Chapter 2: Biological Beginnings

1. Chapter 2: Biological Beginnings

2. Natural Selection Natural Selection: an evolutionary process by which those individuals of a species that are best adapted are the ones that survive and reproduce Based on Darwin�s theory Survival characteristics are passed on in genes Can produce a gradual modification of the population over many generations Survival characteristics may change based on environmental conditions Adaptive Behavior: behavior that promotes an organism�s survival in the natural habitat �2009 The McGraw-Hill Companies, Inc. All rights reserved.

3. Evolutionary Psychology Evolutionary Psychology: emphasizes the importance of adaptation, reproduction, and �survival of the fittest� in shaping behavior Fit: the ability to bear offspring that survive long enough to bear offspring of their own Natural selection favors behaviors that increase reproductive success �2009 The McGraw-Hill Companies, Inc. All rights reserved. Evolutionary theorists took Darwin�s theory a step further by stressing the importance that an organism�s successful lies in how the number of offsprings it leaves behind, not how long it lives. If an organism dies before its peers, but leaves twice as many offsprings who survive to adulthood, the organism�s genes will become more common in the next generation as its descendants multiply and continue to pass on the organism�s genes.Evolutionary theorists took Darwin�s theory a step further by stressing the importance that an organism�s successful lies in how the number of offsprings it leaves behind, not how long it lives. If an organism dies before its peers, but leaves twice as many offsprings who survive to adulthood, the organism�s genes will become more common in the next generation as its descendants multiply and continue to pass on the organism�s genes.

4. Evolutionary Developmental Psychology Extended childhood period allows time to develop a large brain and learn complexity of human society Many evolved psychological mechanisms are domain-specific Information processing Evolved mechanisms are not always adaptive in contemporary society �2009 The McGraw-Hill Companies, Inc. All rights reserved.

5. Brain Sizes of Various Primates and Humans in Relation to Length of Juvenile Period �2009 The McGraw-Hill Companies, Inc. All rights reserved.

6. Evolution and Life-Span Development Why do humans live so long after reproduction? Perhaps older people improve the survival rate of babies Paul Baltes: benefits of evolutionary selection decrease with age Natural selection is tied to reproductive fitness Does not weed out harmful conditions that appear among older adults Increases our need for culture �2009 The McGraw-Hill Companies, Inc. All rights reserved.

7. Evaluating Evolutionary Psychology Evolutionary psychology approach is just one theory of many It has its limitations and weaknesses, and its critics Bidirectional view: environmental and biological conditions influence each other Evolution gives us bodily structures and biological potentialities, but it does not dictate behavior People create behavior in the context of culture �2009 The McGraw-Hill Companies, Inc. All rights reserved.

8. Genetic Foundations Human life begins as a single cell Nucleus of each cell contains chromosomes Chromosomes: thread-like structures made up of DNA DNA: a complex double-helix molecule that contains genetic information Genes: units of hereditary information in each chromosome Genes direct cells to reproduce themselves and to assemble proteins Proteins: building blocks of cells and regulators that direct the body�s processes �2009 The McGraw-Hill Companies, Inc. All rights reserved. Along the DNA strand are sections of genetic material containing genes, which are the basic units of hereditary information that also direct cells to pass genetic traits to offspring.Along the DNA strand are sections of genetic material containing genes, which are the basic units of hereditary information that also direct cells to pass genetic traits to offspring.

9. Genetic Foundations Each gene has its own unique location on a particular chromosome Human Genome Project attempted to map the human genome Genome: complete set of developmental instructions for the making of a human organism Results indicated that humans have about 20,000 to 22,000 genes Humans have far more proteins than they have genes Genetic expression is affected by the environment (light, day length, nutrition, behavior). Internal and external events can excite or inhibit gene expression. �2009 The McGraw-Hill Companies, Inc. All rights reserved.

10. Genes and Chromosomes All cells in the human body (except sperm and egg) have 46 chromosomes arranged in 23 pairs Mitosis: reproduction of cellshttp://www.youtube.com/watch?v=7hQ5xXJSmK4 Nucleus (including chromosomes) duplicate, and the cell divides Meiosis: cell division that forms sperm and eggs (gametes) http://www.pbs.org/wgbh/nova/miracle/program.html http://www.youtube.com/watch?v=D1_-mQS_FZ0 Each cell divides twice, forming four cells with 23 unpaired chromosomes �2009 The McGraw-Hill Companies, Inc. All rights reserved. A main difference between mitosis and meiosis is that mitosis occurs within cells that make up the body, and meiosis occurs within sex cells or gametes for the purpose of reproduction.A main difference between mitosis and meiosis is that mitosis occurs within cells that make up the body, and meiosis occurs within sex cells or gametes for the purpose of reproduction.

11. Genes and Chromosomes Child�s sex determined by 23rd pair of chromosomes XX = female, XY = male �2009 The McGraw-Hill Companies, Inc. All rights reserved.

12. Sources of Variability http://www.youtube.com/watch?v=IydcSuhWoW0&NR=1 Combining genes of both parents increases genetic variability Chromosomes in zygote are not exact copies Gene mutations can permanently alter segments of DNA Identical (monozygotic) twins develop from a single zygote that splits into two Fraternal (dizygotic) twins develop from separate eggs and sperm �2009 The McGraw-Hill Companies, Inc. All rights reserved. Genetic variability & cloning Proteins are essential for cells to function properly. A gene mutation disrupts the job of proteins by altering the genes� instructions for making proteins, sometimes causing the protein to malfunction. A mutation in a gene critical for development can cause a medical condition, otherwise known as a genetic disorder. Some gene mutations will cause the death of an embryo. Genetic variability & cloning Proteins are essential for cells to function properly. A gene mutation disrupts the job of proteins by altering the genes� instructions for making proteins, sometimes causing the protein to malfunction. A mutation in a gene critical for development can cause a medical condition, otherwise known as a genetic disorder. Some gene mutations will cause the death of an embryo.

13. Genetic Principles Genotype: a person�s genetic material Phenotype: observable characteristics A range of phenotypes can be expressed for each genotype �2009 The McGraw-Hill Companies, Inc. All rights reserved.

14. Genetic Principles Dominant-Recessive Genes Principle: a dominant gene always exerts its effects, overriding the potential influence of the recessive gene A recessive gene only exerts influence if both genes in a pair are recessive �2009 The McGraw-Hill Companies, Inc. All rights reserved.

15. Genetic Principles Sex-linked genes: X-linked inheritance occurs when a mutated gene is carried on the X chromosome More likely to affect males than females Females have a second X chromosome, which is likely to be unchanged Men do not have a second X chromosome to counteract the effect Females are still carriers Examples: hemophilia and fragile-X syndrome �2009 The McGraw-Hill Companies, Inc. All rights reserved.

16. Chromosomal Abnormalities �2009 The McGraw-Hill Companies, Inc. All rights reserved. Chromosome abnormalities usually involve the sperm and ovum lacking a normal set of 23 chromosomes Down syndrome: caused by the presence of an extra copy of chromosome 21 Sex-linked abnormalities involve the presence of an extra X or Y chromosome (or the absence of one) Klinefelter syndrome: males born with XXY instead of XY Fragile X syndrome: occurs more often in males than females; X chromosome constricted or breaks off Turner syndrome: females born with XO rather than XX, sometimes causing infertility XYY syndrome: males with extra Y chromosome Fragile X: It is second only to Down's syndrome in genetic or chromosomal causes of mental retardation. It affects 1 in 2,000 males. and 1 in 4,000 females. By adulthood, a long and narrow face is developed. The ears protrude. The jaw is long. The testicles, huge.It is possible to inherit or transmit the chromosomal abnormality without exhibiting symptoms oneself. If this happens, your children will still be at risk. Chromosome abnormalities usually involve the sperm and ovum lacking a normal set of 23 chromosomes Down syndrome: caused by the presence of an extra copy of chromosome 21 Sex-linked abnormalities involve the presence of an extra X or Y chromosome (or the absence of one) Klinefelter syndrome: males born with XXY instead of XY Fragile X syndrome: occurs more often in males than females; X chromosome constricted or breaks off Turner syndrome: females born with XO rather than XX, sometimes causing infertility XYY syndrome: males with extra Y chromosome Fragile X: It is second only to Down's syndrome in genetic or chromosomal causes of mental retardation. It affects 1 in 2,000 males. and 1 in 4,000 females. By adulthood, a long and narrow face is developed. The ears protrude. The jaw is long. The testicles, huge.

17. Chromosomal Abnormalities �2008 The McGraw-Hill Companies, Inc. All rights reserved.

18. Gene-Linked Abnormalities �2009 The McGraw-Hill Companies, Inc. All rights reserved. Gene-linked abnormalities are caused by harmful genes PKU: inability to metabolize phenylalanine fe-n?l-a-l?-nen (fennel-a-la-line) Spina bifida: birth defect in which the backbone and spinal canal do not sufficiently close before birth and can result in the spinal cord to protrude out of the baby�s as a sac. It can cause partial or complete paralysis of the legs, lack of sensation, loss of bowel control. Sickle-cell anemia: impaired red blood cells die more quickly; more often found in African Americans Gene-linked abnormalities are caused by harmful genes PKU: inability to metabolize phenylalanine fe-n?l-a-l?-nen (fennel-a-la-line) Spina bifida: birth defect in which the backbone and spinal canal do not sufficiently close before birth and can result in the spinal cord to protrude out of the baby�s as a sac. It can cause partial or complete paralysis of the legs, lack of sensation, loss of bowel control. Sickle-cell anemia: impaired red blood cells die more quickly; more often found in African Americans

19. Dealing with Genetic Abnormalities Every individual carries DNA variations, but most do not display a disorder Today, many genetic diseases can be detected prior to and immediately after birth However, knowledge of genetic flaws leads to difficult choices about how to manage such information Genetic counselors help people make reproductive decisions �2009 The McGraw-Hill Companies, Inc. All rights reserved.

20. Prenatal Diagnostic Tests Chorionic Villus Sampling: small sample of placenta is removed to detect genetic and chromosomal abnormalities Amniocentesis: samples amniotic fluid to test for chromosomal or metabolic disorders Maternal Blood Screening: identifies pregnancies with elevated risk for certain birth defects �2009 The McGraw-Hill Companies, Inc. All rights reserved. Chorionic villus sampling is done when either parent has a family history of a genetic disorder, such as, Tay-Sachs, sickle-cell anemia, cystic fibrosis, or hemophilia. It is done for women over age 35 to detect down syndrome.Chorionic villus sampling is done when either parent has a family history of a genetic disorder, such as, Tay-Sachs, sickle-cell anemia, cystic fibrosis, or hemophilia. It is done for women over age 35 to detect down syndrome.

21. Prenatal Diagnostic Tests Fetal MRI: magnetic resonance imaging designed to diagnose fetal malformations Ultrasound Sonography: high-frequency sound waves used to create a visual representation of fetus�s inner structures �2008 The McGraw-Hill Companies, Inc. All rights reserved.

22. Infertility and Reproductive Technology Infertility: the inability to conceive a child after 12 months of attempting Success depends on woman�s age Increases risk of multiple births Higher risk of life-threatening problems Health risks to mother Possible psychological effects on children �2009 The McGraw-Hill Companies, Inc. All rights reserved.

23. Infertility and Reproductive Technology �2009 The McGraw-Hill Companies, Inc. All rights reserved.

24. Infertility and Reproductive Technology �2009 The McGraw-Hill Companies, Inc. All rights reserved.

25. Infertility and Reproductive Technology Adoption: an alternative to infertility treatment Children adopted early in life fare better than children adopted later Somewhat more likely to experience psychological and school-related problems than non-adopted children No differences in antisocial behavior or self-esteem Vast majority of adopted children adjust effectively, and most parents are satisfied with their decision to adopt �2009 The McGraw-Hill Companies, Inc. All rights reserved.

26. Behavior Genetics: seeks to discover the influence of heredity and environment on individual differences in human traits and development Twin studies: compare identical (monozygotic) twins with fraternal (dizygotic) twins Adoption studies: compare the characteristics of adopted children with their adoptive parents and their biological parents May also compare adopted and biological siblings http://www.youtube.com/watch?v=Trc2dJgeyvc&NR=1 �2009 The McGraw-Hill Companies, Inc. All rights reserved.

27. Heredity � Environment Correlations: individuals� genes may influence the types of environments to which they are exposed �2009 The McGraw-Hill Companies, Inc. All rights reserved.

28. Behavioral Genetics Shared environmental experiences: siblings� common experiences Non-shared environmental experiences: a child�s unique experiences, both within and outside the family Shared environment accounts for little of the variation in children�s personality or interest Heredity influences the non-shared environments through heredity�environment correlations �2009 The McGraw-Hill Companies, Inc. All rights reserved.

29. The Epigenetic View Epigenetic view: development is an ongoing, bi-directional interchange between heredity and environment Heredity and environment operate together �2009 The McGraw-Hill Companies, Inc. All rights reserved.

30. Conclusions The relative contributions of heredity and environment are not additive Complex behaviors have some genetic loading that gives people a propensity for a particular developmental path Our environment is complex, and the interaction of heredity and environment is extensive Much needs to be learned about specific ways in which environment and genetics interact to influence development �2009 The McGraw-Hill Companies, Inc. All rights reserved.

31. CHAPTER 3: PRENATAL DEVELOPMENT AND BIRTH �2009 The McGraw-Hill Companies, Inc. All rights reserved.

32. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Conception occurs when a single sperm cell from the male unites with an ovum (egg) Prenatal development is divided into 3 periods and lasts approximately 266-280 days: Germinal period: first 2 weeks after conception, zygote created Embryonic period: occurs from 2 to 8 weeks after conception Fetal period: begins 2 months after conception and lasts until birth

33. Prenatal Development Germinal Period: period of development that takes place the first two weeks after conception Rapid cell division by the zygote Blastocyst: group of cells after about 1 week http://www.youtube.com/watch?v=UgT5rUQ9EmQ&feature=related �2009 The McGraw-Hill Companies, Inc. All rights reserved.

34. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved.

35. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Embryonic Period: development from 2 to 8 weeks after conception Begins when blastocyst attaches to uterine wall Mass of cells is now called an embryo Three layers of cells: endoderm, mesoderm, and ectoderm Amnion: a bag that contains a clear fluid (amniotic fluid) in which the embryo floats Umbilical Cord: connects the baby to the placenta Placenta: group of tissues containing mother and baby�s intertwined blood vessels Organogenesis: process of organ formation during the first two months of prenatal development

36. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved.

37. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Fetal Period: development from two months after conception to birth Rapid growth and change Viability: the age at which a fetus has a chance of surviving outside the womb Currently 24 weeks; changes with advances in medical technology

38. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. The Brain: Babies have approximately 100 billion neurons (nerve cells) at birth Architecture of the brain takes shape during the first two trimesters Increases in connectivity and functioning occur from the third trimester to 2 years of age Neural tube develops 18 to 24 days after conception Anencephaly: the neural tube fails to close & results in no forebrain. Spina bifida Ultrasound, MRI can screen for neural tube defects. Women taking meds for epilepsy and insulin for diabetes have a higher risk of having a child with a neural tube defect. It is recommended that women of child bearing age consume folic acid since most pregnant women don�t know they�re pregnant until the 18-24 days of detection has passed.Ultrasound, MRI can screen for neural tube defects. Women taking meds for epilepsy and insulin for diabetes have a higher risk of having a child with a neural tube defect. It is recommended that women of child bearing age consume folic acid since most pregnant women don�t know they�re pregnant until the 18-24 days of detection has passed.

39. Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. The Brain: Neurogenesis: the generation of new neurons Begins at fifth prenatal week and continues throughout prenatal period Neuronal migration: cells move outward from their point of origin to their appropriate locations Occurs approximately 6 to 24 weeks after conception

40. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Teratogen: any agent that can cause a birth defect or negatively alter cognitive and behavioral outcomes Drugs (prescription, nonprescription) Incompatible blood types Environmental pollutants Infectious diseases Nutritional deficiencies Maternal stress Advanced age of parent

41. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Severity of damage to the unborn depends on: Dose Genetic susceptibility Time of exposure Critical period: a fixed time period during which certain experiences or events can have a long-lasting effect on development

42. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved.

43. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Prescription and Non-prescription Drugs: Many women are given drugs while pregnant Some are safe; some can cause devastating birth defects Known prescription teratogens include antibiotics, some antidepressants, some hormones, and Accutane Non-prescription teratogens include aspirin and diet pills

44. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Psychoactive Drugs: drugs that act on the nervous system to alter states of consciousness, modify perceptions, and change moods Includes caffeine, alcohol, nicotine Caffeine: small risk of miscarriage and low birth weight for those consuming more than 150 mg. daily Increased risk of fetal death for those consuming more than 300 mg. daily FDA recommends not consuming caffeine or consuming it sparingly

45. Hazards to Prenatal Development Alcohol: Fetal alcohol syndrome: abnormalities in newborn due to mother�s heavy use of alcohol in pregnancy Facial deformities Defective limbs, face, heart #1 cause of mental retardation in US Even light to moderate drinking during pregnancy has been associated with negative effects on the fetus FDA recommends no alcohol consumption during pregnancy �2009 The McGraw-Hill Companies, Inc. All rights reserved.

46. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Nicotine: Maternal smoking can negatively influence prenatal development, birth, and postnatal development Associated with: Preterm births and low birth weight Fetal and neonatal death Respiratory problems SIDS (sudden infant death syndrome) ADHD (attention deficit hyperactivity disorder)

47. Hazards to Prenatal Development �2009 The McGraw-Hill Companies, Inc. All rights reserved. Illegal drugs that harm during pregnancy: Cocaine Methamphetamine Marijuana Heroin Incompatible blood types (Rh factor) Can cause mother�s immune system to produce antibodies that will attack the fetus

48. Hazards to Prenatal Development Environmental hazards: Radiation (mom or dad) Environmental pollutants and toxic wastes Maternal Diseases: Sexually transmitted diseases (syphilis, genital herpes, AIDS) Rubella Diabetes �2009 The McGraw-Hill Companies, Inc. All rights reserved.

49. Hazards to Prenatal Development Maternal factors: Maternal diet and nutrition Maternal age Emotional states and stress Paternal factors: Exposure to teratogens Paternal age �2009 The McGraw-Hill Companies, Inc. All rights reserved. http://images.google.com/imgres?imgurl=http://www.whale.to/a/image/gulf01.jpg&imgrefurl=http://www.whale.to/a/gulf32.html&usg=__1L1MnJ-HJP8-9MJTeQ_SoI3Y-WI=&h=261&w=259&sz=19&hl=en&start=6&um=1&tbnid=jRxcnxHWbtivjM:&tbnh=112&tbnw=111&prev=/images%3Fq%3Dbirth%2Bdefects%2Bfrom%2Bradiation%26hl%3Den%26rls%3Dcom.microsoft:en-us:IE-SearchBox%26rlz%3D1I7DVXA%26sa%3DN%26um%3D1

50. �2009 The McGraw-Hill Companies, Inc. All rights reserved.

51. Transition from Fetus to Newborn �2009 The McGraw-Hill Companies, Inc. All rights reserved. Birth process is stressful for baby Anoxia: a condition in which the fetus has an insufficient supply of oxygen Baby secretes adrenaline and noradrenalin, hormones that are secreted in stressful circumstances Measuring neonatal health and responsiveness: Apgar Scale: assessed at 1 minute and 5 minutes after birth evaluates heart rate, body color, muscle tone, respiratory effort, and reflex irritability 10 is highest, 3 or below indicates an emergency

52. Transition from Fetus to Newborn �2009 The McGraw-Hill Companies, Inc. All rights reserved.

53. Preterm and Low Birth Weight Infants �2009 The McGraw-Hill Companies, Inc. All rights reserved. Preterm and Small-for-Date Infants: Low birth weight infants weigh less than 5 � lbs. at birth Preterm infants are those born three weeks or more before full term Small-for-date infants are those whose birth weight is below normal when the length of the pregnancy is considered Rate of preterm births has increased Number of births to mothers 35 years and older Rates of multiple births Substance abuse Stress Causes of low birth weight: Poor health and nutrition Cigarette smoking Adolescent births Use of drugs Multiple births/reproductive technology Improved technology and prenatal care

54. Preterm and Low Birth Weight Infants �2009 The McGraw-Hill Companies, Inc. All rights reserved. Possible consequences: Language development delays Lower IQ scores Brain injury Lung or liver diseases More behavioral problems Learning disabilities ADHD Breathing problems (asthma) Approximately 50% are enrolled in special education programs

55. Preterm and Low Birth Weight Infants �2009 The McGraw-Hill Companies, Inc. All rights reserved. Some effects can be improved with: Early speech therapy Intensive enrichment programs Kangaroo care, massage therapy, and breast feeding Kangaroo Care: treatment for preterm infants that involves skin to skin contact Massage: research conducted by Tiffany Field

56. The Postpartum Period �2009 The McGraw-Hill Companies, Inc. All rights reserved. Postpartum period lasts about six weeks or until the mother�s body has completed its adjustment and has returned to a nearly pre-pregnant state Physical Adjustments: Fatigue Hormone changes Return to menstruation Involution: process by which the uterus returns to its pre-pregnant size 5�6 weeks after birth Weight loss/return to exercise

57. The Postpartum Period �2009 The McGraw-Hill Companies, Inc. All rights reserved. Emotional and Psychological Adjustments: Emotional fluctuations are common �Baby Blues� experienced by 70% of new mothers in U.S. Typically resolves in 1�2 weeks, without treatment Postpartum Depression Excessive sadness, anxiety, and despair that lasts for two weeks or longer Experienced by 10% of new mothers Hormonal changes after birth may play a role May affect mother�child interactions

58. �2009 The McGraw-Hill Companies, Inc. All rights reserved.

59. Bonding �2009 The McGraw-Hill Companies, Inc. All rights reserved. Bonding: the formation of a connection, especially a physical bond, between parents and the newborn in the period shortly after birth Isolation of premature babies and use of drugs in birth process may harm bonding process Bonding may be a critical component in the child�s development However, close contact in the first few days may not be necessary Most hospitals offer a rooming-in arrangement while mother and child are in the hospital