Instant Download with all chapters and Answers
*you will get solution manuals in PDF in best viewable format after buy*
Chapter Outline Instruction Ideas Supplements
Genetic Foundations pp. 44–51
The Genetic Code • The Sex Cells • Boy or
Girl? • Multiple Offspring • Patterns of Gene–
Gene Interactions • Chromosomal
Learning Objectives 2.1–2.3
Learning Activities 2.1–2.3
Ask Yourself p. 51
Test Bank Items 1–51, 126–127
(Please contact your Pearson sales
representative for a wide range of video
offerings available to adopters.)
Reproductive Choices pp. 51–56
Genetic Counseling • Prenatal Diagnosis and
Fetal Medicine • Adoption
Learning Objective 2.4
Learning Activity 2.4
Ask Yourself p. 56
Test Bank Items 52–65
Environmental Contexts for Development
The Family • Socioeconomic Status and
Family Functioning • Poverty • Affluence •
Beyond the Family: Neighborhoods and
Schools • The Cultural Context
Learning Objective 2.5
Lecture Enhancement 2.1
Learning Activities 2.5–2.7
Ask Yourself p. 66
Test Bank Items 66–99, 128–129
Understanding the Relationship Between
Heredity and Environment pp. 66–72
The Question, “How Much?” • The Question,
Learning Objective 2.6
Lecture Enhancement 2.2
Learning Activities 2.2, 2.8–2.9
Ask Yourself p. 72
Test Bank Items 100–125, 130–131
BRIEF CHAPTER SUMMARY
This chapter examines the foundations of development: heredity and environment. At conception, chromosomes containing
genetic information from each parent combine to determine characteristics that make us human and also contribute to
individual differences in appearance and behavior. Serious developmental problems often result from inheritance of harmful
recessive alleles and from chromosomal abnormalities. Genetic counseling and prenatal diagnostic methods can help people
make informed decisions about the best reproductive options.
The environment in which human development takes place is a many-layered set of influences. The family is the first and
longest-lasting context for development. Other important influences are socioeconomic status, neighborhoods, schools, cultural
values and practices, and public policies affecting individuals at various stages of the lifespan.
Behavioral genetics examines the contributions of nature and nurture to diversity in human traits and abilities. Researchers
increasingly regard heredity and environment as inseparable and focus on examining how nature and nurture work together.
Heritability estimates confirm that heredity contributes to a broad array of human traits but provide no precise information on
gene–environment interaction, or how children might respond to environments designed to help them develop as far as
possible. According to the concept of gene–environment correlation, our genes influence the environments to which we are exposed.
Epigenesis refers to development resulting from ongoing, bidirectional exchanges between heredity and all levels of the
environment. One mechanism through which these exchanges occur is methylation, a biochemical process through which
environment can alter gene expression without changing the DNA sequence. Overall, development is best understood as a
series of complex exchanges between nature and nurture.
Instructor’s Resource Manual for Berk / Development Through the Lifespan, 7e
After reading this chapter, you should be able to answer the following:
2.1 What are genes, and how are they transmitted from one generation to the next? (pp. 44–46)
2.2 Describe various patterns of gene–gene interaction. (pp. 46–50)
2.3 Describe major chromosomal abnormalities, and explain how they occur. (pp. 50–51)
2.4 What procedures can assist prospective parents in having healthy children? (pp. 51–56)
2.5 Describe family functioning from the perspective of ecological systems theory, along with aspects of the environment
that support family well-being and development. (pp. 56–66)
2.6 Explain the various ways heredity and environment may combine to influence complex traits. (pp. 66–72)
I. GENETIC FOUNDATIONS (pp. 44–51)
• Heredity and environment combine to create phenotypes, which depend in part on each individual’s genotype.
• The nucleus of each cell in the human body contains chromosomes, which are made up of deoxyribonucleic acid
• Human genes are segments of DNA along the length of the chromosome. They include both protein-coding genes
and regulator genes.
• The gametes, or sex cells—the sperm and ovum—are formed through meiosis and contain only 23 chromosomes, half
as many as regular body cells.
• When sperm and ovum unite at conception, the resulting zygote again contains 46 chromosomes.
• Each human cell contains 22 matching pairs of chromosomes, called autosomes, and one pair of sex chromosomes:
in females, XX; in males, XY. The sex of the new organism is determined by whether an X-bearing or a Y-bearing
sperm fertilizes the ovum.
• Fraternal, or dizygotic, twins result from the release and fertilization of two ova. Identical, or monozygotic, twins
result when a single zygote that has started to duplicate separates into two clusters of cells.
• If alleles from both parents are alike, the child is homozygous and will display the inherited trait. If the alleles differ,
the child is heterozygous, and relationships between the alleles influence the phenotype.
• In dominant–recessive inheritance, one allele (called dominant) affects the child’s characteristics, while the second
allele (recessive) has no effect.
• Heterozygous individuals with just one recessive allele are carriers of the recessive trait.
• Serious diseases are rarely due to dominant alleles because the affected individuals seldom live long enough to
• Incomplete dominance is a pattern of inheritance in which both alleles are expressed in the phenotype, resulting in a
combined trait, or one that is intermediate between the two.
• When a harmful allele is carried on the X chromosome, X-linked inheritance applies, and males are more likely to be
• Genomic imprinting is a pattern of inheritance in which some alleles are imprinted, or chemically marked, in such a
way that one pair member is activated, regardless of its makeup. Disruptions in imprinting are involved in several
childhood cancers, in Prader-Willi syndrome, and in fragile X syndrome.
• Harmful genes are created through mutation, a sudden but permanent change in a DNA segment. Germline mutation
takes place in the cells that give rise to gametes. Somatic mutation, in which normal body cells mutate, can occur at
any time of life.
• Polygenic inheritance, in which many genes influence a characteristic, accounts for traits such as height, weight,
intelligence, and personality that vary on a continuum among people.
• The most common chromosomal disorder, Down syndrome, results when the twenty-first pair of chromosomes fails to
separate during meiosis, so the new individual receives three of these chromosomes rather than two.
• Abnormalities of the sex chromosomes often are not recognized until adolescence when, in some deviations, puberty is
II. REPRODUCTIVE CHOICES (pp. 51–56)
• Genetic counseling and prenatal diagnosis help people make informed decisions about conceiving, carrying a
pregnancy to term, or adopting a child.
• Genetic counseling helps couples assess their chances of giving birth to a baby with a hereditary disorder and choose
the best course of action in view of risks and family goals.
• New genomewide testing methods enable genetic counselors to estimate risk for many genetic disorders.
• Increasing numbers of individuals are turning to alternative methods of conception, such as donor insemination, in
vitro fertilization, and surrogate motherhood.
• Prenatal diagnostic methods, including amniocentesis, ultrasound, and maternal blood analysis, permit detection of
developmental problems before birth and have led to advances in fetal medicine.
• Advances in genetic engineering offer hope for correcting hereditary defects.
• Because the availability of healthy babies has declined, adults in North America and Western Europe who choose
adoption are increasingly adopting from other countries or accepting children who are past infancy or who have
known developmental problems.
• Adopted children and adolescents tend to have more emotional and learning difficulties than other children, a
difference that increases with the child’s age at the time of adoption. However, most adopted children fare well.
III. ENVIRONMENTAL CONTEXTS FOR DEVELOPMENT (pp. 56–66)
• The family is the first and longest-lasting context for development. Other environmental influences include friends,
neighbors, school, workplace, and community and religious organizations.
• Environments that powerfully affect development include not only the microsystem but also the macrosystem, or broad
social climate of society.
• Contemporary researchers view the family as a network of interdependent relationships in which the behaviors of each
family member affect those of others through bidirectional influences.
• In addition to direct influences between family members, interaction between any two members is affected by third
parties. For example, mothers and fathers who have a warm, considerate marital relationship are more likely to engage
in effective coparenting.
• The family is a dynamic, ever-changing system of relationships, influenced by life events, the developmental status of
each family member, and historical time period.
• Socioeconomic status (SES) is linked to timing of marriage and parenthood, to family size, and to child-rearing
values and expectations.
• Poverty affects about 15 percent of Americans. Those hit hardest are parents under age 25 with young children, ethnic
minorities, women, and older adults who live alone.
• Of all Western nations, the United States has the highest percentage of extremely poor children. They are more likely
than others to experience lifelong poor physical health, persistent deficits in cognitive development and academic
achievement, high school dropout, mental illness, and impulsivity, aggression, and antisocial behavior.
• A related problem is homelessness. Most homeless families consist of women with children under age 5, many of
whom suffer from developmental delays and chronic emotional stress.
• When affluent parents fail to engage in family interaction and parenting that promote favorable development, their
children are more likely than youths in general to engage in alcohol and drug use, commit delinquent acts, and report
high levels of anxiety and depression.
• Strong family ties to the surrounding social context reduce stress and enhance adjustment. When community life is
disrupted, family violence, child abuse and neglect, adult criminal behavior, and other social problems are especially
• Neighborhood resources and social ties play an important part in children’s development and also affect the well-being
of adults, especially older adults.
• Schools affect many aspects of development through their physical environments, educational philosophies, and social
• The macrosystem, or larger cultural context, affects all environmental contexts for development.
• In the United States, central cultural values include independence, self-reliance, and the privacy of family life—one
reason the public has been slow to endorse government-supported benefits for all families.
• Within the United States, some people belong to subcultures with beliefs and customs, such as cooperative family
structures, that differ from those of the larger culture—for example, the African-American tradition of extended-
Instructor’s Resource Manual for Berk / Development Through the Lifespan, 7e
18 Copyright © 2018 Laura E. Berk. All Rights Reserved.
• Cultures can be compared on two broad sets of values: collectivism (which emphasizes group goals and interdependent
qualities) versus individualism (which emphasizes independence). The United States is more individualistic than most
Western European countries.
• Nations attempt to solve widespread social problems through public policies designed to improve current conditions.
• Compared with other industrialized nations, the United States does not rank well on key measures of children’s health
and well-being, in part because of cultural values of self-reliance and privacy.
• Although the U.S. aging population is financially much better off now than in the past, aging adults in the United
States are less well off than those in many other Western nations, which provide more generous, government-funded
income supplements to older adults.
• Influential interest groups devoted to improving the well-being of children or older adults have emerged.
• Researchers are collaborating with community and government agencies to enhance the social relevance of their
IV. UNDERSTANDING THE RELATIONSHIP BETWEEN HEREDITY AND ENVIRONMENT (pp. 66–72)
• Behavioral genetics is a field devoted to uncovering the contributions of nature and nurture to the diversity of human
traits and abilities.
• A growing consensus of investigators believes that the important question is how nature and nurture work together.
• Heritability estimates, which measure the extent to which individual differences in complex traits in a specific
population are due to genetic factors, are obtained from kinship studies, which compare the characteristics of family
• Research supports a moderate role for heredity in intelligence and in personality.
• Heritability estimates tend to exaggerate the role of heredity, and they can easily be misapplied, as when high
heritabilities have been used to suggest a genetic basis for ethnic differences in intelligence.
• Today, most researchers view development as the result of the dynamic interplay between heredity and environment.
• Gene–environment interaction means that because of their genetic makeup, individuals differ in their responsiveness
to qualities of the environment.
• The concept of gene–environment correlation states that our genes influence the environments to which we are
exposed. In passive correlation, parents provide their children with environments influenced by their own heredity. In
evocative correlation, children evoke responses influenced by the child’s heredity, and these responses strengthen the
child’s original style.
• At older ages, active gene–environment correlation is seen in niche-picking—the tendency to actively choose
environments that complement our heredity.
• Accumulating evidence reveals that the relationship between heredity and environment is bidirectional: Genes affect
people’s behavior and experiences, but their experiences and behavior also affect gene expression.
• Epigenesis refers to development resulting from ongoing, bidirectional exchanges between heredity and all levels of
• Researchers in epigenetics are beginning to clarify the precise mechanisms through which environment can alter gene
expression without changing the DNA sequence. One such mechanism is methylation.
• Findings from epigenetics remind us that development is best understood as a series of complex exchanges between
nature and nurture.
Chapter 2 Genetic and Environmental Foundations
LECTURE ENHANCEMENT 2.1
Environmental Contexts for Development: What Researchers Can Learn from Studying Latino Children and Their
Families (pp. 62–63)
Objective: To consider ways in which an understanding of how Latino children develop within their culture can contribute to
an understanding of the cultural contexts within which all children develop.
The authors of “Learning from Latinos” begin with the observation that two generations ago, Latino children and their families
were assumed to have uniform cultural traits and practices, which were typically seen as deficits compared with those of white,
Research since the 1960s has exposed the limitations of this older conception of child development, which viewed
socialization only in terms of how well children fit into mainstream society. Today’s researchers understand that children are
socialized within a particular cultural community with its own values and practices, which may promote both cognitive and
social development. From this perspective, distinct strengths of Latino families and resulting benefits for children can be
“Learning from Latinos” provides context for class discussion of the text on pages 62–63, which deals with the ways in
which cultural context affects how children are socialized and how they learn within everyday activities. For example, the text
notes that Hispanic extended families in the United States are often characterized by a cooperative family structure in which
grandparents actively collaborate with parents in child rearing. This type of intergenerational shared parenting—consistent with
the Hispanic cultural ideal of familism, which emphasizes close family ties—is beneficial for all generations.
The authors note that schools and other institutions often fail to recognize the distinct social assets that characterize Latino
children, such as respect for adults and a commitment to serve their family by succeeding in school. They conclude that a better
understanding of how Latino children develop within their cultural context can promote our understanding of how all children
and adolescents learn and develop within their own distinct cultural or socioeconomic groups.
Fuller, B., & García Coll, C. (2010). Learning from Latinos: Contexts, families, and child development in motion.
Developmental Psychology, 46, 559–565. doi: 101037/a0019412
LECTURE ENHANCEMENT 2.2
The Role of DNA Methylation in Gene Expression: Examples and Implications (pp. 70–72)
Objective: To consider research evidence for the role of DNA methylation in gene expression, with implications for promoting
health and wellness.
As described in the discussion of environmental influences on gene expression (pages 70–72), research evidence reveals a
bidirectional relationship between heredity and environment. Not only do our genes affect the experiences to which we are
exposed, but our experiences and behavior also influence gene expression, without actually changing the DNA sequence. One
mechanism through which such effects occur is methylation—“a biochemical process triggered by certain experiences, in which
a set of chemical compounds (called a methyl group) lands on top of a gene and changes its impact.”
The Biology and Environment box on page 71 considers how methylation may have accounted for the consequences of
exposure to the 1994 Tutsi genocide in Rwanda for both pregnant mothers and their children. Szyf and Bick’s (2013) review
paper provides additional evidence for such effects. For example, the authors note “a striking resemblance” between differences
in DNA methylation associated with child abuse and those associated with low levels of maternal care in rats.
Countering the widespread belief that differences between individuals in phenotype, disease susceptibility, and behavior
reflect differences in gene sequencing, these authors cite evidence that, in fact, these interindividual differences in gene
sequences “do not operate alone but interact with environmental conditions to predict phenotypic outcomes.” They hope that
future research into the precise mechanisms involved in methylation will eventually lead to the development of strategies for
altering gene expression in a way that promotes healthy outcomes.
Szyf, M., & Bick, J. (2013). DNA methylation: A mechanism for embedding early life experiences in the genome. (Special
Section: Genomics) Child Development, 84, 49–57. doi: 10.1111/j.1467-8624.2012.01793.x
Instructor’s Resource Manual for Berk / Development Through the Lifespan, 7e
20 Copyright © 2018 Laura E. Berk. All Rights Reserved.
LEARNING ACTIVITY 2.1
Observing Similarities and Differences in Phenotypes Among Family Members (p. 44)
Ask students to think of several children and parents whom they know well and to jot down some similarities in physical
characteristics (for example, height, weight, eye and hair color) and behavior (personality, interests, hobbies) between the
children and their parents. Did they find that one child shows combined features of both parents, another resembles just one
parent, or another is unlike either parent?
Next, ask students to trace a visible genetic trait (phenotype), such as hair or eye color, through as many of their family
members as possible, beginning with the youngest generation and working back. When the genetic family tree is complete, ask
them to determine genotypes. Point out that for some dominant traits it is impossible to determine the genotype on the basis of
the phenotype, so students will have to make inferences. For example, it may not be evident whether a dark-haired person is homozygous for dark hair or is heterozygous, with a genetic makeup consisting of a dominant dark-hair and a recessive light-hair allele. Ask students to explain what may be responsible for these differences between family members. Integrate the terms phenotype, genotype, and meiosis into the discussion.
LEARNING ACTIVITY 2.2
Demonstrating Environmental Influences by Comparing Identical Twins (p. 46)
As discussed in the text, identical, or monozygotic, twins have the same genetic makeup. Therefore, phenotypic variation of
identical twins is perhaps the best evidence of the extent to which environmental influences can modify genetic expression. To
demonstrate, invite a pair of identical twins to join your class for observation and interviews. Before the visit, ask students to
generate a list of questions that they would like to ask each twin. These questions should be based on attributes or abilities that
are thought to have a significant genetic component—for example, IQ, personality, interests, and talents. Students should also
note any physical differences between the twins, such as height, weight, or handedness. After the visit, engage students in a discussion about similarities and differences between the twins, including ideas about
how the environment may have contributed to differences.
LEARNING ACTIVITY 2.3
True or False: The Pros and Cons of Reproductive Technologies (pp. 52–53)
Present the following exercise as an in-class activity or quiz.
Directions: Read each of the following statements and determine if it is True (T) or False (F).
_____ 1. One-fourth of all couples who try to conceive discover that they are infertile.
_____ 2. The success rate for donor insemination is only 30 to 40 percent.
_____ 3. Each year, 1 percent of all children in developed countries are conceived through in vitro fertilization.
_____ 4. The overall success rate of assisted reproductive techniques is about 70 percent.
_____ 5. Most parents who have used in vitro fertilization do not tell their children about their origins.
_____ 6. In the United States, doctors are not required to keep records of donor characteristics.
_____ 7. Because surrogacy usually involves the wealthy as contractors for infants and the less economically
advantaged as surrogates, it may promote the exploitation of financially needy women.