The document provides an overview of developmental psychology and the genetic and environmental influences on human development from conception through adulthood. It discusses genetic foundations including DNA, genes, alleles, and patterns of inheritance. It also examines environmental contexts such as family, socioeconomic status, and prenatal influences including teratogens. Key stages of prenatal development and characteristics of newborns are outlined.

1. DEVELOPMENTAL PSYCHOLOGY Week 2: Foundations of Development DEVELOPMENTAL PSYCHOLOGY

2. Influences on development Genetic foundations Environmental context

3. Genetic foundations of development Genetic code conveyed in deoxyribonucleic acid (DNA) Gene: segment of DNA along length of chromosome Allele: viable DNA (deoxyribonucleic acid) coding that occupies a given locus (position) on a chromosome.

4. DNA Ladder-like molecule, formed of chains of nucleotide subunits. deoxyribose sugar a phosphate a base. A set of three bases – a codon – acts as a blueprint for the incorporation of a particular amino acid, the subunit of a protein molecule. The two halves are joined together by the bases – a purine (adenine or guanine) or pyrimidine (cytosine or thymine) – forming pairs (the rungs of the ladder). The bases form into two specific base pairs: adenine with thymine and guanine with cytosine. National Human Genome Research Institute (NHGRI) http://www.genome.gov/12514471 by artist Darryl Leja

5. Genes Length of a gene varies greatly Gene concordance between human and chimpanzee is high (98% - 99%) Only one base pair change is enough to influence human traits and capacities

6. Beginning of life Gametes have 23 chromosomes Combination of two gametes -> zygote Cell division (meiosis) – exchange of material causing variation

7. Twins Monozygote Identical 100% concordance 1 / 285 Dizygote Non-identical, Fraternal 50% concordance

8. Patterns of genetic inheritance An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene. An organism which has two different alleles of the gene is called heterozygous.

9. Class Activity

10. Dominance / recessive inheritance Phenotypes: the expressed characteristics Dominant characteristic: when only one allele affects the expression Recessive characteristic: needs two alleles of the same type before it is expressed Allele Father/Mother B b B BB (dom) Bb (carrier) b Bb (carrier) bb (rec)

11. Importance of genetic inheritance Understanding of how we express physical characteristics Understanding of how some diseases/defects are transmitted e.g. PKU, an inability to metabolise amino acid phenylalanine, causing CNS damage in first year of life, is a recessive code, that strikes 1 / 8k births. Both parents must have recessive allele for child to get PKU

12. Incomplete dominance Cases where the pattern of inheritance in which both alleles are expressed, resulting in a combined trait or one that is intermediate between the two For example, red flower and blue flower, after cross pollination, we get purple flowers

13. X-linked inheritance In cases where the harmful allele is carried on the X chromosome, there is greater chance of the male expressing the disorder due to the fact that males only have one X chromosome Usually is passed on by mother to son Hemophilia, muscular dystrophy, adrenoleukodystrophy, green colourblindness, fragile-x syndrome

14. Genetic imprinting This refers to the chemical marking of a particular allele, such that the trait is always expressed Genetic imprinting is a vaguely similar to monosomy but with different sequelae. Genetic imprinting is the process by which certain mammalian genes are switched off during early embryo development, according to whether they were inherited from the father or mother.

15. Mutation Sudden changes in the DNA which may affect one, two, or many genes. Such mutations could occur spontaneously or as by-product of harmful environmental agent (tetragenic)

16. Chromosomal abnormalities Abnormalities within the chromosomes – give rise to developmental problems Down syndrome: consequences include MR, memory and speech problems, slow motor development Sex chromosome abnormalities: XYY syndrome, Klinefelter syndrome, Turner Syndrome

17. Class Discussion Referring to ecological systems theory, explain why parents of children with genetic disorders often experience increased stress. What factors, within and beyond the family, can help these parents support their children’s development?

18. Genetic counselling Process by which to help ensure healthy babies Maternal age, family background

19. Prenatal Diagnostic Methods Method Description Timing Amniocentesis Obtaining sample of uterine fluid by drawing fluid with syringe through abdominal wall 11-15weeks Chronic Villus sampling Removal of plug of tissue for analysis, entry via vagina 6-8weeks Fetoscopy Visual analysis of the fetus, possible to obtain blood sample 5-18weeks Ultrasound Beaming of high frequency sound waves at uterus Caution <5x Maternal blood analysis Testing for elevated level of alpha-fetoprotein By 2 nd month Preimplantation genetic diagnosis Associated with in vitro fertilisation and duplication of zygote

20. Advantages of GC Improving chances of healthy babies Better prepared for what may come to pass Prenatal diagnosis has led to advances in fetal medicine – administration of drugs, surgery, blood transfusions for fetus.

21. Environmental context for development (1) Family – having family support gives potential for social interaction Direct influence: parents, grandparents Indirect influence: third party effects such as emotional influences

22. Environmental context for development (2) Socioeconomic status – affects duration and timing of phases of family life cycle Early Vs late marriage Number of children Family interactions

23. Environmental context for development (3) Affluence and poverty Collectivist Vs individualistic societies Legal system and society support

24. Policies for the family MCDYS Promoting marriages Supporting families Nurturing and protecting the young National family week – “ eat with your family day ”

25. Relationship between hereditary and environment Hereditary estimate: extent to which individual differences in complex traits in a specific population are due to genetic factors Kinship studies compare characteristics of family members Concordance rate: refers to the percentage of instances in which both twins show a trait when it is present in one twin

26. LifeSpan Development Name the times in life that come to your mind What is lifespan development? When does lifespan development start?

27. Life Span Perspective Leading dynamic systems approach Lifelong Multidimensional and multidirectional Highly plastic Affected by multiple interacting forces

28. Stages in development Conception Embryonic development Fetal development Infant Toddler Childhood Adolescence Young adulthood Middle adulthood Late adulthood

29. Conception / Germinal stage Conception occurs when a sperm joins with an egg When fertilisation has occurred, the newly formed zygote will make its way down to the womb By the end of a week, the blastocyst will implant in the uterine lining

30. Period of Zygote First two weeks, within first trimester Single cell zygote will multiply and form blastocyst

31. Embryonic period 3 – 8 weeks (first trimester) Many major organs developed e.g. CNS, heart, muscles, ribs, backbone, digestive track, arms, legs, feet, toes, fingers

32. Period of the Fetus This is the time of physical growth Organs now get connected New behaviours are learned 9 – 12 weeks – still within first trimester, lasts until birth of the infant

33. Teratogens Any environmental agent that causes damage during the prenatal period Effect is dependent on a few factors Age Dose Heredity Other negative influences

34. Teratogens Substances that can produce birth defects Especially harmful during embryonic period E.g., Alcohol Use may cause Fetal Alcohol Syndrome (leading cause of preventable Mental Retardation) -- Smoking during pregnancy restricts oxygen to the unborn: greater risks for several problems

35. Effect of teratogens (1) Prescriptive and OTC Drugs: for relief from simple ailments – asprin, anti-depressants, caffeine – far reaching consequences Illegal drugs: often consumed as a way of escaping reality – LT potential –ve effect Tobacco: first, second and even third hand, has effect on reducing birth weight Alcohol: fetal OH syndrome, effects

36. Radiation: possibility of physical defects, LBW, miscarriage, etc. Environmental pollution: increased chance of life threatening diseases and future health problems Infectious diseases: possible correlation with cataracts, deafness, heart, genital, urinary and intestinal abnormalities, and even MR Effect of teratogens (2)

37. Effect of Maternal Factors Maternal nutrition Emotional stress Rh factor incompatibility Maternal age and previous birth experience

38. Group Discussion If you had to choose five environmental influences to publicize in a campaign aimed at promoting healthy prenatal development, which ones would you choose, and why?

39. Stages of Childbirth Dilation and effacement of the cervix (12 – 14 hours 1 st birth) to Transition Delivery of the baby (pushing and birth) Delivery of the placenta

40. Developmental scales Apgar scales: measures physical condition Five different scales: Appearance (colour), Pulse (heartrate), Grimace (reflex/irritability), Activity (muscle tone), Respiration (breathing) Score 0, 1, 2

41. New-born Baby’s Capacities Newborn Reflexes Eye blink Rooting Sucking Moro Palmer grasp Tonic neck Stepping Babinski

42. New-born states: Arousal Infant States of Arousal Regular sleep Irregular sleep Quiet alertness Drowsiness Waking actively and crying

43. New-born states: Senses Touch – highly sensitive to pain Taste – able to distinguish basic tastes Smell – shows distinct preference Hearing – preference for complex tones Vision – least developed in the newborn