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THE START OF LIFE: PRENATAL DEVELOPMENT

Chapter 2. THE START OF LIFE: PRENATAL DEVELOPMENT. Learning Objectives. EARLIEST DEVELOPMENT. Beginning of Life. Humans begin life simply Gametes from male and female join ovum and sperm Fused gametes create zygote

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THE START OF LIFE: PRENATAL DEVELOPMENT

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  1. Chapter 2 THE START OF LIFE: PRENATAL DEVELOPMENT

  2. Learning Objectives

  3. EARLIEST DEVELOPMENT

  4. Beginning of Life Humans begin life simply • Gametes from male and female join • ovum and sperm • Fused gametes create zygote • Resulting combination of their genetic instructions—over 2 billion chemically coded messages—is sufficient to begin creation of human

  5. Contents of a Single Human Cell • Genes • Specific DNA sequences • Chromosomes • Rod-shaped DNA portions in 23 pairs • Contain genetic blueprint for individuals • Replicate through mitosis

  6. Multiple Births: Two-or More-for the Genetic Price of One Are there different kinds of multiple births? • Monozygotic • Dizygotic • Trizygotic What causes multiple births? • Fertility drugs • Racial, ethnic, and national differences

  7. Rising Multiples

  8. Establishing the Sex of the Child

  9. Mixing and Matching of Genes Basics of genetics • Dominant traits • Recessive traits • Polygenic traits

  10. Just the right type Genotype • Homozygous • Heterozygous Phenotype

  11. Genetic Information Transmission

  12. Cracking the Genetic Code • The Human Genome • National Human Genome Research Institute • http://www.genome.gov/

  13. In what ways can information from the Human Genome Project affect your life?

  14. Current Understanding of the Genetic Basis of Selected Disorders and Traits

  15. When Development Deviates from the Norm

  16. When Development Deviates

  17. Behavioral Genetics

  18. Genetic Counseling:Predicting the Future from the Genes of the Present • Can you name three diseases for which DNA-based genetic tests are available? • (Hint: see Table 2-3)

  19. Fetal Development Monitoring Techniques

  20. Are “Designer Babies” in Our Future? Should pre-implantation genetic diagnosis (PGD) be available to all families?

  21. Review and Apply

  22. Review and Apply

  23. Review and Apply

  24. THE INTERACTION OF HEREDITY AND ENVIRONMENT

  25. What do you think? A given behavior is not caused just by genetic factors, nor is it caused solely by environmental factors.

  26. Role of the Environment in Determining the Expression of Genes: From Genotypes to Phenotypes Given behavior is not caused just by genetic factors; nor is it caused solely by environmental forces • Multifactorial transmission

  27. Range of Possibilities: Determinants of Intelligence

  28. Studying DevelopmentHow Much Is Development? How Much Is Nature? Nonhuman animal studies • Controlling genetics and environment Human studies • Adoption • Twin studies • Family studies

  29. Do you have your mother's eyes? Family resemblances • More genetically similarity  more likely to share physical characteristics • Obesity, blood pressure, respiration rates, age at death

  30. Nature, Nurture, and Intelligence What motivates this research? • Relative contributions of nature and nurture highly researched • Closer genetic link = greater correspondence of overall IQ scores

  31. Genetics and I.Q.

  32. Do we inherit our personality?

  33. Genetic and Environmental Influence on Personality: Born to Be Outgoing?

  34. What evidence supports this claim?

  35. Psychological Disorders: The Role of Genetics and the Environment • Culture • Parental encouragement Can you think of any others?

  36. Developmental Diversity Can a culture's philosophical outlook be determined by genetics? Are there “good” and “bad” cultures?

  37. Mean Behavioral Scores for Caucasian American, Irish, and Chinese 4-Month-Old Infants

  38. The Genetics of Schizophrenia

  39. Fundamental Principle Within debate about relative influence of nature and nurture • Role of genetics is often to produce tendency toward future course of development • Role of environment affects when and whether a certain behavioral characteristic will actually be displayed

  40. Can Genes Influence the Environment? Sandra Scarrsuggests three ways child's genetic predisposition may influence his or her environment: • Active • Passive • Evocative

  41. Review and Apply

  42. Review and Apply

  43. PRENATAL GROWTH AND CHANGE

  44. Fertilization: The Moment of Conception

  45. Stages of Prenatal Development • Germinal • Embryonic • Fetal • (See Table 2-5 for a concise review)

  46. Stages of the Prenatal Period

  47. Germinal Stage Fertilization  two weeks • Shortest stage • Fertilized egg now called blastocyst • Travels to and implants in uterus • Characterized by methodical cell division • With division comes cell specialization

  48. Embryonic Stage 2 weeks  8 weeks • Organism firmly secures to uterus and called an embryo • Development of major organs and basic anatomy Three distinct layers that ultimately form different set of structures • Ectoderm • Endoderm • Mesoderm

  49. Body Proportions Why might this make infants especially susceptible to “Shaken Baby Syndrome?”

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