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.
- Is there a “one to one correspondence between genes and proteins?” Discussion/Psychology Life Span.
- Why are males more vulnerable to genetic disorders than females?
- Which prenatal procedure is the least invasive? Which is the most invasive? Discussion/Psychology Life Span.
- 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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psyc2314_ppt_ch02.pptx
LIFE-SPAN DEVELOPMENT 17e
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
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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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11
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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16
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)
| Syndrome | Description | Treatment | Incidence |
| Down syndrome | An extra chromosome causes mild to severe intellectual disability and physical abnormalities | Surgery, early intervention, infant stimulation, and special learning programs | 1 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 abnormalities | Hormone therapy can be effective | 1 in 1,000 male births |
| Fragile X syndrome | An abnormality in the X chromosome can cause intellectual disability, learning disabilities, or short attention span | Special education, speech and language therapy | More common in males than in females |
| Turner syndrome (XO) | A missing X chromosome in females can cause intellectual disability and sexual underdevelopment | Hormone therapy in childhood and puberty | 1 in 2,500 female births |
| XYY Syndrome | An extra Y chromosome can cause above-average height | No special treatment required | 1 in 1,000 male births |
©McGraw-Hill Education.
(1 of 2)
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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.
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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)
| Name | Description | Treatment | Incidence |
| Cystic fibrosis | Glandular 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 |
| Diabetes | Body 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 |
| Hemophilia | Delayed 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 disease | Central 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)
| Name | Description | Treatment | Incidence |
| 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 anemia | Blood 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 bifida | Neural 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 disease | Deceleration 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
Diabetes
Body does not produce enough insulin, which causes abnormal metabolism of sugar
©McGraw-Hill Education.
Gene-Linked Abnormalities (4 of 6)
Hemophilia
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
Adoption
©McGraw-Hill Education.
Prenatal Diagnostic Tests
Ultrasound sonography
Brain imaging techniques
Chorionic villus sampling
Amniocentesis
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
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Success Rates of In Vitro Fertilization Vary According to Woman’s Age
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37
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.
FIGURE 13
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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 Correlation | Description | Examples |
| Passive | Children 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. |
| Evocative | The 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.