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Life chapter 2

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Life chapter 2

  1. 1. Chapter 2 Biological Beginnings PowerPoints by Jenni Fauchier Butchered by Professor Carney 1
  2. 2. The Evolutionary Perspective • Natural Selection & Adaptive Behavior – Natural selection • Evolutionary process by which those individuals of a species that are best adapted are the ones that survive & reproduce – Survivors better adapted to their world than are non-survivors 2
  3. 3. Evolutionary Psychology • Emphasizes importance of – Adaptation – Reproduction – “Survival of the fittest” • In shaping behavior – Spatial skills in finding way home • Good spatial skills passed on 3
  4. 4. Evolutionary Psychology • What are the main complaints men have against women? 4
  5. 5. Evolutionary Psychology • TALK TOO MUCH!!! 5
  6. 6. Evolutionary Psychology • What are the main complaints women have against men? 6
  7. 7. Evolutionary Psychology • They don’t listen!!! 7
  8. 8. Evolutionary Psychology • Fit – Ability to • Bare offspring – Survive long enough to bare offspring • Pass your genes to next generation – Pass on good spatial skills • Increased likelihood of survival 8
  9. 9. Developmental Evolutionary Psychology • Humans take longer: – Childhoods – Mature reproductively – Develop large brain – Learn complexity of human societies 9
  10. 10. Learning Complexity of Human Society 10
  11. 11. Evolutionary Psychology • Domain-specific (key concept) – Information processing • We have different abilities that do not have an affect on another. • We can be excellent in: – Math – Science – Spatial skills • Not so good at: – Art – Reading – Spelling 11
  12. 12. Evolutionary Psychology • Evolved mechanisms not always adaptive in present – Prehistoric Days • Gorging self when food available • Crave high calorie food 12
  13. 13. Genetic Foundations of Development • We carry a “genetic code” inherited from our parents & as a species • A fertilized human egg – Carries human code • We begin life as a single cell – Contains our entire genetic code • (Human egg about to pop) 13
  14. 14. Human Cell 14
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  17. 17. • 2 meters = @ 6 ½ feet • Approximately 20,500 genes 17
  18. 18. Chromosomes • Nucleus of each human cell contains – Chromosomes • Thread-like structures made up of deoxyribonucleic acid, or DNA • DNA – Complex molecule that has a double helix shape & contains genetic information • Unique to all individuals • (Except for identical twins) same genetic code 18
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  20. 20. Genes • Genes – Units of hereditary information composed of DNA. – Short segments of DNA – Direct cells to reproduce themselves – & – Make proteins that maintain life • Proteins – Building blocks of cells – Regulators that direct the body’s processes 20
  21. 21. Cells, Chromosomes, Genes, & DNA Cell Chromosomes DNA Nucleus (center of cell) contains chromosomes and genes Fig. 2.2 Chromosomes are threadlike structures composed of DNA molecules Gene: a segment of DNA (spiraled double chain) containing the hereditary code 21
  22. 22. Human Genome Project • Preliminary map of human genome – Complete set of developmental instructions for creating proteins that initiate the making of a human organism • Humans have about 20,500 genes • Human genome consists of – Genes that collaborate with: • Each other • Non-genetic factors inside & outside the body • Genetic expression affected by environment – How? 22
  23. 23. Human Genome Project http://www.youtube.com/watch?v=XuUpnAz5y1g&feature=results_video&playnext=1&list=PLD892F0B7805982EA 23
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  26. 26. Genetic Foundations The Genetic Process • Mitosis, Meiosis, & Fertilization – Mitosis: each chromosome in cell’s nucleus duplicates itself – Meiosis: cell division to form eggs & sperm (or gametes) 26
  27. 27. The Genetic Process • Reproduction: begins when female gamete (ovum) fertilized by male gamete (sperm) • Zygote: single cell formed through fertilization; 23 pairs of chromosome 27
  28. 28. Meiosis VS Mitosis http://www.youtube.com/watch?v=iCL6d0OwKt8&feature=related 28
  29. 29. Mitosis • Mitosis video • All body cells (except red blood cells) have – 46 chromosomes • Arranged in 23 pairs • (Except the sperm & egg) • Body cells reproduce by mitosis • Cell’s nucleus—including chromosomes— duplicates itself & cell divides • 2 new cells formed, each containing same DNA as original cell 29
  30. 30. Meiosis Square Dance 30
  31. 31. Meiosis • • • • Meiosis Square Dance Sex cell division is different type of cell division Eggs & sperm (or gametes) formed in meiosis Cell of testes (in men) or ovaries (in women) – Duplicates its chromosomes – Then divides 2x’s, forming 4 cells • Each has only 1/2 of genetic material of parent cell • End of meiosis, each egg or sperm has 23 unpaired chromosomes 31
  32. 32. Meiosis 32
  33. 33. The 23rd Pair of Chromosomes • Slight difference in 23rd pair • Females, 23rd pair consists of 2 X chromosomes • Males, 23rd pair consists of X & Y chromosome • Y chromosome makes an individual male • Female: XX • Male: XY 33
  34. 34. Genotype & Phenotype • Genotype – All of a person’s genetic material • Phenotype – Observable characteristics • Physical characteristics – Height – Weight – Hair color • Psychological characteristics – Personality – Intelligence 34
  35. 35. • Genotype to Phenotype class exercise. 35
  36. 36. GENETIC PRINCIPLES 36
  37. 37. Dominant-Recessive Genes Principle • Dominant gene – 1 gene of a pair always exerts its effects • Recessive gene – Exerts influence if 2 genes of pair are both recessive • May be overridden by a dominant gene • May be carried from generation to generation but not expressed in phenotype – Red hair 37
  38. 38. Sex-Linked Genes • X-linked inheritance – Mutated gene carried on X chromosome • Most mutations recessive – Males have no “backup” copy to counter harmful gene – Females have a second X chromosome • Usually unchanged • Females who have one changed copy of X gene are known as “carriers” 38
  39. 39. Polygenic Inheritance • Genetic transmission complex – few characteristics reflect influence of only a single gene or pair of genes • Polygenically determined characteristics -determined by the interaction of many different genes 39
  40. 40. Sex-Linked Chromosome Abnormalities 40
  41. 41. Sex-Linked Chromosome Abnormalities   • The Fertility Institutes (Web Page) • Down syndrome – Caused by presence of extra copy of chromosome 21 – 1 x in 700 live births – Women aged 16 - 34 are less likely to give birth to a child with Down syndrome 41
  42. 42. Sex-Linked Chromosome Abnormalities • Klinefelter syndrome – Extra X chromosome • Fragile X syndrome – Abnormality in the X chromosome – X chromosome becomes constricted & often breaks • Turner syndrome – Females have either an X chromosome missing or part of one X chromosome is deleted • XYY syndrome – male has extra Y 42
  43. 43. Klinefelter's Syndrome • • • • • • • • (XXY) Males only Smaller-than-normal genitals Enlarged breasts Poor muscular development May be mentally retarded 75% percent are not identified 1 in 500 males 43
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  45. 45. Klinefelter's Syndrome • Testosterone shots, patches or gels started shortly before or during puberty. • May have symptoms similar to women in menopause – – – – – Hot flashes Increased irritability Inability to concentrate Depression. Most cannot father children. 45
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  47. 47. Turners Syndrome Cont. • • • • Prominent ears Broad chest Eyelid folds Estrogen needed in order to menstruate develop breasts • Can not reproduce 47
  48. 48. Turners Syndrome • • • • • • • • Females 1 X chromosome, normal XX 1 in 2,500 female births. Approximately 98% of pregnancies with Turner's Syndrome abort spontaneously Short stature Webbed neck May have abnormal body proportions, markedly shortened lower extremities. Height range is between 4’5” to 4’8” 48
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  51. 51. Diseases that result from gene linked abnormalities: • • • • • • • Cystic fibrosis Diabetes Hemophilia Huntington disease Spina bifida Tay-Sachs disease Sickle Cell Anemia 51
  52. 52. Behavior Genetics • Examines influence of heredity & environment on individual differences in human traits & development • Behavior geneticists often study either twins or adoption situations 52
  53. 53. The Epigenetic View • Development result of an ongoing, interchange between heredity & environment • Heredity & environment collaborate – To produce • • • • • • Intelligence Temperament Height Weight Ability to pitch a baseball Ability to read, etc. 53
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  55. 55. The Epigenetic View The Ghost in Your Genes 55
  56. 56. Genetic Disorders & Diseases 56
  57. 57. PRENATAL DEVELOPMENT 57
  58. 58. The Course of Prenatal Development • Fertilization to birth • Prenatal development lasts approximately 266 days 58
  59. 59. Fertilization • Zygote – Egg & sperm fuse • Create a single cell – 23 unpaired chromosomes from egg & sperm • Form 1 set of 23 paired chromosomes – 1 chromosome of each pair • mother’s egg • father’s sperm – Each parent contributes 1/2 of offspring’s genetic material 59
  60. 60. Zygote 60
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  62. 62. The Germinal Period Egg goes from ovary through fallopian tube (uterine tube) 62
  63. 63. The Germinal Period • Creation of zygote (fertilized egg) – Mature human egg • – 23 chromosomes Mature human sperm • – 23 chromosomes Egg fertilized by sperm • Creates zygote • 46 chromosomes 63
  64. 64. The Germinal Period • Sperm race to egg – 1 wins…usually. • Makes way to egg by smell • Once sperm penetrates – Chemical released • Prevents other sperm from entering • 2 penetrate – Possible miscarriage 64
  65. 65. The Germinal Period • Blastocyst – inner layer of cells – develops into embryo 65
  66. 66. The Germinal Period • Trophoblast (like trophy) – outer layer of cells – nourishes embryo 66
  67. 67. The Germinal Period • Blastocyst – Inner mass of cells – Eventually develop into the embryo • Trophoblast – Outer layer of cells – Will provide nutrition & support for embryo • Implantation – Attachment of zygote to uterine wall • 10 - 14 days after conception 67
  68. 68. 2. The Embryonic Period 68
  69. 69. The Embryonic Period • 2 - 8 weeks after conception • Rate of cell differentiation intensifies • Begins as the blastocyst attaches to uterine wall • Every body part eventually develops from these 3 layers – endoderm = Internal body parts – ectoderm = Surface parts – mesoderm = Parts surrounding internal organs 69
  70. 70. 2. The Embryonic Period • We looked at cells of the zygote in the germinal period • Now: – Cells of the embryonic period 70
  71. 71. Embryo 3 Layers of Cells 71
  72. 72. The Embryonic Period • The mass of cells is an embryo • Organogenesis -- the process of organ formation during the first 2 mo’s of prenatal development – organs are especially vulnerable to environmental influences • Life-support systems for embryo develop rapidly 72
  73. 73. The Fetal Period • Fetal period begins 2 mo’s after conception & lasts for 7 mo’s • 3 mo.'s after conception – Fetus 3” long; weighs 3 ounces • At birth, average American baby: – 7 ½ lbs & 20” long 73
  74. 74. • Don’t let them fool you….nothing works to stop the excruciating pain! • It was all invented by a man! 74
  75. 75. The Course of Prenatal Development The Brain • At birth – 100 billion neurons • Basic architecture assembled – 1st 2 trimesters – Neural tube: first 18–24 days • Forms the spinal cord • Neural Tube Defects – Effect so severe, won’t show you – Defect tied to nutrition 75
  76. 76. Neural Tube Defects 76
  77. 77. The Brain • Neurogenesis: – Proliferation of new immature neurons – Begins @ 5th prenatal week – Continues through prenatal period • 3rd trimester – Characterized by • Connectivity • Functioning of neurons 77
  78. 78. HAZARDS TO PRENATAL DEVELOPMENT 78
  79. 79. Hazards to Prenatal Development Some General Principles • Teratogen – Any agent that causes a birth defect • Severity & type of defect affected by – Dose – Genetic susceptibility – Time of exposure 79
  80. 80. Some General Principles • All drugs (prescribed, illegal) can have effects on unborn fetus – Antibiotics, analgesics, asthma medications – 1961: thalidomide tragedy 80
  81. 81. Fetal Alcohol Syndrome 81
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  83. 83. Hazards to Prenatal Development Psychoactive Drugs • Psychoactive drugs – Act on nervous system & change moods – Alter states of conscious, modify perceptions – Extent of risk & harm varies 83
  84. 84. Your Doctor Wants You to Smoke 1951 84
  85. 85. Nicotine (March of Dimes longitudinal study, 2011) • – Heart defects – Absence or severe underdevelopment of hands, feet, radius, tibia, ulna or fibula – Missing fused or extra fingers or toes – Clubfoot – Cleft lip or palate – Eye defects – Gastrointestinal defects • Baby more likely • 2 or more defects 85
  86. 86. Teratogens and Timing of Their Effects on Prenatal Development Zygote 1 2 Most serious damage from teratogens in first 2–8 weeks Embryonic period (wks) 3 4 5 6 7 8 Central nervous system Heart Arms Eyes Legs Ears Period of susceptibility to structural defects Period of susceptibility to functional defects Fig. 3.7 (modified) Fetal Period (wks) 9 16 32 38 Teeth Palate External genitalia 86
  87. 87. Hazards to Prenatal Development Maternal Diseases • Diseases & infections cross placenta barrier – Rubella (German measles) – Diabetes • Sexually transmitted infections – Syphilis, Genital herpes – AIDS, HIV infection • New medications & vaccines available 87
  88. 88. Hazards to Prenatal Development Other Maternal Factors • Maternal diet, nutrition, & weight – Folic acid & iron – Fish: PCBs & mercury levels • Maternal age – Highest risks: adolescents, over 35 years – Down syndrome • Maternal emotional states 88
  89. 89. Hazards to Prenatal Development Parental Factors • Paternal factors – Father’s diet & low vitamin C – Drug use effects on sperm – Smoking – effects of second-hand smoke – Father’s age at conception • Birth defects: dwarfism, Marfan’s Syndrome 89
  90. 90. Hazards to Prenatal Development Environmental Hazards • Father’s exposure to lead, radiation • X-ray radiation • Pollutants & toxin wastes • Fertilizers & pesticides • Lead-based paints • Petrochemicals – Why father’s exposure causes harm? 90

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