12 Unit 1 Children and Families in Today’s World
Copyright Goodheart-Willcox Co., Inc.
explains why even identical twins who have the
same structural genome are somewhat different
before birth.
How does the epigenome affect who people
are? Although research is just beginning, the fol-
lowing is what is currently known:
• The epigenome is built through positive
and negative factors from the environment.
Positive factors cause the chemical
compounds to turn on genetic potential—
making the person all they can be. Negative
environmental factors cause harm in all
domains of growth and development.
• Positive environmental factors include
health, quality learning experiences, and
supportive and loving relationships.
Negative factors include toxic substances,
poor health practices, lack of quality
experiences with objects and people, and
some stressors. Stressors are situations
that cause worry and anxiety.
Heredity and Environment
Combined
For years, people argued about which affected
growth and development more—heredity or envi-
ronment. This argument was often called nature
versus nurture. Of course, there is no way to study
environment separate from heredity because the
environment has to act upon the genes. Now, experts
agree they work together. Following are a few exam-
ples of the interaction of heredity and environment:
• Genes control height potential, but a
proper diet is needed to reach this height.
• Potential intelligence is inherited, but
physical factors (nutrition and rest) and
the quality of experiences determine
whether the potential will be reached.
• Basic social-emotional traits are inherited,
but greatly affected by experiences.
Heredity Affected by Environment
In recent years, geneticists have discovered
genes are not fi xed as once thought. The environ-
ment in which a person lives, both before and after
birth, can alter genes through their epigenome.
The epigenome (eh-pih-JEE-nohm), which means
above the genes, consists of chemicals that can turn
genes on and off. Thus, the epigenome is like the
operating system of the computer. The epigenome
Figure 1.4
(Continued)
How would the environmental impact be different in mass media if children…
• have needed and accessible materials to meet their developmental needs versus find needed materials
scarce and/or not accessible?
• see content that is positive and safe for children versus negative and unsafe?
How would the environmental impact be different in the parents’ workplace if the job…
• has secure employment versus less secure employment with many closures and layoffs?
• rewards work with wages or salaries that meet family needs and goals versus gives insufficient monetary
rewards for work?
• has one worksite versus requires frequent mobility?
• is family-friendly (has reasonable work hours, grants parental leaves for new babies and severe family
illnesses, has family benefits, such as child care services and family insurance policies) versus is not
family-friendly?
Toxic stress or prolonged and
frequent tolerable stress can
result in mental health problems throughout life.