Developmental Psychology Chapter 2

Developmental Psychology: Biological and Environmental Foundations

• Developmental psychology explores lifespan development

Chapter 2: Biological and Environmental Foundations

• Genetic foundations are explored
• Reproductive choices are discussed
• Environmental contexts for development
• Relationship between heredity and environment

Genetic Code

• Chromosomes are made of DNA (deoxyribonucleic acid)
• A gene is a segment of DNA
• Humans have approximately 30,000 genes
• Karyotype is a photograph of human chromosomes
• DNA replicates through mitosis

Sex Cells (Gametes)

• Gametes (ova and sperm) have half the genetic information of a regular cell.
• Meiosis is the cell division process that creates gametes.
• Male gametes are produced in testicles, female gametes in ovaries.
• A gamete (sperm or egg) contains 23 chromosomes.
• Union of sperm and egg forms a zygote with 46 chromosomes (23 pairs).

Types of Twins

• Fraternal (dizygotic) twins originate from two different eggs
• Identical (monozygotic) twins originate from one egg

Inheritance Patterns

• Codominance: both genes of a pair influence traits.
• Dominant-recessive inheritance: traits determined by one dominant gene and one recessive gene; recessive genes are carried.
• Dominant and recessive diseases
  • 1-Autosomal diseases e.g. cystic fibrosis, PKU.
  • 2-x-linked diseases, e.g. hemophilia, applies more to males.
• Genetic imprinting: certain genes are activated or deactivated.
• Mutation: permanent change in DNA segment
• Polygenic inheritance: multiple genes determine a characteristic (e.g., height, intelligence, and personality).

Chromosomal Abnormalities

• Errors in meiosis cause chromosomal abnormalities.
• Examples include Down syndrome (mental and physical defects), sex chromosome abnormalities (e.g., extra X or Y chromosome).
• Sex chromosome defects are usually less severe than autosomal defects, tend to have fewer problems

Reproductive Choices

• Genetic counseling provides help with conception.
• Prenatal diagnosis methods (e.g., amniocentesis, ultrasound, maternal blood analysis) help diagnose potential problems.
• Reproductive technologies include IVF, surrogate motherhood, adoption.

Environment Contexts

• Family has a dynamic role in development and adapts to changes over time.
• Direct influences: warmth promotes cooperation
• Indirect influences: interaction between related factors (one factor impacting another)
• Socioeconomic status, education, income levels affect family functioning and child development.
• Poverty negatively affects child development.

Community and Culture

• Supportive communities foster well-being through leisure and positive interactions
• Family values and public policies affect development, with collectivist societies typically supporting family well-being more than individualistic societies.
• USA & Canada usually protect children over the elderly.

Heredity and Environment Interaction

• Heredity and environment interact to influence individual differences.
• Heredity determines traits, such as intelligence, however, this is not universally believed in modern times.
• Development is viewed as the exchange between nature (heredity) and nurture (environment) throughout the lifespan.

Learning Outcomes

• Students learned about genetic foundations, reproductive choices, environmental contexts for development, and the relationship between heredity and environment.