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Slide 1
2
Biological
Beginnings
John W. Santrock
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 2
Biological Beginnings
• What Is the Evolutionary Perspective?
• What Are the Genetic Foundations of
Development?
• What Are Some Reproductive Challenges and
Choices?
• How Do Heredity and Environment Interact?
The Nature-Nurture Debate
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Is the Evolutionary Perspective?
Slide 3
Natural Selection and
Adaptive Behavior
• Stories of the Jim and Jim Twins
– Identical twins separated after birth
– Identical lifestyles after 39 years apart
– Part of Minnesota Study of Twins Reared
Apart; other twin sets with similar
outcomes
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Is the Evolutionary Perspective?
Slide 4
Natural Selection and
Adaptive Behavior
• Natural selection: evolutionary
process favors individuals best
adapted to survive and reproduce
• Evolutionary psychology:
emphasizes adaptation, reproduction,
and “survival of the fittest” in shaping
behavior
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 5
Evolution can explain our behavior:
-Men have better spatial ability
-Women use more verbal instances
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Is the Evolutionary Perspective?
Slide 6
Evolutionary Psychology
• Extended “juvenile” period -> larger brain size
• Aspects of childhood prepare for adulthood ->
Play
• Some childhood characteristics are adaptive at
specific points in life -> Play to adapt to current
environment
• Psychological mechanisms evolved as domainspecific -> modular brain
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Is the Evolutionary Perspective?
Slide 7
Evaluating Evolutionary
Psychology
• Bidirectional view
• Evolution gives bodily structures and
biological potentials; does not dictate
behavior
• Biology allows broad range of cultural
possibilities
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 8
• From a single cell to trillions of cells
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 9
Cells, Chromosomes, Genes, and DNA
Cell
Chromosomes
DNA
Nucleus (center
of cell) contains
chromosomes
and genes
Chromosomes are
threadlike structures
composed of DNA
molecules
Gene: a segment of
DNA (spiraled double
chain) containing the
hereditary code
Fig. 2.2
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 10
The Genetic Process
• DNA and the Collaborative Gene
– Chromosomes: threadlike structures
that come in 23 pairs, one member of
each pair coming from each parent
– DNA: complex molecule; double helix
– Genes: units of heredity
• Human have only about 30,000 genes
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 11
Collaborative Genes
• Genes are short segments of DNA and direct
cells to reproduce themselves and to
assemble protein.
• Human have far more protein than genes.
• Many genes collaborate with each other and
with non-genetic factors in the environment
and this collaboration happens at any point.
• A gene maybe turned on because of the
environment
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 12
Genes and Chromosomes
http://www.youtube.com/watch?v=er8dAh
fM9pA
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 13
How do genes manage?
– Mitosis: all cells have 46 chromosomes in
their nucleus,
• cell’s nucleus duplicates itself
Mitosis
http://www.youtube.com/watch?v=JHRBJ
gq50dk&feature=related
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 14
How do genes manage?
• Mitosis, Meiosis, and Fertilization
– Meiosis: cell division to form eggs and
sperm (or gametes)
• cells from ovaries or testes duplicates, but
then divides twice, forming four cells
• Each cell has 23 unpaired chromosomes
http://www.youtube.com/watch?v=D1_mQS_FZ0&feature=related
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 15
The Genetic Process
• Mitosis, Meiosis, and Fertilization
– Reproduction: begins when female
gamete (ovum) fertilized by male gamete
(sperm)
– Zygote: single cell formed through
fertilization; 23 pairs of chromosomes
• X and Y chromosomes
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 16
The Genetic Difference Between
Males and Females
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 17
• http://www.youtube.com/watch?v=r0bye
qI0FRg&feature=related
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 18
The Genetic Process
• Sources of Variability
– A zygot is not a replica of mom and dad’s
genes
– Identical and fraternal twins
– Mutated gene
– Genotype: genetic heritage
– Phenotype: genotype expressed in
observed and measurable characteristics
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 19
Genetic Principles
• Dominant-Recessive Genes Principle
– Recessive gene is influential only if both
genes are recessive
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 20
Genetic Principles
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 21
Chromosome Abnormalities
• Chromosome
abnormalities:
gamete does not have
normal set of 23
– Down syndrome: extra
copy of chromosome
#21 mental retardation
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 22
Sex-Linked Chromosome
Abnormalities
Klinefelter syndrome
Fragile X syndrome
Turner syndrome
XYY syndrome
Disorder in males; extra X chromosome
undeveloped testes and enlarged breast
Abnormality in X chromosome; becomes
constricted or breaks; mental deficiency,
learning disabilities, more prominent in male
Female disorder; X chromosome missing
Or partially deleted, infertility, lack of math
ability
Disorder in males; extra Y chromosome
no evidence for more aggression
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are the Genetic Foundations of Development?
Slide 23
Gene-Linked Abnormalities
Harmful Genes
• Phenylketonuria (PKU): individual
cannot properly metabolize an amino
acid; easily detected and prevented
• It is a result of a recessive gene
• Sickle-cell anemia: affects red blood
cells; recessive gene influence, 1 in
10 African American carries it
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are Some Reproductive Challenges and Choices?
Slide 24
Prenatal Diagnostic Tests
• Ultrasound sonography: high-frequency
sound waves directed into abdomen,
can detect abnormal structures
• Chorionic villi sampling: sample of the
placenta
• Amniocentesis: sample of amniotic fluid
•
• Maternal blood or triple screening
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
What Are Some Reproductive Challenges and Choices?
Slide 25
Infertility and Reproduction
Technology
• Infertility: inability to conceive after
12 months of regular intercourse
• In vitro fertilization (IVF)
• Gamete intrafallopian transfer (GIFT)
• Zygote intrafallopian transfer (ZIFT)
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 26
Behavior Genetics
• Behavior genetics: influence of
heredity and environment on individual
trait and developmental differences
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 27
Behavior Genetics
– Twin studies: compare behavioral
similarity of identical (monozygotic) twins
with behavioral similarity of fraternal
(dizygotic) twins
– Adoption studies: discover whether
adopted children are more like adoptive
parents or biological parents
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 28
Heredity-Environment
Correlations
• Heredity-environment interaction has
complexities
• Individuals influence environments, yet
individuals “inherit” environments
• The three genotype-environment
correlations change as children grow
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 29
Genotype-Environment
Correlations
Passive
When natural parents
provide rearing
environment
Evocative
When genotype elicits
certain types of physical
and social environments
Active
(niche-picking)
When children seek out
compatible and
stimulating environments
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 30
Shared and Nonshared
Environmental Experiences
• Shared environmental experiences:
Siblings’ common experiences
– Parents’ personalities
– Intellectual orientation
– Family’s socioeconomic status
– Neighborhood
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 31
Shared and Nonshared
Environmental Experiences
• Nonshared environmental
experiences; the unique child
– Within family
– Outside family
– Not shared by another sibling
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
Slide 32
• Shared environments play a little
accounts for little of the variations in
children’s personality or interest.
• Heredity influences the non-shared
environments of the siblings
• Judith Harris “The Nature Assumption”
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
How Do Heredity and Environment Interact? The Nature-Nurture Debate
Slide 33
Conclusions About HeredityEnvironment Interaction
• Operate cooperatively
• Relative contributions are
not additive
• Many complex behaviors
have some genetic loading
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.
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The End
© 2009 The McGraw-Hill Companies, Inc. All rights reserved.