Discussion/Psychology Life Span.

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Discussion/Psychology Life Span.

Discussion/Psychology Life Span.

Respond to the following questions. This assignment is worth 5  points. Make sure that you use complete sentences, college-level grammar  and that you have completely thought about your response.

  1. Is there a “one to one correspondence between genes and proteins?” Discussion/Psychology Life Span.
  2. Why are males more vulnerable to genetic disorders than females?
  3. Which prenatal procedure is the least invasive? Which is the most invasive? Discussion/Psychology Life Span.
  4. Little Gilbert, a six-year-old, is active and alert. He loves to  explore new experiences. He likes to run, yell, make new friends, play  with any animal he sees, asks endless questions, and tries any  experiment which comes to mind including seeing if cats can swim. His  parents and siblings, however, seem to have a different genetic  composition (hint). They are quiet, hate noise, like to sit and read or  discuss ideas. Little Gilbert has discovered that the people who live  next door love noise, excitement, and have already discovered through  experiments that cats have limited appreciation of swimming. He tends to  spend a lot of time with his friends next door. What terms should be  used to classify the correlation between Little Gilbert and his  neighbors? This is an epigenetic concept (hint). Discussion/Psychology Life Span.


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John W. Santrock

©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom.  No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.

Chapter 2

Biological Beginnings

©McGraw-Hill Education. All rights reserved. Authorized only for instructor use in the classroom.  No reproduction or further distribution permitted without the prior written consent of McGraw-Hill Education.

Chapter Outline

The Evolutionary Perspective

Genetic Foundations of Development

Reproductive Challenges and Choices

Heredity-Environment Correlation: The Nature-Nurture Debate

©McGraw-Hill Education.

The Evolutionary Perspective

Natural selection and adaptive behavior

Evolutionary psychology

©Alan and Sandy Carey/Getty Images

©McGraw-Hill Education.

Natural Selection and Adaptive Behavior

Natural selection: evolutionary process by which individuals of a species that are best adapted are the ones that survive and reproduce

Adaptive behavior: promotes an organism’s survival in the natural habitat, because an organism possesses characteristics needed for survival

©McGraw-Hill Education.

Evolutionary Psychology (1 of 3)

Emphasizes the importance of adaptation and reproduction to ensure survival

Offspring that adapt, develop behaviors, and possess self-protective traits survive.

Evolutionary developmental psychology

Growth in interest in using the concepts of evolutionary psychology to understand human development

Psychological mechanisms are domain-specific, for example, we developed sets of problem-solving skills for recurring problems like finding food.

©McGraw-Hill Education.

Evolutionary Psychology (2 of 3)

Connecting evolution and life-span development

Benefits conferred by evolutionary selection decrease with age.

Natural selection primarily operates during the first half of life and during reproductive viability.

Older adults

Weaken biologically and need culture-based resources

Cognitive skills, literacy, medical technology, and social support

©McGraw-Hill Education.

Evolutionary Psychology (3 of 3)

Evaluating Evolutionary Psychology

Evolution gave us biological potentialities but does not dictate behavior and vice versa.

People have used their biological capacities to produce diverse cultures.

Includes aggressive and peace-loving, egalitarian and autocratic

The time scale on which evolution occurs is not suited for empirical study.

Testing evolutionary psychology theories can be done by studying specific genes in humans and other species and their links to traits and behaviors.

©McGraw-Hill Education.

Baltes’ View of Evolution and Culture Across the Life Span

©McGraw-Hill Education.

Genetic Foundations of Development

The collaborative gene

Genes and chromosomes

Genetic principles

Chromosomal and gene-linked abnormalities

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Cells, Chromosomes, DNA, and Genes

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The Collaborative Gene (1 of 4)

Human life begins as a single cell.

The nucleus of each cell contains chromosomes.

Chromosomes: threadlike structures made up of deoxyribonucleic acid

DNA: complex double-helix molecule that contains genetic code or information

Genes: units of hereditary information composed of DNA

Help cells to reproduce themselves

Manufacture the proteins that maintain life

©McGraw-Hill Education.

The Collaborative Gene (2 of 4)

Each gene has its own location or designated place on a particular chromosome.

Completion of the Human Genome project led to

Genome-wide association method: identifies genetic variations linked to a particular disease

Linkage analysis: helps discover the location of a gene or genes in relation to a marker gene

Used in the search for a disease-related genes

©McGraw-Hill Education.

The Collaborative Gene (3 of 4)

Next-generation sequencing

Describes the vast increase in genetic data generated at a reduced cost and in a shorter period of time

Thousand Genomes Project

Most detailed study of human genetic variation to date

Goal is determining the genomic sequences of at least 1,000 individuals from different ethnic groups around the world

With that information, can conduct detailed studies of genetic variations in disease

©McGraw-Hill Education.

The Collaborative Gene (4 of 4)

Research has found that genes are dependent and there are more proteins than genes.

Human genome consists of approximately 20,000 genes.

Genes collaborate with each other and nongenetic factors both inside and outside the body.

Activity of genes is affected by their environment.

Stress, exercise, nutrition, radiation, temperature, and lack of sleep can negatively influence gene expression.

©McGraw-Hill Education.

The Genetic Difference Between Males and Females

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Genes and Chromosomes (1 of 4)

All of the cells in the body, except sperm and egg, have 46 chromosomes in 23 pairs.

Mitosis: cellular reproduction in which the cell’s nucleus duplicates itself into two new cells

Each cell contains the same DNA as parent cell.

Meiosis: cell division forming eggs and sperm or gametes

Fertilization: reproductive stage when egg and sperm fuse to create a zygote.

Zygote: single cell formed through fertilization

©McGraw-Hill Education.

Genes and Chromosomes (2 of 4)

Sources of variability

Unique zygote: combining parents’ two sets of genes increases genetic variability in offspring

Identical or monozygotic twins

A single zygote splits into two genetically identical replicas and becomes two individuals

Fraternal or dizygotic twins

Two eggs fertilized by different sperm create two nonidentical zygotes as genetically similar as ordinary siblings

©McGraw-Hill Education.

Genes and Chromosomes (3 of 4)

Mutated gene: permanently altered segment of DNA.

Susceptibility genes: make the individual more vulnerable to specific diseases or accelerated aging

Longevity genes: make the individual less vulnerable to certain diseases and more likely to live to an older age

©Don W. Fawcett/Science Source

©McGraw-Hill Education.

Genes and Chromosomes (4 of 4)

Genotype: person’s genetic material

Phenotype: how an individual’s genotype is expressed in observable and measurable physical and psychological characteristics

Expression is influenced by environmental factors

Foe example, genetic potential for height may be stunted by lack of access to proper nutrition

©McGraw-Hill Education.

Genetic Principles (1 of 3)

Genetic principles determine how a genotype is expressed to create a particular phenotype.

Dominant-recessive genes principle

One gene of a pair always exerts its effects, overriding the potential influence of the other gene.

Sex-linked genes

When a mutated gene is carried on the X chromosome, the result is called X-linked inheritance.

Most X-linked inherited diseases manifest in males who have only one X chromosome.

©McGraw-Hill Education.

Genetic Principles (2 of 3)

Genetic imprinting

Occurs when the expression of a gene has different effects depending on whether the gene is passed on by mother or father

Chemical process preventing one member of the gene pair from expressing itself

Imprinting is normal but can go awry, disturbing development and leading to growth disorders or cancer

©McGraw-Hill Education.

Genetic Principles (3 of 3)

Polygenic inheritance

Many different genes interacting plus environmental influence determine a characteristic or developing disease

Gene–gene interaction: studies focusing on the interdependence of two or more genes in influencing characteristics, behavior, diseases, and development

©McGraw-Hill Education.

Chromosomal Abnormalities (1 of 3)

Down syndromeAn extra chromosome causes mild to severe intellectual disability and physical abnormalitiesSurgery, early intervention, infant stimulation, and special learning programs1 in 1,900 births at age 20 1 in 300 births at age 35 1 in 30 births at age 45
Klinefelter syndrome (XXY)An extra X chromosome causes physical abnormalitiesHormone therapy can be effective1 in 1,000 male births
Fragile X syndromeAn abnormality in the X chromosome can cause intellectual disability, learning disabilities, or short attention spanSpecial education, speech and language therapyMore common in males than in females
Turner syndrome (XO)A missing X chromosome in females can cause intellectual disability and sexual underdevelopmentHormone therapy in childhood and puberty1 in 2,500 female births
XYY SyndromeAn extra Y chromosome can cause above-average heightNo special treatment required1 in 1,000 male births

©McGraw-Hill Education.

(1 of 2)


Chromosomal Abnormalities (2 of 3)

Down Syndrome: form of an intellectual disability caused by the presence of an extra copy of chromosome 21

Can cause intellectual and physical issues

Klinefelter Syndrome: sex-linked chromosomal disorder giving males an extra X chromosome, making them XXY instead of XY

Characteristics are underdeveloped testes, enlarged breasts, and becoming tall

©McGraw-Hill Education.


Chromosomal Abnormalities (3 of 3)

Fragile X Syndrome (FXS): sex-linked disorder causing an abnormality in the X chromosome

Can cause intellectual disability, learning disability, or short attention span

Turner Syndrome: sex-linked disorder in which a missing X chromosome in females

Can cause intellectual disability and sexual underdevelopment

XYY Syndrome: male has an extra Y chromosome

Can cause above-average height

©McGraw-Hill Education.

Gene-Linked Abnormalities (1 of 6)

Cystic fibrosisGlandular dysfunction that interferes with mucus production; breathing and digestion are hampered, resulting in a shortened life span.Physical and oxygen therapy, synthetic enzymes, and antibiotics; most individuals live to middle age.1 in 2,000 births
DiabetesBody does not produce enough insulin, which causes abnormal metabolism of sugar.Early onset can be fatal unless treated with insulin.1 in 2,500 births
HemophiliaDelayed blood clotting causes internal and external bleeding.Blood transfusions/injections can reduce or prevent damage due to internal bleeding.1 in 10,000 males
Huntington’s diseaseCentral nervous system deteriorates, producing problems in muscle coordination and mental deterioration.Does not usually appear until age 35 or older; death likely 10–20 years after symptoms appear.1 in 20,000 births

©McGraw-Hill Education.

Gene-Linked Abnormalities (2 of 6)

Phenylketonuria (PKU)Metabolic disorder that, left untreated, causes intellectual disability and hyperactivity.Special diet can result in average intelligence and normal life span.1 in 10,000 to 1 in 20,000 births
Sickle-cell anemiaBlood disorder that limits the body’s oxygen supply; it can cause joint swelling as well as heart and kidney failure.Penicillin, medication for pain, antibiotics, blood transfusions, and hydroxyurea therapy (can start as young as 9 months of age).1 in 400 African American children (lower among other groups)
Spina bifidaNeural tube disorder that causes brain and spine abnormalities.Corrective surgery at birth, orthopedic devices, and physical/medical therapy.2 in 1,000 births
Tay-Sachs diseaseDeceleration of mental and physical development caused by an accumulation of lipids in the nervous system.Medication and special diet are used, but death is likely by 5 years of age.1 in 30 American Jews is a carrier

©McGraw-Hill Education.

Gene-Linked Abnormalities (3 of 6)

Cystic fibrosis

Glandular dysfunction that interferes with mucus production

Breathing and digestion are hampered, shortening life span


Body does not produce enough insulin, which causes abnormal metabolism of sugar

©McGraw-Hill Education.

Gene-Linked Abnormalities (4 of 6)


Delayed blood clotting causes uncontrolled internal and external bleeding

Huntington’s disease

Central nervous system deteriorates, producing problems in muscle coordination and mental deterioration

©McGraw-Hill Education.

Gene-Linked Abnormalities (5 of 6)

Phenylketonuria (PKU)

Genetic disorder in which an individual cannot properly metabolize an amino acid called phenylalanine

Sickle-cell anemia

Genetic disorder that impairs the functioning of red blood cells

©McGraw-Hill Education.

Gene-Linked Abnormalities (6 of 6)

Spina bifida

Neural tube disorder that causes brain and spine abnormalities

Tay-Sachs disease

Deceleration of mental and physical development caused by an accumulation of lipids in the nervous system

©McGraw-Hill Education.

Dealing with Genetic Abnormalities

Every individual carries DNA variations that predispose the person to serious physical disease or mental disorder.

Genes that are missing, nonfunctional, or mutated can contribute to disorders.

Identifying genetic flaws enables medical professions to

Predict an individual’s risks

Recommend healthy practices

Prescribe the safest and most effective drugs

©McGraw-Hill Education.

Reproductive Challenges and Choices

Prenatal diagnostic tests

Infertility and reproductive technology


©McGraw-Hill Education.

Prenatal Diagnostic Tests

Ultrasound sonography

Brain imaging techniques

Chorionic villus sampling


Maternal blood screening

Noninvasive prenatal diagnosis (NIPD)

Fetal sex determination

©Du Cane Medical Imaging Ltd./Science Source

©McGraw-Hill Education.

Infertility and Reproductive Technology

Infertility: inability to conceive a child after 12 months of regular intercourse without contraception

In Vitro Fertilization (IVF): eggs and sperm are combined in a laboratory dish by experts

Zygote or fertilized egg is transferred into the woman’s uterus

Multiple zygotes are often transferred but can increase health risks

IVF success rate depends on the mother’s age and other factors

©McGraw-Hill Education.

Success Rates of In Vitro Fertilization Vary According to Woman’s Age

©McGraw-Hill Education.


Adoption (1 of 2)

Social and legal process that establishes parent–child relationship between persons unrelated at birth

Increased diversity of adopted children and adoptive parents

Types of adoption include domestic public welfare system, private domestic, and international private

©McGraw-Hill Education.



Adoption (2 of 2)

Outcomes for adopted children

Fare much better than children raised in long-term foster care

Children who are adopted at a very early age more likely to have positive outcomes

©Don Mason/Getty Images

©McGraw-Hill Education.

Heredity-Environment Interaction: The Nature-Nurture Debate (1 of 2)

Behavior genetics

Heredity-environment correlations

The epigenetic view

Gene × Environment (G × E) interaction

Conclusions about heredity-environment interaction

©McGraw-Hill Education.

Heredity-Environment Interaction: The Nature-Nurture Debate (2 of 2)

Gene × Environment (G × E) interaction

Interaction of

Specific measured variation in the DNA

Specific measured aspect of the environment

©Compassionate Eye Foundation/Getty Images

©McGraw-Hill Education.

Behavior Genetics

Discover the influence of heredity and environment on individual differences in human traits, development, and behavior

Twin study: behavioral similarity of identical and fraternal twins is compared

Adoption study: seeks to discover whether behavioral and psychological characteristics of adopted children are more like their

Adoptive parents who provided a home environment

Biological parents who contributed their heredity

©McGraw-Hill Education.

Exploring Heredity-Environment Correlations

Heredity-Environment CorrelationDescriptionExamples
PassiveChildren inherit genetic tendencies from their parents, and parents also provide an environment that matches their own genetic tendencies.Musically inclined parents usually have musically inclined children, and they are likely to provide an environment rich in music for their children.
EvocativeThe child’s genetic tendencies elicit stimulation from the environment that supports a particular trait. Thus, genes evoke environmental support.A happy, outgoing child elicits smiles and friendly responses from others.
Active (niche-picking)Children actively seek out niches in their environment that reflect their own interests and talents and are thus in accord with their genotype.Libraries, sports fields, and a store with musical instruments are examples of environmental niches children might seek out if they have intellectual interests in books, talent in sports, or musical talents, respectively.

©McGraw-Hill Education.

Heredity-Environment Correlations

Passive genotype-environment correlations

Genetically linked biological parents provide rearing environment for the children.

Evocative genotype-environment correlations

Genetically influenced characteristics elicit certain types of environments.

Active genotype-environment correlations

Also called niche-picking, children seek out environments that they find compatible and stimulating and suited for their genetically influenced abilities.

©McGraw-Hill Education.

Epigenetic View and Gene × Environment (G × E) Interaction

Epigenetic view: development is the result of an ongoing, bidirectional interchange between heredity and environment

Gene × Environment (G × E) Interaction

The interaction between heredity and environment influences development and interactions of specific DNA sequences.

Epigenetic mechanisms involve molecular modification of DNA strand as a result of environmental inputs in ways that alter gene functioning.

©McGraw-Hill Education.

Comparison of the Heredity-Environment Correlation and Epigenetic Views

Heredity-Environment Correlation View

Developmental influence has one direction.

Heredity influences environment.

Epigenetic Views

Developmental influence is bidirectional.

Heredity and environment influence each other.

©McGraw-Hill Education.

Conclusions About Heredity-Environment Interaction

Relative contributions of heredity and environment are not additive.

Complex behaviors are influenced by genes and environments in a way that gives people a propensity for a particular developmental trajectory.

©McGraw-Hill Education.

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