Development Nature vs. Nurture Continuity vs. Discontinuity

Cohort and Cohort Effects Depression Era Era of Excess Gen X Generation 9/11

Prenatal Development Begins with conception –When fertilization creates a zygote (one celled organism) Ends with birth –Rapid rate of physical development (more so than any other growth stage in life)

Physical Development: Prenatal Cephalocaudal – head to tail development Proximodistal – center outward development

Prenatal Order 1.Zygote 2.Embryo 3.Fetus

Germinal Stage First 2 weeks after conception Happens very fast –1 in 5 usually rejected

Embryonic Stage 2 weeks to end of 2 nd month –Most vital organs and bodily systems will form in developing organism –Typically embryo is an inch long, but resembles human with legs, arms, eyes, ears ** super important stage, if anything happens in this stage, it could be devastating  most miscarriages happen here, most birth defects occur here

Fetal Stage 2 months thru birth –Muscles and bones form –Fetus capable of physical mov’t –Hearing becomes functional During final 3 months, brain function starts –Respiratory and digestive systems mature

Threshold of Viability Ability for baby to survive at premature birth –Premature babies often experience a wide range of developmental problems

Viability Laws Roe v. Wade –Must follow state legislation Most abortions will happen before the stage of viability (different weeks, depending on state laws) –Abortions after viability are rare, statistically

Environmental Factors and Prenatal Development Developing organism and mother are linked thru placenta –Mother = mother and fetus teratogens – substances that cause birth defects

Alcohol Fetal alcohol syndrome – collection of congenital (inborn) problems associated with excessive alcohol use during pregnancy –Microcephaly (small head) –Heart defects –Irritability –Hyperactivity –Delayed mental and motor development –Low birth weight –Mental retardation

Other teratogens Tobacco – miscarriages, stillbirth, low birth weight Heroin – baby born addicted to narcotics, premature death, cognitive defects Cocaine – birth complications, cognitive defects thru childhood

Maternal Illness and Exposure to Toxins Immune system matures late in prenatal period –Measles, mumps, rubella, syphilis, chicken pox (all depends on when mother contracted the illness) –HIV/AIDS – may occur prenatally through placenta, during delivery, breastfeeding Mid 1990’s, about 20-30% passed HIV to babies Improved antiretroviral drugs and better prenatal care has reduced that figure to 2% in the US

Environmental Factors: Fetal Organs of Disease Links between prenatal development and later adults’ physical and mental health Prenatal malnutrition linked to vulnerability of schizophrenia Low birth weight can be a marker for heart risk later in life