1. Chapter 2
Biological Beginnings
PowerPoints by Jenni Fauchier
Butchered by Professor Carney
1

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. 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. Evolutionary Psychology
• What are the main complaints men have
against women?
4

5. Evolutionary Psychology
• TALK TOO MUCH!!!
5

6. Evolutionary Psychology
• What are the main complaints women
have against men?
6

7. Evolutionary Psychology
• They don’t listen!!!
7

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. Developmental Evolutionary
Psychology
• Humans take longer:
– Childhoods
– Mature reproductively
– Develop large brain
– Learn complexity of human societies
9

10. Learning Complexity of Human Society
10

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. Evolutionary Psychology
• Evolved mechanisms not always
adaptive in present
– Prehistoric Days
• Gorging self when food available
• Crave high calorie food
12

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. Human Cell
14

15. 15

16. 16

17. • 2 meters = @ 6 ½ feet
• Approximately 20,500 genes
17

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

19. 19

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. 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. 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. Human Genome Project
http://www.youtube.com/watch?v=XuUpnAz5y1g&feature=results_video&playnext=1&list=PLD892F0B7805982EA
23

24. 24

25. 25

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. 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. Meiosis VS Mitosis
http://www.youtube.com/watch?v=iCL6d0OwKt8&feature=related
28

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. Meiosis Square Dance
30

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. Meiosis
32

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. 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. • Genotype to Phenotype class exercise.
35

36. GENETIC PRINCIPLES
36

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. 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. 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. Sex-Linked Chromosome
Abnormalities
40

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. 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. 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

44. 44

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

46. 46

47. Turners Syndrome Cont.
•
•
•
•
Prominent ears
Broad chest
Eyelid folds
Estrogen needed in order to menstruate
develop breasts
• Can not reproduce
47

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

49. 49

50. 50

51. Diseases that result from gene linked
abnormalities:
•
•
•
•
•
•
•
Cystic fibrosis
Diabetes
Hemophilia
Huntington disease
Spina bifida
Tay-Sachs disease
Sickle Cell Anemia
51

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. 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

54. 54

55. The Epigenetic View
The Ghost in Your Genes
55

56. Genetic Disorders & Diseases
56

57. PRENATAL DEVELOPMENT
57

58. The Course of Prenatal Development
• Fertilization to birth
• Prenatal development lasts
approximately 266 days
58

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. Zygote
60

61. 61

62. The Germinal Period
Egg goes from ovary through fallopian tube (uterine tube)
62

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. 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. The Germinal Period
• Blastocyst
– inner layer of cells
– develops into embryo
65

66. The Germinal Period
• Trophoblast (like trophy)
– outer layer of cells
– nourishes embryo
66

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. 2. The Embryonic Period
68

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. 2. The Embryonic Period
• We looked at cells of the zygote in the
germinal period
• Now:
– Cells of the embryonic period
70

71. Embryo
3 Layers of Cells
71

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. 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. • Don’t let them fool you….nothing works
to stop the excruciating pain!
• It was all invented by a man!
74

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. Neural Tube Defects
76

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. HAZARDS TO PRENATAL
DEVELOPMENT
78

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. Some General Principles
• All drugs (prescribed, illegal) can have
effects on unborn fetus
– Antibiotics, analgesics, asthma medications
– 1961: thalidomide tragedy
80

81. Fetal Alcohol Syndrome
81

82. 82

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. Your Doctor Wants You to Smoke 1951
84

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. 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. 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. 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. 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. 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