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Biological Beginnings. The Evolutionary Perspective Genetic Foundations of Development Heredity and Environment interaction: The Nature-Nurture Debate Prenatal Development Birth. The Evolutionary Perspective. The Evolutionary Perspective.
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Biological Beginnings The Evolutionary Perspective Genetic Foundations of Development Heredity and Environment interaction: The Nature-Nurture Debate Prenatal Development Birth
The Evolutionary Perspective The Evolutionary Perspective • Natural selection and adaptive behavior: • Darwin and his observations. • All organisms must adapt in life. • Evolutionary psychology: • Emphasizes adaptation, reproduction, and survival of the fittest in shaping behavior. • Evolution explains human physical features and behaviors.
The Evolutionary Perspective The Evolutionary Perspective • Natural selection and adaptive behavior: • Darwin and his observations. • All organisms must adapt in life. • Evolutionary psychology: • Emphasizes adaptation, reproduction, and survival of the fittest in shaping behavior. • Evolution explains human physical features and behaviors. • Explaining humans and their behavior: • Larger brains and more complex societies. • Takes longest of all mammals to mature. • Some evolved mechanisms of adaptation not compatible with modern society.
The Evolutionary Perspective Evolution and Life-Span Development • Benefits of evolutionary selection decrease with age. • As adults weaken biologically, culture-based needs increase.
Genetic Foundations Genetic Foundations of Development • DNA: Deoxyribonucleic Acid • Chromosomes: Thread-like structures • Genes: Units of hereditary information • Human Genome Project: 30,000 genes in humans.
Genetic Foundations Cells, Chromosomes, Genes, and DNA Nucleus (center of cell) contains chromosomes and genes Gene: a segment of DNA (spiraled double chain) containing the hereditary code Chromosomes are threadlike structures composed of DNA molecules
Genetic Foundations The Collaborative Gene • Mitosis: Cell nucleus duplicates. • Meiosis:Cell division forms gametes. • Fertilization: Egg and sperm form zygote. • Genetic variability in the population. • X and Y chromosomes determine sex. • Genes and chromosomes: • Identical and fraternal twins • Mutated gene • Genotype-All of one’s genetic makeup • Phenotype-Observable characteristics
Genetic Foundations Genetic Principles • Sex-linked genes: • X-linked inheritance for males and females. • Poly-genetically determined characteristics: • Many genes interact to influence a trait. • Sex-linked chromosome abnormalities: • Down Syndrome • Klinefelter syndrome- (males-extra X chromosome) • Fragile X syndrome- (abnormality in X chromosome) • Turner syndrome- (females-extra X chromosome) • XYY syndrome- (males-extra Y chromosome)
Genetic Foundations Gene-Linked Abnormalities • PKU: phenylketonuria • Sickle-cell anemia • Cystic fibrosis • Diabetes • Hemophilia • Genetic disorders can sometimes be compensated for by other genes or events. • Behavior Genetics: • Studies influence of heredity and environment on individual differences. • Studies use twins or adoptees: • Monozygotic and dizygotic twins. • Adoption study: examine behavior and psychological characteristics.
Heredity, Environment, and Individual Differences Heredity-Environment Correlations • In infancy, environment mostly controlled by parents. • As children age, their experiences extend more beyond the family’s influence.
Prenatal Development The Course of Prenatal Development • Germinal period: 2 weeks after conception • Embryonic period: 2 to 8 weeks after conception • Three layers: endodem, mesoderm, ectoderm • Umbilical cord connect to placenta • Organogenesis • Fetal period • From 2 months after conception to birth • Trimesters of pregnancy
Prenatal Development 0 - 4 weeks Less than 1/10th of inch long First trimester 8 weeks Less than 1 inch long 12 weeks 3 inches long, wt: 1 ounce 16 weeks 5.5 inches long, wt: 4 ounces Second trimester 20 weeks 10-12 inches, wt: ½ -1 lbs 24 weeks 11-14 inches, wt: 1-1½ lbs 28 weeks 14-17 inches, wt: 2½ -3 lbs Third trimester 32 weeks 16½ -18 inches, wt: 4-5 lbs 36-38 weeks 19 inches, wt: 6 lbs The three trimesters of prenatal development
Prenatal Development Prenatal Diagnostic Tests • Ultrasound Sonography • Chorionic VilliSampling: • Small sample of placenta taken. • Amniocentesis: • Samples amniotic fluid. • Maternal blood test
Prenatal Development Hazards to Prenatal Development • Teratogen: Agent causing birth defects. • Severity of damage affected by: • Dose • Genetic susceptibility • Time of exposure
Prenatal Development Hazards to Prenatal Development • Psychoactive drugs: • Caffeine • Alcohol and fetal alcohol syndrome (FAS) • Nicotine’s link to SIDS, ADHD, low birth weight • Effect of father’s smoking • Cocaine, marijuana, and heroin • Methamphetamine • Environmental hazards and pollutants. • Incompatible blood types of parents: • Rh-positive and Rh-negative • Maternal diseases like German measles, syphilis, HIV and AIDS • Other prenatal factors: • Nutrition, prenatal education and care • Maternal age and risks • Maternal emotional states and stress • Paternal factors • Environmental factors
Birth Prenatal Care • Prenatal programs: • Education • Medical care • Social and nutritional services • Low birth weight and infant mortality rates • View of pregancy vary among cultures and ethnic groups
Birth The Birth Process Stages of birth: • Stage 1-Uterine contractions • Stage 2-Baby’s head moves through birth canal • Stage 3-Afterbirth when placenta, umbilical cord, and other membranes are detached and expelled
Birth Strategies for Childbirth Home delivery, birthing center, or hospital? • 99% of all U.S. births occur in hospitals • Home births more common outside U.S. • Doula as caregiver • Role of midwife, nurse, and physician
Birth Methods of Delivery • Medication with analgesics (epidural block, oxytocics, etc.) • Possible effects of drugs on fetus • Natural childbirth • Prepared childbirth and the Lamaze method • Cesarean sections for breech babies, other risks and benefits Nonmedicated techniques: • Waterbirth more in European countries • Massage reduces pain and anxiety • Acupuncture is standard in China • Hypnosis has some positive effects • Music therapy reduces stress, manages pain
Birth Assessing the Newborn • Apgar Scale: Evaluates heart, reflexes, and color. • BrazeltonNeonatal Behavioral Assessment Scale (BNBAS): Sensitive index of neurological competence. • Neonatal Intensive Care Unit Network Neurobehavioral Scale (NNNS): Analysis of behavior, neurological and stress responses, and regulatory capacities.
Birth Low Birth Weight and Preterm • Low birth weight infants: • Weigh less than 5.5 lbs • Very low birth weight: • Less than 3 lbs • Preterm infants: • 35 or fewer weeks after conception (about 12% of U.S. births) • Kangaroo care: • Hold infant to promote skin-to-skin contact between infant and caregiver to promote- • Better breathing • Longer sleep periods • Weight gain • Less crying • Longer periods of alertness
Birth Massage Therapy • Leeds to 47% greater weight gain for preterm infants. • Other Benefits: • Labor pain • Asthma • ADHD • Arthritis • Autistic children