10 Unit 1 Children and Families in Today’s World
Copyright Goodheart-Willcox Co., Inc.
Environment
All people live in both a physical and social
environment. The unborn baby lives primarily
in a physical environment that is almost totally
dependent on the mother’s physical condition.
This environment may be benefi cial due to proper
prenatal care or harmful due to the lack of such
care. After birth, physical conditions, such as food
and rest, are part of the environment.
Beyond physical conditions, all other experi-
ences are part of a person’s social environment. To
some degree, even unborn babies have a social envi-
ronment. They can hear outside-the-womb sounds,
especially the mother’s voice that may be soothing
or startling due to fear or anger. These sounds are
reinforced by physical signals sent to the unborn by
the mother—changes in blood pressure, breathing
rate, and hormones. After birth, the social environ-
ment affects the way a child grows and develops in
every developmental domain (Figure 1.4).
that identical twins, who have the same structural
genome, were more alike in physical traits and
intellectual abilities than are brothers and sisters
or other family members. The same similarities
were found in identical twins reared apart.
Researchers also study the effects of heredity in
virtual twins. Virtual twins are unrelated children
of almost the exact same age raised by the same
parents. Although the environment would be very
similar for both children, virtual twins often are
very different in most traits. Thus, heredity has a
major impact in growth and development.
Today, most of the studies of heredity are con-
ducted in a laboratory. Genetics (juh-NET-iks) is the
study of the factors involved in the passing of traits in
living beings from one generation to the next. In short,
genetics is the study of heredity. Geneticists (biologists
who study heredity) continue to make strides in learn-
ing which traits pass from parents to child. Almost
every physical, intellectual, and social-emotional
trait is affected by genes. Thus, genes infl uence your
growth and development in many ways. The follow-
ing points are known about heredity:
• Genes affect some parts of growth and
development more than others. Genes
determine body features, such as blood
type, facial structure, and color of hair, eyes,
and skin (Figure 1.3). Other traits, such as
intellectual ability and social-emotional
traits, are affected by both genes and the
environment. Some genes determine whether
a person will have a trait. For example, a
person either is or is not an albino. (An albino
is a person with white skin, almost white hair,
and pink eyes.) This is determined by genes.
• Other genes affect the range of a trait.
Traits such as height (very short to very
tall) and athletic ability (almost no ability
to greatness) come from these genes. These
genes determine a trait’s potential. (Potential
is the greatest amount or level possible.)
Whether a person will show or use that trait
to its potential depends on the person’s life.
For instance, a healthful diet will help a child
reach his or her height potential. The child
cannot grow, however, beyond this potential.
On the other hand, children with poor
nutrition may not achieve their full potential.
Figure 1.3 Because they share genes, parents and children
often look alike. What physical traits do this mother and
daughter have in common?