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Biological Beginnings Chapter 4 Child Development and Education, Fourth Edition © 2010 Pearson Education, Inc. All rights reserved. Chapter Outline Genetic foundations Prenatal development Birth of the baby Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 2 Genetic Foundations Genes are contained on chromosomes Chromosomes are made up of DNA Most genes are universal Some genes are diverse basic human abilities: language, walking, running, social communication height, weight, activity levels, eagerness to learn, emotionality, etc. Genetic expression affected by time, environment Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 3 Formation of Reproductive Cells Gametes: sperm (m) and ovum (f) contain 23 chromosomes form through meiosis germ cells pair up chromosomes replicate crossing-over occurs chromosomes separate and cell divides Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 4 Conception Sperm fertilizes ovum zygote has 23 + 23 chromosomes gender determined on 23rd pair XX; XY Cells continue to divide 2 separate cell clusters: monozygotic twins 2 ova + 2 sperm: dizygotic twins Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 5 Genetic Transmission Gene pairs include two alleles provide instructions for physical characteristics dominant and recessive genes codominant genes most characteristics: polygenic inheritance Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 6 Problems in Genetic Instruction Chromosomal abnormalities Single-gene defects extra chromosome (e.g., Down syndrome) missing or wrongly formed chromosome 1 in 150 births inherited from one or both parents Other problems defective gene (e.g., Fragile X syndrome) problem with multiple genes (e.g., Spina bifida) Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 7 Genetic Awakening Occurs at different times in the lifespan Some characteristics are canalized Others more influenced by environment canalization – tight genetic control basic motor skills: crawling, sitting, walking not canalized: reading, writing, math, social skills Some characteristics awaken during sensitive periods perception, language, close bond to caregiver Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 8 Blending Heredity & Environment Passive gene-environment relation Active gene-environment relation parents’ genetic tendencies influence child’s environment parents’ choice child’s genetic characteristics influences his/her environment child’s choice Evocative gene-environment relation child’s genetic characteristics elicit responses from environment someone’s response to the child; not the child’s choice Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 9 Acknowledging Nature & Nurture in Children’s Lives Value individual differences Remember that environment & genetics influence every aspect of development Intervene when children struggle Be mindful of your reactions to children’s challenging temperaments Encourage children to make growth-promoting choices Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 10 Prenatal Development 3 Phases of Prenatal Growth zygote embryo conception – 2 weeks post 2 weeks – 8 weeks fetus 8 weeks – birth Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 11 Development of Zygote Begins at conception ovum prevents additional sperm from entering chromosomes combine to form zygote Mitosis occurs Attaches to uterine wall (~ 16 cells) Separates into embryo & placenta Releases hormones telling body to cease menstruation Cells begin to specialize nervous system, brain Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 12 Development of Embryo Life support sytem formed placenta grows larger, stronger, and more refined umbilical cord develops provides food, liquid, oxygen; removes waste secretes hormones to sustain embryonic growth Basic body structures develop from top to bottom (head first, feet last) from inside to outside torso before limbs; internal organs arms & legs before hands & feet fingers and toes recognizable at 8 weeks Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 13 Development of Fetus Third month Fourth month head is large but growing slowly eyes move into place; increasingly human-looking genitalia form reflex and muscular movement (although not felt) rapid growth in length (height) slow weight increase hair growth on head and eyebrows Fifth month rapid growth in length (height) continues fine hair growth covers body movement felt by mother Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 14 Development of Fetus Sixth month (avg. weight 1 lb. 13 oz.) Seventh month (avg. weight 2 lb. 14 oz.) skin red, wrinkled; body lean; fingernails evident development of respiratory & central nervous system eyes open; eyelashes and toenails form body fills out Eighth month (avg. weight 4 lb. 10 oz.) skin becomes pink, smooth; fat grows beneath skin testes descend (in males) Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 15 Development of Fetus Brain development preparation for reflexes sucking, swallowing, looking away from light activates circuits for sensing stimulation can hear/remember music can taste/recognize flavors Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 16 Preparing for Pregnancy Starts before conception Watch diet, take approved vitamin supplements Exercise Avoid alcohol and drugs (includes OTC meds) See genetic counselor Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 17 Avoiding Teratogens Potentially harmful substances prescription or non-prescription drugs infectious agents, e.g., rubella, syphilis, HIV environmental chemicals, e.g., lead maternal stress Effects depend on amount, timing, genetic makeup of mother & child embryonic: development of body fetal: development of brain Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 18 Medical Procedures Ultrasonography CVS (Chorionic Villus Sampling) 10-12 weeks high-risk pregnancies identifies chromosomal abnormalities, X-linked disorders, some blood diseases Amniocentesis 13-18 weeks identifies neural tube defects & chromosomal abnormalities Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 19 Supporting Parents, Protecting Babies Encourage women to evaluate health before pregnancy Remind sexually active individuals to take care Encourage pregnant women to seek medical care Use well-researched strategies to reach women at risk for late or no prenatal care Advise pregnant women from low-income backgrounds about nutritional resources Urge pregnant women to avoid teratogens Encourage them to relax and speak their minds Ask fathers about their experiences and feelings Advise parents about care for children exposed to teratogens Intervene when mothers continue substance abuse Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 20 Birth of the Baby: Preparation Childbirth classes Select location and participants Determine method of controlling pain Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 21 The Birth Process Triggered by mother’s hormonal changes & maturation of fetus Braxton Hicks contractions begin Fetus settles in head-downward position Caesarean delivery if breech or sideways Just before labor: baby descends into pelvis mother may experience rush of energy weight loss (1 to 4 pounds) vaginal secretions difficulty sleeping Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 22 Stages of Labor First stage Second stage cervix dilated (10 cm) baby proceeds down birth canal Third stage regular contractions widening of cervix pelvis and back pain afterbirth expelled by uterus (placenta & fetal membranes) Fourth stage mother’s body readjusts Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 23 Medical Interventions Induced labor using Pitocin Analgesics Anesthetics Opioids/narcotics Caesarean delivery epidural analgesia (spinal injection) in U.S., currently 30% Medical personnel do their best to accommodate women’s cultural practices Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 24 Babies at Risk Born early (“premature”) before the end of week 37 risk of breathing problems, anemia, brain hemorrhages, feeding problems, instability in temperature Born small for date possible neurological deficiencies, structural problems with body parts, difficulty with breathing & vision often due to exposure to teratogens or chromosomal abnormalities Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 25 Guidelines for Care Reduce infant’s exposure to light and noise. Regulate amount of handling of infant by medical staff. Position baby to increase circulation. Encourage parents to participate in care. Inform parents about infant’s needs. Arrange activities such as diapering & changing clothes to minimize interruptions to sleep and rest. Encourage parents to cuddle and carry infant. Swaddle baby, with hands placed near the mouth. Massage baby. Educate parents about caring for the child as he or she grows. Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 26 Enhancing Parents’ Sensitivity Reassure new mothers that they will find necessary energy and insight. Share what you know about infants’ sensory & perceptual abilities. Point out physiological states. Encourage families to watch infants’ responses to stimuli. Ask families about the stimulation that infants find soothing. Model sensitive interactions with infants. Show parents how to care for the baby. Offer early and continued support to parents of fragile infants. Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod © 2010 Pearson Education, Inc. All Rights Reserved. 27 Take-Home Messages All children are born with genetic instructions that are mostly similar. Unique gene differences also predispose children to look & act in different ways. Genetics and environment affect children’s abilities & achievements. Child Development and Education, Fourth Edition Teresa M. McDevitt and Jeanne Ellis Ormrod Prenatal growth consists of three periods: zygote, embryo, & fetus. Avoiding teratogens, seeking medical care, reducing stress, nutrition, and exercise are important. Family & professionals are critical in guiding new parents. © 2010 Pearson Education, Inc. All Rights Reserved. 28