© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Children Biological Beginnings 2

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Images of Child Development 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?

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. 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?

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Brain Sizes of Humans and Primates What is the Evolutionary Perspective? Fig. 2.1

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. 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 Genome Project Genetic Foundations

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. 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

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. The Genetic Process Gene activity – genetic expression Mitosis, Meiosis, and Fertilization –Mitosis: cell’s nucleus duplicates itself –Meiosis: cell division to form eggs and sperm (or gametes) –Reproduction: begins when female gamete (ovum) fertilized by male gamete (sperm) –Zygote: single cell formed through fertilization; 23 pairs of chromosome Genetic Foundations

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Genetic Difference Between Females and Males Fig. 2.4 Genetic Foundations

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Genetic Principles Dominant-Recessive Genes Principle –Recessive gene is influential only if both genes are recessive –Phenotype and genotype Sex-Linked Genes: X-linked inheritance Genetic Imprinting Polygenetic Inheritance Genetic Foundations

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Fig. 2.5 Dominant-Recessive Gene Principle

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Chromosome Abnormalities Chromosome abnormalities –Gamete does not have normal set of 23 Down syndrome –Chromosomal form of mental retardation Phenylketonuria (PKU) – individual cannot properly metabolize an amino acid; easily detected and prevented Sickle-cell anemia –affects red blood cells; recessive gene influence Genetic Foundations

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Sex-Linked Chromosome Abnormalities Klinefelter syndrome Disorder in males; extra X chromosome Fragile X syndrome Abnormality in X chromosome; becomes constricted or breaks Turner syndrome Female disorder; X chromosome missing or partially deleted XYY syndrome Disorder in males; extra Y chromosome Genetic Foundations

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. 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 Noninvasive prenatal diagnosis (NIPD) Reproductive Challenges

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Infertility and Reproduction Infertility – inability to conceive after 12 months of regular intercourse In vitro fertilization (IVF) Gamete intrafallopian transfer (GIFT) Zygote intrafallopian transfer (ZIFT) Adoption - screened in/out couples Reproductive Challenges

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Caring for Children Increased diversity of adopted children and adoptive parents Effective parenting of adopted children –Be supportive and caring –Be involved and monitor the child –Be a good communicator –Help the child develop self-control –Face challenges with a positive approach Reproductive Challenges

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Behavior Genetics Behavior genetics –Influence of heredity and environment on individual trait and developmental differences –Twin studies compare behavioral similarity of identical (monozygotic) twins with behavioral similarity of fraternal (dizygotic) twins –Adoption studies Heredity and Environment

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Heredity and Environment Heredity-environment correlations –Passive genotype-environment –Evocative genotype-environment –Active (niche-picking) Heredity-environment interaction has complexities Individuals influence environments, yet individuals “inherit” environments Heredity and Environment

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. Nature and Nurture Shared environmental experiences –Siblings’ common experiences Parents, family orientation, SES, neighborhood Nonshared environmental experiences –The unique child Heredity and Environment

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. The Epigenetic View Development is the result of ongoing, bidirectional interchange between heredity and environment. Conclusions About Heredity-Environment Interaction –Operate cooperatively –Relative contributions are not additive –Many complex behaviors have some genetic loading Heredity and Environment

© 2010 The McGraw-Hill Companies, Inc. All rights reserved. The End 2