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Section 2
Biological Processes, Physical
Development, and Perceptual
Development
CHAPTER 3
BIOLOGICAL BEGINNINGS
CHAPTER INTRODUCTION
This chapter presents a brief historical perspective on genetic evolution as well as basic concepts and
issues related to reproduction.
I.
II.
Evolutionary Perspective
A.
Natural selection process
1.
Emphasizes that the best adapted individuals survive and reproduce
2.
Charles Darwin proposed this perspective.
B.
Evolutionary psychology
1.
Emphasizes the role of adaptation in “survival of fittest”
2.
Bandura rejects the “biologizing” of psychology and suggest a bidirectional view
in which biological changes enable organisms to affect environmental conditions.
Genetic Foundations
A.
What are genes?
1.
The nucleus of each human cell contains 46 chromosomes (23 pairs). One member
of each pair of chromosomes comes from each parent.
2.
Chromosomes are made up of DNA, a “double helix” shaped molecule that
contains genetic information.
3.
Genes are short segments of DNA. Genes carry the information needed for cells to
reproduce and generate the proteins necessary for life.
B.
Mitosis and Meiosis
1.
Mitosis is the process by which each chromosome in the cell’s nucleus duplicates
itself.
2.
Meiosis is the process by which cells in the reproductive organs divide into
gametes, which have genetic material of the parent cell.
3.
Reproduction begins when a female gamete (ovum) is fertilized by a male gamete
(sperm).
4.
A zygote is the single cell formed when the sperm and ovum unite, and contains
one member of each pair of chromosomes from the mother and one from the father.
C.
Genetic principles
1.
Dominant-recessive genes: Dominant genes override recessive genes.
2.
Sex-linked genes. A number of disorders are carried on the sex chromosome and
this is called x-linked inheritance. Examples are hemophilia and fragile-X
syndrome.
3.
Genetic imprinting is a mechanism in which genes have been modified on one of
the parents. Effects depend on whether transmission is through egg or sperm.
38
4.
D.
E.
F.
G.
Polygenic inheritance is the principle by which genes interact to produce a
characteristic. There are 30,000 to 35,000 genes in the human genome, yielding an
astronomical number of possible combinations.
a.
A genotype refers to a person’s genetic heritage.
b.
The phenotype is one’s genotype expressed in characteristics that can be
observed and measured. It includes physical traits (e.g., height, weight) as
well as psychological characteristics (intelligence, personality).
c.
A reaction range is the range of possible phenotypes for each genotype
and is determined by the range within which the environment can modify
the trait.
d.
Canalization refers to a narrow developmental course of certain
characteristics that are not malleable by the environment.
Behavior genetics
1.
Behavior genetics is the study of the degree and nature of behavior’s hereditary
basis.
2.
Twin studies are used to compare behavioral similarity of identical (monozygotic)
and fraternal twins (dizygotic) to determine the heritability of a behavioral trait.
3.
Adoption studies are used to answer the question about whether adopted children
are more similar to biological or adoptive parents in specific behaviors
Molecular genetics
1.
The Human Genome Project was begun in the 1970s to map the human genome.
2.
The Human Genome Project has linked specific DNA mutations with certain
diseases and conditions.
3.
Ethical issues surround the question of how to use information obtained from the
genetic analysis of individuals.
The collaborative gene
1.
The Human Genome Project revealed that humans have 30,000 or more genes,
fewer than biologists had expected, and more proteins than had been thought.
2.
A book titled The Dependent Gene proposes that DNA does not determine traits
independently but in interaction with the environment.
3.
External sensory and internal neural events can excite or inhibit gene expression.
4.
Barry Commoner argues that it is not DNA that is the unit of life. It is the cell of
which DNA is a component.
Chromosome and gene-linked abnormalities
1.
Down syndrome is a disorder recognized by an extra 47th chromosome.
Characteristics include mental retardation and motor impairment. Physical
abnormalities include these: round face flattened skull, extra fold of skin over the
eyelids, a protruding tongue, and short limbs. The groups most likely to be affected
by Down syndrome include women under 18 or over 38 years of age.
2.
Abnormalities of the sex chromosome
a.
Klinefelter syndrome is a chromosomal disorder in which males have an
extra “X” in the sex chromosome, resulting in the “XXY” pattern.
Characteristics include undeveloped testes, enlarged breasts, and tall
stature.
b.
Fragile X syndrome results from an abnormal X chromosome. The X
chromosome may be restricted or broken. Effects may include mental
39
retardation, learning disabilities, and/or short attention span. It occurs more
frequently in males.
c.
Turner syndrome is a chromosomal disorder in which a female is missing
an “X” chromosome (“XO”) or part of the second X chromosome is
deleted. Such females are short, have webbed necks, may be mentally
retarded, and are sexually underdeveloped.
d.
“XYY” syndrome is a chromosomal disorder in which males have an
extra “Y ”chromosome. There has been controversy as to whether “XYY” males
might be more aggressive but there is no definitive evidence that they are.
3.
Gene-linked abnormalities
d.
Phenylketonuria (PKU) is a metabolic disorder in which the individual
can’t metabolize a substance needed for production of proteins in the body.
It usually affects Caucasians. Left untreated by special diet (an
environmental modification) it can lead to retardation and hyperactivity.
e.
Sickle-cell anemia is a type of disorder in which sickle-shaped red blood
cells limit oxygen supply to joints and organs. It can lead to joint swelling
and heart or kidney failure. Groups usually affected include African
Americans and Latino Americans. Sickle-cell anemia is treatable by
penicillin, antibiotics, and blood transfusions.
f.
Tay-Sachs is a condition in which lipids (fats) accumulate in the nervous
system. It involves a deceleration of mental and physical development and
victims usually die by the age of 5. This genetic condition affects persons
of Jewish descent. Treatment includes medication and diet.
g.
Cystic fibrosis is a glandular dysfunction that interferes with mucus
production, breathing, and digestion and generally shortens the life span. It
can be treated with physical therapy, oxygen therapy, synthetic enzymes,
and antibiotics.
h.
Hemophilia, a blood disorder in which the affected person lacks a clotting
factor, affects males. It is treatable by blood transfusions and injections of
clotting factor.
f.
Spina bifida is a neural tube disorder involving brain and spine abnormalities. Surgery,
orthopedic devices, and physical/medical therapy can be used to treat it.
III.
Reproduction Challenges and Choices
A.
Prenatal Testing for Abnormalities
1.
In amniocentesis, amniotic fluid is withdrawn by syringe (between 12 and 16
weeks of pregnancy) to test for chromosomal or metabolic disorders.
2.
In ultrasound sonography, high-frequency sound waves are directed into the
pregnant woman’s abdomen. Echo from the sounds is used to make a picture of the
inner structures of the fetus. This procedure is useful for determining the location
of the fetus in the uterus, to detect microencephaly (small brain).
3.
In a chorionic villi sampling, a small sample of placenta is taken between the 8th
and 11th week of pregnancy. A diagnosis is available within 10 days.
4.
Maternal Blood Test to assess alpha-fetoprotein level (AFP), which is
associated with neural tube defects.
B.
Infertility
1.
Infertility is experienced by 10 to 15 % of couples in the United States.
2.
High-tech assisted reproduction for infertile couples includes five common
techniques. They are in vitro fertilization (IVF), gamete intrafallopian transfer
40
IV.
(GIFT), intrauterine insemination (IUI), zygote intrafallopian transfer (ZIFT),
and intracytoplasmic sperm injection (ICSI).
C.
Adoption
1.
Adoption is a social and legal process by which a parent-child relationship is
established between persons unrelated at birth.
2.
Adopted children show more psychological problems than nonadopted children do.
Yet, adopted children show more prosocial behaviors.
3.
Adoptive parents must make decisions about what to tell the child about the
adoption.
Heredity-Environment Interaction
A.
Genotype-environmental correlations
1.
Passive genotype-environmental correlations between heredity and the
environment occur when genetic parents also provide the rearing environment.
2.
Evocative genotype-environmental correlations occur when the child’s genotype
elicits certain types of physical and social environments.
3.
Active (niche-picking) genotype-environmental correlations refer to the tendency
of children to seek out environments that they find compatible and stimulating.
B.
Shared and nonshared environmental experiences
1.
Shared environmental experiences include siblings’ common experiences such as
parents’ personalities, family’s environment, SES, and the neighborhood.
2.
Nonshared environmental experiences refer to each child’s own unique
experiences (in and outside of family) that are not shared with a sibling.
C.
Conclusions about heredity-environment interaction
1.
The relative contributions of heredity and environment operate together; they are
not additive, so it is not possible to say what percentage of anything is due to either
heredity or environment.
2.
Complex behaviors may have a genetic loading that predisposes one to a
particular development. But the actual development of the characteristic depends
also on complex environmental influences.
3.
Judith Harris’s 1998 book titled The Nurture Assumption argued that parents make
little difference compared to genes and peers.
4.
Hartup (1998) argues that Harris’s thesis does not take into account the complexity
of peer contexts and developmental trajectories.
5.
There is ample research to document the important influence of parenting on
child development.
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SUGGESTIONS FOR LECTURE TOPICS
1. Prevention of Birth Defects: The March of Dimes Story
The prevention of birth defects is one of the three primary missions of a foundation known as the March of
Dimes. Originally called the National Foundation for Infantile Paralysis, it was established in 1938 by
President Roosevelt. The original mission was to lead a crusade against the crippling childhood virus
called polio. The foundation provided support for Dr. Jonas Salk, who developed the polio vaccine
beginning in the 1940s. The vaccine was tested and shown to be effective in 1952. Later, the March of
Dimes supported Dr. Albert Sabin’s development of an oral polio vaccine. Today virtually all newborns
receive the polio vaccine and no new cases have been reported in the western hemisphere since 1991. The
March of Dimes Web site reports that, though some cases still exist worldwide, it hope to be able to
pronounce the world polio-free by 2005. The work of the National Foundation/March of Dimes is
historically significant:
“Its efforts to provide care for the victims of polio while aggressively working to develop vaccines
against it, represents the first large-scale, nationwide biomedical initiative, led by a charitable
organization.”1
Although the organization’s focus is no longer on polio, it does continue to support the dissemination of
information about post-polio syndrome, a debilitating condition experienced by adult survivors of polio.
Having successfully led the crusade against polio, the March of Dimes turned its mission to the prevention
of birth defects in 1958. Two additional missions, prevention of premature birth and prevention of low
birthweight babies, have now been added. The March of Dimes sponsors genetic research and provides
educational materials to parents and professionals. It has a toll free phone number, and e-mail and chat
lines where specialists can answer questions. It also distributes, free of charge, numerous booklets,
brochures, and magazines that contain information for prospective parents.
In 1973, the March of Dimes funded the first in utero treatment for a birth defect and in 1978 it funded the
first prenatal diagnosis of sickle cell anemia. The list of important “firsts” that were supported by the
March of Dimes is available on the Web at http://www.marchofdimes.com/aboutus/789_4283.asp. A
couple of these historical milestones include these from 1998-2000:
1998: Helped secure passage of the Birth Defects Prevention Act. This act established a national system for
monitoring birth defects. In the same year, research that had been sponsored by MOD resulted in a surgery
to treat spina bifida before birth.
1999: MOD researchers developed gene therapy to treat hemophilia and retinitis pigmentosa.
2000: Helped formulate The Children's Health Act of 2000. This law established a National Center on
Birth Defects and Developmental Disabilities at the Centers for Disease Control and Prevention.
Sources: The March of Dimes Story. Retrieved March 15, 2003 from
http://www.marchofdimes.com/aboutus/789.asp; http://www.marchofdimes.com/aboutus/789_1540.asp
1
http://www.marchofdimes.com/aboutus/789.asp
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2. Genetic Information Resources: GeneTests, NCBI, and OMIM
The volume and complexity of information on genetics is overwhelming to many students (and
teachers) of introductory child development courses. However, the National Institutes of Health
cooperate with other organizations and agencies to provide via the Internet detailed searchable
databases for persons seeking information on genetics, genetic counseling, and genetic testing. Many
university lecture halls now have Internet access. Hence, one or more class lecture periods might be
comprised of “walking through” Web sites devoted to genetics, allowing students to suggest which
links to follow at certain points. Three reliable sites will be described below: GeneTests, National
Center for Biotechnology Information, and OMIM (Online Mendelian Inheritance in Man).
GeneTests, a reliable, publicly funded Web site at http://www.geneclinics.org/, is funded by the
National Institutes of Health, the Health Resources and Services Administration, and the U. S.
Department of Energy. It is supported administratively by the University of Washington School of
Medicine and Children’s Hospital Regional Medical Center in Seattle, Washington. Notable among the
resources available at geneclinics.org are these features:

A free, downloadable, animated PowerPoint presentation titled "The Primary Care Physician:
The Primary Source of Genetic Testing Information," which was prepared for use by non-genetics
practitioners on the use of GeneTests. It covers genetic counseling and testing concepts as well as
the use of the GeneTests Web site. Although the slides are freely available and intended for
educational purposes, they are copyrighted and cannot be modified in any way. Students planning
health-related professions, especially public health or health education, or those who seek specific
detailed information on a genetic condition should be aware of this resource.

GeneReviews is a searchable publication designed for physicians and healthcare professionals.
Genetically inherited conditions are catalogued, along with descriptions of the condition,
diagnostic information, information on disease management, and genetic counseling. By entering
the name of a genetic condition, the reader is linked to information on testing laboratories, genomic
databases, patient resources, and policy guidelines. For example, by entering the term
“thalassemia,” the site offers testing, research, and review links for Beta-Thalassemia (Thalassemia
Intermedia, Thalassemia Major, Thalassemia Minor), Alpha-Thalassemia (Hemoglobin Constant
Spring), and Alpha-Thalassemia X-Linked Mental Retardation Sydrome. By clicking on X-Linked
Mental Retardation Syndrome, the reader is presented a copy of a review titled “AlphaThalassemia X-Linked Mental Retardation Syndrome” by Roger E. Stevenson, MD, FACMG of
the Greenwood Genetic Center in Greenwood, South Carolina. Information includes diagnosis,
clinical description, management, genetic counseling, molecular genetics, resources, references,
and author information.

A searchable Laboratory Directory provides information on locations where specific diseases can
be diagnosed. For example, by typing in Tay-Sachs, the site provides a detailed list of laboratories
where clinical testing on Tay-Sachs is being done, along with the location, the name of a physician
contact, and a direct link to the laboratory’s Web site.

A search for a pediatric clinic treating a specific disorder can be selected for a particular state.
By selecting “cleft palate” and “Oregon,” I was shown a map indicating that there are pediatric
genetics clinics specializing in cleft palate in the Oregon cities of Bend, Eugene, Medford, and
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Portland. By selecting Portland, I was given complete information on the services, telephone, and
fax contact information, and the Genetic Board Certifications of staff.

Educational materials comprise one section of the Web site. Included in this section is an
Illustrated Glossary that defines at least 225 genetics terms, many of which are illustrated.
About Genetic Services explains the difference between genetic testing, clinical testing, and
research testing. Detailed information is provided on diagnostic testing, prenatal testing, carrier
testing, preimplantation testing, and newborn screening. For example, by clicking on
“preimplantation,” one learns that this type of testing is done on early embryos that were fertilized
in vitro and is used only when there is a high chance of the occurrence of a serious genetic
disorder. One can read further to learn that such testing is performed only at a few centers, the cost
is very high and is usually not covered by insurance.
NCBI (National Center for Biotechnology Information), a division of the National Library of Medicine
(NLM) at the National Institutes of Health (NIH), operates a Web site at http://www.ncbi.nlm.nih.gov/ as a
public service providing information on genetics. The site features a link to PubMed Central, which
provides free access to over 80,000 articles from 100 medical journals. Since the site deals with a broad
array of biotechnology topics, it is not restricted to genetics. However, because of the centrality of
molecular genetics to biotechnology, a vast array of information on genetics is available at this site. In fact,
student majoring in computer science might be interested to learn that NCBI develops software tools for
analyzing genome data—a possible career path. The NCBI site’s hot spot links are to a “Gene Expression
Omnibus,” “Genes and Disease,” and “Human Genome Resources,” and the “Cancer Genome Anatomy
Project.” The Outreach and Education section links to a genetics glossary, which includes a Talking
Glossary of Genetic Terms. Here is a goldmine for instructors who could use some help with pronunciation
of genetics terms and their definitions. For example, by clicking on “allele,” one can read the definition of
the term, click to hear an audio recording with a detailed explanation, and/or link to additional information
provided by Senior Investigator, Leslie Biesecker, Head of the Human Development Section of the Genetic
Disease Research Branch of the National Human Genome Research Institute.
OMIM (Online Mendelian Inheritance in Man), a Web site at
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=OMIM, contains a catalog of human genes and genetic
disorders authored by geneticists at Johns Hopkins and made available for the Web by NCBI, the National
Center for Biotechnology Information. Typing in the word “obesity” yielded 221 links to information on
obesity susceptibility, including gene maps focused on chromosome 10p (see
http://www.ncbi.nlm.nih.gov/htbin-post/Omim/getmap?d4096 and
http://www.ncbi.nlm.nih.gov/mapview/maps.cgi?ORG=hum&CHR=10&maps=locr,morbid,gene&R1=on&query=OB10&VERBOSE=ON&ZOOM=3) for examples.
3. Infertility Treatment: Is the Offspring at Risk?
As Santrock points out, 10% of the population is affected by infertility problems. Treatments have included
insemination and ovulation-stimulating drugs, as well as external manipulation of eggs and sperm (in vitro
fertilization and intracytoplasmic sperm injection). What are the risks for infants born as a result of
reproductive technology? Two articles in the March 7, 2002 issue of The New England Journal of
Medicine report address this question. The articles are introduced in an editorial commentary that briefly
summarizes the findings. These articles offer good models for the presentation of population research
projects designed to control for mitigating variables.
It is commonly known that ovulation-stimulating hormones often result in multiple births. It is also known
that newborns of multiple births are typically low birthweight (LBW), a risk factor for newborns. What has
44
not been clear is the extent to which low birthweight can be attributed to the reproductive technology rather
than simply the multiple birth condition. One way to assess that risk is to study the incidence of LBW from
assisted pregnancies that do not involve multiple births. An article by Schieve et al. (2002) reports the
results of a study in which the authors compared the rates of low birthweight (<=2500 g) and very low
birthweight (<1500 g) among 42,463 infants who were conceived as a result of assisted reproductive
technology, with the rates of LBW and very LBW in the a comparison sample born during the same time
period (1996-1997). The study corroborated previous findings that infants born as a result of reproductive
technology comprised a disproportionate number of LBW and very LBW infants when compared to the
general population. This outcome was attributed in part to the condition of multiple births. However, when
only singleton births were studied, the results also confirmed an increased risk to LBW that might be
attributed either to the reproductive technology or to the underlying conditions leading to infertility.
Nevertheless, in an editorial commentary, Dr. B. Mitchell pointed out that a positive outcome is expected
in a high proportion of assisted pregnancies and that prospective parents would need to assess the risk in
relationship to the high proportion of positive outcomes.
A second article in the same issue of the journal reports an Australian study on the risk of major birth
defects after intracytoplasmic sperm injection and in vitro fertilization that indicated an increased risk for
birth defects among this group.
Sources: Hansen, M., Kurinczuk, J. J., Bower, C., & Webb, S. (2002) The risk of major birth defects after
intracytoplasmic sperm injection and in vitro fertilization. The New England Journal of Medicine, 346,
725-730; Mitchell, B. S. (2003). Infertility treatment: More risks and challenges. The New England Journal
of Medicine, 346, 769-770; Schieve, L. A., Meikle, S. F., Ferre, C., Peterson, H. B., Jeng, G., & Wilcox, L.
S. (2002). Low and very low birth weight in infants conceived with use of assisted reproductive
technology. The New England Journal of Medicine,346, 731-737.
4. Bias in Early Attempts to Measure Intelligence
It seems reasonable to suppose that an antidote to subjectivity in observation is to resort to precise,
concrete definitions and procedures for observing and measuring inferred characteristics such as
personality traits and intelligence. However, it turns out that even the most objective quantitative means of
measurement are open to bias and distortion. This is an important lesson, because students often believe
very strongly that much less vigorous descriptive techniques are adequate sources of data about behavior
and personality.
Steven Jay Gould provides a beautiful example of this problem in his book The Mismeasure of Man. In
this book you will find numerous examples of how 19th century scientists' conviction that intelligence was
an entirely biologically determined, inherited trait blinded them to elementary procedural and calculation
errors that happened to confirm their beliefs about such matters as racial and sex differences in
intelligence. Compelling material in its own right, this account establishes clearly and straightforwardly
the problem of bias in observation; the need for clear, reliable, and valid definitions of behavioral or
hypothetical constructs; and the need to make appropriate and wide-ranging comparisons to test hypotheses
and their alternatives adequately.
Gould's treatment also highlights the dangers of the strong hereditarian thesis to social policy and practice
that are still experienced today. For example, you may wish to compare his treatment to the information
presented later in the textbook about the influence of modern research on sex differences in mathematics.
5. Using Twins to Study the Nature-Nurture Issue with Weight
45
Is weight determined by heredity or lifestyle? In one report, researchers analyzed weight and height records
from the Swedish Adoption/Twin Study of Aging (Stunkard et al., 1990). Using 247 identical and 426
fraternal pairs of twins, twin siblings ended up with similar body weights regardless of whether they were
raised together or apart. In fact, the correlation in body-mass index of identical twins reared apart was only
slightly less than that of identical twins reared together. They also were more similar in weight to the
biological parents than to the adopting parents. When both biological parents were fat, 80% of offspring
were fat. Childhood environment was shown not to have an important effect.
Canadian researchers fed 12 pairs of identical twins 1,000 calories above their normal daily intake for 84
days. Weight gains ranged from 4 kg to 13 kg (9 lbs. to 29 lbs.). The difference in the amount gained was
much less between twins than between nonsiblings. In other words, considerable variability in weight gain
and fat distribution was seen between different twin pairs, but little variability was seen within each pair.
Bouchard (1990) concluded, "It seems genes have something to do with the amount you gain when you are
overfed.''
Sources: Chubby? Blame those genes. (1990, June 4). Time, 80; Bouchard, C., et al. (1990, May 24). The
response to long-term overfeeding in identical twins. New England Journal of Medicine, 322, 1477-1482;
Stunkard, A. J., et al. (1990, May 24). The body-mass index of twins who have been reared apart. New
England Journal of Medicine, 322, 1483-1487; Sima, E. A. H. (1990, May 24). Destiny rides again as
twins overeat. New England Journal of Medicine, 322, 1522-1524.
46
TOTAL TEACHING PACKAGE OUTLINE
Use the following annotated outline to determine how to best use the Total Teaching Package, including
the text features and ancillary materials, provided to you by McGraw-Hill to accompany Santrock’s Child
Development, 10th Edition.
Lecture Outline
Chapter 3: Biological Beginnings
I. The Evolutionary Perspective
A. Natural selection process
1. Best adapted individuals survive
and reproduce
2. Proposed by Charles Darwin
B. Evolutionary psychology
1. Emphasizes adaptation,
reproduction, “survival of fittest”
2. Bandura argues for bi-directional
view
II. Genetic Foundations
A. Genes
1. Nucleus of each cell contains 46
chromosomes(23 pairs)
2. Chromosomes made up of DNA
Resources Reference
PPT: PowerPoint Presentation # 3
IG: 1: What does society value?
OHT: 23: Human Reproductive Systems
SLT: 2: Genetic Information Resources
CCD: Holly Ishmael, Genetic Counselor
3. Genes: Short segments of DNA
and blueprint for cells to reproduce
4. Mitosis and Meiosis
5. Reproduction
6. Zygote
B. Genetic Principles
1.
Dominant-recessive
genes
2.
Sex-linked genes
3.
Genetic imprinting
4.
Polygenic Inheritance
a.
genotype
b.
phenotype
c.
reaction range
d.
canalization
C. Behavior genetics
D. Molecular genetics
1.
Genome Project
2.
Ethical issues
OHT: 24: Heredity composition of the zygote
OHT: 25: Determination of sex
CAD: 5
SRP:1: Heritability of Height
OHT: 26: Phenotypes and genotypes
OHT: 46: How brown-eyed parents can have a
blue-eyed child
CTE: 1: Inheritance of Temperament
SLT: 2: Genetic Information Resources
CAD: 7: Human Genome Project
CTQ: 1: Issues in Genetic Testing
47
VI.
VII.
VII.
E. The collaborative gene
1.
Humans have 30,000+
genes
2.
Book: The
DependentGene
Chromosomal abnormalities
A. Down Syndrome
B. Klinefelter
C. Fragile X
D. Turner
Gene-linked abnormalities
A. PKU
B. Sickle cell
C. Tay Sachs
D. Cystic fibrosis
E. Hemophilia
F. Spina bifida
Reproduction Challenges and Choices
A.
Prenatal Dianostic Tests
1.
amniocentesis
2.
Sonography
3.
CV biopsy
4.
AFP
B.
Infertility
1.
About 10-15% of
couples have problems
2.
C.
VIII.
High-tech methods
help solve problems
Adoption
1.
Adopted is a social and
legal process
2.
More negative effects if
adopted after age 10
3.
Adopted children more
prosocial
Heredity-Environment Interaction
A.
Heredity-Environment
Correlations
1.
Shared and Non-Shared
Environmental
Experiences
2.
Scarr’s view: Parents
with certain genotypes
select certain
environments
3.
Three correlations:
SLT: 1: Prevention of Birth Defects: The
March of Dimes Story
OHT: 27: Dominant inheritance of a birth
defect
OHT: 28: Recessive inheritance of a birth
defect
OHT: 29: Sex-linked inheritance of a birth
defect
CAD: 2: School Team Meeting
IG: 2: Guiding Children With Special Needs
SRP: 2: Internet Search
CAD: 6: Genetic Testing
ECD: Genetic Counseling
SRP: 2: Genetic Counseling
CTQ: 5: Genetic Counseling
Jarvis: 4D: The Pros and Cons of Genetic
Testing
Jarvis: 4F: Genetic Counseling
SLT: 3: Infertility Treatment: Risks to
Offspring
OHT: 37: Fertility problems and solutions
CAD: 8: Arts: Music “Happy Adoption Day”
CTQ: 3: Developmental Issues
CTE: 2: Nature of Development
Jarvis: 4A: Explanations for Attention
Deficit Hyperactivity Disorder: Nature and
Nurture
48
Passive, evocative,
active (niche-picking)
B.
C.
D.
E.
Conclusions about heredityenvironment interaction
Many complex behaviors
have genetic loading
Actual developments require
complex environment
Heredity-environment
interaction is extensive
SLT 4: Bias in Early Attempts to Measure
Intelligence
SLT 5: Using Twins to Study Nature-Nurture
CAD: 3: Heritability of IQ: Public Policy
CTQ: 2
CAD: 4: Public Policy
OHT: 30: Some conditions and characteristics
showing genetic influence
CTQ: 4: Famous Quotes
Suggested Assignments—Review of Chapter 3: Biological Beginnings:

Review the “Learning Goals” for Chapter 3.

“Review and Reflect” exercises for Chapter 3.

TTN: Consult the on-line learning center for links to Web sites that provide additional
information on topics presented in Chapter 3.
Suggested Assignments—Preparation for Chapter 4: Prenatal Development and Birth

Preview the “Learning Goals” for Chapter 4.
CLASSROOM ACTIVITIES OR DEMONSTRATIONS
1. Discuss the critical thinking exercises. For exercise 1, be sure the class understands the genetic
principles. They need not fully understand the ramifications of the dominant-recessive gene
principle, but it will help to work toward that understanding. Students often do not understand the
other concepts well either, and you may want to work through carefully. Their performance on this
exercise should be a good indication of their understanding of the concepts. (The class activity
suggested below may be a good context for this.)
The purpose of exercise 2 is to review the material presented in Chapter 1 by applying it; you will
discover that many subsequent thinking exercises are similar to this one. The idea is that these
developmental issues are not easily mastered, but that doing so is important because they define the
nature of developmental psychology. If necessary, review this material in class, and possibly work
through a topic or two in the text in terms of the issue it illustrates.
49
2. Professionals in a variety of careers have the opportunity to improve the lives of children and their
families through the use of knowledge about child development. Create cooperative learning
groups who are charged with dramatizing a school “staffing” on a child with a particular genetic
condition. A “staffing” often consists of a meeting to plan educational objectives for the child and
to map out a plan for achieving the objectives. A typical team meeting would include these career
roles: (a) teacher; (b) primary caregiver (mother, father, foster parents, custodial grandparent, etc.);
(c) school guidance counselor; and (d) pediatrician. Other roles might be a school principal, music
teacher, art teacher, or physical education teacher. However, research has demonstrated that the
optimal size for a cooperative group project is four. Have the student in each role research the
particular genetic condition in terms of information that would be relevant for the person in that
role. What information would the primary caregiver have that the physician or art teacher does not
have? What information is needed? What types of observations might the teacher contribute that
the parent or physician does not have?
Several different cooperative groups can be formed, each one focusing on one genetic condition.
For example, Down syndrome, hemophilia, sickle-cell anemia, or fragile X syndrome. Research
can be done outside of class or in class if the classroom has Web accessibility. Class time can be
set aside for a “role” clarification meeting where actors can collaborate on ways to dramatize the
role. For example, all principals might learn about the school’s legal responsibilities related to the
IDEA act. Guidance counselors will meet to reflect on behavior management, social issues such as
making friends, or emotional ramifications of the special condition. Parents will have their own
support group meeting.
After ample opportunity to research the biological and social science information about the
condition and the opportunity for students playing various roles to collaborate, ask the group
representing each condition to dramatize a “team meeting” focused on planning for the child’s
school experience. During the drama, the audience should take notes on the information regarding
the condition and questions that arise as a result of the drama.
Actors can introduce humor and liven the drama with simple props and costumes (a hard hat for a
dad who is a construction worker, a clipboard or oversized pencil for the teacher, a very gray wig
for a custodial grandparent, etc.). However, actors should be cautioned against portrayals that
stereotype or make fun of any condition. They need to be encouraged to remember that some of
their classmates will have siblings or other relatives with the condition.
Create an evaluation form that the audience can use for each drama. Student evaluators should rate
the presentation on (a) accuracy of Information, (b) mention of reliable information sources, (c)
creative portrayal of the various roles, and (d) the absence of derogatory statements.
3. How might the question of heritability of intelligence become an issue in public policy? Suggest to
the students that data about parents’ (or grandparents') intelligence should be used to determine
what kinds of schooling to give to children. For what kinds of social changes might someone
coming from a strong genetic position argue? How about a strong environmentalist? What
difference does it make whether heritability of intelligence is high or low?
Source: King, M.B., & Clark, D.E. 1990. Instructor's Manual to accompany Children. Dubuque,
IA: Wm. C. Brown Publishers.
4. Have groups of students role-play having roles in different kinds of governments, such as

politicians in a humanitarian, progressive government.
50

politicians in a repressive, prejudicial, and tyrannical government.

a mad, unscrupulous ruler and his committee of advisers.

politicians in a greatly overpopulated country experiencing shortages of food, jobs, and space.
Have them make recommendations for laws or policies involving genetic counseling, reproductive
technology, and related issues (e.g., selective breeding, abortion, and sterilization).
Source: Simons, J. A. 1990. Use of genetic counseling by governments: A role play exercise. West
Des Moines, IA: Central Iowa Psychological Services
5. Ask students to bring in as complete a description as possible of the eye colors of their siblings,
parents, grandparents, and, if possible, great-grandparents. Some students will be unable to get the
information, so it might be a good idea to break them into groups and have them use the data of the
student with the most complete history. Have the students draw genetic models that explain how
they and their siblings got their eye color. If possible, try to get them to draw models that include
their grandparents as well as their parents.
Another activity that can be useful at this time in the course is to force students to adopt a
theoretical perspective and argue it with others who have adopted another perspective. The debate
over the inheritability of intelligence is a good one. Each student should be assigned to one side of
the debate and told to gather at least two pieces of evidence that support their side. The groups can
then pool their evidence, select a couple of spokespersons, and let the debate begin. Bringing in a
colleague to judge the debate can keep you from having to take sides and may help the students
prepare better arguments.
Source: Temple, L. L. (1992) Instructor's Course Planner to accompany Life-span Development,
4th Edition by John Santrock. Dubuque, IA: William C. Brown Publishers.
6. A genetic diagnostic test has been developed for the 100,000 Americans with a history of
Huntington's disease in their families. The test identifies which individuals have inherited the
defective gene. These individuals will usually begin to show symptoms between ages 35 and 45.
The symptoms include progressive dementia and loss of body control; after early symptoms of
irritability and depression, there are symptoms that mimic "drunkenness'' such as slurred speech,
slowed thought processes, impaired memory, and diminished problem-solving ability. These
individuals also exhibit uncontrolled movements.
What are the disadvantages and advantages of conducting these simple blood tests?
Disadvantages

Some people may be unable to cope with the knowledge that they will inevitably suffer from an
incurable disease. Twenty-five percent of individuals diagnosed with early symptoms of the
disease attempt suicide.

Some families may break up and some people may not be able to concentrate on their jobs.

Fetal testing will cause some families to make decisions about abortions that they are
uncomfortable making, or they will have to live with the knowledge of which of their children are
"doomed.''

Sibling relationships may change as one is "liberated'' from the disease and another is pronounced
"doomed.''
Advantages
51

Some people will be relieved to know that they will not get Huntington's disease, lifting a burden
from their shoulders.

Some people who are informed that they will get the disease may prefer the sure knowledge and
plan their lives accordingly, just as many cancer patients would rather know their fates.

The 50 % of family members who will not get the disease can have children without wondering
whether they are passing on a "genetic monster.'' The rest can be more certain about their decisions
not to have children.

This genetic screening test represents a first step in prevention and successful treatment.
Somewhere down the line, potential victims may be treated with medicines or genetic surgery.
Which students would choose to have the test and which would not? For what reasons?
Source: Levin, J., Ajemian, R., & Gorman, C. (1986, October 20). Do they really want to know?
Time, 80.
7. Review the April 10, 2000 issue of Newsweek for an overview of The Human Genome Project.
Give a brief review of the history of the project, its costs, its aims and its potential outcomes. Ask
students to identify the benefits and limitations of the project. What ethical issues are yet to be
settled? What are the benefits and hazards of obtaining information about one’s potential for
genetically inherited traits?
Sources: Begley, S. (2000, April 10). Decoding the human body. Newsweek, 50-57; Cowley, G. &
Underwood, A. 2000 (April 10). A revolution in medicine. Newsweek, 58-62; Bryant, A. (2000, April
10). The gold rush. Newsweek, 64-67. Sapolsky, R. (2000, April 10). It’s not “all in the genes.”
Newsweek, 68.
8. Draw on the Arts
The arts, broadly defined, include drawing, painting, sculpture, music, dance, poetry, and writing, to
name but a few. Both art products and art processes can be used in university teaching in the following
ways:

Existing artistic products can be used to illustrate facts and ideas.

The process of creating can be used to express feelings or reactions to information presented.
Creative expression activities can be used to envision possible worlds, including possible research,
possible public policies, possible human service projects, and possible changes in social institutions.
One example of music is John McCutcheon’s “Happy Adoption Day” (words & music by John
McCutcheon ©1992 John McCutcheon/Appalsongs) (ASCAP). The lyrics were written to honor
adopted children. Lyrics can be read in the Family Garden album on McCutcheon’s Web site (see
http://www.folkmusic.com/record/r_garden.htm).
CRITICAL THINKING EXERCISES
Exercise 1
52
Many developmentalists believe that an important inherited determinant of personality is temperament.
Look ahead to Chapter 11 (Attachment, Temperament, and Emotional Development) to find out how
researchers have attempted to identify basic dimensions of temperament and to describe the extent of their
stability through individuals' lives. Which genetic principle is best illustrated by this work? Circle the letter
of the best answer and explain why it is the best answer and why each other answer is not as good.
A.
Dominant-recessive genes principle
B.
Polygenetic inheritance
C.
Genotype/phenotype differences
D.
Reaction range
E.
Canalization
Exercise 2
Review "The Nature of Development'' in Chapter 1, which describes several important issues in
developmental psychology. Which of these issues receives the greatest emphasis in Chapter 3? Circle the
letter of the best answer and explain why it is the best answer and why each other answer is not as good.
A. Biological, cognitive, and social processes in development
B. Continuity versus discontinuity
C. Nature versus nurture
D. Stability versus change
E. Periods of development
ANSWER KEY FOR CRITICAL THINKING EXERCISES
Exercise 1
A. This is not the best answer. The dominant-recessive gene principle refers to a single gene pairing in
which one gene determines a quality of the trait governed by the gene. There is a distinctive pattern of
probabilities for the expression of each variation of the trait. In any case, temperament is not thought to
be controlled by a single gene pair, nor is there a known pattern of probabilities for any given
dimension of temperament. The text presents no information on how specific genes influence
temperament.
B. This is not the best answer. The important point, as above, is that no information specific to this point
appears in the text. The text does indicate, however, that traits such as intelligence are probably based
on polygenic inheritance.
C. This is not the best answer. Again, the problem is that no systematic comparisons are presented to
indicate the relationship between genotypes and phenotypes for temperament. Given "D'' below, it is
reasonable to suppose, however, that the relationship is not direct.
D. This is the best answer. The text points out that the heritability of temperament seems to decline with
age. Also important is that traits such as introversion and extroversion seem to be changeable, within
53
limits. This most clearly corresponds to what is meant by the concept of range of reaction. Different
environments seem to produce different expressions of the genetic basis for temperament.
E. This is not the best answer. Canalization refers to traits that show little environmentally caused
variability in their expression. Such traits should have uniform heritability during the life span of an
individual, but the dimensions of temperament do not.
54
Exercise 2
A. This is not the best answer. These processes are simply not uniformly discussed in the chapter. The
focus of the chapter is one aspect of biological processes, genetic determination. Moreover, this aspect
is not discussed much as a continuing influence throughout the development of an individual in the
sense of biological maturation.
B. This is not the best answer. The course of development, either prenatally or postnatally, is not
described. Thus the issue of continuity or discontinuity of development is not a focus of this chapter.
C. This is the best answer. This is a continuing theme of the chapter. It is expressed most forcefully in the
quote from Sandra Scarr near the end: "No genes, no organism; no environment, no organism.'' From
the beginning of the chapter throughout, the point is made that environments interact with genotypes in
the course of development. For example, natural selection determines which genotypes survive. In the
discussion of genetic principles it is clear that genetic expression is a function, in varying degrees, of
environmental influence. Research on intelligence and temperament is driven by the question of how
much of the variation in each is determined by heredity and how much by environment.
D. This is not the best answer. There is material on this issue in the discussion of temperament, but the
issue is not as pervasive as the nature-nurture issue.
E. This is not the best answer. These simply receive no treatment. The discussion of the biological bases
of development is not organized around separate developmental periods, although the notion of
different heritabilities at different ages is discussed with respect to intelligence and temperament.
55
STUDENT RESEARCH PROJECTS
RESEARCH PROJECT 1: HERITABILITY OF HEIGHT
The purpose of this project is to demonstrate the concept of heritability by using height as the
characteristic. You will do a kinship study of two families (one of the families can be your own) to collect
the necessary data. Record the height of all family members over 18 years of age and separate them by sex.
Calculate the mean and range of heights of both sexes for both families and compare them. This exercise is
intended to give you experience both with a kinship study design and with the concept of heritability for a
variable with a clear operational definition. Use the following format to record heights. Then answer the
questions that follow.
Person/Sex
Self
Mother
Father
Grandmother 1
Grandmother 2
Grandfather 1
Grandfather 2
Sibling
Sibling
Sibling
Aunt
Aunt
Aunt
Uncle
Uncle
Uncle
Cousin
Cousin
Cousin
Other
Family 1
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
Family 2
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
_______
Data
Average female
Average male
Tallest female
Tallest male
Shortest female
Shortest male
Family 1
_______
_______
_______
_______
_______
_______
Family 2
_______
_______
_______
_______
_______
_______
Questions

Which family in your sample is, on average, taller for both males and females?

Of the taller family, how many females are taller than the females in the shorter family? How many
of the males are taller than the males in the shorter family?

From your data, does it appear that height is an inherited trait?
56

What is the advantage of examining the heritability of a variable like height rather than a variable
such as temperament or intelligence?
Use in Classroom
Have the class pool their data and examine it for family differences in height. Have them discuss: (a) the
evidence for the heritability of height; (b) ideas about environmental differences that might play a role; (c)
the reason for separating the data according to sex; and (d) the advantage of using height as a measure
rather than intelligence or temperament.
The expectation is that the closer the relative is genetically, the more similar the characteristic measured
will be  identical twins, fraternal twins and siblings, parents, (blood) uncles and aunts, cousins, etc. The
data from those in the older generations may be difficult to interpret because 60 or more years ago,
different health and nutrition standards may have influenced growth. The data must be segregated by sex
because humans are sexually dimorphic in height. Males are characteristically larger than females. Height
is a good measure to use because it has an easy, noncontroversial, operational definition. Concepts such as
intelligence and temperament are harder to define in exact terms and are more controversial.
RESEARCH PROJECT 2: GENETIC COUNSELING
For this project, search and report on the availability of genetic counseling. Form groups of up to four
individuals, and divide the following tasks between individuals or pairs. Contact local hospitals or local
offices of the March of Dimes to learn whether they disseminate information about genetic counseling, and
if they do, obtain the pamphlets or handouts that they provide. If there are other services or organizations
for expectant couples (e.g., Planned Parenthood, or divisions of social service agencies), find out what they
offer. If you can identify individuals in the community who provide such information, contact them to see
if they will allow you to interview them about their services. Search the Internet for genetic counseling
resources. In particular, review the Web site for the March of Dimes. Go to the public library and look up
recent books or other reference materials about genetic counseling.
Once you have determined what information is publicly available, write a report that summarizes (a) how
up-to-date the information appears to be; (b) what source of information is most easily available and
affordable; (c) what attitude the materials seem to take toward genetic counseling. For example, Santrock
indicates that what couples do about what they find out concerning their infants' chances of suffering a
genetic defect is largely their own decision. Does this seem to be true in your community? What range of
decisions is available? Are any alternatives discouraged? Finally, can you determine whether these
services are uniformly available to all community members? Would anyone be able to use them? Are
there significant controversies about their use? What political/ethical/legal issues did you discover?
Use in Classroom
Have the teams report their findings to the class. Use a format comfortable to you; an interesting one
would be to have teams present their findings as panels. In any case, have the rest of the class carefully
attend to the presentations by taking notes in a systematic way. One way to do this would be to have them
prepare a data sheet of sorts with categories ready to note answers to the questions posed above.
When all individuals or panels have reported their findings, hold a general discussion of the things people
have found out. Are their reports consistent? Why or why not? How well do their efforts correspond to
the material in the text? What implications do their findings have for people seeking genetic counseling in
your area?
57
RESEARCH PROJECT 3: INTERNET SEARCH
Search the Internet for more information on biological beginnings.

The Human Genome Project has its own Web site so that you can get a frequent update. What major
new findings are available?

Search for organizations oriented toward particular genetic conditions. There are foundations and
organizations with Web sites for specific disorders such as Tay-Sachs, cystic fibrosis, and Down
syndrome. Use the guides presented later in this manual as a guide for evaluating Internet information.
WWW sites such as www.pbs.org/gene and www.nhgri.nih.gov are rich in resources, as are some
private (e.g., March of Dimes), county, and state health organizations.

Join a chat group on a particular topic and participate by asking questions rather than giving opinions.
ESSAY QUESTIONS
Comprehension and Application Essay Questions
We recommend that you provide students with our guidelines for “Answering Essay and Critical Thinking
Questions” when you have them respond to these questions. Their answers to these kinds of questions
demonstrate an ability to comprehend and apply ideas discussed in this chapter.
1. Explain the concepts of natural selection and adaptive behavior.
2. Describe the approach called “evolutionary psychology” and its five main tenets.
3. Explain Bandura’s view of evolutionary psychology.
4. Explain the relationship among genes, chromosomes, and DNA. Also indicate how these entities
function in reproduction.
5. Explain the dominant vs. recessive gene principle.
6. What is meant by “X-linked inheritance?”
7. Define genetic imprinting and give examples of two disorders that might reflect the results of
genetic imprinting.
8. A friend of yours decided to adopt a child. She and her husband are not an infertile couple and
have their own child. They want to adopt a child from another country. What kinds of advice and
recommendations would you like to give to them?
9. Indicate and explain at least three examples of abnormalities in genes and chromosomes.
10. Assume that you have received three tests to assess fetal abnormalities. Identify and explain each
procedure and what you would learn from it.
11. In your own words, what is a genotype and a phenotype? Explain how these concepts relate to the
concepts of dominant and recessive genes.
12. Compare and contrast the concepts of reaction range and canalization.
58
13. Describe the methods used by behavior geneticists to study heredity's influence on behavior. Also,
discuss the potential problems of the methods.
14. Explain the purpose of the Human Genome Project.
15. Indicate how you would explain to a friend that heredity and environment interact in various ways
to produce development. Provide an example of each of the three types of interaction that you
would use to help your friend understand this concept.
16. Compare and contrast shared environment and nonshared environment. Indicate how these
environmental experiences have influenced your own development.
17. Explain why Sandra Scarr’s view of the heredity-environment controversy is also controversial.
18. Imagine that you want to start a family. Explain what you would do before attending a session with
a genetic counselor and what kinds of questions you would ask during the meeting.
Related Content to Use in Analyzing Answers for Essay Questions
1.


Natural selection is the evolutionary process that favors individuals of a species that are best
adapted to survive and reproduce.
Adaptive behavior is behavior that promotes an organism’s survival in the natural habitat.
2.
 Evolutionary psychology emphasizes the importance of adaptation, reproduction, and “survival of
the fittest” in explaining behavior. It focuses on conditions that allow survival.
3.

The views of evolutionary psychology were summarized by Bjorklund & Pellegrini (2002) as
follows:






A “juvenile” period is needed to develop a large brain and learn the complexities of human
communities.
Childhood experiences that prepare for adulthood were selected through evolution.
Some child characteristics are adaptive at specific points in development.
Many evolved psychological mechanisms are domain-specific.
Some evolved mechanisms might not be adaptive in contemporary society.
Bandura acknowledges the influence of evolution, but he purports a more bi-directional view.
He argues that evolutionary pressures created changes in biological structures for tool use.
This in turn enabled organisms to manipulate, alter, and construct new environmental
conditions. Increasingly complex environments then brought pressure for the evolution of
specialized biological systems for consciousness, thought, and language.
4.
 The nucleus of each human cell contains 46 chromosomes, which are composed of DNA.
 Genes are short segments of DNA and act as a blueprint for cells to reproduce and manufacture the
proteins that maintain life.
 Chromosomes contain the remarkable genetic substance deoxyribonucleic acid, or DNA.
59


DNA is a complex molecule that contains genetic information.
In the process of human reproduction, a single-cell zygote is formed and two sets of unpaired
chromosomes combine to form one set of paired chromosomes in the zygote.

Some dominant genes override recessive genes. If one gene of a pair is dominant and one is
recessive, the dominant gene will be expressed. The recessive gene is influential only if two genes
of a pair are recessive.

“X-linked inheritance” is the term describing the inheritance of a defective or mutated gene that is
carried on the X chromosome. Most individuals with X-linked diseases are males. Examples
include hemophilia and fragile-X syndrome.

Genetic imprinting is a mechanism in which genes have been modified in one of the parents and
have differeing effects depending on whether they are transmitted to the offspring through the egg
or sperm. Examples might include a person who inherited Huntington’s disease from the father
showing symptoms at an earlier age than one who inherits it from the mother. Another example is
that persons who inherit Turner syndrome from the father show better cognitive and social
development than if the problem is inherited from the mother.

Phenylketonuria (PKU) is a genetic disorder in which the individual cannot properly metabolize
an amino acid.
Down syndrome is a common genetically transmitted form of mental retardation, caused by the
presence of an extra (47th) chromosome.
Turner syndrome is a genetic disorder in which females are missing an X chromosome, making
them XO instead of XX.
5.
6.
7.
8.


9.



Amniocentesis is a prenatal medical procedure in which a sample of amniotic fluid is withdrawn
by syringe and tested to discover if the fetus is suffering from any chromosomal or metabolic
disorders.
Ultrasound sonography is a prenatal medical procedure in which high frequency sound waves are
directed into the pregnant woman’s abdomen. It is able to detect such disorders as microencephaly,
a form of mental retardation involving an abnormally small brain.
The maternal blood test is a prenatal diagnostic technique that is used to assess blood alphafetoprotein level (AFP), which is associated with neural-tube defects.
10.



A genotype is the person’s genetic heritage, the actual genetic material.
A phenotype is the way an individual’s genotype is expressed in observed and measurable
characteristics.
According to dominant-recessive genes principle, if one gene of the pair is dominant and one is
recessive, the dominant gene exerts its effect, overriding the potential influence of the recessive
gene.
11.
60
 Reaction range is the range of possible phenotypes for each genotype, suggesting the importance
of an environment’s restrictiveness or enrichment.
 Canalization is the term to describe the narrow path, or developmental course, that certain
characteristics take.
12.

Among the most important methods used by behavior geneticists are twin studies and adoption
studies.


The Human Genome project was begun in the 1970s to map the human genome.
The project has linked certain DNA mutations with the risk for certain diseases.


Individuals inherit environments that are related or linked to their genetic propensities.
Behavior geneticists described three ways that heredity and environment are correlated: Passive
genotype-environment correlations occur when biological parents, who are genetically related to
the child, provide a rearing environment for the child. Evocative genotype-environment
correlations occur because a child’s genotype elicits certain types of physical and social
environments. Active (niche-picking) genotype-environment correlations occur when children
and adolescents seek out environments that they find compatible and stimulating.
The relative importance of the three genotype-environment correlations changes as children
develop from infancy through adolescence.
13.
14.

15.


Shared environmental experiences are children’s common experiences, such as their parents’
personalities and intellectual orientation, the family’s social class, and the neighborhood in which
they live.
Nonshared environmental experiences are the child’s own unique experiences, both within a
family and outside the family, that are not shared by another sibling.
16.



Sandra Scarr argues that the environments parents select for their children depend on the parents’
genotypes.
Critics argue that Scarr’s interpretations of behavior genetics studies go far beyond what is
justified, given the inherent limitations of such studies.
Scarr argues that heredity plays a powerful role in heredity-environment interaction, while
Baumrind, Maccoby, and Jackson believe the environment is a much stronger influence on
children’s development than Scarr acknowledges.
17.

Individual responses
CRITICAL THINKING QUESTIONS
We recommend that you have students follow our guidelines for “Answering Essay and Critical Thinking
Questions” when you ask them to prepare responses to these questions. Their answers to these kinds of
questions reflect an ability to apply critical thinking skills to a novel problem or situation that is not
61
specifically discussed in the chapter. These items most appropriately may be used as take-home essay
questions (e.g., due on exam day) or as homework exercises that can be answered either by individuals or
groups. Collaboratively answered questions encourage cooperative learning by students and reduce the
number of papers that must be graded.
1. In Chapter 3, Santrock describes the Human Genome Project. He indicates that it may become possible
for parents to leave the hospital with a newborn baby and a full genome analysis for the child. What are
the advantages and disadvantages that you see with this possibility? What are the ethical and legal
concerns?
2. Chapter 1 defines the nature of development in terms of biological, cognitive, and social processes, and
periods or stages. Indicate your ability to think critically by identifying material in this chapter that
illustrates developmental processes and periods.
3. According to Chapter 1, three fundamental developmental issues concern (a) maturation (nature)
versus experience (nurture), (b) continuity versus discontinuity, and (c) early versus later experience.
Indicate your ability to think critically by identifying material in this chapter that illustrates each of the
three fundamental developmental issues.
4. Santrock sets off several quotations in this chapter. Indicate your ability to think critically by selecting
one of the quotes and (a) learning about the author and indicating why this individual is eminently
quotable (i.e., what was this individual’s contribution to human knowledge and understanding?); (b)
interpreting and restating the quote in your own terms, and (c) explaining what concept, issue,
perspective, or term in this chapter Santrock intended this quote to illuminate. In other words, about
what aspect or issue in development does this quote make you pause and reflect?
5. The Santrock text has a special page (Explorations in Child Development) titled “Genetic Counseling.”
Apply your knowledge about the scientific method by designing a study to determine whether and how
prospective and expectant parents benefit from consultations with a genetic counselor: (a) What
specific problem or question do you want to study? (b) What predictions would you make and test in
your study? (c) What measures would you use (i.e., controlled observation in a laboratory, naturalistic
observation, interviews and questionnaires, case studies, standardized tests, cross-cultural studies,
physiological research, research with animals, or multimeasure, multisource, and multicontext
approach) and how would you define each measure clearly and unambiguously? (d) What strategy
would you follow--correlational or experimental, and what would be the time span of your inquiry-cross-sectional or longitudinal? (e) What ethical considerations must be addressed before you conduct
your study?
6. According to Chapter 2, your author admonishes you to become a wise consumer of information about
child development by: (a) being cautious about media reports, (b) distinguishing between nomothetic
research and idiographic needs, (c) recognizing how easy it is to overgeneralize from a small or clinical
sample, (d) knowing that a single study is usually not the defining word about some aspect of child
development, (e) remembering that causal conclusions cannot be made from correlation studies, and
(f) always considering the source of the information and evaluating its credibility. Indicate your ability
to think critically by, first, selecting an article from either a journal, magazine, or newspaper about any
topic regarding Biological Beginnings, and, second, evaluating it in terms of these six objectives. If the
information in the article is insufficient to evaluate one of these objectives, then specify what kind of
information you would need to evaluate the objective.
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IMPLICATIONS FOR GUIDANCE
1. Guidance, whether for parents, children, or society at large, is a lifelong process consisting of two
major components. The first involves becoming socialized and the second involves transforming
society to promote sociocultural evolution.
Socialization into “the way” of a particular culture requires the acquisition of attitudes, behaviors, and
dispositions expected in that society. What is held as important in any culture depends on the goals of
that society. What really matters? What is important? What is good? What is valuable? Survival of a
culture is dependent upon proper socialization of its members—young and old. Parents and policy
makers make choices on behalf of children and society and guide others toward making choices and
enacting behaviors that either perpetuate “the way” or transform “the way.”
It is difficult to step back and assess just what goals or values are guiding our choices. For most
students, society’s rules are “assumed.” However, current issues in gene therapy, genetic counseling,
and high-tech fertility assistance help us realize more directly which things are valued. Make a list of
societal goals that seem important to preserve. What goals or values might need to be examined and
perhaps transformed?
2. Children with genetic abnormalities often present challenges for guidance depending on the specific
genetic characteristic. There is sometimes a tendency for parents to be more permissive with disabled
children because they feel responsible or guilty about the child’s condition. Children with disabilities
need to be socialized, as do all persons. Yet, special knowledge is needed in order to adapt disciplinary
strategies to the “special needs” of the child. Take two or three different types of genetically
determined conditions that might require special guidance techniques and explain what special
accommodations might be needed. One particular example might be Willie E syndrome, which
involves a tendency toward violence.
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