1. Biological Bases of Behavior Northwest High School
Genetics and Behavior
Biological Bases of Behavior
Northwest High School

2. Genetics and Evolutionary Psych
What other factors contribute to our traits, behavior and thoughts?
Nature/Nurture: how much does the environment and heredity influence our behavior
Evolutionary: studying how natural selection favors behaviors that contribute to survival and spread our ancestor’s genes.

3. How are genes and behavior linked?
Innate – Inborn; present at birth; part of the organism’s biological heritage
Evolution – The gradual process of biological change that occurs in a species as it adapts to its environment

4. Evolution and Natural Selection
Natural selection – The driving force behind evolution, by which the environment “selects” the fittest organisms

5. How Natural Selection Works
Environmental pressure
(changes in the environment)
Competition
(for resources)
Selection of fittest phenotype
(from among a variety of phenotypes)
Reproductive success
(genotype corresponding to fittest
phenotypes passed to next generation)
Frequency of that genotype increases
(in next generation)

6. Genes and Inheritance
Heritability: proportion of variation among individuals in a population that is due to genetic causes.
Genotype – An organism’s genetic makeup
Phenotype – An organism’s observable physical characteristics

7. Genes and Inheritance
Mutations – Genetic variations, which occur randomly, especially during the recombination of chromosomes in sexual reproduction

8. Chromosomes, Genes, and DNA
DNA – A long, complex molecule that encodes genetic characteristics
Genes – The functional units of a chromosome
Composed of nucleotides

9. Chromosomes, Genes, and DNA
Coils of DNA containing gene segments that, when “turned on” affect our body’s building blocks
How do we know?
Studies of identical twins, fraternal twins, and adoptive families help specify the influence of genetic nature, environmental nurture, and the interaction between them.

10. Genetic Explanation for Psychological Processes
Genes influence our psychological characteristics as well as our physical traits