Download Document

Slide 1
3—Biological Beginnings
•
•
•
•
The Evolutionary Perspective
The Genetic Foundations of Development
Reproductive Challenges and Choices
Heredity and Environment Interaction: The
Nature-Nurture Debate
• Summary
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 2
The Evolutionary Perspective
• Natural Selection and Adaptive Behavior
– Natural selection is the evolutionary process that
favors individuals of a species that are best adapted to
survive and reproduce.
– Adaptive behavior is behavior that promotes an
organism’s survival in the natural habitat.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 3
The Evolutionary Perspective
• Natural Selection (continued)
– Evolutionary Psychology
• A contemporary approach that emphasizes the
importance of adaptation, reproduction, and
“survival of the fittest” in shaping behavior.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 4
The Evolutionary Perspective
• Natural Selection (continued)
– Evolutionary Developmental Psychology
• Views proposed by evolutionary developmental
psychologists (Bjorklund & Pellegrini, 2002):
– An extended “juvenile” period is needed to
develop a large brain and learn the complexity of
human social communities.
– Many aspects of childhood function as
preparations for adulthood and were selected
over the course of evolution.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 5
The Evolutionary Perspective
• Natural Selection (continued)
– Evolutionary Developmental Psychology (continued)
– Some child characteristics were selected to be
adaptive at specific points in development and
not as preparation for adulthood.
– Many evolved psychological mechanisms are
domain-specific.
– Evolved mechanisms are not always adaptive in
contemporary society.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 6
The Evolutionary Perspective
The Brain Sizes of Various Primates and
Humans in Relation to the Length of the
Juvenile Period
• Refer to Figure 3.1
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 7
The Evolutionary Perspective
• Natural Selection (continued)
– Evaluating Evolutionary Psychology
• Bandura sees development as bidirectional.
• Evolution gave us body structures and biological
potentialities, not behavioral dictates.
• In most domains of human functioning, biology
allows a broad range of cultural possibilities (Gould,
1998).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 8
Review and Reflect:
Learning Goal 1
• Discuss the evolutionary perspective on
development
– Review
• How can natural selection and adaptive behavior be
defined?
• What is evolutionary psychology? What are some
basic ideas about human development proposed by
evolutionary psychologists? How can evolutionary
psychology be evaluated?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 9
Review and Reflect:
Learning Goal 1
– Reflect
• Which is more persuasive to you: the views of
evolutionary psychologists or their critics? Why?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 10
Genetic Foundations
• The Genetic Process
– Chromosomes
• Threadlike structures that come in 23 pairs, one
member of each pair coming from each parent.
Chromosomes contain the genetic substance DNA.
– DNA (deoxyribonucleic acid)
• A complex, double-helix-shaped molecule that
contains genetic information.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 11
Genetic Foundations
• The Genetic Process (continued)
– Genes
• Units of hereditary information that are short
segments of DNA. They direct cells to reproduce
themselves and to assemble proteins, which are the
building blocks of cells and regulate the body’s
processes.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 12
Genetic Foundations
Cells, Chromosomes, Genes, and DNA
• Refer to Figure 3.2
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 13
Genetic Foundations
• Genes and Chromosomes:
– Genes get passed from generation to generation through
mitosis, meiosis, and fertilization.
• Mitosis: The process by which each chromosome in
a cell’s nucleus duplicates itself and divides.
• Meiosis: The process by which cells in the
reproductive organs (sperm in males, eggs in
females) duplicate their chromosomes, then divide
twice, forming four cells, each having half of the
genetic material of the parent cell.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 14
Genetic Foundations
• Mitosis and Meiosis (continued)
– By the end of meiosis, each egg or sperm has 23
unpaired chromosomes.
– Fertilization: The process in which an egg and a sperm
fuse to create a single cell, the zygote.
– Zygote: The single cell formed through fertilization; in
the zygote, the unpaired chromosomes from the egg and
from the sperm combine to form one set of paired
chromosomes.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 15
Genetic Foundations
Union of Sperm and Egg
• Refer to Figure 3.3
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 16
Genetic Foundations
• Sources of Variability
– Changes during separation and recombination of
chromosomes during meiosis
– Sex differences on 23rd pair of chromosomes: XX and
XY
– Genotype: A person’s genetic heritage; the actual
genetic material.
– Phenotype: The way an individual’s genotype is
expressed in observable and measurable characteristics.
– Mutated genes: Permanently altered DNA segments.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 17
Genetic Foundations
The Genetic Difference Between Males and
Females
• Refer to Figure 3.4
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 18
Genetic Foundations
• Genetic Principles
– Dominant-Recessive Genes Principle
• Some genes are dominant and will always override
so-called recessive genes.
– Sex-Linked Genes
• X-linked inheritance describes inheritance of a
mutated gene carried on the X chromosome.
• Because males have only one X chromosome, they
are more likely than females (who would be
carriers) to manifest an X-linked disease.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 19
Genetic Foundations
• Genetic Principles (continued)
– Genetic Imprinting
• Occurs when genes have differing effects depending
on whether they are inherited from the mother or the
father.
• Imprinted genes dominate over genes that have not
been imprinted.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 20
Genetic Foundations
• Genetic Principles (continued)
– Polygenic Inheritance
• The genetic principle by which many genes interact
to influence a particular characteristic
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 21
Genetic Foundations
How Brown-Haired Parents Can Have a
Blond-Haired Child
• Refer to Figure 3.5
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 22
Genetic Foundations
• Chromosome and Gene-Linked
Abnormalities
– Chromosome Abnormalities
• Sometimes when a gamete is formed, the sperm and
ovum do not have their normal set of 23
chromosomes.
• Down syndrome: A form of mental and motor
retardation and abnormalities of physical features
caused by the presence of an extra copy of
chromosome 21.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 23
Genetic Foundations
– Chromosome Abnormalities (continued)
• Sex-Linked Chromosome Abnormalities
– Most commonly involve an extra X or Y
chromosome or the absence of an X
chromosome.
– Klinefelter syndrome: Males have an extra X
chromosome, making them XXY instead of XY.
– Fragile X syndrome: Abnormality in the X
chromosome, which becomes constricted and
often breaks.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 24
Genetic Foundations
– Chromosome Abnormalities (continued)
• Abnormalities of the Sex Chromosomes (continued)
– Turner syndrome: Females either lack an X
chromosome, making the person XO instead of
XX, or the second X chromosome is partially
deleted.
– The XYY syndrome: Males have an extra Y
chromosome.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 25
Genetic Foundations
Some Chromosome Abnormalities
• Refer to Figure 3.6
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 26
Genetic Foundations
– Gene-Linked Abnormalities
• Phenylketonuria (PKU): A genetic disorder in
which an individual cannot properly metabolize
phenylalanine, an amino acid needed for production
of proteins in the body. PKU is now easily detected,
but if left untreated results in mental retardation and
hyperactivity.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 27
Genetic Foundations
– Gene-Linked Abnormalities (continued)
• Sickle-cell anemia: A genetic disorder that affects
the red blood cells and occurs most often in people
of African descent.
• Other gene-linked abnormalities: Cystic fibrosis,
diabetes, hemophilia, spina bifida, and Tay-Sachs
disease.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 28
Genetic Foundations
Some Gene-Linked Abnormalities
• Refer to Figure 3.7
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 29
Genetic Foundations
– Dealing with Genetic Abnormalities
• Genes are not destiny.
• Missing, nonfunctional, mutated: Gene does not
function normally.
• Identifying abnormalities can help in suggesting
most effective ways to deal with them, but raises
concerns about privacy.
• Genetic counselors are familiar with these problems,
the odds of encountering them, and strategies for
offsetting some of their effects.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 30
Review and Reflect: Learning
Goal 2
• Describe what genes are and how they
influence human development
– Review
• How does the genetic process work?
• How can the genetic principles of dominantrecessive genes, sex-linked genes, genetic
imprinting, and polygenic inheritance be
characterized?
• What are some chromosome and gene-linked
abnormalities?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 31
Review and Reflect: Learning
Goal 2
– Reflect
• What are some possible ethical issues regarding
genetics and development that might arise in the
future?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 32
Reproductive Challenges and
Choices
• Prenatal Diagnostic Tests
– Scientists have developed a number of tests to
determine whether a fetus is developing normally.
• Ultrasound sonography: High-frequency sound
waves are directed into the pregnant woman’s
abdomen (7 weeks into pregnancy and beyond; may
be used during amniocentesis).
• Chorionic villi sampling: A small sample of the
placenta is removed (between weeks 8 and 11).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 33
Reproductive Challenges and
Choices
• Prenatal Diagnostic Tests (continued)
• Amniocentesis: A sample of amniotic fluid is
withdrawn by syringe and tested for chromosomal
or metabolic disorders (between weeks 8 and 11).
• Maternal blood screening: Triple-screen test
measures alpha-fetoprotein (AFP), estriol, and
human chorionic gonadotropin to identify risk for
birth defects (between weeks 16 and 18).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 34
Reproductive Challenges and
Choices
• Infertility and Reproductive Technology
– Infertility: The inability to conceive a child after 12
months of regular intercourse without contraception.
• Causes may rest with the woman (not ovulating,
abnormal ova, blocked fallopian tubes, disease that
prevents implantation) or the man (too few sperm,
sperm lack motility, blocked passageway).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 35
Reproductive Challenges and
Choices
• Infertility and Reproductive Technology
(continued)
– Three common high-tech assisted reproduction
techniques:
• In vitro fertilization (IVF)
• Gamete intrafallopian transfer (GIFT)
• Zygote intrafallopian transfer (ZIFT)
– Often results in multiple births
– Children adjust as well as those who are naturally
conceived or adopted
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 36
Reproductive Challenges and
Choices
Success Rates of Three Different Assisted
Reproduction Techniques
• Refer to Figure 3.8
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 37
Reproductive Challenges and
Choices
• Adoption
– Adoption: The social and legal process by which a
parent-child relationship is established between persons
unrelated at birth.
• Adopted children and adolescents often show more
psychological and school-related problems than
nonadopted children, but are also more outgoing and
more altruistic; the majority of adopted children
adjust effectively.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 38
Reproductive Challenges and
Choices
Socioemotional Development at Adolescence
of Children in Three Family Types: In Vitro
Fertilization, Naturally Conceived, and
Adopted
• Refer to Figure 3.9
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 39
Review and Reflect: Learning
Goal 3
• Identify some important reproductive
challenges and choices
– Review
• What are some common prenatal diagnostic tests?
• What are some causes of infertility? What types of
reproductive technology are used to improve the
success rates of having children for infertile
couples?
• How does adoption affect children’s development?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 40
Review and Reflect: Learning
Goal 3
– Reflect
• We discussed a number of studies indicating that
adoption is linked with negative outcomes for
children. Does that mean that all adopted children
have more negative outcomes than all nonadopted
children? Explain.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 41
Heredity and Environment
Interaction: The Nature-Nurture
Debate
• Behavior Genetics
– Seeks to discover the influence of heredity and
environment on individual differences in human traits
and development.
– To study the link between heredity and behavior,
geneticists often use twin studies or adoption studies.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 42
Heredity and Environment
Interaction
• Behavior Genetics (continued)
– Twin study: Compares the behavioral similarity of
identical (monozygotic) twins with the behavioral
similarity of fraternal (dizygotic) twins.
• Identical twins develop from a single fertilized egg
that splits into two genetically identical replicas.
• Fraternal twins develop from separate eggs and
separate sperm with no more genetic similarity than
ordinary siblings.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 43
Heredity and Environment
Interaction
• Behavior Genetics (continued)
– Adoption study: Investigators seek to discover
whether the behavior or psychological characteristics of
adopted children are more like their adoptive parents
(nurture) or their biological parents (nature).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 44
Heredity-Environment
Interaction
• Heredity-Environment Correlations
– Individuals’ genes influence the types of environments
to which they are exposed.
– Passive genotype-environment correlations
• Correlations that occur because biological parents
provide an environment that matches their own
genetic tendencies, and their children inherit genetic
tendencies from their parents.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 45
Heredity-Environment
Interaction
• Hereditary-Environment Correlations
(continued)
– Evocative genotype-environment correlations
• Correlations that exist when the child’s genotype
elicits certain types of physical and social
environments.
– Active (niche-picking) genotype-environment
correlations
• Correlations that exist when children seek out
environments they find compatible and stimulating.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 46
Heredity-Environment
Interaction
Exploring Heredity-Environment Correlations
• Refer to Figure 3.10
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 47
Heredity-Environment
Interaction
• Shared and Nonshared Environmental
Experience
– Shared environmental experiences
• Children’s common environmental experiences that
are shared with their siblings, such as their parents’
personalities and intellectual orientation, the
family’s social class, and the neighborhood in which
they live.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 48
Heredity-Environment
Interaction
• Shared and Nonshared Environmental
Experience (continued)
– Nonshared environmental experiences
• The child’s unique experiences, both within the
family and outside the family, that are not shared by
another sibling. Experiences occurring within the
family can be part of the “nonshared environment.”
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 49
Heredity-Environment
Interaction
• The Epigenetic View
– Emphasizes that development is the result of an
ongoing, bidirectional interchange between heredity
and environment.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 50
Heredity-Environment
Interaction
• Conclusions About Heredity-Environment
Interaction
– Heredity and environment operate (cooperate) together.
– The relative contributions of heredity and environment
are not additive.
– Emerging view: Many complex behaviors likely have
some genetic loading that gives people a propensity for
a particular developmental trajectory, but actual
development also requires an environment.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 51
Heredity-Environment
Interaction
Comparison of the Heredity-Environment
Correlation and Epigenetic Views
• Refer to Figure 3.11
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 52
Review and Reflect:
Learning Goal 4
• Characterize some of the ways that heredity
and environment interact to produce
individual differences in development
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 53
Review and Reflect:
Learning Goal 4
– Review
• What is behavior genetics?
• What are three types of heredity-environment
correlations and what is an example of each?
• What is meant by the concepts of shared and
nonshared experiences?
• What is the epigenetic view?
• What conclusions can be reached about heredityenvironment interaction?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 54
Review and Reflect:
Learning Goal 4
– Reflect
• Someone tells you that he or she has analyzed his or
her genetic background and environmental
experiences and reached the conclusion that
environment definitely has had little influence on his
or her intelligence. What would you say to this
person about his or her ability to make this selfdiagnosis?
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 55
Summary
• Natural selection is the process that favors the
individuals of a species that are best adapted to
survive and reproduce.
• Evolutionary psychology is the view that
adaptation, reproduction, and “survival of the
fittest” are important in explaining behavior.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 56
Summary
• The nucleus of each human cell contains 46
chromosomes, which are composed of DNA, and
short segments of DNA constitute genes.
• Mitosis and meiosis are two ways in which new
cells are formed.
• In the process of reproduction, an egg and a sperm
unite to form a zygote.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 57
Summary
• Sources of genetic variability distinguish between
genotype and phenotype.
• Genetic principles include those involving
dominant-recessive genes, sex-linked genes,
genetic imprinting, and polygenic inheritance.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 58
Summary
• Chromosomal abnormalities produce Down
syndrome as well as sex-linked chromosomal
abnormalities.
• Gene-linked abnormalities involve harmful genes.
• Genetic counseling has increased in popularity as
more couples desire information about their risk of
having a child with defective characteristics.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 59
Summary
• Ultrasound sonography, chorionic villi sampling,
amniocentesis, and maternal blood screening are
used to determine the presence of defects once
pregnancy has begun.
• Approximately 15% of U.S. couples have
infertility problems, some of which can be
corrected through surgery or fertility drugs.
• Although adopted children and adolescents have
more problems than their nonadoptive
counterparts, the majority adapt effectively.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 60
Summary
• Behavior genetics is the field concerned with the
degree and nature of behavior’s hereditary basis;
major research methods are twin studies and
adoption studies.
• In Scarr’s heredity-environment correlations view,
heredity directs the types of environments children
experience: passive, evocative, and active (nichepicking).
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 61
Summary
• Shared environmental experiences refer to
siblings’ common experiences, such as their
parents’ personalities and intellectual orientation,
the family’s socioeconomic status, and the
neighborhood in which they live.
• Nonshared environmental experiences involve the
child’s unique experiences, both within a family
and outside a family, that are not shared with a
sibling.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..
Slide 62
Summary
• The epigenetic view emphasizes that development
is the result of an ongoing, bidirectional
interchange between heredity and environment.
• Many complex behaviors have some genetic
loading that gives people a propensity for a
particular developmental trajectory, but actual
development also requires an environment, and
that environment is complex.
McGraw-Hill
© 2007 The McGraw-Hill Companies, Inc. All rights reserved..