© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 1 John W. Santrock Biological Beginnings 2

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 2 Biological Beginnings What Is the Evolutionary Perspective? What Are the Genetic Foundations of Development? What Are Some Reproductive Challenges and Choices? How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 3 Natural Selection and Adaptive Behavior Stories of the Jim and Jim Twins –Identical twins separated after birth –Identical lifestyles after 39 years apart –Part of Minnesota Study of Twins Reared Apart; other twin sets with similar outcomes What Is the Evolutionary Perspective?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 4 Natural Selection and Adaptive Behavior Natural selection: evolutionary process favors individuals best adapted to survive and reproduce Evolutionary psychology: emphasizes adaptation, reproduction, and “survival of the fittest” in shaping behavior What Is the Evolutionary Perspective?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 5 Evolution can explain our behavior: -Men have better spatial ability -Women use more verbal instances

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 6 Evolutionary Psychology Extended “juvenile” period -> larger brain size Aspects of childhood prepare for adulthood -> Play Some childhood characteristics are adaptive at specific points in life -> Play to adapt to current environment Psychological mechanisms evolved as domain- specific -> modular brain What Is the Evolutionary Perspective?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 7 Evaluating Evolutionary Psychology Bidirectional view Evolution gives bodily structures and biological potentials; does not dictate behavior Biology allows broad range of cultural possibilities What Is the Evolutionary Perspective?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 8 From a single cell to trillions of cells

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 9 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 Cell Chromosomes DNA Fig. 2.2

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 10 The Genetic Process DNA and the Collaborative Gene –Chromosomes: threadlike structures that come in 23 pairs, one member of each pair coming from each parent –DNA: complex molecule; double helix –Genes: units of heredity Human have only about 30,000 genes What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 11 Collaborative Genes Genes are short segments of DNA and direct cells to reproduce themselves and to assemble protein. Human have far more protein than genes. Many genes collaborate with each other and with non-genetic factors in the environment and this collaboration happens at any point. A gene maybe turned on because of the environment

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 12 Genes and Chromosomes fM9pA

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 13 How do genes manage? –Mitosis: all cells have 46 chromosomes in their nucleus, cell’s nucleus duplicates itself Mitosis gq50dk&feature=related

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 14 How do genes manage? Mitosis, Meiosis, and Fertilization –Meiosis: cell division to form eggs and sperm (or gametes) cells from ovaries or testes duplicates, but then divides twice, forming four cells Each cell has 23 unpaired chromosomes mQS_FZ0&feature=related What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 15 The Genetic Process Mitosis, Meiosis, and Fertilization –Reproduction: begins when female gamete (ovum) fertilized by male gamete (sperm) –Zygote: single cell formed through fertilization; 23 pairs of chromosomes X and Y chromosomes What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 16 The Genetic Difference Between Males and Females What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 17 qI0FRg&feature=related

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 18 The Genetic Process Sources of Variability –A zygot is not a replica of mom and dad’s genes –Identical and fraternal twins –Mutated gene –Genotype: genetic heritage –Phenotype: genotype expressed in observed and measurable characteristics What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 19 Genetic Principles Dominant-Recessive Genes Principle –Recessive gene is influential only if both genes are recessive What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 20 Genetic Principles

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 21 Chromosome Abnormalities Chromosome abnormalities: gamete does not have normal set of 23 –Down syndrome: extra copy of chromosome #21 mental retardation What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 22 Sex-Linked Chromosome Abnormalities Turner syndrome Disorder in males; extra Y chromosome no evidence for more aggression XYY syndrome Fragile X syndrome Klinefelter syndrome Female disorder; X chromosome missing Or partially deleted, infertility, lack of math ability Abnormality in X chromosome; becomes constricted or breaks; mental deficiency, learning disabilities, more prominent in male Disorder in males; extra X chromosome undeveloped testes and enlarged breast What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 23 Gene-Linked Abnormalities Harmful Genes Phenylketonuria (PKU): individual cannot properly metabolize an amino acid; easily detected and prevented It is a result of a recessive gene Sickle-cell anemia: affects red blood cells; recessive gene influence, 1 in 10 African American carries it What Are the Genetic Foundations of Development?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 24 Prenatal Diagnostic Tests Ultrasound sonography: high-frequency sound waves directed into abdomen, can detect abnormal structures Chorionic villi sampling: sample of the placenta Amniocentesis: sample of amniotic fluid Maternal blood or triple screening What Are Some Reproductive Challenges and Choices?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 25 Infertility and Reproduction Technology Infertility: inability to conceive after 12 months of regular intercourse In vitro fertilization (IVF) Gamete intrafallopian transfer (GIFT) Zygote intrafallopian transfer (ZIFT) What Are Some Reproductive Challenges and Choices?

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 26 Behavior Genetics Behavior genetics: influence of heredity and environment on individual trait and developmental differences How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 27 Behavior Genetics –Twin studies: compare behavioral similarity of identical (monozygotic) twins with behavioral similarity of fraternal (dizygotic) twins –Adoption studies: discover whether adopted children are more like adoptive parents or biological parents How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 28 Heredity-Environment Correlations Heredity-environment interaction has complexities Individuals influence environments, yet individuals “inherit” environments The three genotype-environment correlations change as children grow How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 29 Genotype-Environment Correlations Active (niche-picking) Evocative Passive When children seek out compatible and stimulating environments When genotype elicits certain types of physical and social environments When natural parents provide rearing environment How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 30 Shared and Nonshared Environmental Experiences Shared environmental experiences: Siblings’ common experiences –Parents’ personalities –Intellectual orientation –Family’s socioeconomic status –Neighborhood How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 31 Shared and Nonshared Environmental Experiences Nonshared environmental experiences; the unique child –Within family –Outside family –Not shared by another sibling How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 32 Shared environments play a little accounts for little of the variations in children’s personality or interest. Heredity influences the non-shared environments of the siblings Judith Harris “The Nature Assumption”

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 33 Conclusions About Heredity- Environment Interaction Operate cooperatively Relative contributions are not additive Many complex behaviors have some genetic loading How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2009 The McGraw-Hill Companies, Inc. All rights reserved. Slide 34 The End 2