Lifespan psychology lecture chapter 1, module 1.2


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Lifespan psychology lecture chapter 1, module 1.2

  1. 1. Chapter 1: Introduction Module 1.2 The Start of Life
  2. 2. The Beginning of Life <ul><ul><li>Gametes (male and female reproductive cells) from male (sperm) and female (ovum) join, these fused gametes create a zygote </li></ul></ul><ul><li>In humans, the male sex cell (sperm) and the female sex cell (the ovum) provide the developing baby with 23 chromosomes each. </li></ul><ul><li>Each Zygote carries 46 chromosomes, all of the genetic instructions to create a human being </li></ul>
  3. 3. Period of the Zygote
  4. 4. Multiple Births <ul><li>Multiple births: </li></ul><ul><li>Monozygotic (one zygote) Identical Twins </li></ul><ul><li>Dizygotic (two zygotes) Fraternal Twins </li></ul><ul><li>What causes multiple births? </li></ul><ul><ul><li>Fertility drugs, age of mother </li></ul></ul><ul><ul><li>Racial, ethnic, and national differences </li></ul></ul>
  5. 5. The Code of Life <ul><li>Genes-basic unit of genetic information </li></ul><ul><ul><li>DNA </li></ul></ul><ul><li>Chromosomes </li></ul><ul><ul><li>Rod-shaped DNA portions in 23 pairs </li></ul></ul><ul><ul><li>Contain genetic blueprint for individuals </li></ul></ul><ul><ul><li>Replicate through mitosis </li></ul></ul>
  6. 6. Mixing and Matching of Genes <ul><li>Basics of genetics: </li></ul><ul><ul><li>DOMINANT TRAITS – expressed traits </li></ul></ul><ul><ul><li>RECESSIVE TRAITS – not expressed, but still there </li></ul></ul>
  7. 7. Genotype and Phenotype <ul><li>A genotype is the underlying combination of genetic materials present in an organism, but invisible; a phenotype is the visible trait, the expression of the genotype. </li></ul><ul><li>Genotype can be: </li></ul><ul><ul><li>Homozygous - allele contains similar genes from each parent </li></ul></ul><ul><ul><li>Heterozygous - allele contains different forms of genes from parents </li></ul></ul>
  8. 8. Cracking the Genetic Code <ul><li>The Human Genome </li></ul><ul><li>National Human Genome Research Institute </li></ul><ul><li>( ) </li></ul><ul><li>The field of behavioral genetics , a combination of psychology and genetics, studies the effects of genetics on behavior. </li></ul>
  9. 9. When Development Deviates… <ul><li>Causes: </li></ul><ul><ul><li>Genetics </li></ul></ul><ul><ul><li>Spontaneous mutation </li></ul></ul><ul><ul><li>Environmental insult </li></ul></ul>
  10. 10. When Development Deviates… <ul><li>Consequences: </li></ul><ul><ul><li>Down Syndrome - extra chromosome on 21 st pair; 1 in 500/higher in older mothers </li></ul></ul><ul><ul><li>Fragile X Syndrome -Fragile X syndrome is the most common form of inherited mental retardation in males and a significant cause in females. The inheritance is different from common dominant or recessive inheritance patterns. A fragile area on the X chromosome (called FMR1) has repeats in the genetic code. The more repeats, the more likely there is to be a problem. Boys and girls can both be affected, but because boys have only one X chromosome, a single fragile X is likely to affect them more severely. </li></ul></ul><ul><ul><li>Sickle-cell Anemia - Sickle cell anemia is an inherited disease in which the red blood cells, normally disc-shaped, become crescent shaped. As a result, they function abnormally and cause small blood clots . These clots give rise to recurrent painful episodes called &quot;sickle cell pain crises.&quot; Sickle cell anemia is inherited as an autosomal recessive trait , which means it occurs in someone who has inherited hemoglobin S from both parents. Sickle cell disease is much more common in certain ethnic groups, affecting approximately one out of every 500 African Americans. </li></ul></ul>
  11. 11. When Development Deviates… <ul><ul><li>Tay-Sachs Disease - Tay-Sachs disease is a familial disorder (it affects more than 1 member of a family) that results in early death. It is found predominantly in Ashkenazi Jewish families. An enzyme deficiency that interferes with metabolism of crucial nerve tissue chemicals. Tay-Sachs disease is inherited as a recessive gene, and 1 in 25 members of the Ashkenazi Jewish population carries the gene. </li></ul></ul><ul><ul><li>Klinefelter’s Syndrome - Klinefelter syndrome is a chromosome disorder in males. People with this condition are born with at least one extra X chromosome. Klinefelter syndrome is one of the most common chromosomal abnormalities . About one in every 500 to 800 males is born with this disorder. Approximately 3% of the infertile male population have Klinefelter syndrome. </li></ul></ul>
  12. 12. Prenatal Testing <ul><li>Potential tests for deviation in development: </li></ul><ul><li>Amniocentesis </li></ul><ul><li>CVS </li></ul><ul><li>Embryoscopy </li></ul><ul><li>FBS </li></ul><ul><li>Sonoembryology </li></ul><ul><li>Sonogram </li></ul><ul><li>Ultrasound sonography </li></ul><ul><li>Important to remember : Majority of babies born healthy!! </li></ul>
  13. 13. Nature and Nurture <ul><li>Virtually all traits, characteristics, and behaviors are joint result of the combination and interaction of nature and nurture. </li></ul><ul><li>Genetic and environmental factors work in tandem, affecting and being affected by the other, creating the unique individual that each of us is and will become </li></ul>
  14. 14. Nature (Genetics) <ul><li>Genetic influences have been identified in physical characteristics, intelligence, personality traits and behaviors, and psychological disorders. </li></ul><ul><li>There is some speculation that entire cultures may be predisposed genetically toward certain types of philosophical viewpoints and attitudes. </li></ul>
  15. 15. Nurture (environment) includes… <ul><li>Social/Culture </li></ul><ul><li>Geographical location </li></ul><ul><li>Family </li></ul><ul><li>Media </li></ul><ul><li>Peers </li></ul><ul><li>World events </li></ul><ul><li>And everything else! </li></ul>
  16. 16. Nature and Nurture - Physical Similarities <ul><li>Family resemblances: </li></ul><ul><li>More genetically similarity  more likely to share physical characteristics </li></ul><ul><ul><li>Monozygotic twins: best example of relationship between genetic similarity and shared physical characteristics </li></ul></ul>
  17. 17. Nature and Nurture - Intelligence <ul><li>Relative contributions of nature and nurture highly researched </li></ul><ul><li>Closer genetic link = greater correspondence of overall IQ scores </li></ul><ul><ul><li>Intelligence (as measured) by IQ score) is central human characteristic that differentiates humans from other species </li></ul></ul><ul><ul><li>IQ scores of identical twins become increasingly similar over time </li></ul></ul><ul><ul><li>This does not discount importance of environmental influence on intelligence </li></ul></ul>
  18. 18. Nature and Nurture - Personality <ul><li>Research evidence indicates some of most basic personality traits have genetic roots </li></ul><ul><li>Two of “Big Five” personality traits linked to genetic factors: </li></ul><ul><ul><li>Neuroticism </li></ul></ul><ul><ul><li>Extroversion </li></ul></ul>
  19. 19. Nature and Nurture - Personality Research Suggests… <ul><li>Examination reveals specific gene very influential in determining risk-taking (novelty-seeking gene affects production of dopamine) </li></ul><ul><li>Twins reared apart studies: certain traits reflected contribution of genetics considerably more than others </li></ul><ul><li>Some less basic personality trait links: political attitudes, religious interests and values, attitudes toward human sexuality </li></ul>
  20. 20. Fundamental Principle <ul><li>Relative influence of nature and nurture: </li></ul><ul><ul><li>Role of genetics is often to produce tendency toward future course of development </li></ul></ul><ul><ul><li>Role of environment affects when and whether a certain behavioral characteristic will actually be displayed </li></ul></ul>
  21. 21. Theory about Nature/Nurture: <ul><li>Sandra Scarr suggests three ways child’s genetic predisposition may influence his or her environment: </li></ul><ul><ul><li>Active </li></ul></ul><ul><ul><li>Passive </li></ul></ul><ul><ul><li>Evocative </li></ul></ul>
  22. 22. Let’s have a baby! Fertilization <ul><li>Moment of conception: </li></ul><ul><ul><li>Joining of sperm and ovum = zygote </li></ul></ul><ul><ul><li>Fertilization joins the sperm and ovum to start the journey of prenatal development. </li></ul></ul>
  23. 23. Stages of Prenatal Development <ul><li>The prenatal period consists of three stages: germinal, embryonic, and fetal. </li></ul><ul><ul><li>Germinal </li></ul></ul><ul><ul><li>Embryonic </li></ul></ul><ul><ul><li>Fetal </li></ul></ul>
  24. 24. Germinal Stage <ul><li>Fertilization  two weeks: </li></ul><ul><ul><li>Shortest stage </li></ul></ul><ul><ul><li>Fertilized egg now called blastocyst </li></ul></ul><ul><ul><li>Travels to and implants in uterus </li></ul></ul><ul><ul><li>Characterized by methodical cell division </li></ul></ul><ul><ul><li>With division comes cell specialization </li></ul></ul>
  25. 25. Embryonic Stage <ul><li>2 weeks  8 weeks: </li></ul><ul><ul><li>Organism firmly secures to uterus and called an embryo </li></ul></ul><ul><ul><li>Development of major organs and basic anatomy </li></ul></ul><ul><li>Three distinct layers that ultimately form different set of structures: </li></ul><ul><ul><li>Ectoderm - form skin, hair, teeth, sense organs, brain, spinal cord </li></ul></ul><ul><ul><li>Endoderm - inner layer forms digestive system, liver, pancreas, respiratory system </li></ul></ul><ul><ul><li>Mesoderm - sandwiched between other two and forms muscles, bones, blood, circulatory system </li></ul></ul>
  26. 26. Embryonic Stage (cont.) <ul><ul><li>At end of embryonic stage: </li></ul></ul><ul><ul><ul><li>One inch long, gills and tail-like structure; rudimentary eyes, lips, teeth, stubby bulges that become arms and legs; head grows rapidly and begins to represent significant portion of body (50% of total length); rapid growth of nerve cells (100,000 neurons produced EVERY MINUTE); nervous system begins to function at 3 weeks and at 5 weeks weak brain waves detected </li></ul></ul></ul>
  27. 27. Fetal Stage <ul><li>8 weeks  Birth: </li></ul><ul><ul><li>Formally starts when differentiation of major organs has occurred </li></ul></ul><ul><ul><li>Organism now called fetus </li></ul></ul><ul><ul><li>Characterized by rapid development </li></ul></ul><ul><ul><ul><li>Organs become more differentiated and begin working </li></ul></ul></ul><ul><ul><ul><li>Interconnections between body parents become more complex and integrated </li></ul></ul></ul><ul><ul><ul><li>Brain becomes more sophisticated </li></ul></ul></ul>
  28. 28. Fetal Stage (cont.) <ul><li>Rapid development </li></ul><ul><ul><li>Increases in length 20 times and proportions change dramatically </li></ul></ul><ul><ul><li>See Figure 2.13 </li></ul></ul><ul><ul><li>At 4 months = 4 ounces; at 7 months = 3 pounds; at birth = 7 pounds </li></ul></ul><ul><li>Brain waves indicate several different stages of sleep and wakefulness; hear and feel vibrations </li></ul><ul><li>Hormones released between 8 and 24 weeks that lead to gender differentiation </li></ul><ul><li>No two fetuses are alike; broad similarities in sequence of development </li></ul><ul><ul><li>Differences due to genetics and the environment of womb </li></ul></ul>
  29. 29. Pregnancy Problems <ul><li>Infertility - 15% of couples; inability to conceive after 12 to 18 months </li></ul><ul><ul><li>Maternal infertility influenced by age; hormone imbalance, damaged fallopian tubes or uterus, stress, abuse of alcohol or drugs </li></ul></ul><ul><ul><li>Paternal infertility influenced by illicit drugs, tobacco, STDs </li></ul></ul><ul><ul><ul><li>Artificial insemination; IVF; GIFT; ZIFT; ethical issues </li></ul></ul></ul><ul><li>Miscarriage - spontaneous abortion; 15-20% pregnancies ends in miscarriages; many times genetic abnormality </li></ul><ul><li>Abortion - voluntary termination pregnancy; aftereffects; may contribute to increase in future pregnancies </li></ul>
  30. 30. Threats to Development <ul><li>The prenatal environment significantly influences the development of the baby. The diet, age, prenatal support, and illnesses of mothers can affect their babies’ health and growth </li></ul><ul><li>Prenatal environment </li></ul><ul><ul><li>Teratogen - environmental agent or other factor that produces a birth defect </li></ul></ul><ul><ul><li>Timing and quantity of exposure crucial; sensitivity to specific teratogen related to racial and cultural background; different organ systems vulnerable at different times during development (e.g., brain development) </li></ul></ul>
  31. 31. Teratogen Sensitivity Timeline
  32. 32. Parent’s Prenatal Influence <ul><li>Mothers’ use of drugs, alcohol, tobacco, and caffeine can adversely affect the health and development of the unborn child. The behavior of fathers and others can also affect the child. </li></ul>
  33. 33. Mother’s Prenatal Influence <ul><ul><li>Diet - Mother’s diet supports development of fetus; global concern; postnatal enrichment of prenatal undernourishment can sometimes overcome some of effects </li></ul></ul><ul><ul><li>Age - More older women giving birth due to societal transformations; mothers over 30 at greater risk for variety pregnancy and birth complications; condition of ovum; Down syndrome; adolescent mothers more likely to deliver premature babies </li></ul></ul><ul><ul><li>Prenatal support - Young mothers often face adverse social and economic factors which can affect infant health; social support and poverty contribute to lack of resources for prenatal support </li></ul></ul>
  34. 34. Mother’s Prenatal Influence (cont.) <ul><ul><li>Health - Rubella prior to 11 th week of pregnancy; mumps increase miscarriage risk; syphilis directly transmitted to fetus; STD (gonorrhea) transmitted; AIDS (AZT during pregnancy reduces transmission to around 5%) </li></ul></ul><ul><ul><li>Drug use - Poses serious risk to unborn child (legal, illegal, OTC drugs), Thalidomide, DES: diethylstilbestrol to prevent miscarriage later raised daughter risk of vaginal/cervical cancer, Birth control: fetal damage, Illicit drugs: marijuana, cocaine (crack babies) </li></ul></ul><ul><ul><li>Alcohol use: even small amounts can disrupt development of fetus; FAS; FAE </li></ul></ul><ul><ul><li>Tobacco use - Reduces oxygen content and increases carbon monoxide in mother’s blood  fetus respiration slows and heart beat increases and increases miscarriage risk (100,000 miscarriages caused by smoking); low birth weight; shorter; 50% more likely to have mentally retarded or disruptive child </li></ul></ul>
  35. 35. Father’s Prenatal Influence <ul><li>Relatively little research </li></ul><ul><li>Tobacco use - secondhand smoke may influence mother’s health </li></ul><ul><li>Drug & Alcohol use - alcohol and drug use may impair sperm leading to chromosomal damage </li></ul><ul><li>Treatment of mother - physical and emotional abuse can cause maternal stress </li></ul>
  36. 36. Becoming an Informed Consumer Optimizing the Prenatal Environment <ul><li>Avoid X-rays and birth control pills; get rubella vaccination </li></ul><ul><li>Eat well and take prenatal vitamins </li></ul><ul><li>Avoid alcohol use and other drugs </li></ul><ul><li>Monitor caffeine intake. </li></ul><ul><li>Avoid smoking and exposure to secondhand smoke </li></ul><ul><li>Exercise regularly </li></ul>