HDFS 201 LECTURE 6 Heredity and Environment Interaction Epigenetic View development is the result of an ongoing bidirectional interchange between heredity and environment Recognizes the interactive effect of genes on environments AND environments on genes and the unfolding reciprocity of them across the lifespan Individual Heredity The Genetic Code Zygote union of sperm and ovum 23 pairs of chromosomes Each pair contains thousands of genes one from father and one from mother in the pair Estimates of 20 25 000 genes Approx 64 trillion different combinations per breeding couple Stages of Prenatal Development 1 Germinal Period or period of the zygote First 2 weeks after conception Conception to implantation 2 Embryonic Period Weeks 3 through 8 post conception 6 weeks From implantation until first bone cells appear 3 Fetal Period Weeks 9 through 38 about 7 months the longest stage From first bone cells until outcome be it full term abortion early Germinal Period first 2 weeks conception to implantation Fertilization conception Creation of the fertilized egg zygote Cleavage Divisions The fertilized egg splits into new cells exponentially Largely run by the RNA in the cells can still have cleavage divisions with defective DNA Implantation Attachment of the zygote to the uterine wall Embryonic Period Weeks 3 through 8 from implantation until first bone cells appear Organ formation no new organs will form after this time Cells become different and take on different roles Fetal Period Weeks 9 through 38 from first bone cells until outcome Tremendously rapid growth you will never grow at this rate again Organogenesis Differentiation Growth Maturation Age of viability Nugget 1 The age at which if an infant is delivered it has a 50 chance of survival with heroic measures Birth occurs during an ongoing developmental process it neither initiates nor terminates development You were developing for 38 weeks before your birthday and you don t stop developing after you were born Nugget 2 NOW we are beyond theories and principles While we can describe and explain and predict some of this it is truly awesome to see the intricacies FIRST TRIMESTER 26 Days PC Neural tube closed Rudiments of every vital organ Heart beating Length increased 50x Weight increased 8 000x 28 Days PC Heart beating and circulating blood Beginning of eye spot Gill arches some turns into parts of your ears Tissue migration Arm buds Cephalocaudal head to tail development 5 5 Weeks PC More than double in size since last slide Still less than inch Cerebellum growth bulges forehead Faint signs of fingers 11 Weeks PC Yolk sac atrophy Blood cells made in liver and spleen now Fetus for 3 weeks now No new organs Startle and sucking reflexes Fingerprints SECOND TRIMESTER Jacksonian Principle everything is there before you use it the brain develops before everything else because it s the necessary platform for sustaining life Proximodistal center to outer development Blood vessels for the scalp Brain shimmering through can see it below the surface 4 Months PC 4 5 Months PC Lanugo Fine hair follicles Distribution varies across the body relatively thickly situated on the face Normal Protection of the skin traps air bubbles to help insulate the skin 5 Months PC About 10 inches long birth size Fetal position Protection Shock absorption 5 5 Months PC THIRD TRIMESTER 6 5 Months PC 13 inches In birthing position Getting crowded First reflexes in region of the head Sucking Swallowing Amniotic fluid changes rates infants taste Different Cultures Different Transitional Experiences Photographs from a book The circle of life rituals from the human family album Looks at life course transitions are around the world Different does NOT equate with better or worse Naming Ceremony Blackfoot federation tribe an elder bestows a name to the child The name he gives is a tribal name the parents give a first and last It is meant to capture the child s characteristics and destiny Palau Micronesia Healing hut with ritual bathing for 4 days Mother is kept separate from community for 4 days and is attended to by a midwife Mom and toddler have faces painted for spiritual protection for the infant Cameroon West Africa Jerusalem Catholicism Circumcision on the 8th day Baby being baptized with Priest and God parents Kimberly Northern Australia Aboriginal ceremonial konkerberry smoking to protect health Sierra Madre of Western Mexico Woman delivering infant but the father is the in rafters over the birth bed with ropes attached to his testes and when the wife has a contraction she pulls on the ropes Common Themes Role of family and community often extended family and community supports Importance sacred and secular Ties across each of these domains Welcoming child into community Protection Specifics to each culture Traditions hold community together Bio psycho social spiritual stuff