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1 (c) 2012 The McGraw-Hill Companies, Inc. Chapter 2 Biological Beginnings PowerPoints developed by Nicholas Greco IV, College of Lake County, Grayslake, IL

2 (c) 2012 The McGraw-Hill Companies, Inc. The Evolutionary Perspective  Natural Selection and Adaptive Behavior natural selection -- the evolutionary process by which those individuals of a species that are best adapted are the ones that survive and reproduce survivors are better adapted to their world than are the non-survivors (Darwin, 1859; Johnson & Losos, 2008)

3 (c) 2012 The McGraw-Hill Companies, Inc. 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 the ability to pass your genes to the next generation (Promislow, Fedorka, & Burger, 2006)

4 (c) 2012 The McGraw-Hill Companies, Inc. Evolutionary Developmental Psychology  Humans take longer to become reproductively mature  Humans require time to develop a large brain and learn the complexity of human societies  Thus, length of childhood period is extended  Evolved mechanisms are not always adaptive in contemporary society

5 (c) 2012 The McGraw-Hill Companies, Inc. Evaluating Evolutionary Psychology  Bandura (1998) rejects what he calls “one- sided evolutionism”  An alternative is a bidirectional view, in which environmental and biological conditions influence each other  Evolution gave us bodily structures and biological potentialities  People have used their biological capacities to produce diverse cultures -- aggressive and pacific, egalitarian and autocratic

6 (c) 2012 The McGraw-Hill Companies, Inc. Genetic Foundations of Development  Each of us carries a “genetic code” that we inherited from our parents  A fertilized human egg carries this human code  Fertilized human egg cannot grow into any other species  Each of us began life as a single cell which contained our entire genetic code

7 (c) 2012 The McGraw-Hill Companies, Inc. Chromosomes  Nucleus of each human cell contains chromosomes  Chromosomes -- thread-like structures made up of deoxyribonucleic acid, or DNA  DNA is a complex molecule that has a double helix shape, like a spiral staircase, and contains genetic information

8 (c) 2012 The McGraw-Hill Companies, Inc. Genes  Genes -- units of hereditary information short segments of DNA  Genes direct cells to reproduce themselves and to assemble proteins  Proteins the building blocks of cells the regulators that direct the body’s processes (Mader, 2008)

9 (c) 2012 The McGraw-Hill Companies, Inc.

10 Human Genome Project  Preliminary map of the human genome -- the complete set of developmental instructions for creating proteins that initiate the making of a human organism  Each human has approximately 20,500 genes  Human genome consists of many genes that collaborate both with each other and with non-genetic factors inside and outside the body  Genetic expression is affected by their environment

11 (c) 2012 The McGraw-Hill Companies, Inc. Mitosis  All body cells, except the sperm and egg, have 46 chromosomes arranged in 23 pairs  Body cells reproduce by a process called mitosis  During mitosis, the cell’s nucleus—including the chromosomes—duplicates itself and the cell divides  Two new cells are formed, each containing the same DNA as the original cell

12 (c) 2012 The McGraw-Hill Companies, Inc. Meiosis  Sex cell division is different type of cell division  Eggs and sperm (or gametes) are formed in meiosis  A cell of the testes (in men) or ovaries (in women) duplicates its chromosomes but then divides twice, thus forming four cells  Each of these has only half of the genetic material of the parent cell  By the end of meiosis, each egg or sperm has 23 unpaired chromosomes

13 (c) 2012 The McGraw-Hill Companies, Inc. Fertilization  Zygote -- an egg and a sperm fuse to create a single cell  In the zygote, the 23 unpaired chromosomes from the egg and sperm combine to form one set of 23 paired chromosomes One chromosome of each pair is from the mother’s egg and the other from the father’s sperm Each parent contributes half of the offspring’s genetic material

14 (c) 2012 The McGraw-Hill Companies, Inc. The 23rd Pair of Chromosomes  Slight difference in the 23rd pair  In females, the 23rd pair consists of two chromosomes called X chromosomes  In males, the 23rd pair consists of an X and a Y chromosome  The presence of a Y chromosome is what makes an individual male

15 (c) 2012 The McGraw-Hill Companies, Inc. Sources of Variability  Combining genes of two parents increases genetic variability in the population  Chromosomes in the zygote are not exact copies of the parents  Another source of variability comes from DNA mutated gene -- a permanently altered segment of DNA

16 (c) 2012 The McGraw-Hill Companies, Inc. Genotype and Phenotype  Genotype -- all of a person’s genetic material  Phenotype -- observable characteristics  Phenotypes include physical characteristics (such as height, weight, and hair color) psychological characteristics (such as personality and intelligence)

17 (c) 2012 The McGraw-Hill Companies, Inc. Dominant-Recessive Genes Principle  Dominant -- one gene of a pair always exerts its effects  Recessive gene -- exerts its influence only if the two genes of a pair are both recessive may be overridden by a dominant gene may be carried from generation to generation but not expressed in phenotype

18 (c) 2012 The McGraw-Hill Companies, Inc. Sex-Linked Genes  X-linked inheritance -- mutated gene is carried on the X chromosome males have no “backup” copy to counter the harmful gene females have a second X chromosome, which is likely to be unchanged Females who have one changed copy of the X gene are known as “carriers” (Turner, 2006)

19 (c) 2012 The McGraw-Hill Companies, Inc. Polygenic Inheritance  Genetic transmission is usually quite complex few characteristics reflect the influence of only a single gene or pair of genes  Polygenically determined characteristics -- determined by the interaction of many different genes

20 (c) 2012 The McGraw-Hill Companies, Inc. Chromosome- and Gene-Linked Abnormalities  Down syndrome -- caused by the presence of an extra copy of chromosome 21 once in every 700 live births women aged are less likely to give birth to a child with Down syndrome

21 (c) 2012 The McGraw-Hill Companies, Inc. Sex-Linked Chromosome Abnormalities  Klinefelter syndrome -- extra X chromosome  Fragile X syndrome -- results from an abnormality in the X chromosome X chromosome becomes constricted and often breaks  Turner syndrome -- females have either an X chromosome missing or part of one X chromosome is deleted  XYY syndrome -- male has extra Y

22 (c) 2012 The McGraw-Hill Companies, Inc.

23 Gene-Linked Abnormalities  Phenylketonuria (PKU) -- individual cannot properly metabolize phenylalanine, an amino acid left untreated, phenylalanine builds up in the child, producing mental retardation and hyperactivity  Sickle-cell anemia -- genetic disorder that impairs the body’s red blood cells most often in African Americans red blood cell becomes a hook-shaped “sickle” that cannot carry oxygen properly

24 (c) 2012 The McGraw-Hill Companies, Inc.

25  Cystic fibrosis  Diabetes  Hemophilia  Huntington disease  Spina bifida  Tay-Sachs disease Other diseases that result from genetic abnormalities

26 (c) 2012 The McGraw-Hill Companies, Inc. Behavior Genetics  Behavior genetics seeks to discover the influence of heredity and environment on individual differences in human traits and development  Behavior geneticists often study either twins or adoption situations (Plomin, DeFries, & Fulker, 2007; Vogler, 2006)

27 (c) 2012 The McGraw-Hill Companies, Inc. Behavior Genetics  In a twin study, the behavioral similarities between identical twins is compared with the behavioral similarities between fraternal twins  In an adoption study, investigators seek to discover whether the behavior and psychological characteristics of adopted children are more like those of their adopted parents

28 (c) 2012 The McGraw-Hill Companies, Inc. Heredity-Environment Correlations  Passive genotype-environment correlations occur because biological parents, who are genetically related to the child, provide a rearing environment for the child  Evocative genotype-environment correlations occur because a child’s characteristics elicit certain types of environments

29 (c) 2012 The McGraw-Hill Companies, Inc. Heredity-Environment Correlations  Active (niche-picking) genotype-environment correlations occur when children seek out environments that they find compatible and stimulating  Niche-picking refers to finding a setting that is suited to one’s abilities

30 (c) 2012 The McGraw-Hill Companies, Inc. The Epigenetic View  Development is the result of an ongoing, bidirectional interchange between heredity and the environment  Heredity and environment operate together— or collaborate—to produce a person’s intelligence, temperament, height, weight, ability to pitch a baseball, ability to read, etc. (Gottlieb, Wahlsten, & Lickliter, 2006)

31 (c) 2012 The McGraw-Hill Companies, Inc.

32 Gene X Environment (G x E) Interaction  The interaction of a specific measured variation in DNA and a specific measured aspect of the environment

33 (c) 2012 The McGraw-Hill Companies, Inc. The Course of Prenatal Development  Fertilization to birth  Prenatal development lasts approximately 266 days  Three periods Germinal Embryonic Fetal

34 (c) 2012 The McGraw-Hill Companies, Inc. The Germinal Period  First two weeks after conception  Creation of the fertilized egg (the zygote)  Cell division  Attachment of the zygote to the uterine wall

35 (c) 2012 The McGraw-Hill Companies, Inc. The Germinal Period  Blastocyst -- consists of an inner mass of cells that will eventually develop into the embryo  Trophoblast -- outer layer of cells that later provides nutrition and support for the embryo  Implantation -- the attachment of the zygote to the uterine wall takes place about 10 to 14 days after conception

36 (c) 2012 The McGraw-Hill Companies, Inc. The Embryonic Period  Occurs from two to eight weeks after conception  Rate of cell differentiation intensifies  Begins as the blastocyst attaches to the uterine wall  Every body part eventually develops from these three layers endoderm ectoderm mesoderm

37 (c) 2012 The McGraw-Hill Companies, Inc. The Embryonic Period  The mass of cells is an embryo  Organogenesis -- the process of organ formation during the first two months of prenatal development organs are especially vulnerable to environmental influences  Life-support systems for the embryo develop rapidly

38 (c) 2012 The McGraw-Hill Companies, Inc. Life-Support Systems for the Embryo  Amnion -- bag containing a clear fluid in which the developing embryo floats  Umbilical cord contains two arteries and one vein and connects the baby to the placenta  Placenta consists of a disk-shaped group of tissues in which small blood vessels from the mother and the offspring intertwine but do not join

39 (c) 2012 The McGraw-Hill Companies, Inc. The Fetal Period  Fetal period begins two months after conception and lasts for seven months  Three months after conception -- fetus is about 3 inches long; weighs about 3 ounces  By the end of the fifth month, the fetus is about 12 inches long and weighs close to a pound  At birth, the average American baby weighs 7½ pounds and is about 20 inches long

40 (c) 2012 The McGraw-Hill Companies, Inc. The Fetal Period  See Figure 2.8 on page 48

41 (c) 2012 The McGraw-Hill Companies, Inc. Three Trimesters  The germinal and embryonic periods occur in the first trimester  The fetal period begins toward the end of the first trimester and continues through the second and third trimesters  Viability (the chances of surviving outside the womb) occurs at the beginning of the third trimester About weeks after conception

42 (c) 2012 The McGraw-Hill Companies, Inc. The Brain  By the time babies are born, they have approximately 100 billion neurons  The basic architecture of the brain is assembled during the first two trimesters  The third trimester and the first two years of postnatal life are characterized by connectivity and functioning of neurons

43 (c) 2012 The McGraw-Hill Companies, Inc. The Brain  The neural tube develops out of the ectoderm and forms at about 18 to 24 days after conception  Two birth defects related to the failure of the neural tube to close are: Anencephaly Spina bifida  Folic acid may prevent neural tube defects

44 (c) 2012 The McGraw-Hill Companies, Inc. The Brain  The generation of new neurons is called neurogenesis  Neuronal migration occurs at 6-24 weeks after conception  At about the 23rd prenatal week, connections between neurons begin to form

45 (c) 2012 The McGraw-Hill Companies, Inc. Prenatal Tests  Ultrasound sonography non-invasive high-frequency sound waves  Fetal MRI Used to obtain more detailed images than ultrasound  Chorionic villus sampling (CVS) tiny tissue sample from the placenta is removed and analyzed  Amniocentesis sample of amniotic fluid is withdrawn and tested for chromosome or metabolic disorders

46 (c) 2012 The McGraw-Hill Companies, Inc. Prenatal Tests  Maternal blood screening Identifies pregnancies that have an elevated risk for birth defects such as spina bifida and Down syndrome  Triple Screen Measures three substances in the mother’s blood If abnormal, ultrasound is performed, then amniocentesis

47 (c) 2012 The McGraw-Hill Companies, Inc. Infertility and Reproductive Technology  Approximately couples in the United States experience infertility Defined as the inability to conceive a child after 12 months of regular intercourse without conception  In vitro fertilization (IVF) 25 to 30 percent of pregnancies achieved by fertility treatments result in multiple births

48 (c) 2012 The McGraw-Hill Companies, Inc. Hazards to Prenatal Development  A teratogen is any agent that can potentially cause a birth defect or negatively alter cognitive and behavioral outcomes Drugs Incompatible blood types Environmental pollutants Infectious diseases Maternal stress, advanced maternal and paternal age

49 (c) 2012 The McGraw-Hill Companies, Inc. Hazards to Prenatal Development  The dose, genetic susceptibility, and the time of exposure influence both the severity of damage to an embryo or fetus and the type of defect

50 (c) 2012 The McGraw-Hill Companies, Inc. Hazards to Prenatal Development  Prescription drugs Antibiotics Antidepressants Hormones Accutane  Psychoactive drugs Caffeine Alcohol (Fetal alcohol spectrum disorders, FASD) Nicotine Cocaine Methamphetamine Marijuana Heroin

51 (c) 2012 The McGraw-Hill Companies, Inc. Hazards to Prenatal Development  Incompatible blood types Difference in blood groups -- A, B, O, and AB Rh factor  Environmental hazards Toxic wastes X-ray radiation  Maternal diseases Rubella Syphilis, genital herpes, HIV/AIDS Diabetes

52 (c) 2012 The McGraw-Hill Companies, Inc. Hazards to Prenatal Development  Other Parental Factors Maternal diet and nutrition Overweight before and during pregnancy Folic acid is important for normal prenatal development Eating fish -- mercury levels Maternal age years or older at risk Emotional states and stress Anxiety Depression Paternal factors Smoking

53 (c) 2012 The McGraw-Hill Companies, Inc. Prenatal Care  Involves a defined schedule of visits for medical care  Provides screening for manageable conditions and treatable diseases  Includes comprehensive educational, social, and nutritional services  Centering Pregnancy is a new program that is relationship-centered and provides complete prenatal care in a group setting.

54 (c) 2012 The McGraw-Hill Companies, Inc. The Birth Process  The Birth Process first stage -- contractions cause the woman’s cervix to stretch and open second stage begins when the baby’s head starts to move through the cervix third stage is afterbirth placenta, umbilical cord, and other membranes are detached and expelled

55 (c) 2012 The McGraw-Hill Companies, Inc. Childbirth Setting and Attendants  In the United States, 99 percent of births take place in hospitals  Midwives Practiced throughout the world 95 percent of the midwives who delivered babies in the United States were certified nurse-midwives  Doulas A caregiver who provides continuous physical, emotional, and educational support for the mother before, during, and after childbirth

56 (c) 2012 The McGraw-Hill Companies, Inc. Methods of Childbirth  Medications Three basic kinds of drugs Analgesia Anesthesia Oxytocics  Natural and Prepared Childbirth Natural childbirth -- reduce pain with breathing techniques and relaxation Prepared childbirth -- a.k.a. Lamaze

57 (c) 2012 The McGraw-Hill Companies, Inc. Methods of Childbirth  Other Non-Medicated Techniques to Reduce Pain Waterbirth -- giving birth in a tub of warm water likely to be less stressful for the baby and the mother Massage -- reduce pain and anxiety Acupuncture -- insertion of strategically located needles

58 (c) 2012 The McGraw-Hill Companies, Inc. Breech or Cesarean Delivery  Breech position -- buttocks rather than head emerge first Can prevent the baby from breathing normally  Cesarean delivery -- the baby is removed from the mother’s uterus through an incision made in her abdomen May be lifesaving but carries the risks of major surgery

59 (c) 2012 The McGraw-Hill Companies, Inc. Apgar Scale  Used to assess the health of newborns at one and five minutes after birth  A score, or reading, of 0, 1, or 2 on each of these five health signs heart rate, respiratory effort, muscle tone, body color, and reflex irritability  Anoxia -- an insufficient supply of oxygen

60 (c) 2012 The McGraw-Hill Companies, Inc. Low Birth Weight and Preterm Infants  Low birth weight -- less than 5½ pounds at birth Very low birth weight -- under 3 pounds Extremely low birth weight -- under 2 pounds.  Preterm -- born three weeks or more before full term  Small-for-date -- birth weight is below normal when the length of the pregnancy is considered

61 (c) 2012 The McGraw-Hill Companies, Inc. Incidence and Causes of Low Birth Weight  Incidence of low birth weight varies considerably from country to country Related to poverty, maternal health status, maternal nutrition  More health and developmental problems than normal-weight infants At school age, more likely to have a learning disability, attention deficit hyperactivity disorder, or breathing problems such as asthma (Moss, 2006; Wocadlo, & Rieger, 2006)

62 (c) 2012 The McGraw-Hill Companies, Inc. Nurturing Low Birth Weight and Preterm Infants  Kangaroo care -- a way of holding an infant so that there is skin-to-skin contact for two to three hours per day over an extended time in early infancy  Massage therapy -- firm stroking with the palms of the hands three times per day for 15-minute periods  Bonding -- formation of a connection, especially a physical bond, between parents and the newborn in the period shortly after birth (Feldman & others, 2003; Field & others, 1986)

63 (c) 2012 The McGraw-Hill Companies, Inc. The Postpartum Period  Postpartum period -- lasts for about six weeks after childbirth or delivery or until the mother’s body has completed its adjustment and has returned to a nearly pre-pregnant state  Physical and psychological adjustments  Involution -- process by which the uterus returns to its pre-pregnant size

64 (c) 2012 The McGraw-Hill Companies, Inc. Emotional and Psychological Adjustments  Baby blues -- two to three days after birth, many women begin to feel depressed, anxious, and upset  Postpartum depression -- a major depressive episode about four weeks after delivery  Fathers also undergo considerable adjustment in the postpartum period, even when they work away from home all day

65 (c) 2012 The McGraw-Hill Companies, Inc. Postpartum Blues and Postpartum Depression Among U.S. Women  See Figure 2.11 on page 64


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