Chapter 2
Biological Foundations:
Heredity, Prenatal Development, and Birth
DEP 2004 & 2004H Human Development Across the Lifespan
Erica Jordan, Ph.D., University of West Florida
School of Psychological and Behavioral Sciences
S
Lecture Guiding Questions
S How do genes influence behaviors?
S What are the major stages of prenatal development?
S What risks factors are associated with prenatal
development?
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
How do genes influence
behaviors?
S Behavioral Genetics: the branch of genetics that deals with
inheritance of behavioral and psychological traits
S Traits controlled by a single gene typically produce one of two
outcomes (either - or)
S Most behavioral and psychological traits are more complex
S
S
S
Possible phenotypes fall along a continuum or have multiple
possibilities
Result from the instructions/interactions of separate genes—polygenic
inheritance
Influence of each specific gene involved is very difficult to determine
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
NEW SLIDE!
Research Methods Commonly Used
to Study Behavioral Genetics
S Twin studies
S Comparison of monozygotic twins (identical and from the same
fertilized egg) and dizygotic twins (fraternal and from different
eggs).
S Characteristics commonly shared by monozygotic twins that are
often different in dizygotic twins are typically inherited.
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
S _________________________
S Comparing adopted children alongside their biological parents
and their adoptive parents.
S _________________________
S Taking samples of DNA from individuals who differ in some
way then examining the DNA for differences.
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
More about the way genes
influence behaviors:
1.
The behavioral consequences of genetic instructions depend on
the environment in which those instructions are implemented.
-
A specific genotype does not always lead to the same
phenotype.
-
Reaction range—range of potential phenotypes for a
specific genotype.
-
Heritability coefficient—the probability that a characteristic
is inherited; very sensitive to other factors; range from 0 to
1.00.
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
2.
Heredity and environment interact dynamically throughout
development.
3.
Genes can influence the kind of environment to which a
person is exposed.
- Responses from others
—refers to how people seek out
their own environments based on their interests and
strengths
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
4.
Environmental influences typically make children within a
family different.
- Siblings often have similar experiences
- Nonshared environmental influences also occur
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
Common Genetic Disorders
S
Sickle-cell desease
S
PKU
S
Huntington’s disease
S
Down syndrome
S
Klinefelter’s syndrome
S
Turner’s syndrome
S
XYY complement
S
XXX syndrome
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
From Conception to Birth
S Prenatal Development
S The changes that turn a fertilized egg into a newborn human
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
Period of the Zygote
(Week 1 - 2)
S Zygote:
S Period begins with fertilized egg and ends with zygote is
implanted into the uterine wall about 2 weeks later
(implantation)
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
Period of the Embryo
(Week 3 - 8)
S Begins when zygote is completely embedded in the
uterine wall.
S Major body structures are created
S Cells become specialized
S Growth follows the cephalocaudal principle and the
proximodistal principle
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
Period of the Fetus
(Weeks 9 - 38)
S Final and longest phase of prenatal development. Begins
when cartilage begins to turn to bone and ends at birth.
S Fetus becomes much larger and brain regions grow.
S Finishing touches are placed on many systems (eyebrows,
skin thickens, vernix covers skin, etc.).
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
Risks to Prenatal Development
S
Parents’ age
S
Nutrition
S
Stress
S
Disease
S
Drugs
S
Environmental hazards
S
Teratogens—agents that cause abnormal prenatal development
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)
Teratogens: Five Principles
S Impact depends on the genotype of the organism.
S Impact changes over the course of prenatal development.
S Affects a specific aspect (or aspects of prenatal development).
S Impact depends on the dose.
S Damage may not appear until later in life.
Adapted from Kail & Cavanaugh's
Human Development: A Life-Span View
(5th Ed.)