Biological and Environmental Factors

1. Biological and Environmental Factors Chapter 2 Summary Notes * Notes for educational purposes only-use with course textbook

2. Overview • Bases for Genetic make-up • Choices in Reproduction • Development and the Family • The Relationship Between Heredity and Environment

3. Genetics • Heredity and environment are foundations of development • Genotype- genetic make-up • Phenotype- observable characteristics

4. Body composed of over a trillion cells Center of cell is nucleus which contains chromosomes Chromosomes- store and transmit genetic information DNA- double strain molecules that makeup chromosomes and contain genetic code Gene- segment of DNA molecule Mitosis- cell duplication (each cell receives exact copy of genetic code) Genetic Code

5. Sex Cells • Gametes-sex cells (sperm 23 chromosomes and ovum 23 chromosomes) • Meiosis- cell division that forms gametes • No two gametes will ever be the same • Zygote- sperm and ovum unite at conception 46 Chromosomes • Sperm are produced continuously; all ova are present at birth • 22 autosomes; 1 sex chromosome; xy- male; xx- female

6. Mulitiple Births • Twins • Fraternal (dizygotic) most common type • Two ova are fertilized; genetic makeup similar to ordinary siblings • Identical (monozygotic) one zygote separates into two clusters of cells that become two individuals; same genetic makeup • Triplets (3); Quadurplets (4); Quintuplets (5); Sextuplets (6), Septuplets (7)

7. Increase in Multiple Births?!

8. Increase Facts • 1978-1988- 17% single births; 33% twin births; 101% triplets and higher • Trends in family planning and advances in reproductive technology assist in increase

9. 2 forms of genes occur at the same place on the autosome- father & mother Homozygous- alike genes from both parents (inherited trait) Heterozygous- different genes from both parents- relationship of genes determine trait that will appear. Dominant- recessive inheritance- a pattern one gene’s influence is exhibited (heterozygous) Patterns of Genetic Inheritance

10. Dominant- Recessive Terms • Dominant- expressed gene • Recessive- not expressed • Carrier- heterzygous; pass recessive gene to his/her children

11. Diseases that are result of recessive genes • PKU • Cystic Fibrosis • Sickle Cell Anemia • Tay-Sachs disease • Hemophilia (Page 50 in text)

12. Who is more at risk ( Multiple Births)? • Older women • Women with more children • Fertility drug clients • African American Women (fraternal twins) • Tall, normal, or overweight (fraternal twins)

13. Patterns of Genetic Inheritance • 2 forms of each gene occur at the same place on the autosomes- 1 mother; 1 father • Homozygous- both genes are alike • Heterozygous- relationship between genes determine trait that will appear

14. A pattern in a heterozygous relationship only one gene’s influence is exhibited Dominant- expressed Recessive- not expressed Carrier- heterozygous relationship passes recessive gene Dominant- Recessive Inheritance

15. Diseases with recessive trait • PKU • Sickle Cell Anemia • Tay-Sachs Disease • Cystic Fibrosis • Cooley’s Anemia (Pages 50-51 in text) • Genetically linked illnesses

16. Codominance • Codominance • Both genes influence the person’s charateristics • Sickle Cell Anemia

17. Mutation • Change in DNA segment • Harmful genes • By chance • Or by hazardous substances in the environment

18. X-linked inheritance- recessive gene is carried on the X-Chromosome • Males more likely to be affected (sex chromosomes don’t match) • Hemophilia • Males may be at a disadvantage in other areas not necessary linked to X-linked inheritance- miscarriage and infant deaths • Learning disability, behavior disorders mental retardation (Halpern, 1997)

19. Genetic Imprinting • Pattern of inheritance where some genes are chemically marked in such a way that one pair is activated regardless of its makeup • Diabetes in the father • Asthma in the mother • Fragile X syndrome (MR, autism) mother

20. Chromosomal Abnormalities • Defect occurs during meiosis (DNA) • Down Syndrome • 21st chromosome contains extra genetic material • Physical features- short, stocky build, flatten face, protruding tongue, almond shape eyes, possible heart and intestinal defects, speech problems, delayed motor and cognitive defects • Increase chances of having a baby with Down Syndrome with age of mother

21. Abnormalities in Sex Chromosomes • Either the presence of extra chromosome or the lack of one of the X chromosomes • Triple X syndrome (XXX)- girl- verbal difficulties • Turner syndrome- (XO) missing X-spatial relationships • Klinefelter syndrome (XXY)- verbal difficulties

22. Reproductive Choices • Genetic Counseling- communication about chances of couples having a baby with hereditary disorders • Prenatal diagnostic methods • Page 55 in text

23. Other choices • Adoption • In vitro fertilization • Fertility drugs

24. Environmental Factors • Family • Friends • School • Experiences • Society • Culture

25. Social Systems Perspective • Family as complex system • Behavior of family affects those of other family members • Influence is directed or indirect- third party can support or undermine other family relationships • Family dynamic ever- changing system • Can be modified by important life events • Development status of each family member and historical time period effects families

26. Socioeconomic Status (SES) and Family Functioning • 3 variables • Years of education • Job prestige and skills required • Income • SES may affect differences in child-rearing practices • Lower- SES family may focus on external characteristics (obedience, neatness, cleanliness) • Higher SES focus on psychological traits-curiosity • Happiness, and self- direction • As early as 2nd year of life SES affects with cognitive and language development

27. Impact of Poverty • 36 million people • 14% of the population • Hardest hit • Parents under 25 with young children • Elderly who live alone • Ethnic minorities • Women • 20% children; 32% Hispanic; 40% African American; 32% Native American

28. More on Poverty • Parents in poverty • Experience hassles and crises affecting child-rearing ability • Poor housing and dangerous neighborhoods increase stress levels of poor families • Homeless children suffer from developmental delays, emotional stress, health problems, school absenteeism, poor academic performance

29. Beyond the Family • Community impact on family • Child abuse and neglect are greatest • With weak family and community ties • Family stress and child adjustment problems are reduced with strong family ties • Safe neighborhoods and communities with physical and social support • Influence well-being in adulthood • Smaller towns- fewer culture experiences than cities- greater community involvement and safer environments

30. Culture • Cultures shape family interactions and community settings beyond the home • American cultural values- independence • Self-reliance, privacy • Subcultures- groups of people with beliefs and customs that differ from those of the larger culture

31. African American Extended Family • Extended family- 3 or more generations live together • Survival poverty, prejudice and economic deprivation (McAdoo) • More kin visits • Reduce stress • Grandmothers are significant • Elderly have higher life satisfaction • Strong Family bonds, child development • Survival for future generations

32. Individualism vs. Collectivism • Individualism societies- people think of themselves as separate entities; concerned with their own goals (US) • Collectivism societies- people define themselves as part of a group and stress group over individual goals