Developmental Psychology: Development Through the Lifespan PDF

# Developmental Psychology: Development through the Lifespan ## F. Z. Sai, UAE University [email protected] ## Chapter 2: Biological and Environmental Foundations - Genetic Foundations - Reproductive Choices - Environmental Contexts for Development - Understanding the Relationship Between Her...

# Developmental Psychology: Development through the Lifespan ## F. Z. Sai, UAE University [email protected] ## Chapter 2: Biological and Environmental Foundations - Genetic Foundations - Reproductive Choices - Environmental Contexts for Development - Understanding the Relationship Between Heredity and Environment ### Genetic Code - Chromosomes: made up of a chemical substance called deoxyribonucleic acid (DNA) - A gene is a segment of DNA - We have about 30,000 genes - A karyotype: photograph of human chromosome - DNA duplicates itself through a process called mitosis ### The Cell Sex: Reproductive Cells * Called also reproductive cells or gametes or sperm cells and ovum (plural: Ova) * Sex cell have one half of the total amount of human genetic information. * When a sperm cell fertilizes an egg cell, the resulting cell has a full set of genetic information again. * Sex cells are formed through a particular kind of cell division called meiosis. Unlike in normal cell division (mitosis), the genetic material of the original (parent) cell is divided up twice. * These sex cells are also called reproductive cells or gametes. Sperm cells are produced in men's testicles and egg cells are produced in women's ovaries. Sex cells are different from other cells in one special way: Put simply, they only have one half of the total amount of human genetic information. * A male or female Gamete: contains 23 chromosomes * Formed through a cell division (meiosis) * Union of sperm and ovum= zygote= 46 chromosome 23 pairs, one is sex ## Sex Chromosomes - XX = female - XY= male - **Fraternal:** or dizygotic twins (2 Ova), common in the society - **Identical:** cluster of cells that start to divide - Different chromosomes from the parents: heterozygous - Similar chromosomes from the parents: homozygous - **Codominance:** both genes influence the person's characteristics - **Dominant recessive inheritance:** Individuals with one recessive gene are carriers of the recessive trait * Dominant and recessive diseases: * 1-autosomal diseases: e.g., Cystic fibrosis, PKU (see table 2.3 p.48) * 2- X-linked diseases e.g. hemophilia (see table 2.3p.48). (applies more to males) * **Genetic imprinting:** genes are imprinted or chemically marked, in a way that one member of the pair is activated. * **Mutation** is a sudden but permanent change in a segment of DNA. * **Polygenic inheritance:** in which many genes determine the characteristic (height, intelligence, personality) ## Chromosomal Abnormalities * Are due to errors in meiosis. * E.g. Down Syndrome (mental and physical defects) * SEX CHROMOSOMES: are milder than defects of autosomes (see table 2.3,p.48): fewer problems. * Most do not suffer from mental retardation * Extra chromosome: (x or y) or absence of one x in females * Cognitive deficits resulting from: * XYY syndrome (not more aggressive) * XXX syndrome (in girls): language problems * Xxy (Klinefelter syndrome): extra x chromosome * XO:Turner syndrome (girls): problems with spatial and facial expressions ## Reproductive Choices * Get help about conceiving from: * 1-Genetic counseling: * 2-Prenatal diagnosis methods (e.g. Amniocentesis, ultrasound, maternal blood analysis). * **Reproductive technologies:** Help individuals to become parents: * In vitro fertilization, surrogate motherhood, postmenopausal assisted childbirth * Adoption: is a solution sometimes * Having warm parents predicts favorable development in adopted children. ## Environment Contexts: * 1-Family: is dynamic, adjusts to changes. * 2-Direct influences: warmth makes children cooperate * 3-Indirect influences: any two are affected by the 3rd part * 4-Adapting to change: birth of a child, job change ## Socio economic Status and family functioning * Is measured by: * 1- years of Education * 2. the skill required by one's job, * 3. the income * Poverty: Impact; * Development is undermined by poverty * Support foster well being * Community that provides leisure activity, interactions====well being * Values affect development * Extended family houses: 2-3 families live together====protect development under stress * **Public policies**, values that stress collectivism over individualism======affect development * USA, Canada: protect children more than elderly. ## Interaction between Heredity and Environment * How much they contribute to====individual differences * Heredity determines traits: * Intelligence * & personality????? Not believed any more * Development is best understood as an exchange between nature and nurture over the lifespan. ## Learning Outcomes * We learned * Genetic foundations * Reproductive choices * Environmental contexts for development * Understanding the relationship between heredity and environment