Can be used by older
                        thickened cervical mucus prevents                 women. Side effects are
                        sperm from entering the uterus.                   breakthrough bleeding between
                                                                          periods, headaches and slight
                                                                          water retention.

Implantation preventing methods

IUD (intra-uterine      A device made of copper or            3%          Can be inserted and left for a long
device) or coil         stainless steel which is inserted                 period of time. Side effects are
                        into the uterine wall by a doctor                 heavy periods and discomfort. The
                        and which prevents implantation                   IUD may grow into the uterine wall,
                        of the fertilized egg.                            or may dislodge and come out.

Natural methods

Abstinence              No sexual intercourse.                0%          Very effective. No sexually
                                                                          transmitted diseases are
                                                                          transmitted. No side effects.

Rhythm method           Avoid sexual intercourse              20%         It is a natural method, but female
                        (abstinence) at time of ovulation.                cycles may vary and periods may
                                                                          be irregular. The Catholic Church
                                                                          accepts this method. No side
                                                                          effects.

Sterilization methods

Tube tying in           The fallopian tubes are „tied‟ or     1%          The process is difficult to reverse.
females                 cut. This prevents the sperm from                 In some cases the „tied‟ tubes
                        reaching the egg.                                 come undone and fertilization can
                                                                          take place. There are no side
                                                                          effects.




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Teacher Notes

Vasectomy in           Both vas deferens are cut.           1%           This is a simple procedure with no
males                                                                    side effects. Semen is still released
                                                                         but sperm are absent. The process
                                                                         is very difficult to reverse.

Termination methods

Morning-after Pill     The pill contains an anti-           20%          This pill may have long-term
                       progesterone drug and must be                     effects. A doctor prescribes it after
                       taken no more than 48 hours after                 a rape or when other means of
                       sexual intercourse.                               protection were not used. This pill
                                                                         should only be used as a last
                                                                         resort.

Abortion:
Teacher note: Abortion is a very topical debate. Make sure that you instruct the Learners that if they
are asked to give their view, that they only discuss being for OR against abortion. They must never
discuss both views unless they are asked to debate the topic. If they do, it will result in them being
penalized for this in an exam. If the question does ask them to DEBAT the topic then they must
provide both viewpoints or discuss both the advantages and disadvantages. This topic and the use
of contraceptive methods falls into the LO3 component and will be questioned in some form or
manner.

Abortion is the premature and deliberate termination of a pregnancy. The abortion procedures are
performed by qualified staff, up to 12 weeks of pregnancy. It may be legally performed up to 24 weeks in
cases where genetic deformities of the foetus are suspected or the mother is in physical danger. The mother
should be counselled before and after the procedure. Whether abortion is acceptable to you or not will
depend on your belief systems. The following are possible „pros‟ and „cons‟ for the abortion debate.

Possible Anti-abortion points:
    The unborn foetus is a living being from conception (fertilization has taken place)
    The foetus has a brain, heart and other organs early in its development (by 10 weeks) and can
       therefore feel pain
    Abortion is legalized killing/murder since you are taking away a life
    Many religions and cultures do not condone abortion – this goes against their morality/ethics that could
       lead to conflict in the family
    The mother-to-be also experiences deep emotional trauma and depression long after she has aborted
       her child – even if she has made the choice to abort
    Why should abortion be condoned when there are many contraceptive methods available
    Couples that have sexual relations must be responsible/ if a baby is conceived it should be accepted
       and loved - no matter what

Possible Pro-abortion points:
    Abortion is legal in South Africa – it is enshrined in our constitution – women have a choice
    The foetus does not have the status of a child in South Africa
    Abortion is better than bringing an unwanted child into the world and abandoning it
    The abandoned child could possibly have anti-social behaviour and become a problem
    Sometimes women do not have a choice about the use of contraceptives/ it is male controlled – she
       falls pregnant not out of choice – abortion is the only option in this case

Teacher Note: The Learners will be able to provide added pros and cons to this debate as the above
is merely an outline. As long as they make sense and are legitimate, the suggestions will be awarded
marks.

Infertility and technology in reproduction:
Teacher note: Technology plays a very important role in fertility and infertility. This is a very real
issue. The Learners must be able to recognize where technology makes an impact especially with



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Teacher Notes

regard to invetro fertilization. Link this to technology used to control fertility through contraception.

Infertility is the inability to become pregnant and is common in today‟s society. Most couples want to have
children. Women were blamed in the past as the cause of childless couples. Today, research has shown
that infertility is just as likely due to the men.

       Female infertility
        o Failure to ovulate due to poor hormonal function. Cure: hormone therapy.
        o Damage to the fallopian tubes where infections can cause scarring and blocking of the tubes.
            Cure: surgery to open the tubes.
        o Uterus damage will result in a lack of implantation by the fertilized egg to the lining of the
            uterus. Cure: surgery.
        o Cervix damage can result from abortion or a difficult birth where scar tissue blocks the cervix
            and sperm prevented from swimming to the uterus. Cure: Surgery.
        o Antibodies produced to sperm. Cure: drugs to suppress the immune system and by Invitro
            Fertilization.

       Male infertility
        o Low sperm count has many causes, such as obesity, hormonal problems, stress, drugs and
            alcohol abuse.
        o Abnormal sperm where sperm have two heads or tails as a result of hormonal problems or
            infection.
        o Premature ejaculation where the male reaches a climax before penetration.
        o Impotence is the inability to achieve an erection. This is usually due to a psychological problem.
            The male can go for counselling or sex therapy. If the problem persists, then a drug called
            Viagra is prescribed. Viagra assists the male to achieve and maintain an erection. The drug has
            many side effects and cannot be used by males who suffer from heart, liver, kidney and prostate
            problems or high blood pressure.

10.1. Donor insemination
Males donate sperm, stored in sperm banks to be used when a woman wishes to fall pregnant but her
partner is unable to provide sperm. Potential donors are very carefully screened for health and genetic
diseases. The sperm is selected based on the donor‟s records and inserted into the woman when she is
ovulating.
Ethical issues concerning donor insemination:
   Should child be told the identity of his or her biological father
   the emotional impact and commitment of the legal father
   the risk of a child entering into a sexual relationship with other offspring from the donor father
   some groups regard donor insemination as the equivalent to adultery

10.2. Invitro Fertilization (IVF)
This is when one or more eggs are fertilized outside the woman‟s body and transferred into the uterus for
development and growth.
The stages of IVF are as follows:
   Fertility drugs containing FSH are used to stimulate the ovaries to produce many eggs
   The collection of the eggs
   Sperm is collected from the male and seminal fluid is removed
   Fertilization of the eggs takes place in a test-tube within six hours of the harvesting of the eggs
   Three embryos are transferred into the uterus. Any remaining fertilized eggs can be frozen for
    implantation at a later stage should this process be unsuccessful.

10.3. Surrogacy:
Surrogacy is when another woman’s uterus is used to carry the embryo of a couple. The male provides the




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Teacher Notes

sperm and the egg can be from his partner or the surrogate. The egg is fertilized invitro and implanted into
the surrogate. If the surrogate egg is used, then the sperm is simply inserted as with donor insemination.
Agreements and legal documents must be drawn up before the process.
Ethical issues concerning surrogacy:
 exploitation of infertile women by surrogates
 refusal to give the baby to the couple when the surrogate provided the egg
 the legal issues if the baby is born with genetic defects or physical abnormalities, as the donor couple
    may not want the baby
 if the surrogate suffers damage to her health during the pregnancy, does she reserve the right to abort
    the couple‟s baby.




 EXERCISES:

Question 1:
Sportswomen use the contraceptive pill not only for birth control but also to alter their menstrual
cycle to suit their sporting lifestyle. Explain your view on this. (3)

(Taken from NSC Life Science Examination Exemplar 2008 Paper 1)

Question 2:


                                A FOETUS IS A BABY

    The biggest lie of the abortion industry is that the unborn child is a
    worthless, disposable blob of tissue. The second lie is that it is acceptable
    to ruthlessly terminate this life simply because it will be an inconvenience.

    More than 85 000 babies were aborted in South Africa last year bringing
    the total number of abortions since legalisation of abortion on demand, to
    more than half a million since 1997. These statistics indicate that abortion
    on demand is being used as a heartless form of birth control.

    No wonder that baby/child abuse and murders have increased. The only
    difference between abortion and murder victims is that one has been born
    while the other is supposedly in the safety of the mother's womb.

    Abortion, which places little value on human life, breeds a society that is
    heartless, especially towards its most vulnerable citizens.
                                                                                                      Page 5
    [Source: Daily News, 7 June 2006]
Teacher Notes




You are required to respond to this letter by addressing the following points:
2.1. Choose an opinion that is either for or against abortion and discuss at least FOUR reasons to support
      your viewpoint. (8)
2.2. Some people use abortion to get rid of unwanted offspring. Describe TWO methods that they could
      have used to prevent pregnancy in the first place. (4)

       Synthesis (3)
       Total: 15
       NOTE: NO marks will be awarded for answers in the form of flow charts or diagrams.

(Taken from NSC Life Science Examination Exemplar 2008 Paper 1)


    HOMEWORK:

Write a mini-essay explaining how any THREE contraceptive methods affect human reproduction. You
should also explain ONE way in which contraception can influence the quality of human life.
Content (12)
Synthesis (3)
NOTE: NO marks will be awarded for answers in the form of flow charts or diagrams.

(Taken from NSC Life Science Examination Feb/March 2009 Paper 1)



When answering an essay type question:
 Always read the topic with care. There may be “hidden pit-falls”. Underline the operative words and
  answer what is asked in the question. Let‟s look at the Homework question as an example:

Write a mini-essay explaining how any THREE contraceptive methods affect human reproduction. You
should also explain ONE way in which contraception can influence the quality of human life.

So now you should know that this question has TWO parts.

    Prepare for this essay by writing down the contraceptive methods that you can remember. Now select
     any three that you know best noting down briefly points about each of the three methods.
    Under NO circumstances do you number any paragraphs. Any diagrams that you use in an essay will
     be ignored, so don‟t waste time drawing them.
    Never use points in an essay. If you run out of time (you should not if you plan your time properly)
     simply write your information in point form without the points ie. Sentence after sentence and NOT a line
     per fact.
    For all essays (excluding languages such as English, Afrikaans etc) DO NOT use words and phrases
     like “it can be seem”, “ I feel that”, “in my opinion” etc. These essays are factual and objective, even if
     you are asked “In your opinion…”. It MUST be based on facts, which are laid out in a logical, systematic
     order. Be careful of repetition and writing nonsense. This only serves to prove that you did NOT
     prepare the essay properly and marks will be deducted.
    Now check that you have answered all the components in the essay, by rereading the question.




                                                                                                       Page 6
Teacher Notes


   ANSWERS / RUBRICS:


Exercise:
Question 1:
Teacher note: the Learners were expected to know that the pill is clasified as technology. Their
answers had to reflect this or they were not awarded the marks.

Agree  Technology is there to use for their convenience  Against religious beliefs to use any contraceptive
      methods
           OR
Disagree  Negative side effects like infertility after prolonged use/heart disorder Any other logical reason

Question 2:
2.1.
(a) Possible answers for Anti-abortion
      - The unborn foetus is a living being from conception (fertilization has taken place)
      - The foetus has a brain, heart and other organs early in its development(by 10 weeks) and can
         therefore feel pain
      - Abortion is legalized killing/murdersince you are taking away a life
      - Many religions and cultures do not condone abortion – this goes against their morality/ethics
         that could lead to conflict in the family
      - The mother-to-be also experiences deep emotional trauma and depression long after she has
         aborted her child – even if she has made the choice to abort
      - Why should abortion be condoned when there are many contraceptive methods available
      - Couples that have sexual relations must be responsible/ if a baby is conceived  it should be
         accepted and loved - no matter what - Any other acceptable reason Any 4 x 2 (8)

       OR Possible answers for Pro-abortion
        - Abortion is legal in South Africa – it is enshrined in our constitution – women have a choice
        - The foetus does not have the status of a child in South Africa
        - Abortion is better than bringing an unwanted child into the world and abandoning it
        - The abandoned child could possibly have anti-social behaviour and become a problem
        - Sometimes women do not have a choice about the use of contraceptives/ it is male controlled –
           she falls pregnant not out of choice – abortion is the only option in this case Any other
           acceptable reason Any 4 x 2 (8)
2.2.
        Natural methods
        *Abstinence  simply means not having sexual intercourse 
        *Rhythm method  – the couple engages in sexual intercourse but only during times when fertilization
        is not likely to occur i.e. no sexual intercourse 3 - 4 days before and after ovulation 

        Chemical methods
        *Spermicidal – creams or foams that destroys sperm in the vagina
        *Contraceptive pill – hormonal control that prevents ovulation and therefore conception

        Mechanical/barrier methods
         *Condom – sheath that traps sperm and prevents it from entering the vagina
        *Femidom – used by a female – also traps sperm and prevents it from entering the uterus
        *Diaphragm– a cap that fits over the cervix – stops the passage of sperm
        *Intra-uterine-device (IUD)  – small piece of metal or plastic, which is retained inside uterus and
        which prevents implantation of the embryo

        Surgical methods
        *Vasectomy – small cuts are made into the scrotum and the sperm ducts are tied/cut – prevents




                                                                                                         Page 7
Teacher Notes

     sperm from entering the urethra
     *Ligation/female sterilization – two Fallopian tubes are cut/tied so that no ova enters the uterus – also
     sperm can swim up to fertilize the ovum Any 2 x 2 (4)

     Synthesis (3)
     NOTE: NO marks will be awarded for answers in the form of flow charts or diagrams.

     Mark descriptions for synthesis component:
     3 - Well structured – demonstrates insight and understanding of question
     2 - Minor gaps in the logic and flow of the answer
     1 - Attempted but with significant gaps in the logic and flow of the answer
     0 - Not attempted/nothing written other than question number




Home work Answers:
Contraceptive methods and the effect on human reproduction :




                                                                                                      Page 8
Teacher Notes




(Mark first THREE only) any 3 x 3 (9)

Part 2 of the question: The influence on the quality of human life
Limits family size  /unwanted pregnancies
- which allows better care for the children higher standard of living  / less dependant on debt/ more
psychologically stable children
Prevents the transfer of STD‟s  
- the use of e.g. condoms can increase life span  and decrease  the spread of diseases to other people
Might cause conflict
- e.g. the use of IUD could be seen by some people as a form of abortion which may not be acceptable
to some religions 
(Mark first ONE only) any 1 x 3 (3)




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