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
Genetic Code

• 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)

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
Patterns of Genetic Inheritance

• 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
  genes influence is exhibited (heterozygous)

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
Dominant- Recessive Inheritance

• A pattern in a heterozygous relationship only one
  genes influence is exhibited
• Dominant- expressed
• Recessive- not expressed

• Carrier- heterozygous relationship passes
  recessive gene

15
Diseases with recessive trait

• PKU
• Sickle Cell Anemia
• Tay-Sachs Disease
• Cystic Fibrosis
• Cooleys Anemia
• (Pages 50-51 in text)
• Genetically linked illnesses

16
Codominance

• Codominance
• Both genes influence the persons 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
  dont 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