© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 1 John W. Santrock Biological Beginnings 3

© 2007 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 the Genetic Foundations of Development? What Are Some Reproductive Challenges and Choices?What Are Some Reproductive Challenges and Choices? How Do Heredity and Environment Interact? The Nature-Nurture DebateHow Do Heredity and Environment Interact?

© 2007 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?

© 2007 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?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 5 Evolutionary Developmental Psychology Extended “juvenile” period evolved Aspects of childhood prepare for adulthood Some childhood characteristics are adaptive at specific points in life Psychological mechanisms evolved as domain-specific What Is the Evolutionary Perspective?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 6 Brain Sizes of Humans and Primates What Is the Evolutionary Perspective? Fig. 3.1

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 7 Evaluating Evolutionary Psychology Evolution gives bodily structures and biological potentials; does not dictate behavior Biology allows broad range of cultural possibilities What Is the Evolutionary Perspective?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 8 The Genetic Process DNA and the Collaborative Gene –Life begins as a single cell; each has replica of original code –Chromosomes: threadlike structures that come in 23 pairs, one member of each pair coming from each parent What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 9 The Genetic Process DNA: The Collaborative Gene –DNA: complex molecule that contains genetic information –Genes: units of hereditary information composed of DNA; each has its own function What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 10 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. 3.2

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 11 The Genetic Process Human Genome Project –Humans have about 25,000 genes –Each gene is dependent, collaborative Mitosis, Meiosis, and Fertilization –Mitosis: cell’s nucleus duplicates itself –Meiosis: cell division to form eggs and sperm (or gametes) What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 12 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 What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 13 The Genetic Process Sources of Variability –Genotype: genetic heritage –Phenotype: genotype expressed in observed and measurable characteristics What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 14 The Genetic Difference Between Males and Females What Are the Genetic Foundations of Development? The X and Y chromosomes in 23 pairs including sex chromosomes Fig. 3.4

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 15 Genetic Principles Dominant-Recessive Genes Principle –Recessive gene is influential only if both genes are recessive Sex-Liked Genes: X-linked inheritance Genetic Imprinting Polygenetic Inheritance What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 16 Genetic Principles b B b B b B Blond hair Brown hair Brown-haired parents can have a blond- haired child: the gene for blond hair is recessive Mother B b Father B b Fig. 3.5

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 17 Chromosome Abnormalities Chromosome abnormalities: gamete does not have normal set of 23 Down syndrome: chromosomally transmitted form of mental retardation What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 18 Sex-Linked Chromosome Abnormalities Turner syndrome Disorder in males; extra Y chromosome XYY syndrome Fragile X syndrome Klinefelter syndrome Female disorder; X chromosome missing partially deleted Abnormality in X chromosome; becomes constricted or breaks Disorder in males; extra X chromosome What Are the Genetic Foundations of Development? Fig. 3.6

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 19 Gene-Linked Abnormalities Phenylketonuria (PKU): individual cannot properly metabolize an amino acid; easily detected and prevented Sickle-cell anemia: affects red blood cells; recessive gene influence Genetic counselors are available What Are the Genetic Foundations of Development?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 20 Prenatal Diagnostic Tests Ultrasound sonography: high-frequency sound waves directed into abdomen Chorionic villi sampling: sample of the placenta Amniocentesis: sample of amniotic fluid Maternal blood or triple screening What Are Some Reproductive Challenges and Choices?

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 21 The Epigenetic View Development is the result of ongoing, bi-directional interchange between heredity and environment How Do Heredity and Environment Interact? The Nature-Nurture Debate

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 22 Comparison of the Heredity-Environment Correlation and Epigenetic Views Fig. 3.11

© 2007 The McGraw-Hill Companies, Inc. All rights reserved. Slide 23 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