1. Genes, Evolution and Behavior
How does genetic predisposition influence behavior?

2. Behavior Genetics Behavior Genetics
study of the relative power and limits of genetic and environmental influences on behavior

3. Genes: Their Location and Composition
Nucleus
Chromosome
Gene
Cell
DNA

4. Genes: Our Biological Blueprint
Chromosomes
threadlike structures made of DNA that contain the genes
DNA (deoxyribonucleic acid)
complex molecule containing the genetic information that makes up the chromosomes
has two strands-forming a “double helix”- held together by bonds between pairs of nucleotides

5. Genes: Our Biological Blueprint
biochemical units of heredity that make up the chromosomes
a segment of DNA capable of synthesizing a protein

6. Dominant and Recessive Genes
Her T Mo
Dominant and Recessive Genes
Fathers two Genes M O T H E R G N e F1 F2
F1M1
F2M1
F1M2
F2M2 M1 M2

7. Finger length etc Ring finger vs. Forefinger -Draw a line Results
Short forefinger is recessive in females
More males have short forefingers
Thumb bend?
“prayer hands”

8. Taste Sensitivity- PTC & Sodium Benzoate
Results…
If you have the recessive gene-no taste
Approx- 70 % taste
-30 % No Taste
(must be own saliva)
SB- 1) Bitter-salty * 2) Bitter-sweet
3)Bitter-Bitter 4) Tasteless-salty
* Like spinach, turnips, sauerkraut….

9. Behavior Genetics Identical Twins Fraternal Twins
Same
sex only
Same or
opposite sex
Identical Twins
develop from a single fertilized egg that splits in two, creating two genetically identical organisms
Fraternal Twins
develop from separate eggs
genetically no closer than brothers and sisters, but they share the fetal environment

10. Behavior Genetics Temperament Interaction
a person’s characteristic emotional reactivity and intensity
Interaction
the effect of one factor (such as the environment) depends on another factor (such as heredity)

11. Minnesota Twins Study
Striking Similarities
“Body Double” Film

12. Evolutionary Psychology
Natural Selection
the principle that, among the range of inherited trait variations, those that lead to increase reproduction and survival will most likely be passed on to succeeding generations
Mutation
a random error in gene replication that leads to genetic damage

13. Are our preferences inherited?
Survey #1
Results ( board)
Survey # 2