Development across the Life Span 351- 3 Summarize the role of chromosomes and genes in
determining the transmission of traits and the inheritance
of disorders.
- Dominant genes determine the expression of a trait, whereas
recessive gene traits are only expressed when paired with
another recessive gene influencing the same trait. Almost all
traits are the result of combinations of genes working together in
a process called polygenic inheritance. - Chromosome disorders include Down syndrome, Klinefelter ’s
syndrome, and Turner ’s syndrome, whereas genetic disorders
include PKU, cystic fibrosis, sickle-cell anemia, and Tay-Sachs
disease.
Prenatal Development
- 4 Explain the process of fertilization, including the
twinning process.
- The fertilized egg cell is called a zygote and divides into many
cells, eventually forming the baby. - Monozygotic twins are formed when the zygote splits into two
separate masses of cells, each of which will develop into a baby
identical to the other. - Dizygotic twins are formed when the mother ’s body releases
multiple eggs and at least two are fertilized, or when another
ovulation occurs even though the mother has already become
pregnant.
- 5 Describe the three stages of prenatal development.
- The germinal period is the first 2 weeks of pregnancy in which
the dividing mass of cells moves into the uterus. - The embryonic period begins at 2 weeks after conception and
ends at 8 weeks. The vital organs and structures of the baby
form during this period, making it a critical one when terato-
gens may adversely affect the development of those developing
organs and structures. - The fetal period is from the beginning of the 9th week until the
birth of the baby. During the fetal period, tremendous growth
occurs, length and weight increase, and organs continue to
become fully functional.
Infancy and Childhood Development
- 6 Describe the physical and sensory changes that take
place in infancy and childhood.
- Four critical areas of adjustment for the newborn are respiration,
digestion, circulation, and temperature regulation. - Infants are born with reflexes that help the infant survive until
more complex learning is possible. These reflexes include suck-
ing, rooting, Moro (startle), grasping, and stepping. - The senses, except for vision, are fairly well developed at birth.
Vision is blurry and lacking in full color perception until about 6
months of age. Gross and fine motor skills develop at a fast pace
during infancy and early childhood.
8. 7 Compare and contrast two theories of cognitive
development, and define autism spectrum disorder.- Piaget’s stages include the sensorimotor stage of sensory and
physical interaction with the world, preoperational thought in
which language becomes a tool of exploration, concrete oper-
ations in which logical thought becomes possible, and formal
operations in which abstract concepts are understood and hypo-
thetical thinking develops. - Vygotsky believed that children learn best when being helped
by a more highly skilled peer or adult in a process called scaf-
folding. The zone of proximal development is the difference
between the mental age of tasks the child performs without help
and those the child can perform with help. - Autism spectrum disorder (ASD) is a neurode-velopmental
disorder, which involves impairments in thinking, feeling, lan-
guage, and social skills in relating to others. - Parents and others who fear immunizing their children against
dangerous diseases have failed to understand the basic princi-
ples of critical thinking.
8. 8 Identify the development of personality,
relationships, and self-concept in infancy and childhood.
- The three basic infant temperaments are easy (regular, adapt-
able, and happy), difficult (irregular, nonadaptable, and irri-
table), and slow to warm up (need to adjust gradually to
change).
- The four types of attachment are secure, avoidant (unat-
tached), ambivalent (insecurely attached), and disorganized–
disoriented (insecurely attached and sometimes abused or
neglected).
- Harlow’s classic research with infant rhesus monkeys demon-
strated the importance of contact comfort in the attachment
process, contradicting the earlier view that attachment was
merely a function of associating the mother with the delivery
of food.
- In trust versus mistrust, the infant must gain a sense of predict-
ability and trust in caregivers or risk developing a mistrustful
nature; in autonomy versus shame and doubt, the toddler needs
to become physically independent.
- In initiative versus guilt, the preschool child is developing
emotional and psychological independence; in industry ver-
sus inferiority, school-age children are gaining competence and
developing self-esteem.
- Piaget’s stages include the sensorimotor stage of sensory and
Adolescence- 9 Describe the physical changes of puberty.
- Adolescence is the period of life from about age 13 to the early
20s during which physical development reaches completion. - Puberty is a period of about 4 years during which the sexual
organs and systems fully mature and during which secondary
sex characteristics such as body hair, breasts, menstruation,
deepening voices, and the growth spurt occur.