Biological Beginnings

Biological Beginnings The Evolutionary Perspective

Genetic Foundations of Development

Heredity and Environment interaction: The Nature-Nurture Debate Prenatal Development

Birth

The Evolutionary PerspectiveNatural 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 PerspectiveNatural 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 DevelopmentBenefits of evolutionary selection decrease with age.As adults weaken biologically, culture-based needs increase.The Evolutionary Perspective

Genetic Foundations of DevelopmentDNA: Deoxyribonucleic AcidChromosomes: Thread-like structuresGenes: Units of hereditary informationHuman Genome Project: 30,000 genes in humans.Genetic Foundations

Cells, Chromosomes, Genes, and DNA

Genetic Foundations

Nucleus (center of cell) contains chromosomes and genesChromosomes are threadlike structures composed of DNA moleculesGene: a segment of DNA (spiraled double chain) containing the hereditary code

The Collaborative GeneMitosis: 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 twinsMutated geneGenotype-All of ones genetic makeupPhenotype-Observable characteristics

Genetic Foundations

Genetic PrinciplesSex-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 SyndromeKlinefelter 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

Genetic FoundationsGene-Linked AbnormalitiesPKU: phenylketonuriaSickle-cell anemiaCystic fibrosisDiabetesHemophilia 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 CorrelationsIn infancy, environment mostly controlled by parents.As children age, their experiences extend more beyond the familys influence.

Heredity, Environment, and Individual Differences

The Course of Prenatal DevelopmentGerminal period: 2 weeks after conceptionEmbryonic period: 2 to 8 weeks after conception Three layers: endodem, mesoderm, ectodermUmbilical cord connect to placentaOrganogenesis Fetal periodFrom 2 months after conception to birthTrimesters of pregnancy Prenatal Development

Second trimesterThird trimesterFirst trimester

0 - 4 weeks

Less than 1 inch long12 weeks32 weeks 8 weeksLess than 1/10th of inch long16 -18 inches, wt: 4-5 lbs3 inches long, wt: 1 ounce16 weeks5.5 inches long, wt: 4 ounces20 weeks10-12 inches, wt: -1 lbs24 weeks11-14 inches, wt: 1-1 lbs36-38 weeks28 weeks19 inches, wt: 6 lbs14-17 inches, wt: 2 -3 lbsThe three trimesters of prenatal developmentPrenatal Development

Prenatal Diagnostic Tests

Ultrasound SonographyChorionic Villi Sampling: Small sample of placenta taken.Amniocentesis: Samples amniotic fluid.Maternal blood testPrenatal Development

Hazards to Prenatal DevelopmentTeratogen: Agent causing birth defects.

Severity of damage affected by:Dose Genetic susceptibilityTime of exposurePrenatal Development

Teratogen

Types of TeratogensAdverse EffectsPrescription Drugs: ThalidomideArm and leg malformationWarfarinMental retardation,microcephaly(abnormally small head)TrimethadioneDevelopmental delay, V-shapedeyebrows, cleft lip and/or palateTetracyclineTooth malformationsSubstances of Abuse:HeroinFetal/newborn addiction, slower growthCocaineGrowth retardation; possible long-termbehavioral effectsSolventsMicrocephalySocial Drugs:AlcoholFetal alcohol syndrome, fetal alcoholeffectsSmokingSpontaneous abortion, growthretardationCaffeineFew human studies. high doses induceabnormalities in animals.Disease:RubellaCataracts, deafness, heart defectsHerpes SimplexMicrocephaly, microophthalmia(abnormally small or absent eyes,associated with blindness)

Prenatal Development

Hazards to Prenatal DevelopmentPsychoactive drugs:CaffeineAlcohol and fetal alcohol syndrome (FAS)Nicotines link to SIDS, ADHD, low birth weightEffect of fathers smokingCocaine, marijuana, and heroinMethamphetamine Environmental hazards and pollutants.Incompatible blood types of parents:Rh-positive and Rh-negativeMaternal diseases like German measles, syphilis, HIV and AIDSOther prenatal factors:Nutrition, prenatal education and careMaternal age and risksMaternal emotional states and stressPaternal factorsEnvironmental factors

Prenatal Development

Prenatal CarePrenatal programs:EducationMedical careSocial and nutritional servicesLow birth weight and infant mortality ratesView of pregancy vary among cultures and ethnic groupsBirth

The Birth ProcessStages of birth:Stage 1-Uterine contractionsStage 2-Babys head moves through birth canalStage 3-Afterbirth when placenta, umbilical cord, and other membranes are detached and expelledBirth

Strategies for ChildbirthHome delivery, birthing center, or hospital?99% of all U.S. births occur in hospitalsHome births more common outside U.S.Doula as caregiverRole of midwife, nurse, and physician

Birth

Methods of DeliveryMedication with analgesics (epidural block, oxytocics, etc.)Possible effects of drugs on fetusNatural childbirthPrepared childbirth and the Lamaze methodCesarean sections for breech babies, other risks and benefitsNonmedicated techniques:Waterbirth more in European countriesMassage reduces pain and anxietyAcupuncture is standard in ChinaHypnosis has some positive effectsMusic therapy reduces stress, manages pain

Birth

Assessing the NewbornApgar Scale: Evaluates heart, reflexes, and color.Brazelton Neonatal 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 PretermLow birth weight infants:Weigh less than 5.5 lbsVery low birth weight: Less than 3 lbsPreterm 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 breathingLonger sleep periodsWeight gainLess cryingLonger periods of alertness

Birth

Massage Therapy Leeds to 47% greater weight gain for preterm infants. Other Benefits: Labor pain Asthma ADHD Arthritis Autistic childrenBirth