Slide 1 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. A Topical Approach to Life-Span Development 6e John W. Santrock Chapter Two: Biological Beginnings

Slide 2 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. The Evolutionary Perspective Charles Darwin: On the Origin of Species (1859) –All organisms must adapt to survive Natural selection –Evolutionary process where the best adapted (“fittest”) individuals in a species survive and reproduce Adaptation = ability to meet the demands of one’s environments and respond to changes in them

Slide 3 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Reproductive Fitness Possession of characteristics that give one the ability to survive long enough to reproduce –Goal =

Slide 4 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Evolutionary Psychology Emphasizes: –Evolution can explain certain human physical features, behaviors, emotions, and cognitive abilities –Biological certainty associated with increased nurturing of genetically-related offspring

Slide 5 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Mating Strategies & evolution: Why do men “play the field?” Mating strategies differ by gender –Men seek: Best strategy: –Women seek: Best strategy:

Slide 6 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Evolutionary developmental psychology Adaptations to increasingly complex societies –Humans take longest of all mammals to sexually mature Extended childhood & adolescence to learn rules of society, survival & thriving skills –Largest brains of all mammals Brains continue to develop into young adulthood

Slide 7 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Evolutionary developmental psychology Why do humans outlive their reproductive capacity? –Paul Baltes’ theory of natural selection Operates primarily on characteristics tied to reproductive fitness in youth Harmful conditions, non-adaptive traits common in elderly As adults weaken biologically, culture-based needs increase –Give more back to society in turn?

Slide 8 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Bi-directional view Alternative to one-sided biological evolution Social behavior is not just the product of biology Environmental & biological conditions influence each other Biology Environment

Slide 9 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Genetic Foundations of Development Genes carry a code for physical/psychological characteristics inherited through: generations of evolution (shared by all humans) our parents (family traits)

Slide 10 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Genetic Foundations of Development Genetic expression = –Collaborative and environmentally influenced –Direct cells to reproduce and to assemble proteins Proteins form cells and direct biological processes

Genetic Foundations of Development Figure Cells, Chromosomes, Genes, and DNA Nucleus (center of cell) contains chromosomes and genes Chromosomes are threadlike structures composed of DNA molecules Gene: a segment of DNA (spiraled double chain) containing the hereditary code What is DNA?

Slide 12 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Cell Reproduction Mitosis: Cell nucleus duplicates and cell divides mitosis video

Slide 13 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Sexual Reproduction Meiosis: Cell division forms gametes (sex cells) –egg & sperm 23 unpaired chromosomes

Slide 14 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Sexual Reproduction Fertilization: egg and sperm form zygote –Contains 23 chromosomes from each parent, re-paired –On 23 rd pair, X and Y chromosomes determine sex

Male and female chromosome pairs

Slide 16 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Genetics “We are all 99.9 percent genetically equal. It is one one-hundredth of one percent of genetic material that makes the difference between any one of us.” (Barry Schuler)

Slide 17 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Sources of Genetic Variability 1.Each zygote is unique in chromosomal pairings 2.DNA mutations occur by chance or damage 3.Genotypes and phenotypes –Genotype: sets up a range of potential phenotypes –Phenotype: may be influenced by environmental factors

Slide 18 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Poly-genetic determination Poly-genetically determined characteristics

Slide 19 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Behavior Genetics Study of: –Twin studies Identical twins compared to fraternal twins

Slide 21 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Heredity and Environment Interaction: Behavior Genetics –Shared and nonshared environmental experiences Variability in psychological traits is more linked to:

Slide 22 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Heredity and Environment Interaction: The Epigenetic View Epigenetic view –Development is ongoing –Bi-directional interchange of heredity/environment

Slide 23 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Prenatal Development Stages Germinal period: Embryonic period: Fetal period:

Slide 25 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Hazards to Prenatal Development Teratogens

Slide 26 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Teratogens Prescription, nonprescription drugs Psychoactive drugs

Figure Teratogens and Timing of Their Effects on Prenatal Development

Slide 28 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Hazards to Prenatal Development Incompatible blood types (Rh factor) Maternal diseases Diet and nutrition Maternal age, weight, emotional states, stress Environmental hazards (toxins, waste)

Slide 29 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Birth Low birth weight and preterm infants –Low birth weight: Less than 5 ½ lbs at birth –Preterm: Born in 35 weeks or less after conception –Small for date

Slide 30 © 2012 The McGraw-Hill Companies, Inc. All rights reserved. Birth Low birth weight –Causes Cigarette smoking Poor maternal health and nutrition –Maternal diseases and infections –Consequences Learning difficulties, more behavioral problems